The Tor Browser: media/libjpeg/jctrans.c@b8a032363ba2 (annotated)

media/libjpeg/jctrans.c@b8a032363ba2 (annotated)

media/libjpeg/jctrans.c

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /*
  * jctrans.c
  *
  * Copyright (C) 1995-1998, Thomas G. Lane.
  * Modified 2000-2009 by Guido Vollbeding.
  * 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;
 #if JPEG_LIB_VERSION >= 70
   dstinfo->jpeg_width = srcinfo->output_width;
   dstinfo->jpeg_height = srcinfo->output_height;
   dstinfo->min_DCT_h_scaled_size = srcinfo->min_DCT_h_scaled_size;
   dstinfo->min_DCT_v_scaled_size = srcinfo->min_DCT_v_scaled_size;
 #endif
   /* 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) {
 #ifdef C_ARITH_CODING_SUPPORTED
     jinit_arith_encoder(cinfo);
 #else
     ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
 #endif
   } 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;
   }
 }

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media/libjpeg/jctrans.c@b8a032363ba2 (annotated)

media/libjpeg/jctrans.c