Add WebP library to Chromium...

third_party/libwebp/vp8.c

+// Copyright 2010 Google Inc.
+//
+// This code is licensed under the same terms as WebM:
+//  Software License Agreement:  http://www.webmproject.org/license/software/
+//  Additional IP Rights Grant:  http://www.webmproject.org/license/additional/
+// -----------------------------------------------------------------------------
+//
+// main entry for the decoder
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include <stdlib.h>
+#include "vp8i.h"
+
+//-----------------------------------------------------------------------------
+// VP8Decoder
+
+static void SetOk(VP8Decoder* const dec) {
+  dec->status_ = 0;
+  dec->error_msg_ = "OK";
+}
+
+void VP8InitIo(VP8Io* const io) {
+  if (io) {
+    memset(io, 0, sizeof(*io));
+  }
+}
+
+VP8Decoder* VP8New() {
+  VP8Decoder* dec = (VP8Decoder*)calloc(1, sizeof(VP8Decoder));
+  if (dec) {
+    SetOk(dec);
+    dec->ready_ = 0;
+  }
+  return dec;
+}
+
+int VP8Status(VP8Decoder* const dec) {
+  if (!dec) return 2;
+  return dec->status_;
+}
+
+const char* VP8StatusMessage(VP8Decoder* const dec) {
+  if (!dec) return "no object";
+  if (!dec->error_msg_) return "OK";
+  return dec->error_msg_;
+}
+
+void VP8Delete(VP8Decoder* const dec) {
+  if (dec) {
+    VP8Clear(dec);
+    free(dec);
+  }
+}
+
+int VP8SetError(VP8Decoder* const dec, int error, const char *msg) {
+  dec->status_ = error;
+  dec->error_msg_ = msg;
+  dec->ready_ = 0;
+  return 0;
+}
+
+//-----------------------------------------------------------------------------
+// Header parsing
+
+static void ResetSegmentHeader(VP8SegmentHeader* const hdr) {
+  assert(hdr);
+  hdr->use_segment_ = 0;
+  hdr->update_map_ = 0;
+  hdr->absolute_delta_ = 1;
+  memset(hdr->quantizer_, 0, sizeof(hdr->quantizer_));
+  memset(hdr->filter_strength_, 0, sizeof(hdr->filter_strength_));
+}
+
+// Paragraph 9.3
+static int ParseSegmentHeader(VP8BitReader* br,
+                              VP8SegmentHeader* hdr, VP8Proba* proba) {
+  assert(br);
+  assert(hdr);
+  hdr->use_segment_ = VP8Get(br);
+  if (hdr->use_segment_) {
+    hdr->update_map_ = VP8Get(br);
+    const int update_data = VP8Get(br);
+    if (update_data) {
+      hdr->absolute_delta_ = VP8Get(br);
+      for (int s = 0; s < NUM_MB_SEGMENTS; ++s) {
+        hdr->quantizer_[s] = VP8Get(br) ? VP8GetSignedValue(br, 7) : 0;
+      }
+      for (int s = 0; s < NUM_MB_SEGMENTS; ++s) {
+        hdr->filter_strength_[s] = VP8Get(br) ? VP8GetSignedValue(br, 6) : 0;
+      }
+    }
+    if (hdr->update_map_) {
+      for (int s = 0; s < MB_FEATURE_TREE_PROBS; ++s) {
+        proba->segments_[s] = VP8Get(br) ? VP8GetValue(br, 8) : 255u;
+      }
+    }
+  } else {
+    hdr->update_map_ = 0;
+  }
+  return 1;
+}
+
+// Paragraph 9.5
+static int ParsePartitions(VP8Decoder* const dec,
+                           const uint8_t* buf, uint32_t size) {
+  VP8BitReader* const br = &dec->br_;
+  dec->num_parts_ = 1 << VP8GetValue(br, 2);
+  const uint8_t* sz = buf;
+  const int last_part = dec->num_parts_ - 1;
+  uint32_t offset = last_part * 3;
+  if (size <= offset) {
+    return 0;
+  }
+  for (int p = 0; p < last_part; ++p) {
+    const uint32_t psize = sz[0] | (sz[1] << 8) | (sz[2] << 16);
+    if (offset + psize > size) {
+      return 0;
+    }
+    VP8Init(dec->parts_ + p, buf + offset, psize);
+    offset += psize;
+    sz += 3;
+  }
+  size -= offset;
+  VP8Init(dec->parts_ + last_part, buf + offset, size);
+  return 1;
+}
+
+// Paragraph 9.4
+static int ParseFilterHeader(VP8BitReader* br, VP8Decoder* const dec) {
+  VP8FilterHeader* const hdr = &dec->filter_hdr_;
+  hdr->simple_    = VP8Get(br);
+  hdr->level_     = VP8GetValue(br, 6);
+  hdr->sharpness_ = VP8GetValue(br, 3);
+  hdr->use_lf_delta_ = VP8Get(br);
+  if (hdr->use_lf_delta_) {
+    if (VP8Get(br)) {   // update lf-delta?
