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-rw-r--r--src/3rdparty/libwebp/src/utils/bit_writer.c282
1 files changed, 282 insertions, 0 deletions
diff --git a/src/3rdparty/libwebp/src/utils/bit_writer.c b/src/3rdparty/libwebp/src/utils/bit_writer.c
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+++ b/src/3rdparty/libwebp/src/utils/bit_writer.c
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+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING 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.
+// -----------------------------------------------------------------------------
+//
+// Bit writing and boolean coder
+//
+// Author: Skal (pascal.massimino@gmail.com)
+// Vikas Arora (vikaas.arora@gmail.com)
+
+#include <assert.h>
+#include <string.h> // for memcpy()
+#include <stdlib.h>
+#include "./bit_writer.h"
+
+//------------------------------------------------------------------------------
+// VP8BitWriter
+
+static int BitWriterResize(VP8BitWriter* const bw, size_t extra_size) {
+ uint8_t* new_buf;
+ size_t new_size;
+ const uint64_t needed_size_64b = (uint64_t)bw->pos_ + extra_size;
+ const size_t needed_size = (size_t)needed_size_64b;
+ if (needed_size_64b != needed_size) {
+ bw->error_ = 1;
+ return 0;
+ }
+ if (needed_size <= bw->max_pos_) return 1;
+ // If the following line wraps over 32bit, the test just after will catch it.
+ new_size = 2 * bw->max_pos_;
+ if (new_size < needed_size) new_size = needed_size;
+ if (new_size < 1024) new_size = 1024;
+ new_buf = (uint8_t*)malloc(new_size);
+ if (new_buf == NULL) {
+ bw->error_ = 1;
+ return 0;
+ }
+ if (bw->pos_ > 0) {
+ assert(bw->buf_ != NULL);
+ memcpy(new_buf, bw->buf_, bw->pos_);
+ }
+ free(bw->buf_);
+ bw->buf_ = new_buf;
+ bw->max_pos_ = new_size;
+ return 1;
+}
+
+static void kFlush(VP8BitWriter* const bw) {
+ const int s = 8 + bw->nb_bits_;
+ const int32_t bits = bw->value_ >> s;
+ assert(bw->nb_bits_ >= 0);
+ bw->value_ -= bits << s;
+ bw->nb_bits_ -= 8;
+ if ((bits & 0xff) != 0xff) {
+ size_t pos = bw->pos_;
+ if (!BitWriterResize(bw, bw->run_ + 1)) {
+ return;
+ }
+ if (bits & 0x100) { // overflow -> propagate carry over pending 0xff's
+ if (pos > 0) bw->buf_[pos - 1]++;
+ }
+ if (bw->run_ > 0) {
+ const int value = (bits & 0x100) ? 0x00 : 0xff;
+ for (; bw->run_ > 0; --bw->run_) bw->buf_[pos++] = value;
+ }
+ bw->buf_[pos++] = bits;
+ bw->pos_ = pos;
+ } else {
+ bw->run_++; // delay writing of bytes 0xff, pending eventual carry.
+ }
+}
+
+//------------------------------------------------------------------------------
+// renormalization
+
+static const uint8_t kNorm[128] = { // renorm_sizes[i] = 8 - log2(i)
+ 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
+ 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 0
+};
+
+// range = ((range + 1) << kVP8Log2Range[range]) - 1
+static const uint8_t kNewRange[128] = {
+ 127, 127, 191, 127, 159, 191, 223, 127, 143, 159, 175, 191, 207, 223, 239,
+ 127, 135, 143, 151, 159, 167, 175, 183, 191, 199, 207, 215, 223, 231, 239,
+ 247, 127, 131, 135, 139, 143, 147, 151, 155, 159, 163, 167, 171, 175, 179,
+ 183, 187, 191, 195, 199, 203, 207, 211, 215, 219, 223, 227, 231, 235, 239,
+ 243, 247, 251, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149,
+ 151, 153, 155, 157, 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179,
+ 181, 183, 185, 187, 189, 191, 193, 195, 197, 199, 201, 203, 205, 207, 209,
+ 211, 213, 215, 217, 219, 221, 223, 225, 227, 229, 231, 233, 235, 237, 239,
+ 241, 243, 245, 247, 249, 251, 253, 127
+};
+
+int VP8PutBit(VP8BitWriter* const bw, int bit, int prob) {
+ const int split = (bw->range_ * prob) >> 8;
+ if (bit) {
+ bw->value_ += split + 1;
+ bw->range_ -= split + 1;
+ } else {
+ bw->range_ = split;
+ }
+ if (bw->range_ < 127) { // emit 'shift' bits out and renormalize
+ const int shift = kNorm[bw->range_];
+ bw->range_ = kNewRange[bw->range_];
+ bw->value_ <<= shift;
+ bw->nb_bits_ += shift;
+ if (bw->nb_bits_ > 0) kFlush(bw);
+ }
+ return bit;
+}
+
+int VP8PutBitUniform(VP8BitWriter* const bw, int bit) {
+ const int split = bw->range_ >> 1;
+ if (bit) {
+ bw->value_ += split + 1;
+ bw->range_ -= split + 1;
+ } else {
+ bw->range_ = split;
+ }
+ if (bw->range_ < 127) {
+ bw->range_ = kNewRange[bw->range_];
+ bw->value_ <<= 1;
+ bw->nb_bits_ += 1;
