text: /*
   * 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 "jinclude8.h"
  #include "jpeglib8.h"
  #include "jlossy8.h"        /* Private declarations for lossy codec */
  
  
  /* Forward declarations */
  LOCAL(void) transencode_master_selection
      JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
  LOCAL(void) transencode_codec
      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)
  {
    cinfo->data_unit = DCTSIZE;
    /* 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 */);
  
    /* We need a special compression codec. */
    transencode_codec(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 {
    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_DATA_UNITS_IN_MCU];
  } c_coef_controller;
  
  typedef c_coef_controller * c_coef_ptr;
  
  
  LOCAL(void)
  start_iMCU_row (j_compress_ptr cinfo)
  /* Reset within-iMCU-row counters for a new row */
  {
    j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
    c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
  
    /* 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)
  {
    j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
    c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
  
    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)
  {
    (void)input_buf;
    j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
    c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
    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_DATA_UNITS_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 * (JDIMENSION) 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 * (JDIMENSION)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 (! (*lossyc->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_data_units wide and height_in_data_units high,
   * with unitheight at least v_samp_factor.
   */
  
  LOCAL(void)
  transencode_coef_controller (j_compress_ptr cinfo,
                   jvirt_barray_ptr * coef_arrays)
  {
    j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
    c_coef_ptr coef;
    JBLOCKROW buffer;
    int i;
  
    coef = (c_coef_ptr)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
                  SIZEOF(c_coef_controller));
    lossyc->coef_private = (void *) coef;
  
    /* 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_DATA_UNITS_IN_MCU * SIZEOF(JBLOCK));
    jzero_far((void FAR *) buffer, C_MAX_DATA_UNITS_IN_MCU * SIZEOF(JBLOCK));
    for (i = 0; i < C_MAX_DATA_UNITS_IN_MCU; i++) {
      coef->dummy_buffer[i] = buffer + i;
    }
  }
  
  
  /*
   * Initialize the transencoer codec.
   * This is called only once, during master selection.
   */
  
  LOCAL(void)
  transencode_codec (j_compress_ptr cinfo,
             jvirt_barray_ptr * coef_arrays)
  {
    j_lossy_c_ptr lossyc;
  
    /* Create subobject in permanent pool */
    lossyc = (j_lossy_c_ptr)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
                  SIZEOF(jpeg_lossy_c_codec));
    cinfo->codec = (struct jpeg_c_codec *) lossyc;
  
    /* Initialize sub-modules */
  
    /* Entropy encoding: either Huffman or arithmetic coding. */
    if (cinfo->arith_code) {
  #ifdef WITH_ARITHMETIC_PATCH
      jinit_arith_encoder(cinfo);
  #else
      ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
  #endif
    } else {
      if (cinfo->process == JPROC_PROGRESSIVE) {
  #ifdef C_PROGRESSIVE_SUPPORTED
        jinit_phuff_encoder(cinfo);
  #else
        ERREXIT(cinfo, JERR_NOT_COMPILED);
  #endif
      } else
        jinit_shuff_encoder(cinfo);
    }
  
    /* We need a special coefficient buffer controller. */
    transencode_coef_controller(cinfo, coef_arrays);
  
    /* Initialize method pointers */
    lossyc->pub.start_pass = start_pass_coef;
    lossyc->pub.compress_data = compress_output;
  }
  