+      for (int i = 0; i < NUM_REF_LF_DELTAS; ++i) {
+        if (VP8Get(br)) {
+          hdr->ref_lf_delta_[i] = VP8GetSignedValue(br, 6);
+        }
+      }
+      for (int i = 0; i < NUM_MODE_LF_DELTAS; ++i) {
+        if (VP8Get(br)) {
+          hdr->mode_lf_delta_[i] = VP8GetSignedValue(br, 6);
+        }
+      }
+    }
+  }
+  dec->filter_type_ = (hdr->level_ == 0) ? 0 : hdr->simple_ ? 1 : 2;
+  if (dec->filter_type_ > 0) {    // precompute filter levels per segment
+    if (dec->segment_hdr_.use_segment_) {
+      for (int s = 0; s < NUM_MB_SEGMENTS; ++s) {
+        int strength = dec->segment_hdr_.filter_strength_[s];
+        if (!dec->segment_hdr_.absolute_delta_) {
+          strength += hdr->level_;
+        }
+        dec->filter_levels_[s] = strength;
+      }
+    } else {
+      dec->filter_levels_[0] = hdr->level_;
+    }
+  }
+  return 1;
+}
+
+static inline uint32_t get_le32(const uint8_t* const data) {
+  return data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
+}
+
+// Topmost call
+int VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io) {
+  if (dec == NULL) {
+    return 0;
+  }
+  SetOk(dec);
+  if (io == NULL || io->data == NULL || io->data_size <= 4) {
+    return VP8SetError(dec, 2, "null VP8Io passed to VP8GetHeaders()");
+  }
+  const uint8_t* buf = io->data;
+  uint32_t buf_size = io->data_size;
+  if (buf_size < 4) {
+    return VP8SetError(dec, 2, "Not enough data to parse frame header");
+  }
+
+  // Skip over valid RIFF headers
+  if (!memcmp(buf, "RIFF", 4)) {
+    if (buf_size < 20 + 4) {
+      return VP8SetError(dec, 2, "RIFF: Truncated header.");
+    }
+    if (memcmp(buf + 8, "WEBP", 4)) {   // wrong image file signature
+      return VP8SetError(dec, 2, "RIFF: WEBP signature not found.");
+    }
+    const uint32_t riff_size = get_le32(buf + 4);
+    if (memcmp(buf + 12, "VP8 ", 4)) {
+      return VP8SetError(dec, 2, "RIFF: Invalid compression format.");
+    }
+    const uint32_t chunk_size = get_le32(buf + 16);
+    if ((chunk_size > riff_size + 8) || (chunk_size & 1)) {
+      return VP8SetError(dec, 2, "RIFF: Inconsistent size information.");
+    }
+    buf += 20;
+    buf_size -= 20;
+  }
+
+  // Paragraph 9.1
+  VP8FrameHeader* const frm_hdr = &dec->frm_hdr_;
+  const uint32_t bits = buf[0] | (buf[1] << 8) | (buf[2] << 16);
+  frm_hdr->key_frame_ = !(bits & 1);
+  frm_hdr->profile_ = (bits >> 1) & 7;
+  frm_hdr->show_ = (bits >> 4) & 1;
+  frm_hdr->partition_length_ = (bits >> 5);
+  buf += 3;
+  buf_size -= 3;
+
+  VP8PictureHeader* const pic_hdr = &dec->pic_hdr_;
+  if (frm_hdr->key_frame_) {
+    // Paragraph 9.2
+    if (buf_size < 7) {
+      return VP8SetError(dec, 2, "cannot parse picture header");
+    }
+    if (buf[0] != 0x9d || buf[1] != 0x01 || buf[2] != 0x2a) {
+      return VP8SetError(dec, 2, "Bad code word");
+    }
