diff options
Diffstat (limited to 'drivers/webpold/dec/vp8.c')
| -rw-r--r-- | drivers/webpold/dec/vp8.c | 787 |
1 files changed, 787 insertions, 0 deletions
diff --git a/drivers/webpold/dec/vp8.c b/drivers/webpold/dec/vp8.c new file mode 100644 index 0000000000..b0ccfa2a06 --- /dev/null +++ b/drivers/webpold/dec/vp8.c @@ -0,0 +1,787 @@ +// Copyright 2010 Google Inc. All Rights Reserved. +// +// 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" +#include "./vp8li.h" +#include "./webpi.h" +#include "../utils/bit_reader.h" + +#if defined(__cplusplus) || defined(c_plusplus) +extern "C" { +#endif + +//------------------------------------------------------------------------------ + +int WebPGetDecoderVersion(void) { + return (DEC_MAJ_VERSION << 16) | (DEC_MIN_VERSION << 8) | DEC_REV_VERSION; +} + +//------------------------------------------------------------------------------ +// VP8Decoder + +static void SetOk(VP8Decoder* const dec) { + dec->status_ = VP8_STATUS_OK; + dec->error_msg_ = "OK"; +} + +int VP8InitIoInternal(VP8Io* const io, int version) { + if (WEBP_ABI_IS_INCOMPATIBLE(version, WEBP_DECODER_ABI_VERSION)) { + return 0; // mismatch error + } + if (io != NULL) { + memset(io, 0, sizeof(*io)); + } + return 1; +} + +VP8Decoder* VP8New(void) { + VP8Decoder* const dec = (VP8Decoder*)calloc(1, sizeof(*dec)); + if (dec != NULL) { + SetOk(dec); + WebPWorkerInit(&dec->worker_); + dec->ready_ = 0; + dec->num_parts_ = 1; + } + return dec; +} + +VP8StatusCode VP8Status(VP8Decoder* const dec) { + if (!dec) return VP8_STATUS_INVALID_PARAM; + return dec->status_; +} + +const char* VP8StatusMessage(VP8Decoder* const dec) { + if (dec == NULL) return "no object"; + if (!dec->error_msg_) return "OK"; + return dec->error_msg_; +} + +void VP8Delete(VP8Decoder* const dec) { + if (dec != NULL) { + VP8Clear(dec); + free(dec); + } +} + +int VP8SetError(VP8Decoder* const dec, + VP8StatusCode error, const char* const msg) { + // TODO This check would be unnecessary if alpha decompression was separated + // from VP8ProcessRow/FinishRow. This avoids setting 'dec->status_' to + // something other than VP8_STATUS_BITSTREAM_ERROR on alpha decompression + // failure. + if (dec->status_ == VP8_STATUS_OK) { + dec->status_ = error; + dec->error_msg_ = msg; + dec->ready_ = 0; + } + return 0; +} + +//------------------------------------------------------------------------------ + +int VP8CheckSignature(const uint8_t* const data, size_t data_size) { + return (data_size >= 3 && + data[0] == 0x9d && data[1] == 0x01 && data[2] == 0x2a); +} + +int VP8GetInfo(const uint8_t* data, size_t data_size, size_t chunk_size, + int* const width, int* const height) { + if (data == NULL || data_size < VP8_FRAME_HEADER_SIZE) { + return 0; // not enough data + } + // check signature + if (!VP8CheckSignature(data + 3, data_size - 3)) { + return 0; // Wrong signature. + } else { + const uint32_t bits = data[0] | (data[1] << 8) | (data[2] << 16); + const int key_frame = !(bits & 1); + const int w = ((data[7] << 8) | data[6]) & 0x3fff; + const int h = ((data[9] << 8) | data[8]) & 0x3fff; + + if (!key_frame) { // Not a keyframe. + return 0; + } + + if (((bits >> 1) & 7) > 3) { + return 0; // unknown profile + } + if (!