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

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

media/libjpeg/jdpostct.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

 /*
  * jdpostct.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 decompression postprocessing controller.
  * This controller manages the upsampling, color conversion, and color
  * quantization/reduction steps; specifically, it controls the buffering
  * between upsample/color conversion and color quantization/reduction.
  *
  * If no color quantization/reduction is required, then this module has no
  * work to do, and it just hands off to the upsample/color conversion code.
  * An integrated upsample/convert/quantize process would replace this module
  * entirely.
  */
 #define JPEG_INTERNALS
 #include "jinclude.h"
 #include "jpeglib.h"
 /* Private buffer controller object */
 typedef struct {
   struct jpeg_d_post_controller pub; /* public fields */
   /* Color quantization source buffer: this holds output data from
    * the upsample/color conversion step to be passed to the quantizer.
    * For two-pass color quantization, we need a full-image buffer;
    * for one-pass operation, a strip buffer is sufficient.
    */
   jvirt_sarray_ptr whole_image;	/* virtual array, or NULL if one-pass */
   JSAMPARRAY buffer;		/* strip buffer, or current strip of virtual */
   JDIMENSION strip_height;	/* buffer size in rows */
   /* for two-pass mode only: */
   JDIMENSION starting_row;	/* row # of first row in current strip */
   JDIMENSION next_row;		/* index of next row to fill/empty in strip */
 } my_post_controller;
 typedef my_post_controller * my_post_ptr;
 /* Forward declarations */
 METHODDEF(void) post_process_1pass
 	JPP((j_decompress_ptr cinfo,
 	     JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
 	     JDIMENSION in_row_groups_avail,
 	     JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
 	     JDIMENSION out_rows_avail));
 #ifdef QUANT_2PASS_SUPPORTED
 METHODDEF(void) post_process_prepass
 	JPP((j_decompress_ptr cinfo,
 	     JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
 	     JDIMENSION in_row_groups_avail,
 	     JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
 	     JDIMENSION out_rows_avail));
 METHODDEF(void) post_process_2pass
 	JPP((j_decompress_ptr cinfo,
 	     JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
 	     JDIMENSION in_row_groups_avail,
 	     JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
 	     JDIMENSION out_rows_avail));
 #endif
 /*
  * Initialize for a processing pass.
  */
 METHODDEF(void)
 start_pass_dpost (j_decompress_ptr cinfo, J_BUF_MODE pass_mode)
 {
   my_post_ptr post = (my_post_ptr) cinfo->post;
   switch (pass_mode) {
   case JBUF_PASS_THRU:
     if (cinfo->quantize_colors) {
       /* Single-pass processing with color quantization. */
       post->pub.post_process_data = post_process_1pass;
       /* We could be doing buffered-image output before starting a 2-pass
        * color quantization; in that case, jinit_d_post_controller did not
        * allocate a strip buffer.  Use the virtual-array buffer as workspace.
        */
       if (post->buffer == NULL) {
 	post->buffer = (*cinfo->mem->access_virt_sarray)
 	  ((j_common_ptr) cinfo, post->whole_image,
 	   (JDIMENSION) 0, post->strip_height, TRUE);
       }
     } else {
       /* For single-pass processing without color quantization,
        * I have no work to do; just call the upsampler directly.
        */
       post->pub.post_process_data = cinfo->upsample->upsample;
     }
     break;
 #ifdef QUANT_2PASS_SUPPORTED
   case JBUF_SAVE_AND_PASS:
     /* First pass of 2-pass quantization */
     if (post->whole_image == NULL)
       ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
     post->pub.post_process_data = post_process_prepass;
     break;
   case JBUF_CRANK_DEST:
     /* Second pass of 2-pass quantization */
     if (post->whole_image == NULL)
       ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
     post->pub.post_process_data = post_process_2pass;
     break;
 #endif /* QUANT_2PASS_SUPPORTED */
   default:
     ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
     break;
   }
   post->starting_row = post->next_row = 0;
 }
 /*
  * Process some data in the one-pass (strip buffer) case.
  * This is used for color precision reduction as well as one-pass quantization.
  */
 METHODDEF(void)
 post_process_1pass (j_decompress_ptr cinfo,
 		    JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
 		    JDIMENSION in_row_groups_avail,
 		    JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
 		    JDIMENSION out_rows_avail)
 {
   my_post_ptr post = (my_post_ptr) cinfo->post;
   JDIMENSION num_rows, max_rows;
   /* Fill the buffer, but not more than what we can dump out in one go. */
   /* Note we rely on the upsampler to detect bottom of image. */
   max_rows = out_rows_avail - *out_row_ctr;
   if (max_rows > post->strip_height)
     max_rows = post->strip_height;
   num_rows = 0;
   (*cinfo->upsample->upsample) (cinfo,
