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

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

media/libjpeg/jdmerge.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

 /*
  * jdmerge.c
  *
  * This file was part of the Independent JPEG Group's software:
  * Copyright (C) 1994-1996, Thomas G. Lane.
  * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
  * libjpeg-turbo Modifications:
  * Copyright (C) 2009, 2011, D. R. Commander.
  * For conditions of distribution and use, see the accompanying README file.
  *
  * This file contains code for merged upsampling/color conversion.
  *
  * This file combines functions from jdsample.c and jdcolor.c;
  * read those files first to understand what's going on.
  *
  * When the chroma components are to be upsampled by simple replication
  * (ie, box filtering), we can save some work in color conversion by
  * calculating all the output pixels corresponding to a pair of chroma
  * samples at one time.  In the conversion equations
  *	R = Y           + K1 * Cr
  *	G = Y + K2 * Cb + K3 * Cr
  *	B = Y + K4 * Cb
  * only the Y term varies among the group of pixels corresponding to a pair
  * of chroma samples, so the rest of the terms can be calculated just once.
  * At typical sampling ratios, this eliminates half or three-quarters of the
  * multiplications needed for color conversion.
  *
  * This file currently provides implementations for the following cases:
  *	YCbCr => RGB color conversion only.
  *	Sampling ratios of 2h1v or 2h2v.
  *	No scaling needed at upsample time.
  *	Corner-aligned (non-CCIR601) sampling alignment.
  * Other special cases could be added, but in most applications these are
  * the only common cases.  (For uncommon cases we fall back on the more
  * general code in jdsample.c and jdcolor.c.)
  */
 #define JPEG_INTERNALS
 #include "jinclude.h"
 #include "jpeglib.h"
 #include "jsimd.h"
 #include "config.h"
 #ifdef UPSAMPLE_MERGING_SUPPORTED
 /* Private subobject */
 typedef struct {
   struct jpeg_upsampler pub;	/* public fields */
   /* Pointer to routine to do actual upsampling/conversion of one row group */
   JMETHOD(void, upmethod, (j_decompress_ptr cinfo,
 			   JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
 			   JSAMPARRAY output_buf));
   /* Private state for YCC->RGB conversion */
   int * Cr_r_tab;		/* => table for Cr to R conversion */
   int * Cb_b_tab;		/* => table for Cb to B conversion */
   INT32 * Cr_g_tab;		/* => table for Cr to G conversion */
   INT32 * Cb_g_tab;		/* => table for Cb to G conversion */
   /* For 2:1 vertical sampling, we produce two output rows at a time.
    * We need a "spare" row buffer to hold the second output row if the
    * application provides just a one-row buffer; we also use the spare
    * to discard the dummy last row if the image height is odd.
    */
   JSAMPROW spare_row;
   boolean spare_full;		/* T if spare buffer is occupied */
   JDIMENSION out_row_width;	/* samples per output row */
   JDIMENSION rows_to_go;	/* counts rows remaining in image */
 } my_upsampler;
 typedef my_upsampler * my_upsample_ptr;
 #define SCALEBITS	16	/* speediest right-shift on some machines */
 #define ONE_HALF	((INT32) 1 << (SCALEBITS-1))