((bits >> 4) & 1)) { + return 0; // first frame is invisible! + } + if (((bits >> 5)) >= chunk_size) { // partition_length + return 0; // inconsistent size information. + } + + if (width) { + *width = w; + } + if (height) { + *height = h; + } + + return 1; + } +} + +//------------------------------------------------------------------------------ +// Header parsing + +static void ResetSegmentHeader(VP8SegmentHeader* const hdr) { + assert(hdr != NULL); + 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 != NULL); + assert(hdr != NULL); + hdr->use_segment_ = VP8Get(br); + if (hdr->use_segment_) { + hdr->update_map_ = VP8Get(br); + if (VP8Get(br)) { // update data + int s; + hdr->absolute_delta_ = VP8Get(br); + for (s = 0; s < NUM_MB_SEGMENTS; ++s) { + hdr->quantizer_[s] = VP8Get(br) ? VP8GetSignedValue(br, 7) : 0; + } + for (s = 0; s < NUM_MB_SEGMENTS; ++s) { + hdr->filter_strength_[s] = VP8Get(br) ? VP8GetSignedValue(br, 6) : 0; + } + } + if (hdr->update_map_) { + int s; + for (s = 0; s < MB_FEATURE_TREE_PROBS; ++s) { + proba->segments_[s] = VP8Get(br) ? VP8GetValue(br, 8) : 255u; + } + } + } else { + hdr->update_map_ = 0; + } + return !br->eof_; +} + +// Paragraph 9.5 +// This function returns VP8_STATUS_SUSPENDED if we don't have all the +// necessary data in 'buf'. +// This case is not necessarily an error (for incremental decoding). +// Still, no bitreader is ever initialized to make it possible to read +// unavailable memory. +// If we don't even have the partitions' sizes, than VP8_STATUS_NOT_ENOUGH_DATA +// is returned, and this is an unrecoverable error. +// If the partitions were positioned ok, VP8_STATUS_OK is returned. +static VP8StatusCode ParsePartitions(VP8Decoder* const dec, + const uint8_t* buf, size_t size) { + VP8BitReader* const br = &dec->br_; + const uint8_t* sz = buf; + const uint8_t* buf_end = buf + size; + const uint8_t* part_start; + int last_part; + int p; + + dec->num_parts_ = 1 << VP8GetValue(br, 2); + last_part = dec->num_parts_ - 1; + part_start = buf + last_part * 3; + if (buf_end < part_start) { + // we can't even read the sizes with sz[]! That's a failure. + return VP8_STATUS_NOT_ENOUGH_DATA; + } + for (p = 0; p < last_part; ++p) { + const uint32_t psize = sz[0] | (sz[1] << 8) | (sz[2] << 16); + const uint8_t* part_end = part_start + psize; + if (part_end > buf_end) part_end = buf_end; + VP8InitBitReader(dec->parts_ + p, part_start, part_end); + part_start = part_end; + sz += 3; + } + VP8InitBitReader(dec->parts_ + last_part, part_start, buf_end); + return (part_start < buf_end) ? VP8_STATUS_OK : + VP8_STATUS_SUSPENDED; // Init is ok, but there's not enough data +} + +// 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? + int i; + for (i = 0; i < NUM_REF_LF_DELTAS; ++i) { + if (VP8Get(br)) { + hdr->ref_lf_delta_[i] = VP8GetSignedValue(br, 6); + } + } + for (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_) { + int s; + for (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 !br->eof_; +} + +// Topmost call +int VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io) { + const uint8_t* buf; + size_t buf_size; + VP8FrameHeader* frm_hdr; + VP8PictureHeader* pic_hdr; + VP8BitReader* br; + VP8StatusCode status; + WebPHeaderStructure headers; + + if (dec == NULL) { + return 0; + } + SetOk(dec); + if (io == NULL) { + return VP8SetError(dec, VP8_STATUS_INVALID_PARAM, + "null VP8Io passed to VP8GetHeaders()"); + } + + // Process Pre-VP8 chunks. + headers.data = io->data; + headers.data_size = io->data_size; + status = WebPParseHeaders(&headers); + if (status != VP8_STATUS_OK) { + return VP8SetError(dec, status, "Incorrect/incomplete header."); + } + if (headers.is_lossless) { + return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR, + "Unexpected lossless format encountered."); + } + + if (dec->alpha_data_ == NULL) { + assert(dec->alpha_data_size_ == 0); + // We have NOT set alpha data yet. Set it now. + // (This is to ensure that dec->alpha_data_ is NOT reset to NULL if + // WebPParseHeaders() is called more than once, as in incremental decoding + // case.) + dec->alpha_data_ = headers.alpha_data; + dec->alpha_data_size_ = headers.alpha_data_size; + } + + // Process the VP8 frame header. + buf = headers.data + headers.offset; + buf_size = headers.data_size - headers.offset; + assert(headers.data_size >= headers.offset); // WebPParseHeaders' guarantee + if (buf_size < 4) { + return VP8SetError(dec, VP8_STATUS_NOT_ENOUGH_DATA, + "Truncated header."); + } + + // Paragraph 9.1 + { + const uint32_t bits = buf[0] | (buf[1] << 8) | (buf[2] << 16); + frm_hdr = &dec->frm_hdr_; + frm_hdr->key_frame_ = !(bits & 1); + frm_hdr->profile_ = (bits >> 1) & 7; + frm_hdr->show_ = (bits >> 4) & 1; + frm_hdr->partition_length_ = (bits >> 5); + if (frm_hdr->profile_ > 3) + return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR, + "Incorrect keyframe parameters."); + if (!frm_hdr->show_) + return VP8SetError(dec, VP8_STATUS_UNSUPPORTED_FEATURE, + "Frame not displayable."); + buf += 3; + buf_size -= 3; + } + + pic_hdr = &dec->pic_hdr_; + if (frm_hdr->key_frame_) { + // Paragraph 9.2 + if (buf_size < 7) { + return VP8SetError(dec, VP8_STATUS_NOT_ENOUGH_DATA, + "cannot parse picture header"); + } + if (!VP8CheckSignature(buf, buf_size)) { + return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR, + "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; + // Setup default output area (can be later modified during io->setup()) + io->width = pic_hdr->width_; + io->height = pic_hdr->height_; + io->use_scaling = 0; + io->use_cropping = 0; + io->crop_top = 0; + io->crop_left = 0; + io->crop_right = io->width; + io->crop_bottom = io->height; + io->mb_w = io->width; // sanity check + io->mb_h = io->height; // ditto + + VP8ResetProba(&dec->proba_); + ResetSegmentHeader(&dec->segment_hdr_); + dec->segment_ = 0; // default for intra + } + + // Check if we have all the partition #0 available, and initialize dec->br_ + // to read this partition (and this partition only). + if (frm_hdr->partition_length_ > buf_size) { + return VP8SetError(dec, VP8_STATUS_NOT_ENOUGH_DATA, + "bad partition length"); + } + + br = &dec->br_; + VP8InitBitReader(br, buf, buf + frm_hdr->partition_length_); + 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, VP8_STATUS_BITSTREAM_ERROR, + "cannot parse segment header"); + } + // Filter specs + if (!ParseFilterHeader(br, dec)) { + return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR, + "cannot parse filter header"); + } + status = ParsePartitions(dec, buf, buf_size); + if (status != VP8_STATUS_OK) { + return VP8SetError(dec, status, "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, VP8_STATUS_UNSUPPORTED_FEATURE, + "Not a key frame."); +#endif + } else { + dec->buffer_flags_ = 0x003 | 0x100; + } + + // Paragraph 9.8 +#ifndef ONLY_KEYFRAME_CODE + dec->update_proba_ = VP8Get(br); + if (!dec->update_proba_) { // save for later restore + dec->proba_saved_ = dec->proba_; + } + dec->buffer_flags_ &= 1 << 8; + dec->buffer_flags_ |= + (frm_hdr->key_frame_ || VP8Get(br)) << 8; // refresh last frame +#else + VP8Get(br); // just ignore the value of update_proba_ +#endif + + VP8ParseProba(br, dec); + +#ifdef WEBP_EXPERIMENTAL_FEATURES + // Extensions + if (dec->pic_hdr_.colorspace_) { + const size_t kTrailerSize = 8; + const uint8_t kTrailerMarker = 0x01; + const uint8_t* ext_buf = buf - kTrailerSize; + size_t size; + + if (frm_hdr->partition_length_ < kTrailerSize || + ext_buf[kTrailerSize - 1] != kTrailerMarker) { + return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR, + "RIFF: Inconsistent extra information."); + } + + // Layer + size = (ext_buf[0] << 0) | (ext_buf[1] << 8) | (ext_buf[2] << 16); + dec->layer_data_size_ = size; + dec->layer_data_ = NULL; // will be set later + dec->layer_colorspace_ = ext_buf[3]; + } +#endif + + // 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 (*ProbaArray)[NUM_CTX][NUM_PROBAS]; // for const-casting + +// Returns the position of the last non-zero coeff plus one +// (and 0 if there's no coeff at all) +static int GetCoeffs(VP8BitReader* const br, ProbaArray prob, + int ctx, const quant_t dq, int n, int16_t* out) { + // n is either 0 or 1 here. kBands[n] is not necessary for extracting '*p'. + 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] = VP8GetSigned(br, v) * dq[j > 0]; + if (n == 16 || !VP8GetBit(br, p[0])) { // EOB + return n; + } + } + if (n == 16) { + return 16; + } + } +} + +// Alias-safe way of converting 4bytes to 32bits. +typedef union { + uint8_t i8[4]; + uint32_t i32; +} PackedNz; + +// Table to unpack four bits into four bytes +static const PackedNz kUnpackTab[16] = { + {{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. +#if defined(__PPC__) || defined(_M_PPC) || defined(_ARCH_PPC) || \ + defined(__BIG_ENDIAN__) +#define PACK_CST 0x08040201U +#else +#define PACK_CST 0x01020408U +#endif +#define PACK(X, S) ((((X).i32 * PACK_CST) & 0xff000000) >> (S)) + +static void ParseResiduals(VP8Decoder* const dec, + VP8MB* const mb, VP8BitReader* const token_br) { + int out_t_nz, out_l_nz, first; + ProbaArray ac_prob; + const VP8QuantMatrix* q = &dec->dqm_[dec->segment_]; + int16_t* dst = dec->coeffs_; + VP8MB* const left_mb = dec->mb_info_ - 1; + PackedNz nz_ac, nz_dc; + PackedNz tnz, lnz; + uint32_t non_zero_ac = 0; + uint32_t non_zero_dc = 0; + int x, y, ch; + + nz_dc.i32 = nz_ac.i32 = 0; + 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_; + mb->dc_nz_ = left_mb->dc_nz_ = + (GetCoeffs(token_br, (ProbaArray)dec->proba_.coeffs_[1], + ctx, q->y2_mat_, 0, dc) > 0); + first = 1; + ac_prob = (ProbaArray)dec->proba_.coeffs_[0]; + VP8TransformWHT(dc, dst); + } else { + first = 0; + ac_prob = (ProbaArray)dec->proba_.coeffs_[3]; + } + + tnz = kUnpackTab[mb->nz_ & 0xf]; + lnz = kUnpackTab[left_mb->nz_ & 0xf]; + for (y = 0; y < 4; ++y) { + int l = lnz.i8[y]; + for (x = 0; x < 4; ++x) { + const int ctx = l + tnz.i8[x]; + const int nz = GetCoeffs(token_br, ac_prob, ctx, + q->y1_mat_, first, dst); + tnz.i8[x] = l = (nz > 0); + nz_dc.i8[x] = (dst[0] != 0); + nz_ac.i8[x] = (nz > 1); + dst += 16; + } + lnz.i8[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); + + tnz = kUnpackTab[mb->nz_ >> 4]; + lnz = kUnpackTab[left_mb->nz_ >> 4]; + for (ch = 0; ch < 4; ch += 2) { + for (y = 0; y < 2; ++y) { + int l = lnz.i8[ch + y]; + for (x = 