text:
/*
 * transupp.c
 *
 * Copyright (C) 1997, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains image transformation routines and other utility code
 * used by the jpegtran sample application.  These are NOT part of the core
 * JPEG library.  But we keep these routines separate from jpegtran.c to
 * ease the task of maintaining jpegtran-like programs that have other user
 * interfaces.
 */

/* Although this file really shouldn't have access to the library internals,
 * it's helpful to let it call jround_up() and jcopy_block_row().
 */
#define JPEG_INTERNALS

#include "jinclude.h"
#include "jpeglib.h"
#include "transupp.h"		/* My own external interface */

#if TRANSFORMS_SUPPORTED

/*
 * Lossless image transformation routines.  These routines work on DCT
 * coefficient arrays and thus do not require any lossy decompression
 * or recompression of the image.
 * Thanks to Guido Vollbeding for the initial design and code of this feature.
 *
 * Horizontal flipping is done in-place, using a single top-to-bottom
 * pass through the virtual source array.  It will thus be much the
 * fastest option for images larger than main memory.
 *
 * The other routines require a set of destination virtual arrays, so they
 * need twice as much memory as jpegtran normally does.  The destination
 * arrays are always written in normal scan order (top to bottom) because
 * the virtual array manager expects this.  The source arrays will be scanned
 * in the corresponding order, which means multiple passes through the source
 * arrays for most of the transforms.  That could result in much thrashing
 * if the image is larger than main memory.
 *
 * Some notes about the operating environment of the individual transform
 * routines:
 * 1. Both the source and destination virtual arrays are allocated from the
 *    source JPEG object, and therefore should be manipulated by calling the
 *    source's memory manager.
 * 2. The destination's component count should be used.  It may be smaller
 *    than the source's when forcing to grayscale.
 * 3. Likewise the destination's sampling factors should be used.  When
 *    forcing to grayscale the destination's sampling factors will be all 1,
 *    and we may as well take that as the effective iMCU size.
 * 4. When "trim" is in effect, the destination's dimensions will be the
 *    trimmed values but the source's will be untrimmed.
 * 5. All the routines assume that the source and destination buffers are
 *    padded out to a full iMCU boundary.  This is true, although for the
 *    source buffer it is an undocumented property of jdcoefct.c.
 * Notes 2,3,4 boil down to this: generally we should use the destination's
 * dimensions and ignore the source's.
 */

LOCAL(void)
do_flip_h (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
	   jvirt_barray_ptr *src_coef_arrays)
/* Horizontal flip; done in-place, so no separate dest array is required */
{
  JDIMENSION MCU_cols, comp_width, blk_x, blk_y;
  int ci, k, offset_y;
  JBLOCKARRAY buffer;
  JCOEFPTR ptr1, ptr2;
  JCOEF temp1, temp2;
  jpeg_component_info *compptr;

  /* Horizontal mirroring of DCT blocks is accomplished by swapping
   * pairs of blocks in-place.  Within a DCT block, we perform horizontal
   * mirroring by changing the signs of odd-numbered columns.
   * Partial iMCUs at the right edge are left untouched.
   */
  MCU_cols = dstinfo->image_width / (dstinfo->max_h_samp_factor * DCTSIZE);

  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_width = MCU_cols * compptr->h_samp_factor;
    for (blk_y = 0; blk_y < compptr->height_in_blocks;
	 blk_y += compptr->v_samp_factor) {
      buffer = (*srcinfo->mem->access_virt_barray)
	((j_common_ptr) srcinfo, src_coef_arrays[ci], blk_y,
	 (JDIMENSION) compptr->v_samp_factor, TRUE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
	for (blk_x = 0; blk_x * 2 < comp_width; blk_x++) {
	  ptr1 = buffer[offset_y][blk_x];
	  ptr2 = buffer[offset_y][comp_width - blk_x - 1];
	  /* this unrolled loop doesn't need to know which row it's on... */
	  for (k = 0; k < DCTSIZE2; k += 2) {
	    temp1 = *ptr1;	/* swap even column */
	    temp2 = *ptr2;
	    *ptr1++ = temp2;
	    *ptr2++ = temp1;
	    temp1 = *ptr1;	/* swap odd column with sign change */
	    temp2 = *ptr2;
	    *ptr1++ = -temp2;
	    *ptr2++ = -temp1;
	  }
	}
      }
    }
  }
}

LOCAL(void)
do_flip_v (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
	   jvirt_barray_ptr *src_coef_arrays,
	   jvirt_barray_ptr *dst_coef_arrays)
/* Vertical flip */
{
  JDIMENSION MCU_rows, comp_height, dst_blk_x, dst_blk_y;
  int ci, i, j, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  JBLOCKROW src_row_ptr, dst_row_ptr;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;

  /* We output into a separate array because we can't touch different
   * rows of the source virtual array simultaneously.  Otherwise, this
   * is a pretty straightforward analog of horizontal flip.
   * Within a DCT block, vertical mirroring is done by changing the signs
   * of odd-numbered rows.
   * Partial iMCUs at the bottom edge are copied verbatim.
   */
  MCU_rows = dstinfo->image_height / (dstinfo->max_v_samp_factor * DCTSIZE);

  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_height = MCU_rows * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
	 dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
	((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
	 (JDIMENSION) compptr->v_samp_factor, TRUE);
      if (dst_blk_y < comp_height) {
	/* Row is within the mirrorable area. */
	src_buffer = (*srcinfo->mem->access_virt_barray)
	  ((j_common_ptr) srcinfo, src_coef_arrays[ci],
	   comp_height - dst_blk_y - (JDIMENSION) compptr->v_samp_factor,
	   (JDIMENSION) compptr->v_samp_factor, FALSE);
      } else {
	/* Bottom-edge blocks will be copied verbatim. */
	src_buffer = (*srcinfo->mem->access_virt_barray)
	  ((j_common_ptr) srcinfo, src_coef_arrays[ci], dst_blk_y,
	   (JDIMENSION) compptr->v_samp_factor, FALSE);
      }
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
	if (dst_blk_y < comp_height) {
	  /* Row is within the mirrorable area. */
	  dst_row_ptr = dst_buffer[offset_y];
	  src_row_ptr = src_buffer[compptr->v_samp_factor - offset_y - 1];
	  for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
	       dst_blk_x++) {
	    dst_ptr = dst_row_ptr[dst_blk_x];
	    src_ptr = src_row_ptr[dst_blk_x];
	    for (i = 0; i < DCTSIZE; i += 2) {
	      /* copy even row */
	      for (j = 0; j < DCTSIZE; j++)
		*dst_ptr++ = *src_ptr++;
	      /* copy odd row with sign change */
	      for (j = 0; j < DCTSIZE; j++)
		*dst_ptr++ = - *src_ptr++;
	    }
	  }
	} else {
	  /* Just copy row verbatim. */
	  jcopy_block_row(src_buffer[offset_y], dst_buffer[offset_y],
			  compptr->width_in_blocks);
	}
      }
    }
  }
}

LOCAL(void)
do_transpose (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
	      jvirt_barray_ptr *src_coef_arrays,
	      jvirt_barray_ptr *dst_coef_arrays)
/* Transpose source into destination */
{
  JDIMENSION dst_blk_x, dst_blk_y;
  int ci, i, j, offset_x, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;

  /* Transposing pixels within a block just requires transposing the
   * DCT coefficients.
   * Partial iMCUs at the edges require no special treatment; we simply
   * process all the available DCT blocks for every component.
   */
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
	 dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
	((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
	 (JDIMENSION) compptr->v_samp_factor, TRUE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
	for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
	     dst_blk_x += compptr->h_samp_factor) {
	  src_buffer = (*srcinfo->mem->access_virt_barray)
	    ((j_common_ptr) srcinfo, src_coef_arrays[ci], dst_blk_x,
	     (JDIMENSION) compptr->h_samp_factor, FALSE);
	  for (offset_x = 0; offset_x < compptr->h_samp_factor; offset_x++) {
	    src_ptr = src_buffer[offset_x][dst_blk_y + offset_y];
	    dst_ptr = dst_buffer[offset_y][dst_blk_x + offset_x];
	    for (i = 0; i < DCTSIZE; i++)
	      for (j = 0; j < DCTSIZE; j++)
		dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
	  }
	}
      }
    }
  }
}

LOCAL(void)
do_rot_90 (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
	   jvirt_barray_ptr *src_coef_arrays,
	   jvirt_barray_ptr *dst_coef_arrays)
/* 90 degree rotation is equivalent to
 *   1. Transposing the image;
 *   2. Horizontal mirroring.
 * These two steps are merged into a single processing routine.
 */
{
  JDIMENSION MCU_cols, comp_width, dst_blk_x, dst_blk_y;
  int ci, i, j, offset_x, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;

  /* Because of the horizontal mirror step, we can't process partial iMCUs
   * at the (output) right edge properly.  They just get transposed and
   * not mirrored.
   */
  MCU_cols = dstinfo->image_width / (dstinfo->max_h_samp_factor * DCTSIZE);

  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_width = MCU_cols * compptr->h_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
	 dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
	((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
	 (JDIMENSION) compptr->v_samp_factor, TRUE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
	for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
	     dst_blk_x += compptr->h_samp_factor) {
	  src_buffer = (*srcinfo->mem->access_virt_barray)
	    ((j_common_ptr) srcinfo, src_coef_arrays[ci], dst_blk_x,
	     (JDIMENSION) compptr->h_samp_factor, FALSE);
	  for (offset_x = 0; offset_x < compptr->h_samp_factor; offset_x++) {
	    src_ptr = src_buffer[offset_x][dst_blk_y + offset_y];
	    if (dst_blk_x < comp_width) {
	      /* Block is within the mirrorable area. */
	      dst_ptr = dst_buffer[offset_y]
		[comp_width - dst_blk_x - offset_x - 1];
	      for (i = 0; i < DCTSIZE; i++) {
		for (j = 0; j < DCTSIZE; j++)
		  dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
		i++;
		for (j = 0; j < DCTSIZE; j++)
		  dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
	      }
	    } else {
	      /* Edge blocks are transposed but not mirrored. */
	      dst_ptr = dst_buffer[offset_y][dst_blk_x + offset_x];
	      for (i = 0; i < DCTSIZE; i++)
		for (j = 0; j < DCTSIZE; j++)
		  dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
	    }
	  }
	}
      }
    }
  }
}

LOCAL(void)
do_rot_270 (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
	    jvirt_barray_ptr *src_coef_arrays,
	    jvirt_barray_ptr *dst_coef_arrays)
/* 270 degree rotation is equivalent to
 *   1. Horizontal mirroring;
 *   2. Transposing the image.
 * These two steps are merged into a single processing routine.
 */
{
  JDIMENSION MCU_rows, comp_height, dst_blk_x, dst_blk_y;
  int ci, i, j, offset_x, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;

  /* Because of the horizontal mirror step, we can't process partial iMCUs
   * at the (output) bottom edge properly.  They just get transposed and
   * not mirrored.
   */
  MCU_rows = dstinfo->image_height / (dstinfo->max_v_samp_factor * DCTSIZE);

  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_height = MCU_rows * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
	 dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
	((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
	 (JDIMENSION) compptr->v_samp_factor, TRUE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
	for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
	     dst_blk_x += compptr->h_samp_factor) {
	  src_buffer = (*srcinfo->mem->access_virt_barray)
	    ((j_common_ptr) srcinfo, src_coef_arrays[ci], dst_blk_x,
	     (JDIMENSION) compptr->h_samp_factor, FALSE);
	  for (offset_x = 0; offset_x < compptr->h_samp_factor; offset_x++) {
	    dst_ptr = dst_buffer[offset_y][dst_blk_x + offset_x];
	    if (dst_blk_y < comp_height) {
	      /* Block is within the mirrorable area. */
	      src_ptr = src_buffer[offset_x]
		[comp_height - dst_blk_y - offset_y - 1];
	      for (i = 0; i < DCTSIZE; i++) {
		for (j = 0; j < DCTSIZE; j++) {
		  dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
		  j++;
		  dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
		}
	      }
	    } else {
	      /* Edge blocks are transposed but not mirrored. */
	      src_ptr = src_buffer[offset_x][dst_blk_y + offset_y];
	      for (i = 0; i < DCTSIZE; i++)
		for (j = 0; j < DCTSIZE; j++)
		  dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
	    }
	  }
	}
      }
    }
  }
}

LOCAL(void)
do_rot_180 (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
	    jvirt_barray_ptr *src_coef_arrays,
	    jvirt_barray_ptr *dst_coef_arrays)
/* 180 degree rotation is equivalent to
 *   1. Vertical mirroring;
 *   2. Horizontal mirroring.
 * These two steps are merged into a single processing routine.
 */
{
  JDIMENSION MCU_cols, MCU_rows, comp_width, comp_height, dst_blk_x, dst_blk_y;
  int ci, i, j, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  JBLOCKROW src_row_ptr, dst_row_ptr;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;

  MCU_cols = dstinfo->image_width / (dstinfo->max_h_samp_factor * DCTSIZE);
  MCU_rows = dstinfo->image_height / (dstinfo->max_v_samp_factor * DCTSIZE);

