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

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

media/libjpeg/jcmainct.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

 /*
  * jcmainct.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 the main buffer controller for compression.
  * The main buffer lies between the pre-processor and the JPEG
  * compressor proper; it holds downsampled data in the JPEG colorspace.
  */
 #define JPEG_INTERNALS
 #include "jinclude.h"
 #include "jpeglib.h"
 /* Note: currently, there is no operating mode in which a full-image buffer
  * is needed at this step.  If there were, that mode could not be used with
  * "raw data" input, since this module is bypassed in that case.  However,
  * we've left the code here for possible use in special applications.
  */
 #undef FULL_MAIN_BUFFER_SUPPORTED
 /* Private buffer controller object */
 typedef struct {
   struct jpeg_c_main_controller pub; /* public fields */
   JDIMENSION cur_iMCU_row;	/* number of current iMCU row */
   JDIMENSION rowgroup_ctr;	/* counts row groups received in iMCU row */
   boolean suspended;		/* remember if we suspended output */
   J_BUF_MODE pass_mode;		/* current operating mode */
   /* If using just a strip buffer, this points to the entire set of buffers
    * (we allocate one for each component).  In the full-image case, this
    * points to the currently accessible strips of the virtual arrays.
    */
   JSAMPARRAY buffer[MAX_COMPONENTS];
 #ifdef FULL_MAIN_BUFFER_SUPPORTED
   /* If using full-image storage, this array holds pointers to virtual-array
    * control blocks for each component.  Unused if not full-image storage.
    */
   jvirt_sarray_ptr whole_image[MAX_COMPONENTS];
 #endif
 } my_main_controller;
 typedef my_main_controller * my_main_ptr;
 /* Forward declarations */
 METHODDEF(void) process_data_simple_main
 	JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
 	     JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
 #ifdef FULL_MAIN_BUFFER_SUPPORTED
 METHODDEF(void) process_data_buffer_main
 	JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
 	     JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
 #endif
 /*
  * Initialize for a processing pass.
  */
 METHODDEF(void)
 start_pass_main (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
 {
   my_main_ptr main_ptr = (my_main_ptr) cinfo->main;
   /* Do nothing in raw-data mode. */
   if (cinfo->raw_data_in)
     return;
   main_ptr->cur_iMCU_row = 0;	/* initialize counters */
   main_ptr->rowgroup_ctr = 0;
   main_ptr->suspended = FALSE;
   main_ptr->pass_mode = pass_mode;	/* save mode for use by process_data */
   switch (pass_mode) {
   case JBUF_PASS_THRU:
 #ifdef FULL_MAIN_BUFFER_SUPPORTED
     if (main_ptr->whole_image[0] != NULL)
       ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
 #endif
     main_ptr->pub.process_data = process_data_simple_main;
     break;
 #ifdef FULL_MAIN_BUFFER_SUPPORTED
   case JBUF_SAVE_SOURCE:
   case JBUF_CRANK_DEST:
   case JBUF_SAVE_AND_PASS:
     if (main_ptr->whole_image[0] == NULL)
       ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
     main_ptr->pub.process_data = process_data_buffer_main;
     break;
 #endif
   default:
     ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
     break;
   }
 }
 /*
  * Process some data.
  * This routine handles the simple pass-through mode,
  * where we have only a strip buffer.
  */
 METHODDEF(void)
 process_data_simple_main (j_compress_ptr cinfo,
 			  JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
 			  JDIMENSION in_rows_avail)
 {
   my_main_ptr main_ptr = (my_main_ptr) cinfo->main;
   while (main_ptr->cur_iMCU_row < cinfo->total_iMCU_rows) {
     /* Read input data if we haven't filled the main buffer yet */
     if (main_ptr->rowgroup_ctr < DCTSIZE)
       (*cinfo->prep->pre_process_data) (cinfo,
 					input_buf, in_row_ctr, in_rows_avail,
 					main_ptr->buffer, &main_ptr->rowgroup_ctr,
 					(JDIMENSION) DCTSIZE);
     /* If we don't have a full iMCU row buffered, return to application for
      * more data.  Note that preprocessor will always pad to fill the iMCU row
      * at the bottom of the image.
      */
     if (main_ptr->rowgroup_ctr != DCTSIZE)
       return;
     /* Send the completed row to the compressor */
     if (! (*cinfo->coef->compress_data) (cinfo, main_ptr->buffer)) {
       /* If compressor did not consume the whole row, then we must need to
        * suspend processing and return to the application.  In this situation
        * we pretend we didn't yet consume the last input row; otherwise, if
        * it happened to be the last row of the image, the application would
        * think we were done.
        */
       if (! main_ptr->suspended) {
 	(*in_row_ctr)--;
 	main_ptr->suspended = TRUE;
       }
       return;
     }