 		input_buf, in_row_group_ctr, in_row_groups_avail,
 		post->buffer, &num_rows, max_rows);
   /* Quantize and emit data. */
   (*cinfo->cquantize->color_quantize) (cinfo,
 		post->buffer, output_buf + *out_row_ctr, (int) num_rows);
   *out_row_ctr += num_rows;
 }
 #ifdef QUANT_2PASS_SUPPORTED
 /*
  * Process some data in the first pass of 2-pass quantization.
  */
 METHODDEF(void)
 post_process_prepass (j_decompress_ptr cinfo,
 		      JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
 		      JDIMENSION in_row_groups_avail,
 		      JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
 		      JDIMENSION out_rows_avail)
 {
   my_post_ptr post = (my_post_ptr) cinfo->post;
   JDIMENSION old_next_row, num_rows;
   /* Reposition virtual buffer if at start of strip. */
   if (post->next_row == 0) {
     post->buffer = (*cinfo->mem->access_virt_sarray)
 	((j_common_ptr) cinfo, post->whole_image,
 	 post->starting_row, post->strip_height, TRUE);
   }
   /* Upsample some data (up to a strip height's worth). */
   old_next_row = post->next_row;
   (*cinfo->upsample->upsample) (cinfo,
 		input_buf, in_row_group_ctr, in_row_groups_avail,
 		post->buffer, &post->next_row, post->strip_height);
   /* Allow quantizer to scan new data.  No data is emitted, */
   /* but we advance out_row_ctr so outer loop can tell when we're done. */
   if (post->next_row > old_next_row) {
     num_rows = post->next_row - old_next_row;
     (*cinfo->cquantize->color_quantize) (cinfo, post->buffer + old_next_row,
 					 (JSAMPARRAY) NULL, (int) num_rows);
     *out_row_ctr += num_rows;
   }
   /* Advance if we filled the strip. */
   if (post->next_row >= post->strip_height) {
     post->starting_row += post->strip_height;
     post->next_row = 0;
   }
 }
 /*
  * Process some data in the second pass of 2-pass quantization.
  */
 METHODDEF(void)
 post_process_2pass (j_decompress_ptr cinfo,
 		    JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
 		    JDIMENSION in_row_groups_avail,
 		    JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
 		    JDIMENSION out_rows_avail)
 {
   my_post_ptr post = (my_post_ptr) cinfo->post;
   JDIMENSION num_rows, max_rows;
   /* Reposition virtual buffer if at start of strip. */
   if (post->next_row == 0) {
     post->buffer = (*cinfo->mem->access_virt_sarray)
 	((j_common_ptr) cinfo, post->whole_image,
 	 post->starting_row, post->strip_height, FALSE);
   }
   /* Determine number of rows to emit. */
   num_rows = post->strip_height - post->next_row; /* available in strip */
   max_rows = out_rows_avail - *out_row_ctr; /* available in output area */
   if (num_rows > max_rows)
     num_rows = max_rows;
   /* We have to check bottom of image here, can't depend on upsampler. */
   max_rows = cinfo->output_height - post->starting_row;
   if (num_rows > max_rows)
     num_rows = max_rows;
   /* Quantize and emit data. */
   (*cinfo->cquantize->color_quantize) (cinfo,
 		post->buffer + post->next_row, output_buf + *out_row_ctr,
 		(int) num_rows);
   *out_row_ctr += num_rows;
   /* Advance if we filled the strip. */
   post->next_row += num_rows;
   if (post->next_row >= post->strip_height) {
     post->starting_row += post->strip_height;
     post->next_row = 0;
   }
 }
 #endif /* QUANT_2PASS_SUPPORTED */
 /*
  * Initialize postprocessing controller.
  */
 GLOBAL(void)
 jinit_d_post_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
 {
   my_post_ptr post;
   post = (my_post_ptr)
     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 				SIZEOF(my_post_controller));
   cinfo->post = (struct jpeg_d_post_controller *) post;
   post->pub.start_pass = start_pass_dpost;
   post->whole_image = NULL;	/* flag for no virtual arrays */
   post->buffer = NULL;		/* flag for no strip buffer */
   /* Create the quantization buffer, if needed */
   if (cinfo->quantize_colors) {
     /* The buffer strip height is max_v_samp_factor, which is typically
      * an efficient number of rows for upsampling to return.
      * (In the presence of output rescaling, we might want to be smarter?)
      */
     post->strip_height = (JDIMENSION) cinfo->max_v_samp_factor;
     if (need_full_buffer) {
       /* Two-pass color quantization: need full-image storage. */
       /* We round up the number of rows to a multiple of the strip height. */
 #ifdef QUANT_2PASS_SUPPORTED
       post->whole_image = (*cinfo->mem->request_virt_sarray)
 	((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
 	 cinfo->output_width * cinfo->out_color_components,
 	 (JDIMENSION) jround_up((long) cinfo->output_height,
 				(long) post->strip_height),
 	 post->strip_height);
 #else
       ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
 #endif /* QUANT_2PASS_SUPPORTED */
     } else {
       /* One-pass color quantization: just make a strip buffer. */
       post->buffer = (*cinfo->mem->alloc_sarray)
 	((j_common_ptr) cinfo, JPOOL_IMAGE,
 	 cinfo->output_width * cinfo->out_color_components,
 	 post->strip_height);
     }
   }
 }

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

media/libjpeg/jdpostct.c