+    pic_hdr->width_ = ((buf[4] << 8) | buf[3]) & 0x3fff;
+    pic_hdr->xscale_ = buf[4] >> 6;   // ratio: 1, 5/4 5/3 or 2
+    pic_hdr->height_ = ((buf[6] << 8) | buf[5]) & 0x3fff;
+    pic_hdr->yscale_ = buf[6] >> 6;
+    buf += 7;
+    buf_size -= 7;
+
+    dec->mb_w_ = (pic_hdr->width_ + 15) >> 4;
+    dec->mb_h_ = (pic_hdr->height_ + 15) >> 4;
+    io->width = pic_hdr->width_;
+    io->height = pic_hdr->height_;
+
+    VP8ResetProba(&dec->proba_);
+    ResetSegmentHeader(&dec->segment_hdr_);
+    dec->segment_ = 0;    // default for intra
+  }
+
+  VP8BitReader* const br = &dec->br_;
+  VP8Init(br, buf, buf_size);
+  buf += frm_hdr->partition_length_;
+  buf_size -= frm_hdr->partition_length_;
+  if (frm_hdr->key_frame_) {
+    pic_hdr->colorspace_ = VP8Get(br);
+    pic_hdr->clamp_type_ = VP8Get(br);
+  }
+  if (!ParseSegmentHeader(br, &dec->segment_hdr_, &dec->proba_)) {
+    return VP8SetError(dec, 2, "cannot parse segment header");
+  }
+  // Filter specs
+  if (!ParseFilterHeader(br, dec)) {
+    return VP8SetError(dec, 2, "cannot parse filter header");
+  }
+  if (!ParsePartitions(dec, buf, buf_size)) {
+    return VP8SetError(dec, 2, "cannot parse partitions");
+  }
+
+  // quantizer change
+  VP8ParseQuant(dec);
+
+  // Frame buffer marking
+  if (!frm_hdr->key_frame_) {
+    // Paragraph 9.7
+#ifndef ONLY_KEYFRAME_CODE
+    dec->buffer_flags_ = VP8Get(br) << 0;   // update golden
+    dec->buffer_flags_ |= VP8Get(br) << 1;  // update alt ref
+    if (!(dec->buffer_flags_ & 1)) {
+      dec->buffer_flags_ |= VP8GetValue(br, 2) << 2;
+    }
+    if (!(dec->buffer_flags_ & 2)) {
+      dec->buffer_flags_ |= VP8GetValue(br, 2) << 4;
+    }
+    dec->buffer_flags_ |= VP8Get(br) << 6;    // sign bias golden
+    dec->buffer_flags_ |= VP8Get(br) << 7;    // sign bias alt ref
+#else
+    return VP8SetError(dec, 2, "Not a key frame.");
+#endif
+  } else {
+    dec->buffer_flags_ = 0x003 | 0x100;
+  }
+
+  // Paragraph 9.8
+  dec->update_proba_ = VP8Get(br);
+  if (!dec->update_proba_) {    // save for later restore
+    dec->proba_saved_ = dec->proba_;
+  }
+
+#ifndef ONLY_KEYFRAME_CODE
+  dec->buffer_flags_ &= 1 << 8;
+  dec->buffer_flags_ |=
+      (frm_hdr->key_frame_ || VP8Get(br)) << 8;    // refresh last frame
+#endif
+
+  VP8ParseProba(br, dec);
+
+  // sanitized state
+  dec->ready_ = 1;
+  return 1;
+}
+
+//-----------------------------------------------------------------------------
+// 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
+};
+
+typedef const uint8_t PROBA_ARRAY[NUM_CTX][NUM_PROBAS];
+
+static int GetCoeffs(VP8BitReader* const br,
+                     const uint8_t (*prob)[NUM_CTX][NUM_PROBAS],
+                     int ctx, const uint16_t dq[2], int n, int16_t* out) {
+  const uint8_t* p = prob[kBands[n]][ctx];
+  if (!VP8GetBit(br, p[0])) {   // first EOB is more a 'CBP' bit.