     /* We did finish the row.  Undo our little suspension hack if a previous
      * call suspended; then mark the main buffer empty.
      */
     if (main_ptr->suspended) {
       (*in_row_ctr)++;
       main_ptr->suspended = FALSE;
     }
     main_ptr->rowgroup_ctr = 0;
     main_ptr->cur_iMCU_row++;
   }
 }
 #ifdef FULL_MAIN_BUFFER_SUPPORTED
 /*
  * Process some data.
  * This routine handles all of the modes that use a full-size buffer.
  */
 METHODDEF(void)
 process_data_buffer_main (j_compress_ptr cinfo,
 			  JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
 			  JDIMENSION in_rows_avail)
 {
   my_main_ptr main_ptr = (my_main_ptr) cinfo->main;
   int ci;
   jpeg_component_info *compptr;
   boolean writing = (main_ptr->pass_mode != JBUF_CRANK_DEST);
   while (main_ptr->cur_iMCU_row < cinfo->total_iMCU_rows) {
     /* Realign the virtual buffers if at the start of an iMCU row. */
     if (main_ptr->rowgroup_ctr == 0) {
       for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 	   ci++, compptr++) {
 	main_ptr->buffer[ci] = (*cinfo->mem->access_virt_sarray)
 	  ((j_common_ptr) cinfo, main_ptr->whole_image[ci],
 	   main_ptr->cur_iMCU_row * (compptr->v_samp_factor * DCTSIZE),
 	   (JDIMENSION) (compptr->v_samp_factor * DCTSIZE), writing);
       }
       /* In a read pass, pretend we just read some source data. */
       if (! writing) {
 	*in_row_ctr += cinfo->max_v_samp_factor * DCTSIZE;
 	main_ptr->rowgroup_ctr = DCTSIZE;
       }
     }
     /* If a write pass, read input data until the current iMCU row is full. */
     /* Note: preprocessor will pad if necessary to fill the last iMCU row. */
     if (writing) {
       (*cinfo->prep->pre_process_data) (cinfo,
 					input_buf, in_row_ctr, in_rows_avail,
 					main_ptr->buffer, &main_ptr->rowgroup_ctr,
 					(JDIMENSION) DCTSIZE);
       /* Return to application if we need more data to fill the iMCU row. */
       if (main_ptr->rowgroup_ctr < DCTSIZE)
 	return;
     }
     /* Emit data, unless this is a sink-only pass. */
     if (main_ptr->pass_mode != JBUF_SAVE_SOURCE) {
       if (! (*cinfo->coef->compress_data) (cinfo, main_ptr->buffer)) {
 	/* If compressor did not consume the whole row, then we must need to
 	 * suspend processing and return to the application.  In this situation
 	 * we pretend we didn't yet consume the last input row; otherwise, if
 	 * it happened to be the last row of the image, the application would
 	 * think we were done.
 	 */
 	if (! main_ptr->suspended) {
 	  (*in_row_ctr)--;
 	  main_ptr->suspended = TRUE;
 	}
 	return;
       }
       /* We did finish the row.  Undo our little suspension hack if a previous
        * call suspended; then mark the main buffer empty.
        */
       if (main_ptr->suspended) {
 	(*in_row_ctr)++;
 	main_ptr->suspended = FALSE;
       }
     }
     /* If get here, we are done with this iMCU row.  Mark buffer empty. */
     main_ptr->rowgroup_ctr = 0;
     main_ptr->cur_iMCU_row++;
   }
 }
 #endif /* FULL_MAIN_BUFFER_SUPPORTED */
 /*
  * Initialize main buffer controller.
  */
 GLOBAL(void)
 jinit_c_main_controller (j_compress_ptr cinfo, boolean need_full_buffer)
 {
   my_main_ptr main_ptr;
   int ci;
   jpeg_component_info *compptr;
   main_ptr = (my_main_ptr)
     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 				SIZEOF(my_main_controller));
   cinfo->main = (struct jpeg_c_main_controller *) main_ptr;
   main_ptr->pub.start_pass = start_pass_main;
   /* We don't need to create a buffer in raw-data mode. */
   if (cinfo->raw_data_in)
     return;
   /* Create the buffer.  It holds downsampled data, so each component
    * may be of a different size.
    */
   if (need_full_buffer) {
 #ifdef FULL_MAIN_BUFFER_SUPPORTED
     /* Allocate a full-image virtual array for each component */
     /* Note we pad the bottom to a multiple of the iMCU height */
     for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 	 ci++, compptr++) {
       main_ptr->whole_image[ci] = (*cinfo->mem->request_virt_sarray)
 	((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
 	 compptr->width_in_blocks * DCTSIZE,
 	 (JDIMENSION) jround_up((long) compptr->height_in_blocks,
 				(long) compptr->v_samp_factor) * DCTSIZE,
 	 (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));
     }
 #else
     ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
 #endif
   } else {
 #ifdef FULL_MAIN_BUFFER_SUPPORTED
     main_ptr->whole_image[0] = NULL; /* flag for no virtual arrays */
 #endif
     /* Allocate a strip buffer for each component */
     for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 	 ci++, compptr++) {
       main_ptr->buffer[ci] = (*cinfo->mem->alloc_sarray)
 	((j_common_ptr) cinfo, JPOOL_IMAGE,
 	 compptr->width_in_blocks * DCTSIZE,
 	 (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));
     }
   }
 }

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

media/libjpeg/jcmainct.c