The Tor Browser: media/libvpx/vp8/encoder/tokenize.c@ac0c01689b40 (annotated)

media/libvpx/vp8/encoder/tokenize.c@ac0c01689b40 (annotated)

media/libvpx/vp8/encoder/tokenize.c

Thu, 15 Jan 2015 15:59:08 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 15 Jan 2015 15:59:08 +0100
branch: TOR_BUG_9701
changeset 10: ac0c01689b40
permissions: -rw-r--r--

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /*
  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include <math.h>
 #include <stdio.h>
 #include <string.h>
 #include <assert.h>
 #include "onyx_int.h"
 #include "tokenize.h"
 #include "vpx_mem/vpx_mem.h"
 /* Global event counters used for accumulating statistics across several
    compressions, then generating context.c = initial stats. */
 #ifdef VP8_ENTROPY_STATS
 _int64 context_counters[BLOCK_TYPES] [COEF_BANDS] [PREV_COEF_CONTEXTS] [MAX_ENTROPY_TOKENS];
 #endif
 void vp8_stuff_mb(VP8_COMP *cpi, MACROBLOCK *x, TOKENEXTRA **t) ;
 void vp8_fix_contexts(MACROBLOCKD *x);
 #include "dct_value_tokens.h"
 #include "dct_value_cost.h"
 const TOKENVALUE *const vp8_dct_value_tokens_ptr = dct_value_tokens +
         DCT_MAX_VALUE;
 const short *const vp8_dct_value_cost_ptr = dct_value_cost + DCT_MAX_VALUE;
 #if 0
 int skip_true_count = 0;
 int skip_false_count = 0;
 #endif
 /* function used to generate dct_value_tokens and dct_value_cost tables */
 /*
 static void fill_value_tokens()
 {
     TOKENVALUE *t = dct_value_tokens + DCT_MAX_VALUE;
     const vp8_extra_bit_struct *e = vp8_extra_bits;
     int i = -DCT_MAX_VALUE;
     int sign = 1;
     do
     {
         if (!i)
             sign = 0;
         {
             const int a = sign ? -i : i;
             int eb = sign;
             if (a > 4)
             {
                 int j = 4;
                 while (++j < 11  &&  e[j].base_val <= a) {}
                 t[i].Token = --j;
                 eb |= (a - e[j].base_val) << 1;
             }
             else
                 t[i].Token = a;
             t[i].Extra = eb;
         }
         // initialize the cost for extra bits for all possible coefficient value.
         {
             int cost = 0;
             const vp8_extra_bit_struct *p = vp8_extra_bits + t[i].Token;
             if (p->base_val)
             {
                 const int extra = t[i].Extra;
                 const int Length = p->Len;
                 if (Length)
                     cost += vp8_treed_cost(p->tree, p->prob, extra >> 1, Length);
                 cost += vp8_cost_bit(vp8_prob_half, extra & 1); // sign
                 dct_value_cost[i + DCT_MAX_VALUE] = cost;
             }
         }
     }
     while (++i < DCT_MAX_VALUE);
     vp8_dct_value_tokens_ptr = dct_value_tokens + DCT_MAX_VALUE;
     vp8_dct_value_cost_ptr   = dct_value_cost + DCT_MAX_VALUE;
 }
 */
 static void tokenize2nd_order_b
 (
     MACROBLOCK *x,
     TOKENEXTRA **tp,
     VP8_COMP *cpi
 )
 {
     MACROBLOCKD *xd = &x->e_mbd;
     int pt;             /* near block/prev token context index */
     int c;              /* start at DC */
     TOKENEXTRA *t = *tp;/* store tokens starting here */
     const BLOCKD *b;
     const short *qcoeff_ptr;