  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_width = MCU_cols * compptr->h_samp_factor;
    comp_height = MCU_rows * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
	 dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
	((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
	 (JDIMENSION) compptr->v_samp_factor, TRUE);
      if (dst_blk_y < comp_height) {
	/* Row is within the vertically mirrorable area. */
	src_buffer = (*srcinfo->mem->access_virt_barray)
	  ((j_common_ptr) srcinfo, src_coef_arrays[ci],
	   comp_height - dst_blk_y - (JDIMENSION) compptr->v_samp_factor,
	   (JDIMENSION) compptr->v_samp_factor, FALSE);
      } else {
	/* Bottom-edge rows are only mirrored horizontally. */
	src_buffer = (*srcinfo->mem->access_virt_barray)
	  ((j_common_ptr) srcinfo, src_coef_arrays[ci], dst_blk_y,
	   (JDIMENSION) compptr->v_samp_factor, FALSE);
      }
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
	if (dst_blk_y < comp_height) {
	  /* Row is within the mirrorable area. */
	  dst_row_ptr = dst_buffer[offset_y];
	  src_row_ptr = src_buffer[compptr->v_samp_factor - offset_y - 1];
	  /* Process the blocks that can be mirrored both ways. */
	  for (dst_blk_x = 0; dst_blk_x < comp_width; dst_blk_x++) {
	    dst_ptr = dst_row_ptr[dst_blk_x];
	    src_ptr = src_row_ptr[comp_width - dst_blk_x - 1];
	    for (i = 0; i < DCTSIZE; i += 2) {
	      /* For even row, negate every odd column. */
	      for (j = 0; j < DCTSIZE; j += 2) {
		*dst_ptr++ = *src_ptr++;
		*dst_ptr++ = - *src_ptr++;
	      }
	      /* For odd row, negate every even column. */
	      for (j = 0; j < DCTSIZE; j += 2) {
		*dst_ptr++ = - *src_ptr++;
		*dst_ptr++ = *src_ptr++;
	      }
	    }
	  }
	  /* Any remaining right-edge blocks are only mirrored vertically. */
	  for (; dst_blk_x < compptr->width_in_blocks; dst_blk_x++) {
	    dst_ptr = dst_row_ptr[dst_blk_x];
	    src_ptr = src_row_ptr[dst_blk_x];
	    for (i = 0; i < DCTSIZE; i += 2) {
	      for (j = 0; j < DCTSIZE; j++)
		*dst_ptr++ = *src_ptr++;
	      for (j = 0; j < DCTSIZE; j++)
		*dst_ptr++ = - *src_ptr++;
	    }
	  }
	} else {
	  /* Remaining rows are just mirrored horizontally. */
	  dst_row_ptr = dst_buffer[offset_y];
	  src_row_ptr = src_buffer[offset_y];
	  /* Process the blocks that can be mirrored. */
	  for (dst_blk_x = 0; dst_blk_x < comp_width; dst_blk_x++) {
	    dst_ptr = dst_row_ptr[dst_blk_x];
	    src_ptr = src_row_ptr[comp_width - dst_blk_x - 1];
	    for (i = 0; i < DCTSIZE2; i += 2) {
	      *dst_ptr++ = *src_ptr++;
	      *dst_ptr++ = - *src_ptr++;
	    }
	  }
	  /* Any remaining right-edge blocks are only copied. */
	  for (; dst_blk_x < compptr->width_in_blocks; dst_blk_x++) {
	    dst_ptr = dst_row_ptr[dst_blk_x];
	    src_ptr = src_row_ptr[dst_blk_x];
	    for (i = 0; i < DCTSIZE2; i++)
	      *dst_ptr++ = *src_ptr++;
	  }
	}
      }
    }
  }
}

LOCAL(void)
do_transverse (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
	       jvirt_barray_ptr *src_coef_arrays,
	       jvirt_barray_ptr *dst_coef_arrays)
/* Transverse transpose is equivalent to
 *   1. 180 degree rotation;
 *   2. Transposition;
 * or
 *   1. Horizontal mirroring;
 *   2. Transposition;
 *   3. Horizontal mirroring.
 * These steps are merged into a single processing routine.
 */
{
  JDIMENSION MCU_cols, MCU_rows, comp_width, comp_height, dst_blk_x, dst_blk_y;
  int ci, i, j, offset_x, offset_y;
  JBLOCKARRAY src_buffer, dst_buffer;
  JCOEFPTR src_ptr, dst_ptr;
  jpeg_component_info *compptr;

  MCU_cols = dstinfo->image_width / (dstinfo->max_h_samp_factor * DCTSIZE);
  MCU_rows = dstinfo->image_height / (dstinfo->max_v_samp_factor * DCTSIZE);

  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    comp_width = MCU_cols * compptr->h_samp_factor;
    comp_height = MCU_rows * compptr->v_samp_factor;
    for (dst_blk_y = 0; dst_blk_y < compptr->height_in_blocks;
	 dst_blk_y += compptr->v_samp_factor) {
      dst_buffer = (*srcinfo->mem->access_virt_barray)
	((j_common_ptr) srcinfo, dst_coef_arrays[ci], dst_blk_y,
	 (JDIMENSION) compptr->v_samp_factor, TRUE);
      for (offset_y = 0; offset_y < compptr->v_samp_factor; offset_y++) {
	for (dst_blk_x = 0; dst_blk_x < compptr->width_in_blocks;
	     dst_blk_x += compptr->h_samp_factor) {
	  src_buffer = (*srcinfo->mem->access_virt_barray)
	    ((j_common_ptr) srcinfo, src_coef_arrays[ci], dst_blk_x,
	     (JDIMENSION) compptr->h_samp_factor, FALSE);
	  for (offset_x = 0; offset_x < compptr->h_samp_factor; offset_x++) {
	    if (dst_blk_y < comp_height) {
	      src_ptr = src_buffer[offset_x]
		[comp_height - dst_blk_y - offset_y - 1];
	      if (dst_blk_x < comp_width) {
		/* Block is within the mirrorable area. */
		dst_ptr = dst_buffer[offset_y]
		  [comp_width - dst_blk_x - offset_x - 1];
		for (i = 0; i < DCTSIZE; i++) {
		  for (j = 0; j < DCTSIZE; j++) {
		    dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
		    j++;
		    dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
		  }
		  i++;
		  for (j = 0; j < DCTSIZE; j++) {
		    dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
		    j++;
		    dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
		  }
		}
	      } else {
		/* Right-edge blocks are mirrored in y only */
		dst_ptr = dst_buffer[offset_y][dst_blk_x + offset_x];
		for (i = 0; i < DCTSIZE; i++) {
		  for (j = 0; j < DCTSIZE; j++) {
		    dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
		    j++;
		    dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
		  }
		}
	      }
	    } else {
	      src_ptr = src_buffer[offset_x][dst_blk_y + offset_y];
	      if (dst_blk_x < comp_width) {
		/* Bottom-edge blocks are mirrored in x only */
		dst_ptr = dst_buffer[offset_y]
		  [comp_width - dst_blk_x - offset_x - 1];
		for (i = 0; i < DCTSIZE; i++) {
		  for (j = 0; j < DCTSIZE; j++)
		    dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
		  i++;
		  for (j = 0; j < DCTSIZE; j++)
		    dst_ptr[j*DCTSIZE+i] = -src_ptr[i*DCTSIZE+j];
		}
	      } else {
		/* At lower right corner, just transpose, no mirroring */
		dst_ptr = dst_buffer[offset_y][dst_blk_x + offset_x];
		for (i = 0; i < DCTSIZE; i++)
		  for (j = 0; j < DCTSIZE; j++)
		    dst_ptr[j*DCTSIZE+i] = src_ptr[i*DCTSIZE+j];
	      }
	    }
	  }
	}
      }
    }
  }
}

/* Request any required workspace.
 *
 * We allocate the workspace virtual arrays from the source decompression
 * object, so that all the arrays (both the original data and the workspace)
 * will be taken into account while making memory management decisions.
 * Hence, this routine must be called after jpeg_read_header (which reads
 * the image dimensions) and before jpeg_read_coefficients (which realizes
 * the source's virtual arrays).
 */

GLOBAL(void)
jtransform_request_workspace (j_decompress_ptr srcinfo,
			      jpeg_transform_info *info)
{
  jvirt_barray_ptr *coef_arrays = NULL;
  jpeg_component_info *compptr;
  int ci;

  if (info->force_grayscale &&
      srcinfo->jpeg_color_space == JCS_YCbCr &&
      srcinfo->num_components == 3) {
    /* We'll only process the first component */
    info->num_components = 1;
  } else {
    /* Process all the components */
    info->num_components = srcinfo->num_components;
  }

  switch (info->transform) {
  case JXFORM_NONE:
  case JXFORM_FLIP_H:
    /* Don't need a workspace array */
    break;
  case JXFORM_FLIP_V:
  case JXFORM_ROT_180:
    /* Need workspace arrays having same dimensions as source image.
     * Note that we allocate arrays padded out to the next iMCU boundary,
     * so that transform routines need not worry about missing edge blocks.
     */
    coef_arrays = (jvirt_barray_ptr *)
      (*srcinfo->mem->alloc_small) ((j_common_ptr) srcinfo, JPOOL_IMAGE,
	SIZEOF(jvirt_barray_ptr) * info->num_components);
    for (ci = 0; ci < info->num_components; ci++) {
      compptr = srcinfo->comp_info + ci;
      coef_arrays[ci] = (*srcinfo->mem->request_virt_barray)
	((j_common_ptr) srcinfo, JPOOL_IMAGE, FALSE,
	 (JDIMENSION) jround_up((long) compptr->width_in_blocks,
				(long) compptr->h_samp_factor),
	 (JDIMENSION) jround_up((long) compptr->height_in_blocks,
				(long) compptr->v_samp_factor),
	 (JDIMENSION) compptr->v_samp_factor);
    }
    break;
  case JXFORM_TRANSPOSE:
  case JXFORM_TRANSVERSE:
  case JXFORM_ROT_90:
  case JXFORM_ROT_270:
    /* Need workspace arrays having transposed dimensions.
     * Note that we allocate arrays padded out to the next iMCU boundary,
     * so that transform routines need not worry about missing edge blocks.
     */
    coef_arrays = (jvirt_barray_ptr *)
      (*srcinfo->mem->alloc_small) ((j_common_ptr) srcinfo, JPOOL_IMAGE,
	SIZEOF(jvirt_barray_ptr) * info->num_components);
    for (ci = 0; ci < info->num_components; ci++) {
      compptr = srcinfo->comp_info + ci;
      coef_arrays[ci] = (*srcinfo->mem->request_virt_barray)
	((j_common_ptr) srcinfo, JPOOL_IMAGE, FALSE,
	 (JDIMENSION) jround_up((long) compptr->height_in_blocks,
				(long) compptr->v_samp_factor),
	 (JDIMENSION) jround_up((long) compptr->width_in_blocks,
				(long) compptr->h_samp_factor),
	 (JDIMENSION) compptr->h_samp_factor);
    }
    break;
  }
  info->workspace_coef_arrays = coef_arrays;
}

/* Transpose destination image parameters */

LOCAL(void)
transpose_critical_parameters (j_compress_ptr dstinfo)
{
  int tblno, i, j, ci, itemp;
  jpeg_component_info *compptr;
  JQUANT_TBL *qtblptr;
  JDIMENSION dtemp;
  UINT16 qtemp;

  /* Transpose basic image dimensions */
  dtemp = dstinfo->image_width;
  dstinfo->image_width = dstinfo->image_height;
  dstinfo->image_height = dtemp;

  /* Transpose sampling factors */
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    compptr = dstinfo->comp_info + ci;
    itemp = compptr->h_samp_factor;
    compptr->h_samp_factor = compptr->v_samp_factor;
    compptr->v_samp_factor = itemp;
  }

  /* Transpose quantization tables */
  for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {
    qtblptr = dstinfo->quant_tbl_ptrs[tblno];
    if (qtblptr != NULL) {
      for (i = 0; i < DCTSIZE; i++) {
	for (j = 0; j < i; j++) {
	  qtemp = qtblptr->quantval[i*DCTSIZE+j];
	  qtblptr->quantval[i*DCTSIZE+j] = qtblptr->quantval[j*DCTSIZE+i];
	  qtblptr->quantval[j*DCTSIZE+i] = qtemp;
	}
      }
    }
  }
}

/* Trim off any partial iMCUs on the indicated destination edge */

LOCAL(void)
trim_right_edge (j_compress_ptr dstinfo)
{
  int ci, max_h_samp_factor;
  JDIMENSION MCU_cols;

  /* We have to compute max_h_samp_factor ourselves,
   * because it hasn't been set yet in the destination
   * (and we don't want to use the source's value).
   */
  max_h_samp_factor = 1;
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    int h_samp_factor = dstinfo->comp_info[ci].h_samp_factor;
    max_h_samp_factor = MAX(max_h_samp_factor, h_samp_factor);
  }
  MCU_cols = dstinfo->image_width / (max_h_samp_factor * DCTSIZE);
  if (MCU_cols > 0)		/* can't trim to 0 pixels */
    dstinfo->image_width = MCU_cols * (max_h_samp_factor * DCTSIZE);
}