 #define FIX(x)		((INT32) ((x) * (1L<<SCALEBITS) + 0.5))
 /* Include inline routines for colorspace extensions */
 #include "jdmrgext.c"
 #undef RGB_RED
 #undef RGB_GREEN
 #undef RGB_BLUE
 #undef RGB_PIXELSIZE
 #define RGB_RED EXT_RGB_RED
 #define RGB_GREEN EXT_RGB_GREEN
 #define RGB_BLUE EXT_RGB_BLUE
 #define RGB_PIXELSIZE EXT_RGB_PIXELSIZE
 #define h2v1_merged_upsample_internal extrgb_h2v1_merged_upsample_internal
 #define h2v2_merged_upsample_internal extrgb_h2v2_merged_upsample_internal
 #include "jdmrgext.c"
 #undef RGB_RED
 #undef RGB_GREEN
 #undef RGB_BLUE
 #undef RGB_PIXELSIZE
 #undef h2v1_merged_upsample_internal
 #undef h2v2_merged_upsample_internal
 #define RGB_RED EXT_RGBX_RED
 #define RGB_GREEN EXT_RGBX_GREEN
 #define RGB_BLUE EXT_RGBX_BLUE
 #define RGB_ALPHA 3
 #define RGB_PIXELSIZE EXT_RGBX_PIXELSIZE
 #define h2v1_merged_upsample_internal extrgbx_h2v1_merged_upsample_internal
 #define h2v2_merged_upsample_internal extrgbx_h2v2_merged_upsample_internal
 #include "jdmrgext.c"
 #undef RGB_RED
 #undef RGB_GREEN
 #undef RGB_BLUE
 #undef RGB_ALPHA
 #undef RGB_PIXELSIZE
 #undef h2v1_merged_upsample_internal
 #undef h2v2_merged_upsample_internal
 #define RGB_RED EXT_BGR_RED
 #define RGB_GREEN EXT_BGR_GREEN
 #define RGB_BLUE EXT_BGR_BLUE
 #define RGB_PIXELSIZE EXT_BGR_PIXELSIZE
 #define h2v1_merged_upsample_internal extbgr_h2v1_merged_upsample_internal
 #define h2v2_merged_upsample_internal extbgr_h2v2_merged_upsample_internal
 #include "jdmrgext.c"
 #undef RGB_RED
 #undef RGB_GREEN
 #undef RGB_BLUE
 #undef RGB_PIXELSIZE
 #undef h2v1_merged_upsample_internal
 #undef h2v2_merged_upsample_internal
 #define RGB_RED EXT_BGRX_RED
 #define RGB_GREEN EXT_BGRX_GREEN
 #define RGB_BLUE EXT_BGRX_BLUE
 #define RGB_ALPHA 3
 #define RGB_PIXELSIZE EXT_BGRX_PIXELSIZE
 #define h2v1_merged_upsample_internal extbgrx_h2v1_merged_upsample_internal
 #define h2v2_merged_upsample_internal extbgrx_h2v2_merged_upsample_internal
 #include "jdmrgext.c"
 #undef RGB_RED
 #undef RGB_GREEN
 #undef RGB_BLUE
 #undef RGB_ALPHA
 #undef RGB_PIXELSIZE
 #undef h2v1_merged_upsample_internal
 #undef h2v2_merged_upsample_internal
 #define RGB_RED EXT_XBGR_RED
 #define RGB_GREEN EXT_XBGR_GREEN
 #define RGB_BLUE EXT_XBGR_BLUE
 #define RGB_ALPHA 0
 #define RGB_PIXELSIZE EXT_XBGR_PIXELSIZE
 #define h2v1_merged_upsample_internal extxbgr_h2v1_merged_upsample_internal
 #define h2v2_merged_upsample_internal extxbgr_h2v2_merged_upsample_internal
 #include "jdmrgext.c"
 #undef RGB_RED
 #undef RGB_GREEN
 #undef RGB_BLUE
 #undef RGB_ALPHA
 #undef RGB_PIXELSIZE
 #undef h2v1_merged_upsample_internal
 #undef h2v2_merged_upsample_internal
 #define RGB_RED EXT_XRGB_RED
 #define RGB_GREEN EXT_XRGB_GREEN
 #define RGB_BLUE EXT_XRGB_BLUE
 #define RGB_ALPHA 0
 #define RGB_PIXELSIZE EXT_XRGB_PIXELSIZE
 #define h2v1_merged_upsample_internal extxrgb_h2v1_merged_upsample_internal
 #define h2v2_merged_upsample_internal extxrgb_h2v2_merged_upsample_internal
 #include "jdmrgext.c"
 #undef RGB_RED
 #undef RGB_GREEN
 #undef RGB_BLUE
 #undef RGB_ALPHA
 #undef RGB_PIXELSIZE
 #undef h2v1_merged_upsample_internal
 #undef h2v2_merged_upsample_internal
 /*
  * Initialize tables for YCC->RGB colorspace conversion.
  * This is taken directly from jdcolor.c; see that file for more info.