     ENTROPY_CONTEXT * a;
     ENTROPY_CONTEXT * l;
     int band, rc, v, token;
     int eob;
     b = xd->block + 24;
     qcoeff_ptr = b->qcoeff;
     a = (ENTROPY_CONTEXT *)xd->above_context + 8;
     l = (ENTROPY_CONTEXT *)xd->left_context + 8;
     eob = xd->eobs[24];
     VP8_COMBINEENTROPYCONTEXTS(pt, *a, *l);
     if(!eob)
     {
         /* c = band for this case */
         t->Token = DCT_EOB_TOKEN;
         t->context_tree = cpi->common.fc.coef_probs [1] [0] [pt];
         t->skip_eob_node = 0;
         ++x->coef_counts       [1] [0] [pt] [DCT_EOB_TOKEN];
         t++;
         *tp = t;
         *a = *l = 0;
         return;
     }
     v = qcoeff_ptr[0];
     t->Extra = vp8_dct_value_tokens_ptr[v].Extra;
     token    = vp8_dct_value_tokens_ptr[v].Token;
     t->Token = token;
     t->context_tree = cpi->common.fc.coef_probs [1] [0] [pt];
     t->skip_eob_node = 0;
     ++x->coef_counts       [1] [0] [pt] [token];
     pt = vp8_prev_token_class[token];
     t++;
     c = 1;
     for (; c < eob; c++)
     {
         rc = vp8_default_zig_zag1d[c];
         band = vp8_coef_bands[c];
         v = qcoeff_ptr[rc];
         t->Extra = vp8_dct_value_tokens_ptr[v].Extra;
         token    = vp8_dct_value_tokens_ptr[v].Token;
         t->Token = token;
         t->context_tree = cpi->common.fc.coef_probs [1] [band] [pt];
         t->skip_eob_node = ((pt == 0));
         ++x->coef_counts       [1] [band] [pt] [token];
         pt = vp8_prev_token_class[token];
         t++;
     }
     if (c < 16)
     {
         band = vp8_coef_bands[c];
         t->Token = DCT_EOB_TOKEN;
         t->context_tree = cpi->common.fc.coef_probs [1] [band] [pt];
         t->skip_eob_node = 0;
         ++x->coef_counts       [1] [band] [pt] [DCT_EOB_TOKEN];
         t++;
     }
     *tp = t;
     *a = *l = 1;
 }
 static void tokenize1st_order_b
 (
     MACROBLOCK *x,
     TOKENEXTRA **tp,
     int type,           /* which plane: 0=Y no DC, 1=Y2, 2=UV, 3=Y with DC */
     VP8_COMP *cpi
 )
 {
     MACROBLOCKD *xd = &x->e_mbd;
     unsigned int block;
     const BLOCKD *b;
     int pt;             /* near block/prev token context index */
     int c;
     int token;
     TOKENEXTRA *t = *tp;/* store tokens starting here */
     const short *qcoeff_ptr;
     ENTROPY_CONTEXT * a;
     ENTROPY_CONTEXT * l;
     int band, rc, v;
     int tmp1, tmp2;
     b = xd->block;
     /* Luma */
     for (block = 0; block < 16; block++, b++)
     {
         tmp1 = vp8_block2above[block];
         tmp2 = vp8_block2left[block];
         qcoeff_ptr = b->qcoeff;
         a = (ENTROPY_CONTEXT *)xd->above_context + tmp1;
         l = (ENTROPY_CONTEXT *)xd->left_context + tmp2;
         VP8_COMBINEENTROPYCONTEXTS(pt, *a, *l);
         c = type ? 0 : 1;
         if(c >= *b->eob)
         {
             /* c = band for this case */
             t->Token = DCT_EOB_TOKEN;
             t->context_tree = cpi->common.fc.coef_probs [type] [c] [pt];
             t->skip_eob_node = 0;
             ++x->coef_counts       [type] [c] [pt] [DCT_EOB_TOKEN];
             t++;
             *tp = t;
             *a = *l = 0;
             continue;
         }
         v = qcoeff_ptr[c];