LOCAL(void)
trim_bottom_edge (j_compress_ptr dstinfo)
{
  int ci, max_v_samp_factor;
  JDIMENSION MCU_rows;

  /* We have to compute max_v_samp_factor ourselves,
   * because it hasn't been set yet in the destination
   * (and we don't want to use the source's value).
   */
  max_v_samp_factor = 1;
  for (ci = 0; ci < dstinfo->num_components; ci++) {
    int v_samp_factor = dstinfo->comp_info[ci].v_samp_factor;
    max_v_samp_factor = MAX(max_v_samp_factor, v_samp_factor);
  }
  MCU_rows = dstinfo->image_height / (max_v_samp_factor * DCTSIZE);
  if (MCU_rows > 0)		/* can't trim to 0 pixels */
    dstinfo->image_height = MCU_rows * (max_v_samp_factor * DCTSIZE);
}

/* Adjust output image parameters as needed.
 *
 * This must be called after jpeg_copy_critical_parameters()
 * and before jpeg_write_coefficients().
 *
 * The return value is the set of virtual coefficient arrays to be written
 * (either the ones allocated by jtransform_request_workspace, or the
 * original source data arrays).  The caller will need to pass this value
 * to jpeg_write_coefficients().
 */

GLOBAL(jvirt_barray_ptr *)
jtransform_adjust_parameters (j_decompress_ptr,
			      j_compress_ptr dstinfo,
			      jvirt_barray_ptr *src_coef_arrays,
			      jpeg_transform_info *info)
{
  /* If force-to-grayscale is requested, adjust destination parameters */
  if (info->force_grayscale) {
    /* We use jpeg_set_colorspace to make sure subsidiary settings get fixed
     * properly.  Among other things, the target h_samp_factor & v_samp_factor
     * will get set to 1, which typically won't match the source.
     * In fact we do this even if the source is already grayscale; that
     * provides an easy way of coercing a grayscale JPEG with funny sampling
     * factors to the customary 1,1.  (Some decoders fail on other factors.)
     */
    if ((dstinfo->jpeg_color_space == JCS_YCbCr &&
	 dstinfo->num_components == 3) ||
	(dstinfo->jpeg_color_space == JCS_GRAYSCALE &&
	 dstinfo->num_components == 1)) {
      /* We have to preserve the source's quantization table number. */
      int sv_quant_tbl_no = dstinfo->comp_info[0].quant_tbl_no;
      jpeg_set_colorspace(dstinfo, JCS_GRAYSCALE);
      dstinfo->comp_info[0].quant_tbl_no = sv_quant_tbl_no;
    } else {
      /* Sorry, can't do it */
      ERREXIT(dstinfo, JERR_CONVERSION_NOTIMPL);
    }
  }

  /* Correct the destination's image dimensions etc if necessary */
  switch (info->transform) {
  case JXFORM_NONE:
    /* Nothing to do */
    break;
  case JXFORM_FLIP_H:
    if (info->trim)
      trim_right_edge(dstinfo);
    break;
  case JXFORM_FLIP_V:
    if (info->trim)
      trim_bottom_edge(dstinfo);
    break;
  case JXFORM_TRANSPOSE:
    transpose_critical_parameters(dstinfo);
    /* transpose does NOT have to trim anything */
    break;
  case JXFORM_TRANSVERSE:
    transpose_critical_parameters(dstinfo);
    if (info->trim) {
      trim_right_edge(dstinfo);
      trim_bottom_edge(dstinfo);
    }
    break;
  case JXFORM_ROT_90:
    transpose_critical_parameters(dstinfo);
    if (info->trim)
      trim_right_edge(dstinfo);
    break;
  case JXFORM_ROT_180:
    if (info->trim) {
      trim_right_edge(dstinfo);
      trim_bottom_edge(dstinfo);
    }
    break;
  case JXFORM_ROT_270:
    transpose_critical_parameters(dstinfo);
    if (info->trim)
      trim_bottom_edge(dstinfo);
    break;
  }

  /* Return the appropriate output data set */
  if (info->workspace_coef_arrays != NULL)
    return info->workspace_coef_arrays;
  return src_coef_arrays;
}

/* Execute the actual transformation, if any.
 *
 * This must be called *after* jpeg_write_coefficients, because it depends
 * on jpeg_write_coefficients to have computed subsidiary values such as
 * the per-component width and height fields in the destination object.
 *
 * Note that some transformations will modify the source data arrays!
 */

GLOBAL(void)
jtransform_execute_transformation (j_decompress_ptr srcinfo,
				   j_compress_ptr dstinfo,
				   jvirt_barray_ptr *src_coef_arrays,
				   jpeg_transform_info *info)
{
  jvirt_barray_ptr *dst_coef_arrays = info->workspace_coef_arrays;

  switch (info->transform) {
  case JXFORM_NONE:
    break;
  case JXFORM_FLIP_H:
    do_flip_h(srcinfo, dstinfo, src_coef_arrays);
    break;
  case JXFORM_FLIP_V:
    do_flip_v(srcinfo, dstinfo, src_coef_arrays, dst_coef_arrays);
    break;
  case JXFORM_TRANSPOSE:
    do_transpose(srcinfo, dstinfo, src_coef_arrays, dst_coef_arrays);
    break;
  case JXFORM_TRANSVERSE:
    do_transverse(srcinfo, dstinfo, src_coef_arrays, dst_coef_arrays);
    break;
  case JXFORM_ROT_90:
    do_rot_90(srcinfo, dstinfo, src_coef_arrays, dst_coef_arrays);
    break;
  case JXFORM_ROT_180:
    do_rot_180(srcinfo, dstinfo, src_coef_arrays, dst_coef_arrays);
    break;
  case JXFORM_ROT_270:
    do_rot_270(srcinfo, dstinfo, src_coef_arrays, dst_coef_arrays);
    break;
  }
}

#endif /* TRANSFORMS_SUPPORTED */

/* Setup decompression object to save desired markers in memory.
 * This must be called before jpeg_read_header() to have the desired effect.
 */

GLOBAL(void)
jcopy_markers_setup (j_decompress_ptr srcinfo, JCOPY_OPTION option)
{
#ifdef SAVE_MARKERS_SUPPORTED
  int m;

  /* Save comments except under NONE option */
  if (option != JCOPYOPT_NONE) {
    jpeg_save_markers(srcinfo, JPEG_COM, 0xFFFF);
  }
  /* Save all types of APPn markers iff ALL option */
  if (option == JCOPYOPT_ALL) {
    for (m = 0; m < 16; m++)
      jpeg_save_markers(srcinfo, JPEG_APP0 + m, 0xFFFF);
  }
#endif /* SAVE_MARKERS_SUPPORTED */
}

/* Copy markers saved in the given source object to the destination object.
 * This should be called just after jpeg_start_compress() or
 * jpeg_write_coefficients().
 * Note that those routines will have written the SOI, and also the
 * JFIF APP0 or Adobe APP14 markers if selected.
 */

GLOBAL(void)
jcopy_markers_execute (j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
		       JCOPY_OPTION)
{
  jpeg_saved_marker_ptr marker;

  /* In the current implementation, we don't actually need to examine the
   * option flag here; we just copy everything that got saved.
   * But to avoid confusion, we do not output JFIF and Adobe APP14 markers
   * if the encoder library already wrote one.
   */
  for (marker = srcinfo->marker_list; marker != NULL; marker = marker->next) {
    if (dstinfo->write_JFIF_header &&
	marker->marker == JPEG_APP0 &&
	marker->data_length >= 5 &&
	GETJOCTET(marker->data[0]) == 0x4A &&
	GETJOCTET(marker->data[1]) == 0x46 &&
	GETJOCTET(marker->data[2]) == 0x49 &&
	GETJOCTET(marker->data[3]) == 0x46 &&
	GETJOCTET(marker->data[4]) == 0)
      continue;			/* reject duplicate JFIF */
    if (dstinfo->write_Adobe_marker &&
	marker->marker == JPEG_APP0+14 &&
	marker->data_length >= 5 &&
	GETJOCTET(marker->data[0]) == 0x41 &&
	GETJOCTET(marker->data[1]) == 0x64 &&
	GETJOCTET(marker->data[2]) == 0x6F &&
	GETJOCTET(marker->data[3]) == 0x62 &&
	GETJOCTET(marker->data[4]) == 0x65)
      continue;			/* reject duplicate Adobe */
#ifdef NEED_FAR_POINTERS
    /* We could use jpeg_write_marker if the data weren't FAR... */
    {
      unsigned int i;
      jpeg_write_m_header(dstinfo, marker->marker, marker->data_length);
      for (i = 0; i < marker->data_length; i++)
	jpeg_write_m_byte(dstinfo, marker->data[i]);
    }
#else
    jpeg_write_marker(dstinfo, marker->marker,
		      marker->data, marker->data_length);
#endif
  }
}


text:
/*
 * jdapistd.c
 *
 * Copyright (C) 1994-1996, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains application interface code for the decompression half
 * of the JPEG library.  These are the "standard" API routines that are
 * used in the normal full-decompression case.  They are not used by a
 * transcoding-only application.  Note that if an application links in
 * jpeg_start_decompress, it will end up linking in the entire decompressor.
 * We thus must separate this file from jdapimin.c to avoid linking the
 * whole decompression library into a transcoder.
 */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"

/* Forward declarations */
LOCAL(boolean) output_pass_setup JPP((j_decompress_ptr cinfo));

/*
 * Decompression initialization.
 * jpeg_read_header must be completed before calling this.
 *
 * If a multipass operating mode was selected, this will do all but the
 * last pass, and thus may take a great deal of time.
 *
 * Returns FALSE if suspended.  The return value need be inspected only if
 * a suspending data source is used.
 */

GLOBAL(boolean)
jpeg_start_decompress (j_decompress_ptr cinfo)
{
  if (cinfo->global_state == DSTATE_READY) {
    /* First call: initialize master control, select active modules */
    jinit_master_decompress(cinfo);
    if (cinfo->buffered_image) {
      /* No more work here; expecting jpeg_start_output next */
      cinfo->global_state = DSTATE_BUFIMAGE;
      return TRUE;
    }
    cinfo->global_state = DSTATE_PRELOAD;
  }
  if (cinfo->global_state == DSTATE_PRELOAD) {
    /* If file has multiple scans, absorb them all into the coef buffer */
    if (cinfo->inputctl->has_multiple_scans) {
#ifdef D_MULTISCAN_FILES_SUPPORTED
      for (;;) {
	int retcode;
	/* Call progress monitor hook if present */
	if (cinfo->progress != NULL)
	  (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
	/* Absorb some more input */
	retcode = (*cinfo->inputctl->consume_input) (cinfo);
	if (retcode == JPEG_SUSPENDED)
	  return FALSE;
	if (retcode == JPEG_REACHED_EOI)
	  break;
	/* Advance progress counter if appropriate */
	if (cinfo->progress != NULL &&
	    (retcode == JPEG_ROW_COMPLETED || retcode == JPEG_REACHED_SOS)) {
	  if (++cinfo->progress->pass_counter >= cinfo->progress->pass_limit) {
	    /* jdmaster underestimated number of scans; ratchet up one scan */
	    cinfo->progress->pass_limit += (long) cinfo->total_iMCU_rows;
	  }
	}
      }
#else
      ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif /* D_MULTISCAN_FILES_SUPPORTED */
    }
    cinfo->output_scan_number = cinfo->input_scan_number;
  } else if (cinfo->global_state != DSTATE_PRESCAN)
    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  /* Perform any dummy output passes, and set up for the final pass */
  return output_pass_setup(cinfo);
}

/*
 * Set up for an output pass, and perform any dummy pass(es) needed.
 * Common subroutine for jpeg_start_decompress and jpeg_start_output.
 * Entry: global_state = DSTATE_PRESCAN only if previously suspended.
 * Exit: If done, returns TRUE and sets global_state for proper output mode.
 *       If suspended, returns FALSE and sets global_state = DSTATE_PRESCAN.
 */

LOCAL(boolean)
output_pass_setup (j_decompress_ptr cinfo)
{
  if (cinfo->global_state != DSTATE_PRESCAN) {
    /* First call: do pass setup */
    (*cinfo->master->prepare_for_output_pass) (cinfo);
    cinfo->output_scanline = 0;
    cinfo->global_state = DSTATE_PRESCAN;
  }
  /* Loop over any required dummy passes */
  while (cinfo->master->is_dummy_pass) {
#ifdef QUANT_2PASS_SUPPORTED
    /* Crank through the dummy pass */
    while (cinfo->output_scanline < cinfo->output_height) {
      JDIMENSION last_scanline;
      /* Call progress monitor hook if present */
      if (cinfo->progress != NULL) {
	cinfo->progress->pass_counter = (long) cinfo->output_scanline;
	cinfo->progress->pass_limit = (long) cinfo->output_height;
	(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
      }
      /* Process some data */
      last_scanline = cinfo->output_scanline;
      (*cinfo->main->process_data) (cinfo, (JSAMPARRAY) NULL,
				    &cinfo->output_scanline, (JDIMENSION) 0);
      if (cinfo->output_scanline == last_scanline)
	return FALSE;		/* No progress made, must suspend */
    }
    /* Finish up dummy pass, and set up for another one */
    (*cinfo->master->finish_output_pass) (cinfo);
    (*cinfo->master->prepare_for_output_pass) (cinfo);
    cinfo->output_scanline = 0;
#else
    ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif /* QUANT_2PASS_SUPPORTED */
  }
  /* Ready for application to drive output pass through
   * jpeg_read_scanlines or jpeg_read_raw_data.
   */
  cinfo->global_state = cinfo->raw_data_out ? DSTATE_RAW_OK : DSTATE_SCANNING;
  return TRUE;
}

