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

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

media/libjpeg/jdinput.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

 /*
  * jdinput.c
  *
  * This file was part of the Independent JPEG Group's software:
  * Copyright (C) 1991-1997, Thomas G. Lane.
  * libjpeg-turbo Modifications:
  * Copyright (C) 2010, D. R. Commander.
  * For conditions of distribution and use, see the accompanying README file.
  *
  * This file contains input control logic for the JPEG decompressor.
  * These routines are concerned with controlling the decompressor's input
  * processing (marker reading and coefficient decoding).  The actual input
  * reading is done in jdmarker.c, jdhuff.c, and jdphuff.c.
  */
 #define JPEG_INTERNALS
 #include "jinclude.h"
 #include "jpeglib.h"
 #include "jpegcomp.h"
 /* Private state */
 typedef struct {
   struct jpeg_input_controller pub; /* public fields */
   boolean inheaders;		/* TRUE until first SOS is reached */
 } my_input_controller;
 typedef my_input_controller * my_inputctl_ptr;
 /* Forward declarations */
 METHODDEF(int) consume_markers JPP((j_decompress_ptr cinfo));
 /*
  * Routines to calculate various quantities related to the size of the image.
  */
 LOCAL(void)
 initial_setup (j_decompress_ptr cinfo)
 /* Called once, when first SOS marker is reached */
 {
   int ci;
   jpeg_component_info *compptr;
   /* Make sure image isn't bigger than I can handle */
   if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
       (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
     ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
   /* For now, precision must match compiled-in value... */
   if (cinfo->data_precision != BITS_IN_JSAMPLE)
     ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
   /* Check that number of components won't exceed internal array sizes */
   if (cinfo->num_components > MAX_COMPONENTS)
     ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
 	     MAX_COMPONENTS);
   /* Compute maximum sampling factors; check factor validity */
   cinfo->max_h_samp_factor = 1;
   cinfo->max_v_samp_factor = 1;
   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
        ci++, compptr++) {
     if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
 	compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
       ERREXIT(cinfo, JERR_BAD_SAMPLING);
     cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
 				   compptr->h_samp_factor);
     cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
 				   compptr->v_samp_factor);
   }
 #if JPEG_LIB_VERSION >=80
     cinfo->block_size = DCTSIZE;
     cinfo->natural_order = jpeg_natural_order;
     cinfo->lim_Se = DCTSIZE2-1;
 #endif
   /* We initialize DCT_scaled_size and min_DCT_scaled_size to DCTSIZE.
    * In the full decompressor, this will be overridden by jdmaster.c;
    * but in the transcoder, jdmaster.c is not used, so we must do it here.
    */
 #if JPEG_LIB_VERSION >= 70
   cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = DCTSIZE;
 #else
   cinfo->min_DCT_scaled_size = DCTSIZE;
 #endif
   /* Compute dimensions of components */
   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
        ci++, compptr++) {
 #if JPEG_LIB_VERSION >= 70
     compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = DCTSIZE;
 #else
     compptr->DCT_scaled_size = DCTSIZE;
 #endif
     /* Size in DCT blocks */
     compptr->width_in_blocks = (JDIMENSION)
       jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
 		    (long) (cinfo->max_h_samp_factor * DCTSIZE));
     compptr->height_in_blocks = (JDIMENSION)
       jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
 		    (long) (cinfo->max_v_samp_factor * DCTSIZE));
     /* downsampled_width and downsampled_height will also be overridden by
      * jdmaster.c if we are doing full decompression.  The transcoder library
      * doesn't use these values, but the calling application might.
      */
     /* Size in samples */
     compptr->downsampled_width = (JDIMENSION)
       jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
 		    (long) cinfo->max_h_samp_factor);
     compptr->downsampled_height = (JDIMENSION)
       jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
 		    (long) cinfo->max_v_samp_factor);
     /* Mark component needed, until color conversion says otherwise */
     compptr->component_needed = TRUE;
     /* Mark no quantization table yet saved for component */
     compptr->quant_table = NULL;
   }
   /* Compute number of fully interleaved MCU rows. */
   cinfo->total_iMCU_rows = (JDIMENSION)
     jdiv_round_up((long) cinfo->image_height,