  */
 LOCAL(void)
 build_ycc_rgb_table (j_decompress_ptr cinfo)
 {
   my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
   int i;
   INT32 x;
   SHIFT_TEMPS
   upsample->Cr_r_tab = (int *)
     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 				(MAXJSAMPLE+1) * SIZEOF(int));
   upsample->Cb_b_tab = (int *)
     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 				(MAXJSAMPLE+1) * SIZEOF(int));
   upsample->Cr_g_tab = (INT32 *)
     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 				(MAXJSAMPLE+1) * SIZEOF(INT32));
   upsample->Cb_g_tab = (INT32 *)
     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 				(MAXJSAMPLE+1) * SIZEOF(INT32));
   for (i = 0, x = -CENTERJSAMPLE; i <= MAXJSAMPLE; i++, x++) {
     /* i is the actual input pixel value, in the range 0..MAXJSAMPLE */
     /* The Cb or Cr value we are thinking of is x = i - CENTERJSAMPLE */
     /* Cr=>R value is nearest int to 1.40200 * x */
     upsample->Cr_r_tab[i] = (int)
 		    RIGHT_SHIFT(FIX(1.40200) * x + ONE_HALF, SCALEBITS);
     /* Cb=>B value is nearest int to 1.77200 * x */
     upsample->Cb_b_tab[i] = (int)
 		    RIGHT_SHIFT(FIX(1.77200) * x + ONE_HALF, SCALEBITS);
     /* Cr=>G value is scaled-up -0.71414 * x */
     upsample->Cr_g_tab[i] = (- FIX(0.71414)) * x;
     /* Cb=>G value is scaled-up -0.34414 * x */
     /* We also add in ONE_HALF so that need not do it in inner loop */
     upsample->Cb_g_tab[i] = (- FIX(0.34414)) * x + ONE_HALF;
   }
 }
 /*
  * Initialize for an upsampling pass.
  */
 METHODDEF(void)
 start_pass_merged_upsample (j_decompress_ptr cinfo)
 {
   my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
   /* Mark the spare buffer empty */
   upsample->spare_full = FALSE;
   /* Initialize total-height counter for detecting bottom of image */
   upsample->rows_to_go = cinfo->output_height;
 }
 /*
  * Control routine to do upsampling (and color conversion).
  *
  * The control routine just handles the row buffering considerations.
  */
 METHODDEF(void)
 merged_2v_upsample (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)
 /* 2:1 vertical sampling case: may need a spare row. */
 {
   my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
   JSAMPROW work_ptrs[2];
   JDIMENSION num_rows;		/* number of rows returned to caller */
   if (upsample->spare_full) {
     /* If we have a spare row saved from a previous cycle, just return it. */
     jcopy_sample_rows(& upsample->spare_row, 0, output_buf + *out_row_ctr, 0,
 , upsample->out_row_width);
     num_rows = 1;
     upsample->spare_full = FALSE;
   } else {
     /* Figure number of rows to return to caller. */
     num_rows = 2;
     /* Not more than the distance to the end of the image. */
     if (num_rows > upsample->rows_to_go)
       num_rows = upsample->rows_to_go;
     /* And not more than what the client can accept: */
     out_rows_avail -= *out_row_ctr;
     if (num_rows > out_rows_avail)
       num_rows = out_rows_avail;
     /* Create output pointer array for upsampler. */
     work_ptrs[0] = output_buf[*out_row_ctr];
     if (num_rows > 1) {
       work_ptrs[1] = output_buf[*out_row_ctr + 1];
     } else {
       work_ptrs[1] = upsample->spare_row;
       upsample->spare_full = TRUE;
     }
     /* Now do the upsampling. */
     (*upsample->upmethod) (cinfo, input_buf, *in_row_group_ctr, work_ptrs);
   }
   /* Adjust counts */
   *out_row_ctr += num_rows;
   upsample->rows_to_go -= num_rows;
   /* When the buffer is emptied, declare this input row group consumed */
   if (! upsample->spare_full)
     (*in_row_group_ctr)++;
 }
 METHODDEF(void)
 merged_1v_upsample (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)
 /* 1:1 vertical sampling case: much easier, never need a spare row. */
 {
   my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
   /* Just do the upsampling. */
   (*upsample->upmethod) (cinfo, input_buf, *in_row_group_ctr,
 			 output_buf + *out_row_ctr);
   /* Adjust counts */
   (*out_row_ctr)++;
   (*in_row_group_ctr)++;
 }
 /*
  * These are the routines invoked by the control routines to do
  * the actual upsampling/conversion.  One row group is processed per call.
  *
  * Note: since we may be writing directly into application-supplied buffers,
  * we have to be honest about the output width; we can't assume the buffer
  * has been rounded up to an even width.
  */
 /*
  * Upsample and color convert for the case of 2:1 horizontal and 1:1 vertical.