/*
 * Read some scanlines of data from the JPEG decompressor.
 *
 * The return value will be the number of lines actually read.
 * This may be less than the number requested in several cases,
 * including bottom of image, data source suspension, and operating
 * modes that emit multiple scanlines at a time.
 *
 * Note: we warn about excess calls to jpeg_read_scanlines() since
 * this likely signals an application programmer error.  However,
 * an oversize buffer (max_lines > scanlines remaining) is not an error.
 */

GLOBAL(JDIMENSION)
jpeg_read_scanlines (j_decompress_ptr cinfo, JSAMPARRAY scanlines,
		     JDIMENSION max_lines)
{
  JDIMENSION row_ctr;

  if (cinfo->global_state != DSTATE_SCANNING)
    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  if (cinfo->output_scanline >= cinfo->output_height) {
    WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
    return 0;
  }

  /* Call progress monitor hook if present */
  if (cinfo->progress != NULL) {
    cinfo->progress->pass_counter = (long) cinfo->output_scanline;
    cinfo->progress->pass_limit = (long) cinfo->output_height;
    (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
  }

  /* Process some data */
  row_ctr = 0;
  (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, max_lines);
  cinfo->output_scanline += row_ctr;
  return row_ctr;
}

/*
 * Alternate entry point to read raw data.
 * Processes exactly one iMCU row per call, unless suspended.
 */

GLOBAL(JDIMENSION)
jpeg_read_raw_data (j_decompress_ptr cinfo, JSAMPIMAGE data,
		    JDIMENSION max_lines)
{
  JDIMENSION lines_per_iMCU_row;

  if (cinfo->global_state != DSTATE_RAW_OK)
    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  if (cinfo->output_scanline >= cinfo->output_height) {
    WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
    return 0;
  }

  /* Call progress monitor hook if present */
  if (cinfo->progress != NULL) {
    cinfo->progress->pass_counter = (long) cinfo->output_scanline;
    cinfo->progress->pass_limit = (long) cinfo->output_height;
    (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
  }

  /* Verify that at least one iMCU row can be returned. */
  lines_per_iMCU_row = cinfo->max_v_samp_factor * cinfo->min_DCT_scaled_size;
  if (max_lines < lines_per_iMCU_row)
    ERREXIT(cinfo, JERR_BUFFER_SIZE);

  /* Decompress directly into user's buffer. */
  if (! (*cinfo->coef->decompress_data) (cinfo, data))
    return 0;			/* suspension forced, can do nothing more */

  /* OK, we processed one iMCU row. */
  cinfo->output_scanline += lines_per_iMCU_row;
  return lines_per_iMCU_row;
}

/* Additional entry points for buffered-image mode. */

#ifdef D_MULTISCAN_FILES_SUPPORTED

/*
 * Initialize for an output pass in buffered-image mode.
 */

GLOBAL(boolean)
jpeg_start_output (j_decompress_ptr cinfo, int scan_number)
{
  if (cinfo->global_state != DSTATE_BUFIMAGE &&
      cinfo->global_state != DSTATE_PRESCAN)
    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  /* Limit scan number to valid range */
  if (scan_number <= 0)
    scan_number = 1;
  if (cinfo->inputctl->eoi_reached &&
      scan_number > cinfo->input_scan_number)
    scan_number = cinfo->input_scan_number;
  cinfo->output_scan_number = scan_number;
  /* Perform any dummy output passes, and set up for the real pass */
  return output_pass_setup(cinfo);
}

/*
 * Finish up after an output pass in buffered-image mode.
 *
 * Returns FALSE if suspended.  The return value need be inspected only if
 * a suspending data source is used.
 */

GLOBAL(boolean)
jpeg_finish_output (j_decompress_ptr cinfo)
{
  if ((cinfo->global_state == DSTATE_SCANNING ||
       cinfo->global_state == DSTATE_RAW_OK) && cinfo->buffered_image) {
    /* Terminate this pass. */
    /* We do not require the whole pass to have been completed. */
    (*cinfo->master->finish_output_pass) (cinfo);
    cinfo->global_state = DSTATE_BUFPOST;
  } else if (cinfo->global_state != DSTATE_BUFPOST) {
    /* BUFPOST = repeat call after a suspension, anything else is error */
    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
  }
  /* Read markers looking for SOS or EOI */
  while (cinfo->input_scan_number <= cinfo->output_scan_number &&
	 ! cinfo->inputctl->eoi_reached) {
    if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
      return FALSE;		/* Suspend, come back later */
  }
  cinfo->global_state = DSTATE_BUFIMAGE;
  return TRUE;
}

#endif /* D_MULTISCAN_FILES_SUPPORTED */

repo_name: fedden/RenderMan

mime_type: text/x-c++


text:
/*
 * jfdctfst.c
 *
 * Copyright (C) 1994-1996, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains a fast, not so accurate integer implementation of the
 * forward DCT (Discrete Cosine Transform).
 *
 * A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT
 * on each column.  Direct algorithms are also available, but they are
 * much more complex and seem not to be any faster when reduced to code.
 *
 * This implementation is based on Arai, Agui, and Nakajima's algorithm for
 * scaled DCT.  Their original paper (Trans. IEICE E-71(11):1095) is in
 * Japanese, but the algorithm is described in the Pennebaker & Mitchell
 * JPEG textbook (see REFERENCES section in file README).  The following code
 * is based directly on figure 4-8 in P&M.
 * While an 8-point DCT cannot be done in less than 11 multiplies, it is
 * possible to arrange the computation so that many of the multiplies are
 * simple scalings of the final outputs.  These multiplies can then be
 * folded into the multiplications or divisions by the JPEG quantization
 * table entries.  The AA&N method leaves only 5 multiplies and 29 adds
 * to be done in the DCT itself.
 * The primary disadvantage of this method is that with fixed-point math,
 * accuracy is lost due to imprecise representation of the scaled
 * quantization values.  The smaller the quantization table entry, the less
 * precise the scaled value, so this implementation does worse with high-
 * quality-setting files than with low-quality ones.
 */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
#include "jdct.h"		/* Private declarations for DCT subsystem */

#ifdef DCT_IFAST_SUPPORTED

/*
 * This module is specialized to the case DCTSIZE = 8.
 */

#if DCTSIZE != 8
  Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
#endif

/* Scaling decisions are generally the same as in the LL&M algorithm;
 * see jfdctint.c for more details.  However, we choose to descale
 * (right shift) multiplication products as soon as they are formed,
 * rather than carrying additional fractional bits into subsequent additions.
 * This compromises accuracy slightly, but it lets us save a few shifts.
 * More importantly, 16-bit arithmetic is then adequate (for 8-bit samples)
 * everywhere except in the multiplications proper; this saves a good deal
 * of work on 16-bit-int machines.
 *
 * Again to save a few shifts, the intermediate results between pass 1 and
 * pass 2 are not upscaled, but are represented only to integral precision.
 *
 * A final compromise is to represent the multiplicative constants to only
 * 8 fractional bits, rather than 13.  This saves some shifting work on some
 * machines, and may also reduce the cost of multiplication (since there
 * are fewer one-bits in the constants).
 */

#define CONST_BITS  8

/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus
 * causing a lot of useless floating-point operations at run time.
 * To get around this we use the following pre-calculated constants.
 * If you change CONST_BITS you may want to add appropriate values.
 * (With a reasonable C compiler, you can just rely on the FIX() macro...)
 */

#if CONST_BITS == 8
#define FIX_0_382683433  ((INT32)   98)		/* FIX(0.382683433) */
#define FIX_0_541196100  ((INT32)  139)		/* FIX(0.541196100) */
#define FIX_0_707106781  ((INT32)  181)		/* FIX(0.707106781) */
#define FIX_1_306562965  ((INT32)  334)		/* FIX(1.306562965) */
#else
#define FIX_0_382683433  FIX(0.382683433)
#define FIX_0_541196100  FIX(0.541196100)
#define FIX_0_707106781  FIX(0.707106781)
#define FIX_1_306562965  FIX(1.306562965)
#endif

/* We can gain a little more speed, with a further compromise in accuracy,
 * by omitting the addition in a descaling shift.  This yields an incorrectly
 * rounded result half the time...
 */

#ifndef USE_ACCURATE_ROUNDING
#undef DESCALE
#define DESCALE(x,n)  RIGHT_SHIFT(x, n)
#endif

/* Multiply a DCTELEM variable by an INT32 constant, and immediately
 * descale to yield a DCTELEM result.
 */

#define MULTIPLY(var,const)  ((DCTELEM) DESCALE((var) * (const), CONST_BITS))

/*
 * Perform the forward DCT on one block of samples.
 */

GLOBAL(void)
jpeg_fdct_ifast (DCTELEM * data)
{
  DCTELEM tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
  DCTELEM tmp10, tmp11, tmp12, tmp13;
  DCTELEM z1, z2, z3, z4, z5, z11, z13;
  DCTELEM *dataptr;
  int ctr;
  SHIFT_TEMPS

  /* Pass 1: process rows. */

  dataptr = data;
  for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
    tmp0 = dataptr[0] + dataptr[7];
    tmp7 = dataptr[0] - dataptr[7];
    tmp1 = dataptr[1] + dataptr[6];
    tmp6 = dataptr[1] - dataptr[6];
    tmp2 = dataptr[2] + dataptr[5];
    tmp5 = dataptr[2] - dataptr[5];
    tmp3 = dataptr[3] + dataptr[4];
    tmp4 = dataptr[3] - dataptr[4];

    /* Even part */

    tmp10 = tmp0 + tmp3;	/* phase 2 */
    tmp13 = tmp0 - tmp3;
    tmp11 = tmp1 + tmp2;
    tmp12 = tmp1 - tmp2;

    dataptr[0] = tmp10 + tmp11; /* phase 3 */
    dataptr[4] = tmp10 - tmp11;

    z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
    dataptr[2] = tmp13 + z1;	/* phase 5 */
    dataptr[6] = tmp13 - z1;

    /* Odd part */

    tmp10 = tmp4 + tmp5;	/* phase 2 */
    tmp11 = tmp5 + tmp6;
    tmp12 = tmp6 + tmp7;

    /* The rotator is modified from fig 4-8 to avoid extra negations. */
    z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
    z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */
    z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */
    z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */

    z11 = tmp7 + z3;		/* phase 5 */
    z13 = tmp7 - z3;

    dataptr[5] = z13 + z2;	/* phase 6 */
    dataptr[3] = z13 - z2;
    dataptr[1] = z11 + z4;
    dataptr[7] = z11 - z4;

    dataptr += DCTSIZE;		/* advance pointer to next row */
  }

  /* Pass 2: process columns. */

  dataptr = data;
  for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
    tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7];
    tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7];
    tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6];
    tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6];
    tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5];
    tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5];
    tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4];
    tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4];

    /* Even part */

    tmp10 = tmp0 + tmp3;	/* phase 2 */
    tmp13 = tmp0 - tmp3;
    tmp11 = tmp1 + tmp2;
    tmp12 = tmp1 - tmp2;

    dataptr[DCTSIZE*0] = tmp10 + tmp11; /* phase 3 */
    dataptr[DCTSIZE*4] = tmp10 - tmp11;

    z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
    dataptr[DCTSIZE*2] = tmp13 + z1; /* phase 5 */
    dataptr[DCTSIZE*6] = tmp13 - z1;

    /* Odd part */

    tmp10 = tmp4 + tmp5;	/* phase 2 */
    tmp11 = tmp5 + tmp6;
    tmp12 = tmp6 + tmp7;

    /* The rotator is modified from fig 4-8 to avoid extra negations. */
    z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
    z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */
    z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */
    z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */

    z11 = tmp7 + z3;		/* phase 5 */
    z13 = tmp7 - z3;

    dataptr[DCTSIZE*5] = z13 + z2; /* phase 6 */
    dataptr[DCTSIZE*3] = z13 - z2;
    dataptr[DCTSIZE*1] = z11 + z4;
    dataptr[DCTSIZE*7] = z11 - z4;

    dataptr++;			/* advance pointer to next column */
  }
}

#endif /* DCT_IFAST_SUPPORTED */


text:
/*
 * jdcoefct.c
 *
 * Copyright (C) 1994-1997, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains the coefficient buffer controller for decompression.
 * This controller is the top level of the JPEG decompressor proper.
 * The coefficient buffer lies between entropy decoding and inverse-DCT steps.
 *
 * In buffered-image mode, this controller is the interface between
 * input-oriented processing and output-oriented processing.
 * Also, the input side (only) is used when reading a file for transcoding.
 */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"

/* Block smoothing is only applicable for progressive JPEG, so: */
#ifndef D_PROGRESSIVE_SUPPORTED
#undef BLOCK_SMOOTHING_SUPPORTED
#endif