0; x < 2; ++x) { + const int ctx = l + tnz.i8[ch + x]; + const int nz = + GetCoeffs(token_br, (ProbaArray)dec->proba_.coeffs_[2], + ctx, q->uv_mat_, 0, dst); + tnz.i8[ch + x] = l = (nz > 0); + nz_dc.i8[y * 2 + x] = (dst[0] != 0); + nz_ac.i8[y * 2 + x] = (nz > 1); + dst += 16; + } + lnz.i8[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_; +} +#undef PACK + +//------------------------------------------------------------------------------ +// Main loop + +int VP8DecodeMB(VP8Decoder* const dec, VP8BitReader* const token_br) { + VP8BitReader* const br = &dec->br_; + VP8MB* const left = dec->mb_info_ - 1; + 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 (br->eof_) { + return 0; + } + + if (!info->skip_) { + ParseResiduals(dec, info, token_br); + } 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; + } + + return (!token_br->eof_); +} + +void VP8InitScanline(VP8Decoder* const dec) { + VP8MB* const left = dec->mb_info_ - 1; + left->nz_ = 0; + left->dc_nz_ = 0; + memset(dec->intra_l_, B_DC_PRED, sizeof(dec->intra_l_)); + dec->filter_row_ = + (dec->filter_type_ > 0) && + (dec->mb_y_ >= dec->tl_mb_y_) && (dec->mb_y_ <= dec->br_mb_y_); +} + +static int ParseFrame(VP8Decoder* const dec, VP8Io* io) { + for (dec->mb_y_ = 0; dec->mb_y_ < dec->br_mb_y_; ++dec->mb_y_) { + VP8BitReader* const token_br = + &dec->parts_[dec->mb_y_ & (dec->num_parts_ - 1)]; + VP8InitScanline(dec); + for (dec->mb_x_ = 0; dec->mb_x_ < dec->mb_w_; dec->mb_x_++) { + if (!VP8DecodeMB(dec, token_br)) { + return VP8SetError(dec, VP8_STATUS_NOT_ENOUGH_DATA, + "Premature end-of-file encountered."); + } + VP8ReconstructBlock(dec); + + // Store data and save block's filtering params + VP8StoreBlock(dec); + } + if (!VP8ProcessRow(dec, io)) { + return VP8SetError(dec, VP8_STATUS_USER_ABORT, "Output aborted."); + } + } + if (dec->use_threads_ && !WebPWorkerSync(&dec->worker_)) { + return 0; + } + + // Finish +#ifndef ONLY_KEYFRAME_CODE + if (!dec->update_proba_) { + dec->proba_ = dec->proba_saved_; + } +#endif + +#ifdef WEBP_EXPERIMENTAL_FEATURES + if (dec->layer_data_size_ > 0) { + if (!VP8DecodeLayer(dec)) { + return 0; + } + } +#endif + + return 1; +} + +// Main entry point +int VP8Decode(VP8Decoder* const dec, VP8Io* const io) { + int ok = 0; + if (dec == NULL) { + return 0; + } + if (io == NULL) { + return VP8SetError(dec, VP8_STATUS_INVALID_PARAM, + "NULL VP8Io parameter in VP8Decode()."); + } + + if (!dec->ready_) { + if (!VP8GetHeaders(dec, io)) { + return 0; + } + } + assert(dec->ready_); + + // Finish setting up the decoding parameter. Will call io->setup(). + ok = (VP8EnterCritical(dec, io) == VP8_STATUS_OK); + if (ok) { // good to go. + // Will allocate memory and prepare everything. + if (ok) ok = VP8InitFrame(dec, io); + + // Main decoding loop + if (ok) ok = ParseFrame(dec, io); + + // Exit. + ok &= VP8ExitCritical(dec, io); + } + + if (!ok) { + VP8Clear(dec); + return 0; + } + + dec->ready_ = 0; + return ok; +} + +void VP8Clear(VP8Decoder* const dec) { + if (dec == NULL) { + return; + } + if (dec->use_threads_) { + WebPWorkerEnd(&dec->worker_); + } + if (dec->mem_) { + free(dec->mem_); + } + dec->mem_ = NULL; + dec->mem_size_ = 0; + memset(&dec->br_, 0, sizeof(dec->br_)); + dec->ready_ = 0; +} + +//------------------------------------------------------------------------------ + +#if defined(__cplusplus) || defined(c_plusplus) +} // extern "C" +#endif |