  */
 METHODDEF(void)
 h2v1_merged_upsample (j_decompress_ptr cinfo,
 		      JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
 		      JSAMPARRAY output_buf)
 {
   switch (cinfo->out_color_space) {
     case JCS_EXT_RGB:
       extrgb_h2v1_merged_upsample_internal(cinfo, input_buf, in_row_group_ctr,
                                            output_buf);
       break;
     case JCS_EXT_RGBX:
     case JCS_EXT_RGBA:
       extrgbx_h2v1_merged_upsample_internal(cinfo, input_buf, in_row_group_ctr,
                                             output_buf);
       break;
     case JCS_EXT_BGR:
       extbgr_h2v1_merged_upsample_internal(cinfo, input_buf, in_row_group_ctr,
                                            output_buf);
       break;
     case JCS_EXT_BGRX:
     case JCS_EXT_BGRA:
       extbgrx_h2v1_merged_upsample_internal(cinfo, input_buf, in_row_group_ctr,
                                             output_buf);
       break;
     case JCS_EXT_XBGR:
     case JCS_EXT_ABGR:
       extxbgr_h2v1_merged_upsample_internal(cinfo, input_buf, in_row_group_ctr,
                                             output_buf);
       break;
     case JCS_EXT_XRGB:
     case JCS_EXT_ARGB:
       extxrgb_h2v1_merged_upsample_internal(cinfo, input_buf, in_row_group_ctr,
                                             output_buf);
       break;
     default:
       h2v1_merged_upsample_internal(cinfo, input_buf, in_row_group_ctr,
                                     output_buf);
       break;
   }
 }
 /*
  * Upsample and color convert for the case of 2:1 horizontal and 2:1 vertical.
  */
 METHODDEF(void)
 h2v2_merged_upsample (j_decompress_ptr cinfo,
 		      JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
 		      JSAMPARRAY output_buf)
 {
   switch (cinfo->out_color_space) {
     case JCS_EXT_RGB:
       extrgb_h2v2_merged_upsample_internal(cinfo, input_buf, in_row_group_ctr,
                                            output_buf);
       break;
     case JCS_EXT_RGBX:
     case JCS_EXT_RGBA:
       extrgbx_h2v2_merged_upsample_internal(cinfo, input_buf, in_row_group_ctr,
                                             output_buf);
       break;
     case JCS_EXT_BGR:
       extbgr_h2v2_merged_upsample_internal(cinfo, input_buf, in_row_group_ctr,
                                            output_buf);
       break;
     case JCS_EXT_BGRX:
     case JCS_EXT_BGRA:
       extbgrx_h2v2_merged_upsample_internal(cinfo, input_buf, in_row_group_ctr,
                                             output_buf);
       break;
     case JCS_EXT_XBGR:
     case JCS_EXT_ABGR:
       extxbgr_h2v2_merged_upsample_internal(cinfo, input_buf, in_row_group_ctr,
                                             output_buf);
       break;
     case JCS_EXT_XRGB:
     case JCS_EXT_ARGB:
       extxrgb_h2v2_merged_upsample_internal(cinfo, input_buf, in_row_group_ctr,
                                             output_buf);
       break;
     default:
       h2v2_merged_upsample_internal(cinfo, input_buf, in_row_group_ctr,
                                     output_buf);
       break;
   }
 }
 /*
  * Module initialization routine for merged upsampling/color conversion.
  *
  * NB: this is called under the conditions determined by use_merged_upsample()
  * in jdmaster.c.  That routine MUST correspond to the actual capabilities
  * of this module; no safety checks are made here.
  */
 GLOBAL(void)
 jinit_merged_upsampler (j_decompress_ptr cinfo)
 {
   my_upsample_ptr upsample;
   upsample = (my_upsample_ptr)
     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 				SIZEOF(my_upsampler));
   cinfo->upsample = (struct jpeg_upsampler *) upsample;
   upsample->pub.start_pass = start_pass_merged_upsample;
   upsample->pub.need_context_rows = FALSE;
   upsample->out_row_width = cinfo->output_width * cinfo->out_color_components;
   if (cinfo->max_v_samp_factor == 2) {
     upsample->pub.upsample = merged_2v_upsample;
     if (jsimd_can_h2v2_merged_upsample())
       upsample->upmethod = jsimd_h2v2_merged_upsample;
     else
       upsample->upmethod = h2v2_merged_upsample;
     /* Allocate a spare row buffer */
     upsample->spare_row = (JSAMPROW)
       (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 		(size_t) (upsample->out_row_width * SIZEOF(JSAMPLE)));
   } else {
     upsample->pub.upsample = merged_1v_upsample;
     if (jsimd_can_h2v1_merged_upsample())
       upsample->upmethod = jsimd_h2v1_merged_upsample;
     else
       upsample->upmethod = h2v1_merged_upsample;
     /* No spare row needed */
     upsample->spare_row = NULL;
   }
   build_ycc_rgb_table(cinfo);
 }
 #endif /* UPSAMPLE_MERGING_SUPPORTED */

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

media/libjpeg/jdmerge.c