         t->Extra = vp8_dct_value_tokens_ptr[v].Extra;
         token    = vp8_dct_value_tokens_ptr[v].Token;
         t->Token = token;
         t->context_tree = cpi->common.fc.coef_probs [type] [c] [pt];
         t->skip_eob_node = 0;
         ++x->coef_counts       [type] [c] [pt] [token];
         pt = vp8_prev_token_class[token];
         t++;
         c++;
         for (; c < *b->eob; c++)
         {
             rc = vp8_default_zig_zag1d[c];
             band = vp8_coef_bands[c];
             v = qcoeff_ptr[rc];
             t->Extra = vp8_dct_value_tokens_ptr[v].Extra;
             token    = vp8_dct_value_tokens_ptr[v].Token;
             t->Token = token;
             t->context_tree = cpi->common.fc.coef_probs [type] [band] [pt];
             t->skip_eob_node = (pt == 0);
             ++x->coef_counts       [type] [band] [pt] [token];
             pt = vp8_prev_token_class[token];
             t++;
         }
         if (c < 16)
         {
             band = vp8_coef_bands[c];
             t->Token = DCT_EOB_TOKEN;
             t->context_tree = cpi->common.fc.coef_probs [type] [band] [pt];
             t->skip_eob_node = 0;
             ++x->coef_counts       [type] [band] [pt] [DCT_EOB_TOKEN];
             t++;
         }
         *tp = t;
         *a = *l = 1;
     }
     /* Chroma */
     for (block = 16; block < 24; block++, b++)
     {
         tmp1 = vp8_block2above[block];
         tmp2 = vp8_block2left[block];
         qcoeff_ptr = b->qcoeff;
         a = (ENTROPY_CONTEXT *)xd->above_context + tmp1;
         l = (ENTROPY_CONTEXT *)xd->left_context + tmp2;
         VP8_COMBINEENTROPYCONTEXTS(pt, *a, *l);
         if(!(*b->eob))
         {
             /* c = band for this case */
             t->Token = DCT_EOB_TOKEN;
             t->context_tree = cpi->common.fc.coef_probs [2] [0] [pt];
             t->skip_eob_node = 0;
             ++x->coef_counts       [2] [0] [pt] [DCT_EOB_TOKEN];
             t++;
             *tp = t;
             *a = *l = 0;
             continue;
         }
         v = qcoeff_ptr[0];
         t->Extra = vp8_dct_value_tokens_ptr[v].Extra;
         token    = vp8_dct_value_tokens_ptr[v].Token;
         t->Token = token;
         t->context_tree = cpi->common.fc.coef_probs [2] [0] [pt];
         t->skip_eob_node = 0;
         ++x->coef_counts       [2] [0] [pt] [token];
         pt = vp8_prev_token_class[token];
         t++;
         c = 1;
         for (; c < *b->eob; c++)
         {
             rc = vp8_default_zig_zag1d[c];
             band = vp8_coef_bands[c];
             v = qcoeff_ptr[rc];
             t->Extra = vp8_dct_value_tokens_ptr[v].Extra;
             token    = vp8_dct_value_tokens_ptr[v].Token;
             t->Token = token;
             t->context_tree = cpi->common.fc.coef_probs [2] [band] [pt];
             t->skip_eob_node = (pt == 0);
             ++x->coef_counts       [2] [band] [pt] [token];
             pt = vp8_prev_token_class[token];
             t++;
         }
         if (c < 16)
         {
             band = vp8_coef_bands[c];
             t->Token = DCT_EOB_TOKEN;
             t->context_tree = cpi->common.fc.coef_probs [2] [band] [pt];