/* Private buffer controller object */

typedef struct {
  struct jpeg_d_coef_controller pub; /* public fields */

  /* These variables keep track of the current location of the input side. */
  /* cinfo->input_iMCU_row is also used for this. */
  JDIMENSION MCU_ctr;		/* counts MCUs processed in current row */
  int MCU_vert_offset;		/* counts MCU rows within iMCU row */
  int MCU_rows_per_iMCU_row;	/* number of such rows needed */

  /* The output side's location is represented by cinfo->output_iMCU_row. */

  /* In single-pass modes, it's sufficient to buffer just one MCU.
   * We allocate a workspace of D_MAX_BLOCKS_IN_MCU coefficient blocks,
   * and let the entropy decoder write into that workspace each time.
   * (On 80x86, the workspace is FAR even though it's not really very big;
   * this is to keep the module interfaces unchanged when a large coefficient
   * buffer is necessary.)
   * In multi-pass modes, this array points to the current MCU's blocks
   * within the virtual arrays; it is used only by the input side.
   */
  JBLOCKROW MCU_buffer[D_MAX_BLOCKS_IN_MCU];

#ifdef D_MULTISCAN_FILES_SUPPORTED
  /* In multi-pass modes, we need a virtual block array for each component. */
  jvirt_barray_ptr whole_image[MAX_COMPONENTS];
#endif

#ifdef BLOCK_SMOOTHING_SUPPORTED
  /* When doing block smoothing, we latch coefficient Al values here */
  int * coef_bits_latch;
#define SAVED_COEFS  6		/* we save coef_bits[0..5] */
#endif
} my_coef_controller3;

typedef my_coef_controller3 * my_coef_ptr3;

/* Forward declarations */
METHODDEF(int) decompress_onepass
	JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
#ifdef D_MULTISCAN_FILES_SUPPORTED
METHODDEF(int) decompress_data
	JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
#endif
#ifdef BLOCK_SMOOTHING_SUPPORTED
LOCAL(boolean) smoothing_ok JPP((j_decompress_ptr cinfo));
METHODDEF(int) decompress_smooth_data
	JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
#endif

LOCAL(void)
start_iMCU_row3 (j_decompress_ptr cinfo)
/* Reset within-iMCU-row counters for a new row (input side) */
{
  my_coef_ptr3 coef = (my_coef_ptr3) cinfo->coef;

  /* In an interleaved scan, an MCU row is the same as an iMCU row.
   * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
   * But at the bottom of the image, process only what's left.
   */
  if (cinfo->comps_in_scan > 1) {
    coef->MCU_rows_per_iMCU_row = 1;
  } else {
    if (cinfo->input_iMCU_row < (cinfo->total_iMCU_rows-1))
      coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
    else
      coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
  }

  coef->MCU_ctr = 0;
  coef->MCU_vert_offset = 0;
}

/*
 * Initialize for an input processing pass.
 */

METHODDEF(void)
start_input_pass (j_decompress_ptr cinfo)
{
  cinfo->input_iMCU_row = 0;
  start_iMCU_row3(cinfo);
}

/*
 * Initialize for an output processing pass.
 */

METHODDEF(void)
start_output_pass (j_decompress_ptr cinfo)
{
#ifdef BLOCK_SMOOTHING_SUPPORTED
  my_coef_ptr3 coef = (my_coef_ptr3) cinfo->coef;

  /* If multipass, check to see whether to use block smoothing on this pass */
  if (coef->pub.coef_arrays != NULL) {
    if (cinfo->do_block_smoothing && smoothing_ok(cinfo))
      coef->pub.decompress_data = decompress_smooth_data;
    else
      coef->pub.decompress_data = decompress_data;
  }
#endif
  cinfo->output_iMCU_row = 0;
}

/*
 * Decompress and return some data in the single-pass case.
 * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
 * Input and output must run in lockstep since we have only a one-MCU buffer.
 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
 *
 * NB: output_buf contains a plane for each component in image,
 * which we index according to the component's SOF position.
 */

METHODDEF(int)
decompress_onepass (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
{
  my_coef_ptr3 coef = (my_coef_ptr3) cinfo->coef;
  JDIMENSION MCU_col_num;	/* index of current MCU within row */
  JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
  JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
  int blkn, ci, xindex, yindex, yoffset, useful_width;
  JSAMPARRAY output_ptr;
  JDIMENSION start_col, output_col;
  jpeg_component_info *compptr;
  inverse_DCT_method_ptr inverse_DCT;

  /* Loop to process as much as one whole iMCU row */
  for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
       yoffset++) {
    for (MCU_col_num = coef->MCU_ctr; MCU_col_num <= last_MCU_col;
	 MCU_col_num++) {
      /* Try to fetch an MCU.  Entropy decoder expects buffer to be zeroed. */
      jzero_far((void FAR *) coef->MCU_buffer[0],
		(size_t) (cinfo->blocks_in_MCU * SIZEOF(JBLOCK)));
      if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
	/* Suspension forced; update state counters and exit */
	coef->MCU_vert_offset = yoffset;
	coef->MCU_ctr = MCU_col_num;
	return JPEG_SUSPENDED;
      }
      /* Determine where data should go in output_buf and do the IDCT thing.
       * We skip dummy blocks at the right and bottom edges (but blkn gets
       * incremented past them!).  Note the inner loop relies on having
       * allocated the MCU_buffer[] blocks sequentially.
       */
      blkn = 0;			/* index of current DCT block within MCU */
      for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
	compptr = cinfo->cur_comp_info[ci];
	/* Don't bother to IDCT an uninteresting component. */
	if (! compptr->component_needed) {
	  blkn += compptr->MCU_blocks;
	  continue;
	}
	inverse_DCT = cinfo->idct->inverse_DCT[compptr->component_index];
	useful_width = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
						    : compptr->last_col_width;
	output_ptr = output_buf[compptr->component_index] +
	  yoffset * compptr->DCT_scaled_size;
	start_col = MCU_col_num * compptr->MCU_sample_width;
	for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
	  if (cinfo->input_iMCU_row < last_iMCU_row ||
	      yoffset+yindex < compptr->last_row_height) {
	    output_col = start_col;
	    for (xindex = 0; xindex < useful_width; xindex++) {
	      (*inverse_DCT) (cinfo, compptr,
			      (JCOEFPTR) coef->MCU_buffer[blkn+xindex],
			      output_ptr, output_col);
	      output_col += compptr->DCT_scaled_size;
	    }
	  }
	  blkn += compptr->MCU_width;
	  output_ptr += compptr->DCT_scaled_size;
	}
      }
    }
    /* Completed an MCU row, but perhaps not an iMCU row */
    coef->MCU_ctr = 0;
  }
  /* Completed the iMCU row, advance counters for next one */
  cinfo->output_iMCU_row++;
  if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
    start_iMCU_row3(cinfo);
    return JPEG_ROW_COMPLETED;
  }
  /* Completed the scan */
  (*cinfo->inputctl->finish_input_pass) (cinfo);
  return JPEG_SCAN_COMPLETED;
}

/*
 * Dummy consume-input routine for single-pass operation.
 */

METHODDEF(int)
dummy_consume_data (j_decompress_ptr)
{
  return JPEG_SUSPENDED;	/* Always indicate nothing was done */
}

#ifdef D_MULTISCAN_FILES_SUPPORTED

/*
 * Consume input data and store it in the full-image coefficient buffer.
 * We read as much as one fully interleaved MCU row ("iMCU" row) per call,
 * ie, v_samp_factor block rows for each component in the scan.
 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
 */

METHODDEF(int)
consume_data (j_decompress_ptr cinfo)
{
  my_coef_ptr3 coef = (my_coef_ptr3) cinfo->coef;
  JDIMENSION MCU_col_num;	/* index of current MCU within row */
  int blkn, ci, xindex, yindex, yoffset;
  JDIMENSION start_col;
  JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
  JBLOCKROW buffer_ptr;
  jpeg_component_info *compptr;

  /* Align the virtual buffers for the components used in this scan. */
  for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
    compptr = cinfo->cur_comp_info[ci];
    buffer[ci] = (*cinfo->mem->access_virt_barray)
      ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
       cinfo->input_iMCU_row * compptr->v_samp_factor,
       (JDIMENSION) compptr->v_samp_factor, TRUE);
    /* Note: entropy decoder expects buffer to be zeroed,
     * but this is handled automatically by the memory manager
     * because we requested a pre-zeroed array.
     */
  }

  /* Loop to process one whole iMCU row */
  for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
       yoffset++) {
    for (MCU_col_num = coef->MCU_ctr; MCU_col_num < cinfo->MCUs_per_row;
	 MCU_col_num++) {
      /* Construct list of pointers to DCT blocks belonging to this MCU */
      blkn = 0;			/* index of current DCT block within MCU */
      for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
	compptr = cinfo->cur_comp_info[ci];
	start_col = MCU_col_num * compptr->MCU_width;
	for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
	  buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
	  for (xindex = 0; xindex < compptr->MCU_width; xindex++) {
	    coef->MCU_buffer[blkn++] = buffer_ptr++;
	  }
	}
      }
      /* Try to fetch the MCU. */
      if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
	/* Suspension forced; update state counters and exit */
	coef->MCU_vert_offset = yoffset;
	coef->MCU_ctr = MCU_col_num;
	return JPEG_SUSPENDED;
      }
    }
    /* Completed an MCU row, but perhaps not an iMCU row */
    coef->MCU_ctr = 0;
  }
  /* Completed the iMCU row, advance counters for next one */
  if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
    start_iMCU_row3(cinfo);
    return JPEG_ROW_COMPLETED;
  }
  /* Completed the scan */
  (*cinfo->inputctl->finish_input_pass) (cinfo);
  return JPEG_SCAN_COMPLETED;
}

/*
 * Decompress and return some data in the multi-pass case.
 * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
 *
 * NB: output_buf contains a plane for each component in image.
 */

METHODDEF(int)
decompress_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
{
  my_coef_ptr3 coef = (my_coef_ptr3) cinfo->coef;
  JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
  JDIMENSION block_num;
  int ci, block_row, block_rows;
  JBLOCKARRAY buffer;
  JBLOCKROW buffer_ptr;
  JSAMPARRAY output_ptr;
  JDIMENSION output_col;
  jpeg_component_info *compptr;
  inverse_DCT_method_ptr inverse_DCT;

  /* Force some input to be done if we are getting ahead of the input. */
  while (cinfo->input_scan_number < cinfo->output_scan_number ||
	 (cinfo->input_scan_number == cinfo->output_scan_number &&
	  cinfo->input_iMCU_row <= cinfo->output_iMCU_row)) {
    if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
      return JPEG_SUSPENDED;
  }

  /* OK, output from the virtual arrays. */
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    /* Don't bother to IDCT an uninteresting component. */
    if (! compptr->component_needed)
      continue;
    /* Align the virtual buffer for this component. */
    buffer = (*cinfo->mem->access_virt_barray)
      ((j_common_ptr) cinfo, coef->whole_image[ci],
       cinfo->output_iMCU_row * compptr->v_samp_factor,
       (JDIMENSION) compptr->v_samp_factor, FALSE);
    /* Count non-dummy DCT block rows in this iMCU row. */
    if (cinfo->output_iMCU_row < last_iMCU_row)
      block_rows = compptr->v_samp_factor;
    else {
      /* NB: can't use last_row_height here; it is input-side-dependent! */
      block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
      if (block_rows == 0) block_rows = compptr->v_samp_factor;
    }
    inverse_DCT = cinfo->idct->inverse_DCT[ci];
    output_ptr = output_buf[ci];
    /* Loop over all DCT blocks to be processed. */
    for (block_row = 0; block_row < block_rows; block_row++) {
      buffer_ptr = buffer[block_row];
      output_col = 0;
      for (block_num = 0; block_num < compptr->width_in_blocks; block_num++) {
	(*inverse_DCT) (cinfo, compptr, (JCOEFPTR) buffer_ptr,
			output_ptr, output_col);
	buffer_ptr++;
	output_col += compptr->DCT_scaled_size;
      }
      output_ptr += compptr->DCT_scaled_size;
    }
  }

  if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
    return JPEG_ROW_COMPLETED;
  return JPEG_SCAN_COMPLETED;
}

#endif /* D_MULTISCAN_FILES_SUPPORTED */

#ifdef BLOCK_SMOOTHING_SUPPORTED

/*
 * This code applies interblock smoothing as described by section K.8
 * of the JPEG standard: the first 5 AC coefficients are estimated from
 * the DC values of a DCT block and its 8 neighboring blocks.
 * We apply smoothing only for progressive JPEG decoding, and only if
 * the coefficients it can estimate are not yet known to full precision.
 */

/* Natural-order array positions of the first 5 zigzag-order coefficients */
#define Q01_POS  1
#define Q10_POS  8
#define Q20_POS  16
#define Q11_POS  9
#define Q02_POS  2

/*
 * Determine whether block smoothing is applicable and safe.
 * We also latch the current states of the coef_bits[] entries for the
 * AC coefficients; otherwise, if the input side of the decompressor
 * advances into a new scan, we might think the coefficients are known
 * more accurately than they really are.
 */