+    return -1;
+  }
+  while (1) {
+    ++n;
+    if (!VP8GetBit(br, p[1])) {
+      p = prob[kBands[n]][0];
+    } else {  // non zero coeff
+      int v;
+      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) + VP8GetBit(br, 145);
+            }
+          } else {
+            const int bit1 = VP8GetBit(br, p[8]);
+            const int bit0 = VP8GetBit(br, p[9 + bit1]);
+            const int cat = 2 * bit1 + bit0;
+            v = 0;
+            for (const uint8_t* tab = kCat3456[cat]; *tab; ++tab) {
+              v += v + VP8GetBit(br, *tab);
+            }
+            v += 3 + (8 << cat);
+          }
+        }
+        p = prob[kBands[n]][2];
+      }
+      const int j = kZigzag[n - 1];
+      out[j] = VP8GetSigned(br, v) * dq[j > 0];
+      if (n == 16) break;
+      if (!VP8GetBit(br, p[0])) {   // EOB
+        return n;
+      }
+    }
+  }
+  return 15;
+}
+
+// Table to unpack four bits into four bytes
+static const uint8_t kUnpackTab[16][4] = {
+  {0, 0, 0, 0},  {1, 0, 0, 0},  {0, 1, 0, 0},  {1, 1, 0, 0},
+  {0, 0, 1, 0},  {1, 0, 1, 0},  {0, 1, 1, 0},  {1, 1, 1, 0},
+  {0, 0, 0, 1},  {1, 0, 0, 1},  {0, 1, 0, 1},  {1, 1, 0, 1},
+  {0, 0, 1, 1},  {1, 0, 1, 1},  {0, 1, 1, 1},  {1, 1, 1, 1} };
+
+// Macro to pack four LSB of four bytes into four bits.