             t->skip_eob_node = 0;
             ++x->coef_counts       [2] [band] [pt] [DCT_EOB_TOKEN];
             t++;
         }
         *tp = t;
         *a = *l = 1;
     }
 }
 static int mb_is_skippable(MACROBLOCKD *x, int has_y2_block)
 {
     int skip = 1;
     int i = 0;
     if (has_y2_block)
     {
         for (i = 0; i < 16; i++)
             skip &= (x->eobs[i] < 2);
     }
     for (; i < 24 + has_y2_block; i++)
         skip &= (!x->eobs[i]);
     return skip;
 }
 void vp8_tokenize_mb(VP8_COMP *cpi, MACROBLOCK *x, TOKENEXTRA **t)
 {
     MACROBLOCKD *xd = &x->e_mbd;
     int plane_type;
     int has_y2_block;
     has_y2_block = (xd->mode_info_context->mbmi.mode != B_PRED
                     && xd->mode_info_context->mbmi.mode != SPLITMV);
     xd->mode_info_context->mbmi.mb_skip_coeff =
         mb_is_skippable(xd, has_y2_block);
     if (xd->mode_info_context->mbmi.mb_skip_coeff)
     {
         if (!cpi->common.mb_no_coeff_skip)
         {
             vp8_stuff_mb(cpi, x, t);
         }
         else
         {
             vp8_fix_contexts(xd);
             x->skip_true_count++;
         }
         return;
     }
     plane_type = 3;
     if(has_y2_block)
     {
         tokenize2nd_order_b(x, t, cpi);
         plane_type = 0;
     }
     tokenize1st_order_b(x, t, plane_type, cpi);
 }
 #ifdef VP8_ENTROPY_STATS
 void init_context_counters(void)
 {
     vpx_memset(context_counters, 0, sizeof(context_counters));
 }
 void print_context_counters()
 {
     int type, band, pt, t;
     FILE *const f = fopen("context.c", "w");
     fprintf(f, "#include \"entropy.h\"\n");
     fprintf(f, "\n/* *** GENERATED FILE: DO NOT EDIT *** */\n\n");
     fprintf(f, "int Contexts[BLOCK_TYPES] [COEF_BANDS] [PREV_COEF_CONTEXTS] [MAX_ENTROPY_TOKENS];\n\n");
     fprintf(f, "const int default_contexts[BLOCK_TYPES] [COEF_BANDS] [PREV_COEF_CONTEXTS] [MAX_ENTROPY_TOKENS] = {");
 # define Comma( X) (X? ",":"")
     type = 0;
     do
     {
         fprintf(f, "%s\n  { /* block Type %d */", Comma(type), type);
         band = 0;
         do
         {
             fprintf(f, "%s\n    { /* Coeff Band %d */", Comma(band), band);
             pt = 0;
             do
             {
                 fprintf(f, "%s\n      {", Comma(pt));
                 t = 0;
                 do
                 {
                     const _int64 x = context_counters [type] [band] [pt] [t];
                     const int y = (int) x;
                     assert(x == (_int64) y);  /* no overflow handling yet */
                     fprintf(f, "%s %d", Comma(t), y);
                 }
                 while (++t < MAX_ENTROPY_TOKENS);
                 fprintf(f, "}");
             }
             while (++pt < PREV_COEF_CONTEXTS);
             fprintf(f, "\n    }");
         }
         while (++band < COEF_BANDS);
         fprintf(f, "\n  }");
     }
     while (++type < BLOCK_TYPES);
     fprintf(f, "\n};\n");
     fclose(f);
 }
 #endif
 static void stuff2nd_order_b
 (
     TOKENEXTRA **tp,
     ENTROPY_CONTEXT *a,
     ENTROPY_CONTEXT *l,
     VP8_COMP *cpi,
     MACROBLOCK *x
 )
 {
     int pt; /* near block/prev token context index */
