/* *  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 "vpx_config.h"#include "vp8/common/blockd.h"#include "onyxd_int.h"#include "vpx_mem/vpx_mem.h"#include "vpx_ports/compiler_attributes.h"#include "vpx_ports/mem.h"#include "detokenize.h" void vp8_reset_mb_tokens_context(MACROBLOCKD *x) {  ENTROPY_CONTEXT *a_ctx = ((ENTROPY_CONTEXT *)x->above_context);  ENTROPY_CONTEXT *l_ctx = ((ENTROPY_CONTEXT *)x->left_context);   memset(a_ctx, 0, sizeof(ENTROPY_CONTEXT_PLANES) - 1);  memset(l_ctx, 0, sizeof(ENTROPY_CONTEXT_PLANES) - 1);   /* Clear entropy contexts for Y2 blocks */  if (!x->mode_info_context->mbmi.is_4x4) {    a_ctx[8] = l_ctx[8] = 0;  }} /*    ------------------------------------------------------------------------------    Residual decoding (Paragraph 13.2 / 13.3)*/static const uint8_t kBands[16 + 1] = {  0, 1, 2, 3, 6, 4, 5, 6, 6,  6, 6, 6, 6, 6, 6, 7, 0 /* extra entry as sentinel */}; static const uint8_t kCat3[] = { 173, 148, 140, 0 };static const uint8_t kCat4[] = { 176, 155, 140, 135, 0 };static const uint8_t kCat5[] = { 180, 157, 141, 134, 130, 0 };static const uint8_t kCat6[] = { 254, 254, 243, 230, 196, 177,                                 153, 140, 133, 130, 129, 0 };static const uint8_t *const kCat3456[] = { kCat3, kCat4, kCat5, kCat6 };static const uint8_t kZigzag[16] = { 0, 1,  4,  8,  5, 2,  3,  6,                                     9, 12, 13, 10, 7, 11, 14, 15 }; #define VP8GetBit vp8dx_decode_bool#define NUM_PROBAS 11#define NUM_CTX 3 /* for const-casting */typedef const uint8_t (*ProbaArray)[NUM_CTX][NUM_PROBAS]; // With corrupt / fuzzed streams the calculation of br->value may overflow. See// b/148271109.static VPX_NO_UNSIGNED_OVERFLOW_CHECK int GetSigned(BOOL_DECODER *br,                                                    int value_to_sign) {  int split = (br->range + 1) >> 1;  VP8_BD_VALUE bigsplit = (VP8_BD_VALUE)split << (VP8_BD_VALUE_SIZE - 8);  int v;   if (br->count < 0) vp8dx_bool_decoder_fill(br);   if (br->value < bigsplit) {    br->range = split;    v = value_to_sign;  } else {    br->range = br->range - split;    br->value = br->value - bigsplit;    v = -value_to_sign;  }  br->range += br->range;  br->value += br->value;  br->count--;   return v;}/*   Returns the position of the last non-zero coeff plus one   (and 0 if there's no coeff at all)*/static int GetCoeffs(BOOL_DECODER *br, ProbaArray prob, int ctx, int n,                     int16_t *out) {  const uint8_t *p = prob[n][ctx];  if (!VP8GetBit(br, p[0])) { /* first EOB is more a 'CBP' bit. */    return 0;  }  while (1) {    ++n;    if (!VP8GetBit(br, p[1])) {      p = prob[kBands[n]][0];    } else { /* non zero coeff */      int v, j;      if (!VP8GetBit(br, p[2])) {        p = prob[kBands[n]][1];        v = 1;      } else {        if (!VP8GetBit(br, p[3])) {          if (!VP8GetBit(br, p[4])) {            v = 2;          } else {            v = 3 + VP8GetBit(br, p[5]);          }        } else {          if (!VP8GetBit(br, p[6])) {            if (!VP8GetBit(br, p[7])) {              v = 5 + VP8GetBit(br, 159);            } else {              v = 7 + 2 * VP8GetBit(br, 165);              v += VP8GetBit(br, 145);            }          } else {            const uint8_t *tab;            const int bit1 = VP8GetBit(br, p[8]);            const int bit0 = VP8GetBit(br, p[9 + bit1]);            const int cat = 2 * bit1 + bit0;            v = 0;            for (tab = kCat3456[cat]; *tab; ++tab) {              v += v + VP8GetBit(br, *tab);            }            v += 3 + (8 << cat);          }        }        p = prob[kBands[n]][2];      }      j = kZigzag[n - 1];       out[j] = GetSigned(br, v);       if (n == 16 || !VP8GetBit(br, p[0])) { /* EOB */        return n;      }    }    if (n == 16) {      return 16;    }  }} int vp8_decode_mb_tokens(VP8D_COMP *dx, MACROBLOCKD *x) {  BOOL_DECODER *bc = x->current_bc;  const FRAME_CONTEXT *const fc = &dx->common.fc;  char *eobs = x->eobs;   int i;  int nonzeros;  int eobtotal = 0;   short *qcoeff_ptr;  ProbaArray coef_probs;  ENTROPY_CONTEXT *a_ctx = ((ENTROPY_CONTEXT *)x->above_context);  ENTROPY_CONTEXT *l_ctx = ((ENTROPY_CONTEXT *)x->left_context);  ENTROPY_CONTEXT *a;  ENTROPY_CONTEXT *l;  int skip_dc = 0;   qcoeff_ptr = &x->qcoeff[0];   if (!x->mode_info_context->mbmi.is_4x4) {    a = a_ctx + 8;    l = l_ctx + 8;     coef_probs = fc->coef_probs[1];     nonzeros = GetCoeffs(bc, coef_probs, (*a + *l), 0, qcoeff_ptr + 24 * 16);    *a = *l = (nonzeros > 0);     eobs[24] = nonzeros;    eobtotal += nonzeros - 16;     coef_probs = fc->coef_probs[0];    skip_dc = 1;  } else {    coef_probs = fc->coef_probs[3];    skip_dc = 0;  }   for (i = 0; i < 16; ++i) {    a = a_ctx + (i & 3);    l = l_ctx + ((i & 0xc) >> 2);     nonzeros = GetCoeffs(bc, coef_probs, (*a + *l), skip_dc, qcoeff_ptr);    *a = *l = (nonzeros > 0);     nonzeros += skip_dc;    eobs[i] = nonzeros;    eobtotal += nonzeros;    qcoeff_ptr += 16;  }   coef_probs = fc->coef_probs[2];   a_ctx += 4;  l_ctx += 4;  for (i = 16; i < 24; ++i) {    a = a_ctx + ((i > 19) << 1) + (i & 1);    l = l_ctx + ((i > 19) << 1) + ((i & 3) > 1);     nonzeros = GetCoeffs(bc, coef_probs, (*a + *l), 0, qcoeff_ptr);    *a = *l = (nonzeros > 0);     eobs[i] = nonzeros;    eobtotal += nonzeros;    qcoeff_ptr += 16;  }   return eobtotal;}