+#define PACK(X, S) \
+  ((((*(uint32_t*)(X)) * 0x01020408U) & 0xff000000) >> (S))
+
+typedef const uint8_t (*Proba_t)[NUM_CTX][NUM_PROBAS];  // for const-casting
+static int ParseResiduals(VP8Decoder* const dec,
+                          VP8MB* const mb, VP8BitReader* const token_br) {
+  int out_t_nz, out_l_nz, first;
+  Proba_t ac_prob;
+  const VP8QuantMatrix* q = &dec->dqm_[dec->segment_];
+  int16_t* dst = dec->coeffs_;
+  VP8MB* const left_mb = dec->mb_info_ - 1;
+  memset(dst, 0, 384 * sizeof(*dst));
+  if (!dec->is_i4x4_) {    // parse DC
+    int16_t dc[16] = { 0 };
+    const int ctx = mb->dc_nz_ + left_mb->dc_nz_;
+    const int last = GetCoeffs(token_br, (Proba_t)dec->proba_.coeffs_[1],
+                               ctx, q->y2_mat_, 0, dc);
+    mb->dc_nz_ = left_mb->dc_nz_ = (last >= 0);
+    first = 1;
+    ac_prob = (Proba_t)dec->proba_.coeffs_[0];
+    VP8TransformWHT(dc, dst);
+  } else {
+    first = 0;
+    ac_prob = (Proba_t)dec->proba_.coeffs_[3];
+  }
+
+  uint8_t nz_ac[4], nz_dc[4];
+  uint32_t non_zero_ac = 0;
+  uint32_t non_zero_dc = 0;
+
+  uint8_t tnz[4], lnz[4];
+  memcpy(tnz, kUnpackTab[mb->nz_ & 0xf], sizeof(tnz));
+  memcpy(lnz, kUnpackTab[left_mb->nz_ & 0xf], sizeof(lnz));
+  for (int y = 0; y < 4; ++y) {
+    int l = lnz[y];
+    for (int x = 0; x < 4; ++x) {
+      const int ctx = l + tnz[x];
+      const int last = GetCoeffs(token_br, ac_prob, ctx,
+                                 q->y1_mat_, first, dst);
+      nz_dc[x] = (dst[0] != 0);
+      nz_ac[x] = (last > 0);
+      tnz[x] = l = (last >= 0);
+      dst += 16;
+    }
+    lnz[y] = l;
+    non_zero_dc |= PACK(nz_dc, 24 - y * 4);
+    non_zero_ac |= PACK(nz_ac, 24 - y * 4);
+  }
+  out_t_nz = PACK(tnz, 24);
+  out_l_nz = PACK(lnz, 24);
+
+  memcpy(tnz, kUnpackTab[mb->nz_ >> 4], sizeof(tnz));
+  memcpy(lnz, kUnpackTab[left_mb->nz_ >> 4], sizeof(lnz));
+  for (int ch = 0; ch < 4; ch += 2) {
+    for (int y = 0; y < 2; ++y) {
+      int l = lnz[ch + y];
+      for (int x = 0; x < 2; ++x) {
+        const int ctx = l + tnz[ch + x];
+        const int last =
+            GetCoeffs(token_br, (Proba_t)dec->proba_.coeffs_[2],
+                      ctx, q->uv_mat_, 0, dst);
+        nz_dc[y * 2 + x] = (dst[0] != 0);
+        nz_ac[y * 2 + x] = (last > 0);
+        tnz[ch + x] = l = (last >= 0);
+        dst += 16;
+      }
+      lnz[ch + y] = l;
+    }
+    non_zero_dc |= PACK(nz_dc, 8 - ch * 2);
+    non_zero_ac |= PACK(nz_ac, 8 - ch * 2);
+  }
+  out_t_nz |= PACK(tnz, 20);
+  out_l_nz |= PACK(lnz, 20);
+  mb->nz_ = out_t_nz;
+  left_mb->nz_ = out_l_nz;
+
+  dec->non_zero_ac_ = non_zero_ac;
+  dec->non_zero_ = non_zero_ac | non_zero_dc;
+  mb->skip_ = !dec->non_zero_;
+
+  return 1;
+}
+#undef PACK
+
+//-----------------------------------------------------------------------------
+// Main loop
+
+static void SendBlock(VP8Decoder* const dec, VP8Io* io) {
+  if (io->put) {
+    io->mb_x = dec->mb_x_ * 16;
+    io->mb_y = dec->mb_y_ * 16;
+    io->mb_w = io->width - io->mb_x;
+    io->mb_h = io->height - io->mb_y;
+    if (io->mb_w > 16) io->mb_w = 16;
+    if (io->mb_h > 16) io->mb_h = 16;
+    io->put(io);
+  }
+}
+
+static int ParseFrame(VP8Decoder* const dec, VP8Io* io) {
+  int ok = 1;
+  VP8BitReader* const br = &dec->br_;
+
+  for (dec->mb_y_ = 0; dec->mb_y_ < dec->mb_h_; ++dec->mb_y_) {
+    memset(dec->intra_l_, B_DC_PRED, sizeof(dec->intra_l_));
+    VP8MB* const left = dec->mb_info_ - 1;
+    left->nz_ = 0;
+    left->dc_nz_ = 0;
+    VP8BitReader* token_br = &dec->parts_[dec->mb_y_ & (dec->num_parts_ - 1)];
+    for (dec->mb_x_ = 0; dec->mb_x_ < dec->mb_w_;  dec->mb_x_++) {
+      VP8MB* const info = dec->mb_info_ + dec->mb_x_;
+
+      // Note: we don't save segment map (yet), as we don't expect
+      // to decode more than 1 keyframe.