LOCAL(boolean)
smoothing_ok (j_decompress_ptr cinfo)
{
  my_coef_ptr3 coef = (my_coef_ptr3) cinfo->coef;
  boolean smoothing_useful = FALSE;
  int ci, coefi;
  jpeg_component_info *compptr;
  JQUANT_TBL * qtable;
  int * coef_bits;
  int * coef_bits_latch;

  if (! cinfo->progressive_mode || cinfo->coef_bits == NULL)
    return FALSE;

  /* Allocate latch area if not already done */
  if (coef->coef_bits_latch == NULL)
    coef->coef_bits_latch = (int *)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
				  cinfo->num_components *
				  (SAVED_COEFS * SIZEOF(int)));
  coef_bits_latch = coef->coef_bits_latch;

  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    /* All components' quantization values must already be latched. */
    if ((qtable = compptr->quant_table) == NULL)
      return FALSE;
    /* Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide. */
    if (qtable->quantval[0] == 0 ||
	qtable->quantval[Q01_POS] == 0 ||
	qtable->quantval[Q10_POS] == 0 ||
	qtable->quantval[Q20_POS] == 0 ||
	qtable->quantval[Q11_POS] == 0 ||
	qtable->quantval[Q02_POS] == 0)
      return FALSE;
    /* DC values must be at least partly known for all components. */
    coef_bits = cinfo->coef_bits[ci];
    if (coef_bits[0] < 0)
      return FALSE;
    /* Block smoothing is helpful if some AC coefficients remain inaccurate. */
    for (coefi = 1; coefi <= 5; coefi++) {
      coef_bits_latch[coefi] = coef_bits[coefi];
      if (coef_bits[coefi] != 0)
	smoothing_useful = TRUE;
    }
    coef_bits_latch += SAVED_COEFS;
  }

  return smoothing_useful;
}

/*
 * Variant of decompress_data for use when doing block smoothing.
 */

METHODDEF(int)
decompress_smooth_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
{
  my_coef_ptr3 coef = (my_coef_ptr3) cinfo->coef;
  JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
  JDIMENSION block_num, last_block_column;
  int ci, block_row, block_rows, access_rows;
  JBLOCKARRAY buffer;
  JBLOCKROW buffer_ptr, prev_block_row, next_block_row;
  JSAMPARRAY output_ptr;
  JDIMENSION output_col;
  jpeg_component_info *compptr;
  inverse_DCT_method_ptr inverse_DCT;
  boolean first_row, last_row;
  JBLOCK workspace;
  int *coef_bits;
  JQUANT_TBL *quanttbl;
  INT32 Q00,Q01,Q02,Q10,Q11,Q20, num;
  int DC1,DC2,DC3,DC4,DC5,DC6,DC7,DC8,DC9;
  int Al, pred;

  /* Force some input to be done if we are getting ahead of the input. */
  while (cinfo->input_scan_number <= cinfo->output_scan_number &&
	 ! cinfo->inputctl->eoi_reached) {
    if (cinfo->input_scan_number == cinfo->output_scan_number) {
      /* If input is working on current scan, we ordinarily want it to
       * have completed the current row.  But if input scan is DC,
       * we want it to keep one row ahead so that next block row's DC
       * values are up to date.
       */
      JDIMENSION delta = (cinfo->Ss == 0) ? 1 : 0;
      if (cinfo->input_iMCU_row > cinfo->output_iMCU_row+delta)
	break;
    }
    if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
      return JPEG_SUSPENDED;
  }

  /* OK, output from the virtual arrays. */
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    /* Don't bother to IDCT an uninteresting component. */
    if (! compptr->component_needed)
      continue;
    /* Count non-dummy DCT block rows in this iMCU row. */
    if (cinfo->output_iMCU_row < last_iMCU_row) {
      block_rows = compptr->v_samp_factor;
      access_rows = block_rows * 2; /* this and next iMCU row */
      last_row = FALSE;
    } else {
      /* NB: can't use last_row_height here; it is input-side-dependent! */
      block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
      if (block_rows == 0) block_rows = compptr->v_samp_factor;
      access_rows = block_rows; /* this iMCU row only */
      last_row = TRUE;
    }
    /* Align the virtual buffer for this component. */
    if (cinfo->output_iMCU_row > 0) {
      access_rows += compptr->v_samp_factor; /* prior iMCU row too */
      buffer = (*cinfo->mem->access_virt_barray)
	((j_common_ptr) cinfo, coef->whole_image[ci],
	 (cinfo->output_iMCU_row - 1) * compptr->v_samp_factor,
	 (JDIMENSION) access_rows, FALSE);
      buffer += compptr->v_samp_factor;	/* point to current iMCU row */
      first_row = FALSE;
    } else {
      buffer = (*cinfo->mem->access_virt_barray)
	((j_common_ptr) cinfo, coef->whole_image[ci],
	 (JDIMENSION) 0, (JDIMENSION) access_rows, FALSE);
      first_row = TRUE;
    }
    /* Fetch component-dependent info */
    coef_bits = coef->coef_bits_latch + (ci * SAVED_COEFS);
    quanttbl = compptr->quant_table;
    Q00 = quanttbl->quantval[0];
    Q01 = quanttbl->quantval[Q01_POS];
    Q10 = quanttbl->quantval[Q10_POS];
    Q20 = quanttbl->quantval[Q20_POS];
    Q11 = quanttbl->quantval[Q11_POS];
    Q02 = quanttbl->quantval[Q02_POS];
    inverse_DCT = cinfo->idct->inverse_DCT[ci];
    output_ptr = output_buf[ci];
    /* Loop over all DCT blocks to be processed. */
    for (block_row = 0; block_row < block_rows; block_row++) {
      buffer_ptr = buffer[block_row];
      if (first_row && block_row == 0)
	prev_block_row = buffer_ptr;
      else
	prev_block_row = buffer[block_row-1];
      if (last_row && block_row == block_rows-1)
	next_block_row = buffer_ptr;
      else
	next_block_row = buffer[block_row+1];
      /* We fetch the surrounding DC values using a sliding-register approach.
       * Initialize all nine here so as to do the right thing on narrow pics.
       */
      DC1 = DC2 = DC3 = (int) prev_block_row[0][0];
      DC4 = DC5 = DC6 = (int) buffer_ptr[0][0];
      DC7 = DC8 = DC9 = (int) next_block_row[0][0];
      output_col = 0;
      last_block_column = compptr->width_in_blocks - 1;
      for (block_num = 0; block_num <= last_block_column; block_num++) {
	/* Fetch current DCT block into workspace so we can modify it. */
	jcopy_block_row(buffer_ptr, (JBLOCKROW) workspace, (JDIMENSION) 1);
	/* Update DC values */
	if (block_num < last_block_column) {
	  DC3 = (int) prev_block_row[1][0];
	  DC6 = (int) buffer_ptr[1][0];
	  DC9 = (int) next_block_row[1][0];
	}
	/* Compute coefficient estimates per K.8.
	 * An estimate is applied only if coefficient is still zero,
	 * and is not known to be fully accurate.
	 */
	/* AC01 */
	if ((Al=coef_bits[1]) != 0 && workspace[1] == 0) {
	  num = 36 * Q00 * (DC4 - DC6);
	  if (num >= 0) {
	    pred = (int) (((Q01<<7) + num) / (Q01<<8));
	    if (Al > 0 && pred >= (1<<Al))
	      pred = (1<<Al)-1;
	  } else {
	    pred = (int) (((Q01<<7) - num) / (Q01<<8));
	    if (Al > 0 && pred >= (1<<Al))
	      pred = (1<<Al)-1;
	    pred = -pred;
	  }
	  workspace[1] = (JCOEF) pred;
	}
	/* AC10 */
	if ((Al=coef_bits[2]) != 0 && workspace[8] == 0) {
	  num = 36 * Q00 * (DC2 - DC8);
	  if (num >= 0) {
	    pred = (int) (((Q10<<7) + num) / (Q10<<8));
	    if (Al > 0 && pred >= (1<<Al))
	      pred = (1<<Al)-1;
	  } else {
	    pred = (int) (((Q10<<7) - num) / (Q10<<8));
	    if (Al > 0 && pred >= (1<<Al))
	      pred = (1<<Al)-1;
	    pred = -pred;
	  }
	  workspace[8] = (JCOEF) pred;
	}
	/* AC20 */
	if ((Al=coef_bits[3]) != 0 && workspace[16] == 0) {
	  num = 9 * Q00 * (DC2 + DC8 - 2*DC5);
	  if (num >= 0) {
	    pred = (int) (((Q20<<7) + num) / (Q20<<8));
	    if (Al > 0 && pred >= (1<<Al))
	      pred = (1<<Al)-1;
	  } else {
	    pred = (int) (((Q20<<7) - num) / (Q20<<8));
	    if (Al > 0 && pred >= (1<<Al))
	      pred = (1<<Al)-1;
	    pred = -pred;
	  }
	  workspace[16] = (JCOEF) pred;
	}
	/* AC11 */
	if ((Al=coef_bits[4]) != 0 && workspace[9] == 0) {
	  num = 5 * Q00 * (DC1 - DC3 - DC7 + DC9);
	  if (num >= 0) {
	    pred = (int) (((Q11<<7) + num) / (Q11<<8));
	    if (Al > 0 && pred >= (1<<Al))
	      pred = (1<<Al)-1;
	  } else {
	    pred = (int) (((Q11<<7) - num) / (Q11<<8));
	    if (Al > 0 && pred >= (1<<Al))
	      pred = (1<<Al)-1;
	    pred = -pred;
	  }
	  workspace[9] = (JCOEF) pred;
	}
	/* AC02 */
	if ((Al=coef_bits[5]) != 0 && workspace[2] == 0) {
	  num = 9 * Q00 * (DC4 + DC6 - 2*DC5);
	  if (num >= 0) {
	    pred = (int) (((Q02<<7) + num) / (Q02<<8));
	    if (Al > 0 && pred >= (1<<Al))
	      pred = (1<<Al)-1;
	  } else {
	    pred = (int) (((Q02<<7) - num) / (Q02<<8));
	    if (Al > 0 && pred >= (1<<Al))
	      pred = (1<<Al)-1;
	    pred = -pred;
	  }
	  workspace[2] = (JCOEF) pred;
	}
	/* OK, do the IDCT */
	(*inverse_DCT) (cinfo, compptr, (JCOEFPTR) workspace,
			output_ptr, output_col);
	/* Advance for next column */
	DC1 = DC2; DC2 = DC3;
	DC4 = DC5; DC5 = DC6;
	DC7 = DC8; DC8 = DC9;
	buffer_ptr++, prev_block_row++, next_block_row++;
	output_col += compptr->DCT_scaled_size;
      }
      output_ptr += compptr->DCT_scaled_size;
    }
  }

  if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
    return JPEG_ROW_COMPLETED;
  return JPEG_SCAN_COMPLETED;
}

#endif /* BLOCK_SMOOTHING_SUPPORTED */

/*
 * Initialize coefficient buffer controller.
 */

GLOBAL(void)
jinit_d_coef_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
{
  my_coef_ptr3 coef;

  coef = (my_coef_ptr3)
    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
				SIZEOF(my_coef_controller3));
  cinfo->coef = (struct jpeg_d_coef_controller *) coef;
  coef->pub.start_input_pass = start_input_pass;
  coef->pub.start_output_pass = start_output_pass;
#ifdef BLOCK_SMOOTHING_SUPPORTED
  coef->coef_bits_latch = NULL;
#endif

  /* Create the coefficient buffer. */
  if (need_full_buffer) {
#ifdef D_MULTISCAN_FILES_SUPPORTED
    /* Allocate a full-image virtual array for each component, */
    /* padded to a multiple of samp_factor DCT blocks in each direction. */
    /* Note we ask for a pre-zeroed array. */
    int ci, access_rows;
    jpeg_component_info *compptr;

    for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
	 ci++, compptr++) {
      access_rows = compptr->v_samp_factor;
#ifdef BLOCK_SMOOTHING_SUPPORTED
      /* If block smoothing could be used, need a bigger window */
      if (cinfo->progressive_mode)
	access_rows *= 3;
#endif
      coef->whole_image[ci] = (*cinfo->mem->request_virt_barray)
	((j_common_ptr) cinfo, JPOOL_IMAGE, TRUE,
	 (JDIMENSION) jround_up((long) compptr->width_in_blocks,
				(long) compptr->h_samp_factor),
	 (JDIMENSION) jround_up((long) compptr->height_in_blocks,
				(long) compptr->v_samp_factor),
	 (JDIMENSION) access_rows);
    }
    coef->pub.consume_data = consume_data;
    coef->pub.decompress_data = decompress_data;
    coef->pub.coef_arrays = coef->whole_image; /* link to virtual arrays */
#else
    ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
  } else {
    /* We only need a single-MCU buffer. */
    JBLOCKROW buffer;
    int i;

    buffer = (JBLOCKROW)
      (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
				  D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
    for (i = 0; i < D_MAX_BLOCKS_IN_MCU; i++) {
      coef->MCU_buffer[i] = buffer + i;
    }
    coef->pub.consume_data = dummy_consume_data;
    coef->pub.decompress_data = decompress_onepass;
    coef->pub.coef_arrays = NULL; /* flag for no virtual arrays */
  }
}


text:
/*
 * transupp.h
 *
 * Copyright (C) 1997, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains declarations for image transformation routines and
 * other utility code used by the jpegtran sample application.  These are
 * NOT part of the core JPEG library.  But we keep these routines separate
 * from jpegtran.c to ease the task of maintaining jpegtran-like programs
 * that have other user interfaces.
 *
 * NOTE: all the routines declared here have very specific requirements
 * about when they are to be executed during the reading and writing of the
 * source and destination files.  See the comments in transupp.c, or see
 * jpegtran.c for an example of correct usage.
 */

