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c7e86abab6
add additional '-' to //----... style comments globally instead of polluting further commits Change-Id: I951acc68b7b5384b4d6e235349b0067d1aa6fa8b
115 lines
2.8 KiB
C
115 lines
2.8 KiB
C
// Copyright 2011 Google Inc.
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//
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// This code is licensed under the same terms as WebM:
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// Software License Agreement: http://www.webmproject.org/license/software/
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// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
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// -----------------------------------------------------------------------------
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//
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// Alpha-plane compression.
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//
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// Author: Skal (pascal.massimino@gmail.com)
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#include <assert.h>
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#include <stdlib.h>
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#include "vp8enci.h"
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#ifdef WEBP_EXPERIMENTAL_FEATURES
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#include "zlib.h"
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#endif
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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#ifdef WEBP_EXPERIMENTAL_FEATURES
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#define CHUNK_SIZE 8192
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//------------------------------------------------------------------------------
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static int CompressAlpha(const uint8_t* data, size_t data_size,
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uint8_t** output, size_t* output_size,
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int algo) {
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int ret = Z_OK;
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z_stream strm;
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unsigned char chunk[CHUNK_SIZE];
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*output = NULL;
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*output_size = 0;
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memset(&strm, 0, sizeof(strm));
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if (deflateInit(&strm, algo ? Z_BEST_SPEED : Z_BEST_COMPRESSION) != Z_OK) {
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return 0;
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}
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strm.next_in = (unsigned char*)data;
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strm.avail_in = data_size;
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do {
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size_t size_out;
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strm.next_out = chunk;
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strm.avail_out = CHUNK_SIZE;
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ret = deflate(&strm, Z_FINISH);
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if (ret == Z_STREAM_ERROR) {
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break;
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}
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size_out = CHUNK_SIZE - strm.avail_out;
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if (size_out) {
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size_t new_size = *output_size + size_out;
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uint8_t* new_output = realloc(*output, new_size);
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if (new_output == NULL) {
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ret = Z_MEM_ERROR;
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break;
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}
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memcpy(new_output + *output_size, chunk, size_out);
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*output_size = new_size;
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*output = new_output;
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}
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} while (ret != Z_STREAM_END || strm.avail_out == 0);
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deflateEnd(&strm);
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if (ret != Z_STREAM_END) {
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free(*output);
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output_size = 0;
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return 0;
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}
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return 1;
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}
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#endif /* WEBP_EXPERIMENTAL_FEATURES */
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void VP8EncInitAlpha(VP8Encoder* enc) {
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enc->has_alpha_ = (enc->pic_->a != NULL);
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enc->alpha_data_ = NULL;
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enc->alpha_data_size_ = 0;
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}
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void VP8EncCodeAlphaBlock(VP8EncIterator* it) {
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(void)it;
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// Nothing for now. We just ZLIB-compress in the end.
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}
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int VP8EncFinishAlpha(VP8Encoder* enc) {
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if (enc->has_alpha_) {
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#ifdef WEBP_EXPERIMENTAL_FEATURES
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const WebPPicture* pic = enc->pic_;
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assert(pic->a);
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if (!CompressAlpha(pic->a, pic->width * pic->height,
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&enc->alpha_data_, &enc->alpha_data_size_,
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enc->config_->alpha_compression)) {
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return 0;
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}
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#endif
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}
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return 1;
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}
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void VP8EncDeleteAlpha(VP8Encoder* enc) {
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free(enc->alpha_data_);
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enc->alpha_data_ = NULL;
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enc->alpha_data_size_ = 0;
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enc->has_alpha_ = 0;
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}
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#if defined(__cplusplus) || defined(c_plusplus)
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} // extern "C"
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#endif
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