 		  (long) (cinfo->max_v_samp_factor*DCTSIZE));
   /* Decide whether file contains multiple scans */
   if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode)
     cinfo->inputctl->has_multiple_scans = TRUE;
   else
     cinfo->inputctl->has_multiple_scans = FALSE;
 }
 LOCAL(void)
 per_scan_setup (j_decompress_ptr cinfo)
 /* Do computations that are needed before processing a JPEG scan */
 /* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */
 {
   int ci, mcublks, tmp;
   jpeg_component_info *compptr;
   if (cinfo->comps_in_scan == 1) {
     /* Noninterleaved (single-component) scan */
     compptr = cinfo->cur_comp_info[0];
     /* Overall image size in MCUs */
     cinfo->MCUs_per_row = compptr->width_in_blocks;
     cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
     /* For noninterleaved scan, always one block per MCU */
     compptr->MCU_width = 1;
     compptr->MCU_height = 1;
     compptr->MCU_blocks = 1;
     compptr->MCU_sample_width = compptr->_DCT_scaled_size;
     compptr->last_col_width = 1;
     /* For noninterleaved scans, it is convenient to define last_row_height
      * as the number of block rows present in the last iMCU row.
      */
     tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
     if (tmp == 0) tmp = compptr->v_samp_factor;
     compptr->last_row_height = tmp;
     /* Prepare array describing MCU composition */
     cinfo->blocks_in_MCU = 1;
     cinfo->MCU_membership[0] = 0;
   } else {
     /* Interleaved (multi-component) scan */
     if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
 	       MAX_COMPS_IN_SCAN);
     /* Overall image size in MCUs */
     cinfo->MCUs_per_row = (JDIMENSION)
       jdiv_round_up((long) cinfo->image_width,
 		    (long) (cinfo->max_h_samp_factor*DCTSIZE));
     cinfo->MCU_rows_in_scan = (JDIMENSION)
       jdiv_round_up((long) cinfo->image_height,
 		    (long) (cinfo->max_v_samp_factor*DCTSIZE));
     cinfo->blocks_in_MCU = 0;
     for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
       compptr = cinfo->cur_comp_info[ci];
       /* Sampling factors give # of blocks of component in each MCU */
       compptr->MCU_width = compptr->h_samp_factor;
       compptr->MCU_height = compptr->v_samp_factor;
       compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
       compptr->MCU_sample_width = compptr->MCU_width * compptr->_DCT_scaled_size;
       /* Figure number of non-dummy blocks in last MCU column & row */
       tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
       if (tmp == 0) tmp = compptr->MCU_width;
       compptr->last_col_width = tmp;
       tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
       if (tmp == 0) tmp = compptr->MCU_height;
       compptr->last_row_height = tmp;
       /* Prepare array describing MCU composition */
       mcublks = compptr->MCU_blocks;
       if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU)
 	ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
       while (mcublks-- > 0) {
 	cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
       }
     }
   }
 }
 /*
  * Save away a copy of the Q-table referenced by each component present
  * in the current scan, unless already saved during a prior scan.
  *
  * In a multiple-scan JPEG file, the encoder could assign different components
  * the same Q-table slot number, but change table definitions between scans
  * so that each component uses a different Q-table.  (The IJG encoder is not
  * currently capable of doing this, but other encoders might.)  Since we want
  * to be able to dequantize all the components at the end of the file, this
  * means that we have to save away the table actually used for each component.
  * We do this by copying the table at the start of the first scan containing
  * the component.
  * The JPEG spec prohibits the encoder from changing the contents of a Q-table
  * slot between scans of a component using that slot.  If the encoder does so
  * anyway, this decoder will simply use the Q-table values that were current
  * at the start of the first scan for the component.
  *
  * The decompressor output side looks only at the saved quant tables,
  * not at the current Q-table slots.
  */
 LOCAL(void)
 latch_quant_tables (j_decompress_ptr cinfo)
 {
   int ci, qtblno;
   jpeg_component_info *compptr;
   JQUANT_TBL * qtbl;
   for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
     compptr = cinfo->cur_comp_info[ci];
     /* No work if we already saved Q-table for this component */
     if (compptr->quant_table != NULL)
       continue;
     /* Make sure specified quantization table is present */
     qtblno = compptr->quant_tbl_no;
     if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