+ if (bw->nb_bits_ > 0) kFlush(bw);
+ }
+ return bit;
+}
+
+void VP8PutValue(VP8BitWriter* const bw, int value, int nb_bits) {
+ int mask;
+ for (mask = 1 << (nb_bits - 1); mask; mask >>= 1)
+ VP8PutBitUniform(bw, value & mask);
+}
+
+void VP8PutSignedValue(VP8BitWriter* const bw, int value, int nb_bits) {
+ if (!VP8PutBitUniform(bw, value != 0))
+ return;
+ if (value < 0) {
+ VP8PutValue(bw, ((-value) << 1) | 1, nb_bits + 1);
+ } else {
+ VP8PutValue(bw, value << 1, nb_bits + 1);
+ }
+}
+
+//------------------------------------------------------------------------------
+
+int VP8BitWriterInit(VP8BitWriter* const bw, size_t expected_size) {
+ bw->range_ = 255 - 1;
+ bw->value_ = 0;
+ bw->run_ = 0;
+ bw->nb_bits_ = -8;
+ bw->pos_ = 0;
+ bw->max_pos_ = 0;
+ bw->error_ = 0;
+ bw->buf_ = NULL;
+ return (expected_size > 0) ? BitWriterResize(bw, expected_size) : 1;
+}
+
+uint8_t* VP8BitWriterFinish(VP8BitWriter* const bw) {
+ VP8PutValue(bw, 0, 9 - bw->nb_bits_);
+ bw->nb_bits_ = 0; // pad with zeroes
+ kFlush(bw);
+ return bw->buf_;
+}
+
+int VP8BitWriterAppend(VP8BitWriter* const bw,
+ const uint8_t* data, size_t size) {
+ assert(data);
+ if (bw->nb_bits_ != -8) return 0; // kFlush() must have been called
+ if (!BitWriterResize(bw, size)) return 0;
+ memcpy(bw->buf_ + bw->pos_, data, size);
+ bw->pos_ += size;
+ return 1;
+}
+
+void VP8BitWriterWipeOut(VP8BitWriter* const bw) {
+ if (bw) {
+ free(bw->buf_);
+ memset(bw, 0, sizeof(*bw));
+ }
+}
+
+//------------------------------------------------------------------------------
+// VP8LBitWriter
+
+// Returns 1 on success.
+static int VP8LBitWriterResize(VP8LBitWriter* const bw, size_t extra_size) {
+ uint8_t* allocated_buf;
+ size_t allocated_size;
+ const size_t current_size = VP8LBitWriterNumBytes(bw);
+ const uint64_t size_required_64b = (uint64_t)current_size + extra_size;
+ const size_t size_required = (size_t)size_required_64b;
+ if (size_required != size_required_64b) {
+ bw->error_ = 1;
+ return 0;
+ }
+ if (bw->max_bytes_ > 0 && size_required <= bw->max_bytes_) return 1;
+ allocated_size = (3 * bw->max_bytes_) >> 1;
+ if (allocated_size < size_required) allocated_size = size_required;
+ // make allocated size multiple of 1k
+ allocated_size = (((allocated_size >> 10) + 1) << 10);
+ allocated_buf = (uint8_t*)malloc(allocated_size);
+ if (allocated_buf == NULL) {
+ bw->error_ = 1;
+ return 0;
+ }
+ memcpy(allocated_buf, bw->buf_, current_size);
+ free(bw->buf_);
+ bw->buf_ = allocated_buf;
+ bw->max_bytes_ = allocated_size;
+ memset(allocated_buf + current_size, 0, allocated_size - current_size);
+ return 1;
+}
+
+int VP8LBitWriterInit(VP8LBitWriter* const bw, size_t expected_size) {
+ memset(bw, 0, sizeof(*bw));
+ return VP8LBitWriterResize(bw, expected_size);
+}
+
+void VP8LBitWriterDestroy(VP8LBitWriter* const bw) {
+ if (bw != NULL) {
+ free(bw->buf_);
+ memset(bw, 0, sizeof(*bw));
+ }
+}
+
+void VP8LWriteBits(VP8LBitWriter* const bw, int n_bits, uint32_t bits) {
+ if (n_bits < 1) return;
+#if !defined(__BIG_ENDIAN__)
+ // Technically, this branch of the code can write up to 25 bits at a time,
+ // but in prefix encoding, the maximum number of bits written is 18 at a time.
+ {
+ uint8_t* const p = &bw->buf_[bw->bit_pos_ >> 3];
+ uint32_t v = *(const uint32_t*)p;
+ v |= bits << (bw->bit_pos_ & 7);
+ *(uint32_t*)p = v;
+ bw->bit_pos_ += n_bits;
+ }
+#else // BIG_ENDIAN
+ {
+ uint8_t* p = &bw->buf_[bw->bit_pos_ >> 3];
+ const int bits_reserved_in_first_byte = bw->bit_pos_ & 7;
+ const int bits_left_to_write = n_bits - 8 + bits_reserved_in_first_byte;
+ // implicit & 0xff is assumed for uint8_t arithmetic
+ *p++ |= bits << bits_reserved_in_first_byte;
+ bits >>= 8 - bits_reserved_in_first_byte;
+ if (bits_left_to_write >= 1) {
+ *p++ = bits;
+ bits >>= 8;
+ if (bits_left_to_write >= 9) {
+ *p++ = bits;
+ bits >>= 8;
+ }
+ }
+ assert(n_bits <= 25);
+ *p = bits;
+ bw->bit_pos_ += n_bits;
+ }
+#endif
+ if ((bw->bit_pos_ >> 3) > (bw->max_bytes_ - 8)) {
+ const uint64_t extra_size = 32768ULL + bw->max_bytes_;
+ if (extra_size != (size_t)extra_size ||
+ !VP8LBitWriterResize(bw, (size_t)extra_size)) {
+ bw->bit_pos_ = 0;
+ bw->error_ = 1;
+ }
+ }
+}
+
+//------------------------------------------------------------------------------
+
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