/* If you happen not to want the image transform support, disable it here */
#ifndef TRANSFORMS_SUPPORTED
#define TRANSFORMS_SUPPORTED 1		/* 0 disables transform code */
#endif

/* Short forms of external names for systems with brain-damaged linkers. */

#ifdef NEED_SHORT_EXTERNAL_NAMES
#define jtransform_request_workspace		jTrRequest
#define jtransform_adjust_parameters		jTrAdjust
#define jtransform_execute_transformation	jTrExec
#define jcopy_markers_setup			jCMrkSetup
#define jcopy_markers_execute			jCMrkExec
#endif /* NEED_SHORT_EXTERNAL_NAMES */

/*
 * Codes for supported types of image transformations.
 */

typedef enum {
	JXFORM_NONE,		/* no transformation */
	JXFORM_FLIP_H,		/* horizontal flip */
	JXFORM_FLIP_V,		/* vertical flip */
	JXFORM_TRANSPOSE,	/* transpose across UL-to-LR axis */
	JXFORM_TRANSVERSE,	/* transpose across UR-to-LL axis */
	JXFORM_ROT_90,		/* 90-degree clockwise rotation */
	JXFORM_ROT_180,		/* 180-degree rotation */
	JXFORM_ROT_270		/* 270-degree clockwise (or 90 ccw) */
} JXFORM_CODE;

/*
 * Although rotating and flipping data expressed as DCT coefficients is not
 * hard, there is an asymmetry in the JPEG format specification for images
 * whose dimensions aren't multiples of the iMCU size.  The right and bottom
 * image edges are padded out to the next iMCU boundary with junk data; but
 * no padding is possible at the top and left edges.  If we were to flip
 * the whole image including the pad data, then pad garbage would become
 * visible at the top and/or left, and real pixels would disappear into the
 * pad margins --- perhaps permanently, since encoders & decoders may not
 * bother to preserve DCT blocks that appear to be completely outside the
 * nominal image area.  So, we have to exclude any partial iMCUs from the
 * basic transformation.
 *
 * Transpose is the only transformation that can handle partial iMCUs at the
 * right and bottom edges completely cleanly.  flip_h can flip partial iMCUs
 * at the bottom, but leaves any partial iMCUs at the right edge untouched.
 * Similarly flip_v leaves any partial iMCUs at the bottom edge untouched.
 * The other transforms are defined as combinations of these basic transforms
 * and process edge blocks in a way that preserves the equivalence.
 *
 * The "trim" option causes untransformable partial iMCUs to be dropped;
 * this is not strictly lossless, but it usually gives the best-looking
 * result for odd-size images.  Note that when this option is active,
 * the expected mathematical equivalences between the transforms may not hold.
 * (For example, -rot 270 -trim trims only the bottom edge, but -rot 90 -trim
 * followed by -rot 180 -trim trims both edges.)
 *
 * We also offer a "force to grayscale" option, which simply discards the
 * chrominance channels of a YCbCr image.  This is lossless in the sense that
 * the luminance channel is preserved exactly.  It's not the same kind of
 * thing as the rotate/flip transformations, but it's convenient to handle it
 * as part of this package, mainly because the transformation routines have to
 * be aware of the option to know how many components to work on.
 */

typedef struct {
  /* Options: set by caller */
  JXFORM_CODE transform;	/* image transform operator */
  boolean trim;			/* if TRUE, trim partial MCUs as needed */
  boolean force_grayscale;	/* if TRUE, convert color image to grayscale */

  /* Internal workspace: caller should not touch these */
  int num_components;		/* # of components in workspace */
  jvirt_barray_ptr * workspace_coef_arrays; /* workspace for transformations */
} jpeg_transform_info;

#if TRANSFORMS_SUPPORTED

/* Request any required workspace */
EXTERN(void) jtransform_request_workspace
	JPP((j_decompress_ptr srcinfo, jpeg_transform_info *info));
/* Adjust output image parameters */
EXTERN(jvirt_barray_ptr *) jtransform_adjust_parameters
	JPP((j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
	     jvirt_barray_ptr *src_coef_arrays,
	     jpeg_transform_info *info));
/* Execute the actual transformation, if any */
EXTERN(void) jtransform_execute_transformation
	JPP((j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
	     jvirt_barray_ptr *src_coef_arrays,
	     jpeg_transform_info *info));

#endif /* TRANSFORMS_SUPPORTED */

/*
 * Support for copying optional markers from source to destination file.
 */

typedef enum {
	JCOPYOPT_NONE,		/* copy no optional markers */
	JCOPYOPT_COMMENTS,	/* copy only comment (COM) markers */
	JCOPYOPT_ALL		/* copy all optional markers */
} JCOPY_OPTION;

#define JCOPYOPT_DEFAULT  JCOPYOPT_COMMENTS	/* recommended default */

/* Setup decompression object to save desired markers in memory */
EXTERN(void) jcopy_markers_setup
	JPP((j_decompress_ptr srcinfo, JCOPY_OPTION option));
/* Copy markers saved in the given source object to the destination object */
EXTERN(void) jcopy_markers_execute
	JPP((j_decompress_ptr srcinfo, j_compress_ptr dstinfo,
	     JCOPY_OPTION option));


text:
/*
 * jcmarker.c
 *
 * Copyright (C) 1991-1998, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains routines to write JPEG datastream markers.
 */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"

/* Private state */

typedef struct {
  struct jpeg_marker_writer pub; /* public fields */

  unsigned int last_restart_interval; /* last DRI value emitted; 0 after SOI */
} my_marker_writer;

typedef my_marker_writer * my_marker_ptr;

/*
 * Basic output routines.
 *
 * Note that we do not support suspension while writing a marker.
 * Therefore, an application using suspension must ensure that there is
 * enough buffer space for the initial markers (typ. 600-700 bytes) before
 * calling jpeg_start_compress, and enough space to write the trailing EOI
 * (a few bytes) before calling jpeg_finish_compress.  Multipass compression
 * modes are not supported at all with suspension, so those two are the only
 * points where markers will be written.
 */

LOCAL(void)
emit_byte (j_compress_ptr cinfo, int val)
/* Emit a byte */
{
  struct jpeg_destination_mgr * dest = cinfo->dest;

  *(dest->next_output_byte)++ = (JOCTET) val;
  if (--dest->free_in_buffer == 0) {
    if (! (*dest->empty_output_buffer) (cinfo))
      ERREXIT(cinfo, JERR_CANT_SUSPEND);
  }
}

LOCAL(void)
emit_marker (j_compress_ptr cinfo, JPEG_MARKER mark)
/* Emit a marker code */
{
  emit_byte(cinfo, 0xFF);
  emit_byte(cinfo, (int) mark);
}

LOCAL(void)
emit_2bytes (j_compress_ptr cinfo, int value)
/* Emit a 2-byte integer; these are always MSB first in JPEG files */
{
  emit_byte(cinfo, (value >> 8) & 0xFF);
  emit_byte(cinfo, value & 0xFF);
}

/*
 * Routines to write specific marker types.
 */

LOCAL(int)
emit_dqt (j_compress_ptr cinfo, int index)
/* Emit a DQT marker */
/* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */
{
  JQUANT_TBL * qtbl = cinfo->quant_tbl_ptrs[index];
  int prec;
  int i;

  if (qtbl == NULL)
    ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index);

  prec = 0;
  for (i = 0; i < DCTSIZE2; i++) {
    if (qtbl->quantval[i] > 255)
      prec = 1;
  }

  if (! qtbl->sent_table) {
    emit_marker(cinfo, M_DQT);

    emit_2bytes(cinfo, prec ? DCTSIZE2*2 + 1 + 2 : DCTSIZE2 + 1 + 2);

    emit_byte(cinfo, index + (prec<<4));

    for (i = 0; i < DCTSIZE2; i++) {
      /* The table entries must be emitted in zigzag order. */
      unsigned int qval = qtbl->quantval[jpeg_natural_order[i]];
      if (prec)
	emit_byte(cinfo, (int) (qval >> 8));
      emit_byte(cinfo, (int) (qval & 0xFF));
    }

    qtbl->sent_table = TRUE;
  }

  return prec;
}

LOCAL(void)
emit_dht (j_compress_ptr cinfo, int index, boolean is_ac)
/* Emit a DHT marker */
{
  JHUFF_TBL * htbl;
  int length, i;

  if (is_ac) {
    htbl = cinfo->ac_huff_tbl_ptrs[index];
    index += 0x10;		/* output index has AC bit set */
  } else {
    htbl = cinfo->dc_huff_tbl_ptrs[index];
  }

  if (htbl == NULL)
    ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index);

  if (! htbl->sent_table) {
    emit_marker(cinfo, M_DHT);

    length = 0;
    for (i = 1; i <= 16; i++)
      length += htbl->bits[i];

    emit_2bytes(cinfo, length + 2 + 1 + 16);
    emit_byte(cinfo, index);

    for (i = 1; i <= 16; i++)
      emit_byte(cinfo, htbl->bits[i]);

    for (i = 0; i < length; i++)
      emit_byte(cinfo, htbl->huffval[i]);

    htbl->sent_table = TRUE;
  }
}

LOCAL(void)
emit_dac (j_compress_ptr)
/* Emit a DAC marker */
/* Since the useful info is so small, we want to emit all the tables in */
/* one DAC marker.  Therefore this routine does its own scan of the table. */
{
#ifdef C_ARITH_CODING_SUPPORTED
  char dc_in_use[NUM_ARITH_TBLS];
  char ac_in_use[NUM_ARITH_TBLS];
  int length, i;
  jpeg_component_info *compptr;

  for (i = 0; i < NUM_ARITH_TBLS; i++)
    dc_in_use[i] = ac_in_use[i] = 0;

  for (i = 0; i < cinfo->comps_in_scan; i++) {
    compptr = cinfo->cur_comp_info[i];
    dc_in_use[compptr->dc_tbl_no] = 1;
    ac_in_use[compptr->ac_tbl_no] = 1;
  }

  length = 0;
  for (i = 0; i < NUM_ARITH_TBLS; i++)
    length += dc_in_use[i] + ac_in_use[i];

  emit_marker(cinfo, M_DAC);

  emit_2bytes(cinfo, length*2 + 2);

  for (i = 0; i < NUM_ARITH_TBLS; i++) {
    if (dc_in_use[i]) {
      emit_byte(cinfo, i);
      emit_byte(cinfo, cinfo->arith_dc_L[i] + (cinfo->arith_dc_U[i]<<4));
    }
    if (ac_in_use[i]) {
      emit_byte(cinfo, i + 0x10);
      emit_byte(cinfo, cinfo->arith_ac_K[i]);
    }
  }
#endif /* C_ARITH_CODING_SUPPORTED */
}

LOCAL(void)
emit_dri (j_compress_ptr cinfo)
/* Emit a DRI marker */
{
  emit_marker(cinfo, M_DRI);

  emit_2bytes(cinfo, 4);	/* fixed length */

  emit_2bytes(cinfo, (int) cinfo->restart_interval);
}

LOCAL(void)
emit_sof (j_compress_ptr cinfo, JPEG_MARKER code)
/* Emit a SOF marker */
{
  int ci;
  jpeg_component_info *compptr;

  emit_marker(cinfo, code);

  emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1); /* length */

  /* Make sure image isn't bigger than SOF field can handle */
  if ((long) cinfo->image_height > 65535L ||
      (long) cinfo->image_width > 65535L)
    ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) 65535);

  emit_byte(cinfo, cinfo->data_precision);
  emit_2bytes(cinfo, (int) cinfo->image_height);
  emit_2bytes(cinfo, (int) cinfo->image_width);

  emit_byte(cinfo, cinfo->num_components);

  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    emit_byte(cinfo, compptr->component_id);
    emit_byte(cinfo, (compptr->h_samp_factor << 4) + compptr->v_samp_factor);
    emit_byte(cinfo, compptr->quant_tbl_no);
  }
}

LOCAL(void)
emit_sos (j_compress_ptr cinfo)
/* Emit a SOS marker */
{
  int i, td, ta;
  jpeg_component_info *compptr;

  emit_marker(cinfo, M_SOS);

  emit_2bytes(cinfo, 2 * cinfo->comps_in_scan + 2 + 1 + 3); /* length */

  emit_byte(cinfo, cinfo->comps_in_scan);

  for (i = 0; i < cinfo->comps_in_scan; i++) {
    compptr = cinfo->cur_comp_info[i];
    emit_byte(cinfo, compptr->component_id);
    td = compptr->dc_tbl_no;
    ta = compptr->ac_tbl_no;
    if (cinfo->progressive_mode) {
      /* Progressive mode: only DC or only AC tables are used in one scan;
       * furthermore, Huffman coding of DC refinement uses no table at all.
       * We emit 0 for unused field(s); this is recommended by the P&M text
       * but does not seem to be specified in the standard.
       */
      if (cinfo->Ss == 0) {
	ta = 0;			/* DC scan */
	if (cinfo->Ah != 0 && !cinfo->arith_code)
	  td = 0;		/* no DC table either */
      } else {
	td = 0;			/* AC scan */
      }
    }
    emit_byte(cinfo, (td << 4) + ta);
  }

  emit_byte(cinfo, cinfo->Ss);
  emit_byte(cinfo, cinfo->Se);
  emit_byte(cinfo, (cinfo->Ah << 4) + cinfo->Al);
}