 	cinfo->quant_tbl_ptrs[qtblno] == NULL)
       ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
     /* OK, save away the quantization table */
     qtbl = (JQUANT_TBL *)
       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 				  SIZEOF(JQUANT_TBL));
     MEMCOPY(qtbl, cinfo->quant_tbl_ptrs[qtblno], SIZEOF(JQUANT_TBL));
     compptr->quant_table = qtbl;
   }
 }
 /*
  * Initialize the input modules to read a scan of compressed data.
  * The first call to this is done by jdmaster.c after initializing
  * the entire decompressor (during jpeg_start_decompress).
  * Subsequent calls come from consume_markers, below.
  */
 METHODDEF(void)
 start_input_pass (j_decompress_ptr cinfo)
 {
   per_scan_setup(cinfo);
   latch_quant_tables(cinfo);
   (*cinfo->entropy->start_pass) (cinfo);
   (*cinfo->coef->start_input_pass) (cinfo);
   cinfo->inputctl->consume_input = cinfo->coef->consume_data;
 }
 /*
  * Finish up after inputting a compressed-data scan.
  * This is called by the coefficient controller after it's read all
  * the expected data of the scan.
  */
 METHODDEF(void)
 finish_input_pass (j_decompress_ptr cinfo)
 {
   cinfo->inputctl->consume_input = consume_markers;
 }
 /*
  * Read JPEG markers before, between, or after compressed-data scans.
  * Change state as necessary when a new scan is reached.
  * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
  *
  * The consume_input method pointer points either here or to the
  * coefficient controller's consume_data routine, depending on whether
  * we are reading a compressed data segment or inter-segment markers.
  */
 METHODDEF(int)
 consume_markers (j_decompress_ptr cinfo)
 {
   my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
   int val;
   if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */
     return JPEG_REACHED_EOI;
   val = (*cinfo->marker->read_markers) (cinfo);
   switch (val) {
   case JPEG_REACHED_SOS:	/* Found SOS */
     if (inputctl->inheaders) {	/* 1st SOS */
       initial_setup(cinfo);
       inputctl->inheaders = FALSE;
       /* Note: start_input_pass must be called by jdmaster.c
        * before any more input can be consumed.  jdapimin.c is
        * responsible for enforcing this sequencing.
        */
     } else {			/* 2nd or later SOS marker */
       if (! inputctl->pub.has_multiple_scans)
 	ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */
       start_input_pass(cinfo);
     }
     break;
   case JPEG_REACHED_EOI:	/* Found EOI */
     inputctl->pub.eoi_reached = TRUE;
     if (inputctl->inheaders) {	/* Tables-only datastream, apparently */
       if (cinfo->marker->saw_SOF)
 	ERREXIT(cinfo, JERR_SOF_NO_SOS);
     } else {
       /* Prevent infinite loop in coef ctlr's decompress_data routine
        * if user set output_scan_number larger than number of scans.
        */
       if (cinfo->output_scan_number > cinfo->input_scan_number)
 	cinfo->output_scan_number = cinfo->input_scan_number;
     }
     break;
   case JPEG_SUSPENDED:
     break;
   }
   return val;
 }
 /*
  * Reset state to begin a fresh datastream.
  */
 METHODDEF(void)
 reset_input_controller (j_decompress_ptr cinfo)
 {
   my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
   inputctl->pub.consume_input = consume_markers;
   inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
   inputctl->pub.eoi_reached = FALSE;
   inputctl->inheaders = TRUE;
   /* Reset other modules */
   (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
   (*cinfo->marker->reset_marker_reader) (cinfo);
   /* Reset progression state -- would be cleaner if entropy decoder did this */
   cinfo->coef_bits = NULL;
 }
 /*
  * Initialize the input controller module.
  * This is called only once, when the decompression object is created.
  */
 GLOBAL(void)
 jinit_input_controller (j_decompress_ptr cinfo)
 {
   my_inputctl_ptr inputctl;
   /* Create subobject in permanent pool */
   inputctl = (my_inputctl_ptr)
     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
 				SIZEOF(my_input_controller));
   cinfo->inputctl = (struct jpeg_input_controller *) inputctl;
   /* Initialize method pointers */
   inputctl->pub.consume_input = consume_markers;
   inputctl->pub.reset_input_controller = reset_input_controller;
   inputctl->pub.start_input_pass = start_input_pass;
   inputctl->pub.finish_input_pass = finish_input_pass;
   /* Initialize state: can't use reset_input_controller since we don't
    * want to try to reset other modules yet.
    */
   inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
   inputctl->pub.eoi_reached = FALSE;
   inputctl->inheaders = TRUE;
 }

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

media/libjpeg/jdinput.c