+      if (dec->segment_hdr_.update_map_) {
+        // Hardcoded tree parsing
+        dec->segment_ = !VP8GetBit(br, dec->proba_.segments_[0]) ?
+              VP8GetBit(br, dec->proba_.segments_[1]) :
+          2 + VP8GetBit(br, dec->proba_.segments_[2]);
+      }
+      info->skip_ = dec->use_skip_proba_ ? VP8GetBit(br, dec->skip_p_) : 0;
+
+      VP8ParseIntraMode(br, dec);
+
+      if (!info->skip_) {
+        if (!ParseResiduals(dec, info, token_br)) {
+          ok = 0;
+          break;
+        }
+      } else {
+        left->nz_ = info->nz_ = 0;
+        if (!dec->is_i4x4_) {
+          left->dc_nz_ = info->dc_nz_ = 0;
+        }
+        dec->non_zero_ = 0;
+        dec->non_zero_ac_ = 0;
+      }
+      VP8ReconstructBlock(dec);
+
+      // Store filter params
+      if (dec->filter_type_ > 0) {
+        VP8StoreBlock(dec);
+      } else {  // We're done. Send block to user at once.
+        SendBlock(dec, io);
+      }
+    }
+    if (!ok) {
+      break;
+    }
+    if (dec->filter_type_ > 0) {   // filter a row
+      VP8FilterRow(dec, io);
+    }
+    if (dec->br_.eof_ || token_br->eof_) {
+      ok = 0;
+      break;
+    }
+  }
+
+  // Finish
+  if (!dec->update_proba_) {
+    dec->proba_ = dec->proba_saved_;
+  }
+  return ok;
+}
+
+// Main entry point
+int VP8Decode(VP8Decoder* const dec, VP8Io* const io) {
+  if (dec == NULL) {
+    return 0;
+  }
+  if (io == NULL) {
+    return VP8SetError(dec, 2, "NULL VP8Io parameter in VP8Decode().");
+  }
+
+  if (!dec->ready_) {
+    if (!VP8GetHeaders(dec, io)) {
+      return 0;
+    }
+  }
+  assert(dec->ready_);
+
+  // will allocate memory and prepare everything.
+  if (!VP8InitFrame(dec, io)) {
+    VP8Clear(dec);
+    return VP8SetError(dec, 3, "Allocation failed");
+  }
+
+  // set-up
+  if (io->setup) io->setup(io);
+
+  // Main decoding loop
+  if (!ParseFrame(dec, io)) {
+    VP8Clear(dec);
+    return VP8SetError(dec, 3, "Frame decoding failed");
+  }
+
+  // tear-down
+  if (io->teardown) io->teardown(io);
+
+  dec->ready_ = 0;
+  return 1;
+}
+
+void VP8Clear(VP8Decoder* const dec) {
+  if (dec == NULL) {
+    return;
+  }
+  if (dec->mem_) {
+    free(dec->mem_);
+  }
+  dec->mem_ = NULL;
+  dec->mem_size_ = 0;
+  memset(&dec->br_, 0, sizeof(dec->br_));
+  dec->ready_ = 0;
+}