/* * jctrans.c * * Copyright (C) 1995-1998, 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 library routines for transcoding compression, * that is, writing raw DCT coefficient arrays to an output JPEG file. * The routines in jcapimin.c will also be needed by a transcoder. */#define JPEG_INTERNALS#include "jinclude.h"#include "jpeglib.h"/* Forward declarations */LOCAL(void) transencode_master_selection	JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));LOCAL(void) transencode_coef_controller	JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));/* * Compression initialization for writing raw-coefficient data. * Before calling this, all parameters and a data destination must be set up. * Call jpeg_finish_compress() to actually write the data. * * The number of passed virtual arrays must match cinfo->num_components. * Note that the virtual arrays need not be filled or even realized at * the time write_coefficients is called; indeed, if the virtual arrays * were requested from this compression object's memory manager, they * typically will be realized during this routine and filled afterwards. */GLOBAL(void)jpeg_write_coefficients (j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays){  if (cinfo->global_state != CSTATE_START)    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);  /* Mark all tables to be written */  jpeg_suppress_tables(cinfo, FALSE);  /* (Re)initialize error mgr and destination modules */  (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);  (*cinfo->dest->init_destination) (cinfo);  /* Perform master selection of active modules */  transencode_master_selection(cinfo, coef_arrays);  /* Wait for jpeg_finish_compress() call */  cinfo->next_scanline = 0;	/* so jpeg_write_marker works */  cinfo->global_state = CSTATE_WRCOEFS;}/* * Initialize the compression object with default parameters, * then copy from the source object all parameters needed for lossless * transcoding.  Parameters that can be varied without loss (such as * scan script and Huffman optimization) are left in their default states. */GLOBAL(void)jpeg_copy_critical_parameters (j_decompress_ptr srcinfo,			       j_compress_ptr dstinfo){  JQUANT_TBL ** qtblptr;  jpeg_component_info *incomp, *outcomp;  JQUANT_TBL *c_quant, *slot_quant;  int tblno, ci, coefi;  /* Safety check to ensure start_compress not called yet. */  if (dstinfo->global_state != CSTATE_START)    ERREXIT1(dstinfo, JERR_BAD_STATE, dstinfo->global_state);  /* Copy fundamental image dimensions */  dstinfo->image_width = srcinfo->image_width;  dstinfo->image_height = srcinfo->image_height;  dstinfo->input_components = srcinfo->num_components;  dstinfo->in_color_space = srcinfo->jpeg_color_space;  /* Initialize all parameters to default values */  jpeg_set_defaults(dstinfo);  /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB.   * Fix it to get the right header markers for the image colorspace.   */  jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space);  dstinfo->data_precision = srcinfo->data_precision;  dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling;  /* Copy the source's quantization tables. */  for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {    if (srcinfo->quant_tbl_ptrs[tblno] != NULL) {      qtblptr = & dstinfo->quant_tbl_ptrs[tblno];      if (*qtblptr == NULL)	*qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo);      MEMCOPY((*qtblptr)->quantval,	      srcinfo->quant_tbl_ptrs[tblno]->quantval,	      SIZEOF((*qtblptr)->quantval));      (*qtblptr)->sent_table = FALSE;    }  }  /* Copy the source's per-component info.   * Note we assume jpeg_set_defaults has allocated the dest comp_info array.   */  dstinfo->num_components = srcinfo->num_components;  if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS)    ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components,	     MAX_COMPONENTS);  for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info;       ci < dstinfo->num_components; ci++, incomp++, outcomp++) {    outcomp->component_id = incomp->component_id;    outcomp->h_samp_factor = incomp->h_samp_factor;    outcomp->v_samp_factor = incomp->v_samp_factor;    outcomp->quant_tbl_no = incomp->quant_tbl_no;    /* Make sure saved quantization table for component matches the qtable     * slot.  If not, the input file re-used this qtable slot.     * IJG encoder currently cannot duplicate this.     */    tblno = outcomp->quant_tbl_no;    if (tblno < 0 || tblno >= NUM_QUANT_TBLS ||	srcinfo->quant_tbl_ptrs[tblno] == NULL)      ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno);    slot_quant = srcinfo->quant_tbl_ptrs[tblno];    c_quant = incomp->quant_table;    if (c_quant != NULL) {      for (coefi = 0; coefi < DCTSIZE2; coefi++) {	if (c_quant->quantval[coefi] != slot_quant->quantval[coefi])	  ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno);      }    }    /* Note: we do not copy the source's Huffman table assignments;     * instead we rely on jpeg_set_colorspace to have made a suitable choice.     */  }  /* Also copy JFIF version and resolution information, if available.   * Strictly speaking this isn't "critical" info, but it's nearly   * always appropriate to copy it if available.  In particular,   * if the application chooses to copy JFIF 1.02 extension markers from   * the source file, we need to copy the version to make sure we don't   * emit a file that has 1.02 extensions but a claimed version of 1.01.   * We will *not*, however, copy version info from mislabeled "2.01" files.   */  if (srcinfo->saw_JFIF_marker) {    if (srcinfo->JFIF_major_version == 1) {      dstinfo->JFIF_major_version = srcinfo->JFIF_major_version;      dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version;    }    dstinfo->density_unit = srcinfo->density_unit;    dstinfo->X_density = srcinfo->X_density;    dstinfo->Y_density = srcinfo->Y_density;  }}/* * Master selection of compression modules for transcoding. * This substitutes for jcinit.c's initialization of the full compressor. */LOCAL(void)transencode_master_selection (j_compress_ptr cinfo,			      jvirt_barray_ptr * coef_arrays){  /* Although we don't actually use input_components for transcoding,   * jcmaster.c's initial_setup will complain if input_components is 0.   */  cinfo->input_components = 1;  /* Initialize master control (includes parameter checking/processing) */  jinit_c_master_control(cinfo, TRUE /* transcode only */);  /* 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);  }  /* We need a special coefficient buffer controller. */  transencode_coef_controller(cinfo, coef_arrays);  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, JFIF) immediately.   * Frame and scan headers are postponed till later.   * This lets application insert special markers after the SOI.   */  (*cinfo->marker->write_file_header) (cinfo);}/* * The rest of this file is a special implementation of the coefficient * buffer controller.  This is similar to jccoefct.c, but it handles only * output from presupplied virtual arrays.  Furthermore, we generate any * dummy padding blocks on-the-fly rather than expecting them to be present * in the arrays. *//* Private buffer controller object */typedef struct {  struct jpeg_c_coef_controller pub; /* public fields */  JDIMENSION iMCU_row_num;	/* iMCU row # within image */  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 */  /* Virtual block array for each component. */  jvirt_barray_ptr * whole_image;  /* Workspace for constructing dummy blocks at right/bottom edges. */  JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU];} my_coef_controller;typedef my_coef_controller * my_coef_ptr;LOCAL(void)start_iMCU_row (j_compress_ptr cinfo)/* Reset within-iMCU-row counters for a new row */{  my_coef_ptr coef = (my_coef_ptr) 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 (coef->iMCU_row_num < (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 a processing pass. */METHODDEF(void)start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode){  my_coef_ptr coef = (my_coef_ptr) cinfo->coef;  if (pass_mode != JBUF_CRANK_DEST)    ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);  coef->iMCU_row_num = 0;  start_iMCU_row(cinfo);}/* * Process some data. * We process the equivalent of one fully interleaved MCU row ("iMCU" row) * per call, ie, v_samp_factor block rows for each component in the scan. * The data is obtained from the virtual arrays and fed to the entropy coder. * Returns TRUE if the iMCU row is completed, FALSE if suspended. * * NB: input_buf is ignored; it is likely to be a NULL pointer. */METHODDEF(boolean)compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf){  my_coef_ptr coef = (my_coef_ptr) 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, blockcnt;  JDIMENSION start_col;  JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];  JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU];  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],       coef->iMCU_row_num * compptr->v_samp_factor,       (JDIMENSION) compptr->v_samp_factor, FALSE);  }  /* 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;	blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width						: compptr->last_col_width;	for (yindex = 0; yindex < compptr->MCU_height; yindex++) {	  if (coef->iMCU_row_num < last_iMCU_row ||	      yindex+yoffset < compptr->last_row_height) {	    /* Fill in pointers to real blocks in this row */	    buffer_ptr = buffer[ci][yindex+yoffset] + start_col;	    for (xindex = 0; xindex < blockcnt; xindex++)	      MCU_buffer[blkn++] = buffer_ptr++;	  } else {	    /* At bottom of image, need a whole row of dummy blocks */	    xindex = 0;	  }	  /* Fill in any dummy blocks needed in this row.	   * Dummy blocks are filled in the same way as in jccoefct.c:	   * all zeroes in the AC entries, DC entries equal to previous	   * block's DC value.  The init routine has already zeroed the	   * AC entries, so we need only set the DC entries correctly.	   */	  for (; xindex < compptr->MCU_width; xindex++) {	    MCU_buffer[blkn] = coef->dummy_buffer[blkn];	    MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0];	    blkn++;	  }	}      }      /* Try to write the MCU. */      if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) {	/* Suspension forced; update state counters and exit */	coef->MCU_vert_offset = yoffset;	coef->mcu_ctr = MCU_col_num;	return FALSE;      }    }    /* Completed an MCU row, but perhaps not an iMCU row */    coef->mcu_ctr = 0;  }  /* Completed the iMCU row, advance counters for next one */  coef->iMCU_row_num++;  start_iMCU_row(cinfo);  return TRUE;}/* * Initialize coefficient buffer controller. * * Each passed coefficient array must be the right size for that * coefficient: width_in_blocks wide and height_in_blocks high, * with unitheight at least v_samp_factor. */LOCAL(void)transencode_coef_controller (j_compress_ptr cinfo,			     jvirt_barray_ptr * coef_arrays){  my_coef_ptr coef;  JBLOCKROW buffer;  int i;  coef = (my_coef_ptr)    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,				SIZEOF(my_coef_controller));  cinfo->coef = (struct jpeg_c_coef_controller *) coef;  coef->pub.start_pass = start_pass_coef;  coef->pub.compress_data = compress_output;  /* Save pointer to virtual arrays */  coef->whole_image = coef_arrays;  /* Allocate and pre-zero space for dummy DCT blocks. */  buffer = (JBLOCKROW)    (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,				C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));  jzero_far((void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));  for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) {    coef->dummy_buffer[i] = buffer + i;  }}