LOCAL(void)
emit_jfif_app0 (j_compress_ptr cinfo)
/* Emit a JFIF-compliant APP0 marker */
{
  /*
   * Length of APP0 block	(2 bytes)
   * Block ID			(4 bytes - ASCII "JFIF")
   * Zero byte			(1 byte to terminate the ID string)
   * Version Major, Minor	(2 bytes - major first)
   * Units			(1 byte - 0x00 = none, 0x01 = inch, 0x02 = cm)
   * Xdpu			(2 bytes - dots per unit horizontal)
   * Ydpu			(2 bytes - dots per unit vertical)
   * Thumbnail X size		(1 byte)
   * Thumbnail Y size		(1 byte)
   */

  emit_marker(cinfo, M_APP0);

  emit_2bytes(cinfo, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); /* length */

  emit_byte(cinfo, 0x4A);	/* Identifier: ASCII "JFIF" */
  emit_byte(cinfo, 0x46);
  emit_byte(cinfo, 0x49);
  emit_byte(cinfo, 0x46);
  emit_byte(cinfo, 0);
  emit_byte(cinfo, cinfo->JFIF_major_version); /* Version fields */
  emit_byte(cinfo, cinfo->JFIF_minor_version);
  emit_byte(cinfo, cinfo->density_unit); /* Pixel size information */
  emit_2bytes(cinfo, (int) cinfo->X_density);
  emit_2bytes(cinfo, (int) cinfo->Y_density);
  emit_byte(cinfo, 0);		/* No thumbnail image */
  emit_byte(cinfo, 0);
}

LOCAL(void)
emit_adobe_app14 (j_compress_ptr cinfo)
/* Emit an Adobe APP14 marker */
{
  /*
   * Length of APP14 block	(2 bytes)
   * Block ID			(5 bytes - ASCII "Adobe")
   * Version Number		(2 bytes - currently 100)
   * Flags0			(2 bytes - currently 0)
   * Flags1			(2 bytes - currently 0)
   * Color transform		(1 byte)
   *
   * Although Adobe TN 5116 mentions Version = 101, all the Adobe files
   * now in circulation seem to use Version = 100, so that's what we write.
   *
   * We write the color transform byte as 1 if the JPEG color space is
   * YCbCr, 2 if it's YCCK, 0 otherwise.  Adobe's definition has to do with
   * whether the encoder performed a transformation, which is pretty useless.
   */

  emit_marker(cinfo, M_APP14);

  emit_2bytes(cinfo, 2 + 5 + 2 + 2 + 2 + 1); /* length */

  emit_byte(cinfo, 0x41);	/* Identifier: ASCII "Adobe" */
  emit_byte(cinfo, 0x64);
  emit_byte(cinfo, 0x6F);
  emit_byte(cinfo, 0x62);
  emit_byte(cinfo, 0x65);
  emit_2bytes(cinfo, 100);	/* Version */
  emit_2bytes(cinfo, 0);	/* Flags0 */
  emit_2bytes(cinfo, 0);	/* Flags1 */
  switch (cinfo->jpeg_color_space) {
  case JCS_YCbCr:
    emit_byte(cinfo, 1);	/* Color transform = 1 */
    break;
  case JCS_YCCK:
    emit_byte(cinfo, 2);	/* Color transform = 2 */
    break;
  default:
    emit_byte(cinfo, 0);	/* Color transform = 0 */
    break;
  }
}

/*
 * These routines allow writing an arbitrary marker with parameters.
 * The only intended use is to emit COM or APPn markers after calling
 * write_file_header and before calling write_frame_header.
 * Other uses are not guaranteed to produce desirable results.
 * Counting the parameter bytes properly is the caller's responsibility.
 */

METHODDEF(void)
write_marker_header (j_compress_ptr cinfo, int marker, unsigned int datalen)
/* Emit an arbitrary marker header */
{
  if (datalen > (unsigned int) 65533)		/* safety check */
    ERREXIT(cinfo, JERR_BAD_LENGTH);

  emit_marker(cinfo, (JPEG_MARKER) marker);

  emit_2bytes(cinfo, (int) (datalen + 2));	/* total length */
}

METHODDEF(void)
write_marker_byte (j_compress_ptr cinfo, int val)
/* Emit one byte of marker parameters following write_marker_header */
{
  emit_byte(cinfo, val);
}

/*
 * Write datastream header.
 * This consists of an SOI and optional APPn markers.
 * We recommend use of the JFIF marker, but not the Adobe marker,
 * when using YCbCr or grayscale data.  The JFIF marker should NOT
 * be used for any other JPEG colorspace.  The Adobe marker is helpful
 * to distinguish RGB, CMYK, and YCCK colorspaces.
 * Note that an application can write additional header markers after
 * jpeg_start_compress returns.
 */

METHODDEF(void)
write_file_header (j_compress_ptr cinfo)
{
  my_marker_ptr marker = (my_marker_ptr) cinfo->marker;

  emit_marker(cinfo, M_SOI);	/* first the SOI */

  /* SOI is defined to reset restart interval to 0 */
  marker->last_restart_interval = 0;

  if (cinfo->write_JFIF_header)	/* next an optional JFIF APP0 */
    emit_jfif_app0(cinfo);
  if (cinfo->write_Adobe_marker) /* next an optional Adobe APP14 */
    emit_adobe_app14(cinfo);
}

/*
 * Write frame header.
 * This consists of DQT and SOFn markers.
 * Note that we do not emit the SOF until we have emitted the DQT(s).
 * This avoids compatibility problems with incorrect implementations that
 * try to error-check the quant table numbers as soon as they see the SOF.
 */

METHODDEF(void)
write_frame_header (j_compress_ptr cinfo)
{
  int ci, prec;
  boolean is_baseline;
  jpeg_component_info *compptr;

  /* Emit DQT for each quantization table.
   * Note that emit_dqt() suppresses any duplicate tables.
   */
  prec = 0;
  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    prec += emit_dqt(cinfo, compptr->quant_tbl_no);
  }
  /* now prec is nonzero iff there are any 16-bit quant tables. */

  /* Check for a non-baseline specification.
   * Note we assume that Huffman table numbers won't be changed later.
   */
  if (cinfo->arith_code || cinfo->progressive_mode ||
      cinfo->data_precision != 8) {
    is_baseline = FALSE;
  } else {
    is_baseline = TRUE;
    for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
	 ci++, compptr++) {
      if (compptr->dc_tbl_no > 1 || compptr->ac_tbl_no > 1)
	is_baseline = FALSE;
    }
    if (prec && is_baseline) {
      is_baseline = FALSE;
      /* If it's baseline except for quantizer size, warn the user */
      TRACEMS(cinfo, 0, JTRC_16BIT_TABLES);
    }
  }

  /* Emit the proper SOF marker */
  if (cinfo->arith_code) {
    emit_sof(cinfo, M_SOF9);	/* SOF code for arithmetic coding */
  } else {
    if (cinfo->progressive_mode)
      emit_sof(cinfo, M_SOF2);	/* SOF code for progressive Huffman */
    else if (is_baseline)
      emit_sof(cinfo, M_SOF0);	/* SOF code for baseline implementation */
    else
      emit_sof(cinfo, M_SOF1);	/* SOF code for non-baseline Huffman file */
  }
}

/*
 * Write scan header.
 * This consists of DHT or DAC markers, optional DRI, and SOS.
 * Compressed data will be written following the SOS.
 */

METHODDEF(void)
write_scan_header (j_compress_ptr cinfo)
{
  my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
  int i;
  jpeg_component_info *compptr;

  if (cinfo->arith_code) {
    /* Emit arith conditioning info.  We may have some duplication
     * if the file has multiple scans, but it's so small it's hardly
     * worth worrying about.
     */
    emit_dac(cinfo);
  } else {
    /* Emit Huffman tables.
     * Note that emit_dht() suppresses any duplicate tables.
     */
    for (i = 0; i < cinfo->comps_in_scan; i++) {
      compptr = cinfo->cur_comp_info[i];
      if (cinfo->progressive_mode) {
	/* Progressive mode: only DC or only AC tables are used in one scan */
	if (cinfo->Ss == 0) {
	  if (cinfo->Ah == 0)	/* DC needs no table for refinement scan */
	    emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
	} else {
	  emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
	}
      } else {
	/* Sequential mode: need both DC and AC tables */
	emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
	emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
      }
    }
  }

  /* Emit DRI if required --- note that DRI value could change for each scan.
   * We avoid wasting space with unnecessary DRIs, however.
   */
  if (cinfo->restart_interval != marker->last_restart_interval) {
    emit_dri(cinfo);
    marker->last_restart_interval = cinfo->restart_interval;
  }

  emit_sos(cinfo);
}

/*
 * Write datastream trailer.
 */

METHODDEF(void)
write_file_trailer (j_compress_ptr cinfo)
{
  emit_marker(cinfo, M_EOI);
}

/*
 * Write an abbreviated table-specification datastream.
 * This consists of SOI, DQT and DHT tables, and EOI.
 * Any table that is defined and not marked sent_table = TRUE will be
 * emitted.  Note that all tables will be marked sent_table = TRUE at exit.
 */

METHODDEF(void)
write_tables_only (j_compress_ptr cinfo)
{
  int i;

  emit_marker(cinfo, M_SOI);

  for (i = 0; i < NUM_QUANT_TBLS; i++) {
    if (cinfo->quant_tbl_ptrs[i] != NULL)
      (void) emit_dqt(cinfo, i);
  }

  if (! cinfo->arith_code) {
    for (i = 0; i < NUM_HUFF_TBLS; i++) {
      if (cinfo->dc_huff_tbl_ptrs[i] != NULL)
	emit_dht(cinfo, i, FALSE);
      if (cinfo->ac_huff_tbl_ptrs[i] != NULL)
	emit_dht(cinfo, i, TRUE);
    }
  }

  emit_marker(cinfo, M_EOI);
}

/*
 * Initialize the marker writer module.
 */

GLOBAL(void)
jinit_marker_writer (j_compress_ptr cinfo)
{
  my_marker_ptr marker;

  /* Create the subobject */
  marker = (my_marker_ptr)
    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
				SIZEOF(my_marker_writer));
  cinfo->marker = (struct jpeg_marker_writer *) marker;
  /* Initialize method pointers */
  marker->pub.write_file_header = write_file_header;
  marker->pub.write_frame_header = write_frame_header;
  marker->pub.write_scan_header = write_scan_header;
  marker->pub.write_file_trailer = write_file_trailer;
  marker->pub.write_tables_only = write_tables_only;
  marker->pub.write_marker_header = write_marker_header;
  marker->pub.write_marker_byte = write_marker_byte;
  /* Initialize private state */
  marker->last_restart_interval = 0;
}


text:
/*
 * jcinit.c
 *
 * Copyright (C) 1991-1997, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains initialization logic for the JPEG compressor.
 * This routine is in charge of selecting the modules to be executed and
 * making an initialization call to each one.
 *
 * Logically, this code belongs in jcmaster.c.  It's split out because
 * linking this routine implies linking the entire compression library.
 * For a transcoding-only application, we want to be able to use jcmaster.c
 * without linking in the whole library.
 */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"

/*
 * Master selection of compression modules.
 * This is done once at the start of processing an image.  We determine
 * which modules will be used and give them appropriate initialization calls.
 */

GLOBAL(void)
jinit_compress_master (j_compress_ptr cinfo)
{
  /* Initialize master control (includes parameter checking/processing) */
  jinit_c_master_control(cinfo, FALSE /* full compression */);

  /* Preprocessing */
  if (! cinfo->raw_data_in) {
    jinit_color_converter(cinfo);
    jinit_downsampler(cinfo);
    jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);
  }
  /* Forward DCT */
  jinit_forward_dct(cinfo);
  /* Entropy encoding: either Huffman or arithmetic coding. */
  if (cinfo->arith_code) {
    ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
  } else {
    if (cinfo->progressive_mode) {
#ifdef C_PROGRESSIVE_SUPPORTED
      jinit_phuff_encoder(cinfo);
#else
      ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
    } else
      jinit_huff_encoder(cinfo);
  }

  /* Need a full-image coefficient buffer in any multi-pass mode. */
  jinit_c_coef_controller(cinfo,
		(boolean) (cinfo->num_scans > 1 || cinfo->optimize_coding));
  jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);

  jinit_marker_writer(cinfo);

  /* We can now tell the memory manager to allocate virtual arrays. */
  (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);

  /* Write the datastream header (SOI) immediately.
   * Frame and scan headers are postponed till later.
   * This lets application insert special markers after the SOI.
   */
  (*cinfo->marker->write_file_header) (cinfo);
}