     TOKENEXTRA *t = *tp;        /* store tokens starting here */
     VP8_COMBINEENTROPYCONTEXTS(pt, *a, *l);
     t->Token = DCT_EOB_TOKEN;
     t->context_tree = cpi->common.fc.coef_probs [1] [0] [pt];
     t->skip_eob_node = 0;
     ++x->coef_counts       [1] [0] [pt] [DCT_EOB_TOKEN];
     ++t;
     *tp = t;
     pt = 0;
     *a = *l = pt;
 }
 static void stuff1st_order_b
 (
     TOKENEXTRA **tp,
     ENTROPY_CONTEXT *a,
     ENTROPY_CONTEXT *l,
     int type,
     VP8_COMP *cpi,
     MACROBLOCK *x
 )
 {
     int pt; /* near block/prev token context index */
     int band;
     TOKENEXTRA *t = *tp;        /* store tokens starting here */
     VP8_COMBINEENTROPYCONTEXTS(pt, *a, *l);
     band = type ? 0 : 1;
     t->Token = DCT_EOB_TOKEN;
     t->context_tree = cpi->common.fc.coef_probs [type] [band] [pt];
     t->skip_eob_node = 0;
     ++x->coef_counts       [type] [band] [pt] [DCT_EOB_TOKEN];
     ++t;
     *tp = t;
     pt = 0; /* 0 <-> all coeff data is zero */
     *a = *l = pt;
 }
 static
 void stuff1st_order_buv
 (
     TOKENEXTRA **tp,
     ENTROPY_CONTEXT *a,
     ENTROPY_CONTEXT *l,
     VP8_COMP *cpi,
     MACROBLOCK *x
 )
 {
     int pt; /* near block/prev token context index */
     TOKENEXTRA *t = *tp;        /* store tokens starting here */
     VP8_COMBINEENTROPYCONTEXTS(pt, *a, *l);
     t->Token = DCT_EOB_TOKEN;
     t->context_tree = cpi->common.fc.coef_probs [2] [0] [pt];
     t->skip_eob_node = 0;
     ++x->coef_counts[2] [0] [pt] [DCT_EOB_TOKEN];
     ++t;
     *tp = t;
     pt = 0; /* 0 <-> all coeff data is zero */
     *a = *l = pt;
 }
 void vp8_stuff_mb(VP8_COMP *cpi, MACROBLOCK *x, TOKENEXTRA **t)
 {
     MACROBLOCKD *xd = &x->e_mbd;
     ENTROPY_CONTEXT * A = (ENTROPY_CONTEXT *)xd->above_context;
     ENTROPY_CONTEXT * L = (ENTROPY_CONTEXT *)xd->left_context;
     int plane_type;
     int b;
     plane_type = 3;
     if((xd->mode_info_context->mbmi.mode != B_PRED
                         && xd->mode_info_context->mbmi.mode != SPLITMV))
     {
         stuff2nd_order_b(t,
                      A + vp8_block2above[24], L + vp8_block2left[24], cpi, x);
         plane_type = 0;
     }
     for (b = 0; b < 16; b++)
         stuff1st_order_b(t,
                          A + vp8_block2above[b],
                          L + vp8_block2left[b], plane_type, cpi, x);
     for (b = 16; b < 24; b++)
         stuff1st_order_buv(t,
                            A + vp8_block2above[b],
                            L + vp8_block2left[b], cpi, x);
 }
 void vp8_fix_contexts(MACROBLOCKD *x)
 {
     /* Clear entropy contexts for Y2 blocks */
     if (x->mode_info_context->mbmi.mode != B_PRED && x->mode_info_context->mbmi.mode != SPLITMV)
     {
         vpx_memset(x->above_context, 0, sizeof(ENTROPY_CONTEXT_PLANES));
         vpx_memset(x->left_context, 0, sizeof(ENTROPY_CONTEXT_PLANES));
     }
     else
     {
         vpx_memset(x->above_context, 0, sizeof(ENTROPY_CONTEXT_PLANES)-1);
         vpx_memset(x->left_context, 0, sizeof(ENTROPY_CONTEXT_PLANES)-1);
     }
 }

The Tor Browser / annotate

media/libvpx/vp8/encoder/tokenize.c@ac0c01689b40 (annotated)

media/libvpx/vp8/encoder/tokenize.c