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Diffstat (limited to 'media/libwebp/src/utils/bit_writer_utils.c')
| -rw-r--r-- | media/libwebp/src/utils/bit_writer_utils.c | 347 |
1 files changed, 347 insertions, 0 deletions
diff --git a/media/libwebp/src/utils/bit_writer_utils.c b/media/libwebp/src/utils/bit_writer_utils.c new file mode 100644 index 0000000000..2f408508f1 --- /dev/null +++ b/media/libwebp/src/utils/bit_writer_utils.c @@ -0,0 +1,347 @@ +// 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 "src/utils/bit_writer_utils.h" +#include "src/utils/endian_inl_utils.h" +#include "src/utils/utils.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*)WebPSafeMalloc(1ULL, 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_); + } + WebPSafeFree(bw->buf_); + bw->buf_ = new_buf; + bw->max_pos_ = new_size; + return 1; +} + +static void Flush(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 & 0xff; + 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) Flush(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) Flush(bw); + } + return bit; +} + +void VP8PutBits(VP8BitWriter* const bw, uint32_t value, int nb_bits) { + uint32_t mask; + assert(nb_bits > 0 && nb_bits < 32); + for (mask = 1u << (nb_bits - 1); mask; mask >>= 1) { + VP8PutBitUniform(bw, value & mask); + } +} + +void VP8PutSignedBits(VP8BitWriter* const bw, int value, int nb_bits) { + if (!VP8PutBitUniform(bw, value != 0)) return; + if (value < 0) { + VP8PutBits(bw, ((-value) << 1) | 1, nb_bits + 1); + } else { + VP8PutBits(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) { + VP8PutBits(bw, 0, 9 - bw->nb_bits_); + bw->nb_bits_ = 0; // pad with zeroes + Flush(bw); + return bw->buf_; +} + +int VP8BitWriterAppend(VP8BitWriter* const bw, + const uint8_t* data, size_t size) { + assert(data != NULL); + if (bw->nb_bits_ != -8) return 0; // Flush() 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 != NULL) { + WebPSafeFree(bw->buf_); + memset(bw, 0, sizeof(*bw)); + } +} + +//------------------------------------------------------------------------------ +// VP8LBitWriter + +// This is the minimum amount of size the memory buffer is guaranteed to grow +// when extra space is needed. +#define MIN_EXTRA_SIZE (32768ULL) + +// 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 max_bytes = bw->end_ - bw->buf_; + const size_t current_size = bw->cur_ - bw->buf_; + 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 (max_bytes > 0 && size_required <= max_bytes) return 1; + allocated_size = (3 * 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*)WebPSafeMalloc(1ULL, allocated_size); + if (allocated_buf == NULL) { + bw->error_ = 1; + return 0; + } + if (current_size > 0) { + memcpy(allocated_buf, bw->buf_, current_size); + } + WebPSafeFree(bw->buf_); + bw->buf_ = allocated_buf; + bw->cur_ = bw->buf_ + current_size; + bw->end_ = bw->buf_ + allocated_size; + return 1; +} + +int VP8LBitWriterInit(VP8LBitWriter* const bw, size_t expected_size) { + memset(bw, 0, sizeof(*bw)); + return VP8LBitWriterResize(bw, expected_size); +} + +int VP8LBitWriterClone(const VP8LBitWriter* const src, + VP8LBitWriter* const dst) { + const size_t current_size = src->cur_ - src->buf_; + assert(src->cur_ >= src->buf_ && src->cur_ <= src->end_); + if (!VP8LBitWriterResize(dst, current_size)) return 0; + memcpy(dst->buf_, src->buf_, current_size); + dst->bits_ = src->bits_; + dst->used_ = src->used_; + dst->error_ = src->error_; + dst->cur_ = dst->buf_ + current_size; + return 1; +} + +void VP8LBitWriterWipeOut(VP8LBitWriter* const bw) { + if (bw != NULL) { + WebPSafeFree(bw->buf_); + memset(bw, 0, sizeof(*bw)); + } +} + +void VP8LBitWriterReset(const VP8LBitWriter* const bw_init, + VP8LBitWriter* const bw) { + bw->bits_ = bw_init->bits_; + bw->used_ = bw_init->used_; + bw->cur_ = bw->buf_ + (bw_init->cur_ - bw_init->buf_); + assert(bw->cur_ <= bw->end_); + bw->error_ = bw_init->error_; +} + +void VP8LBitWriterSwap(VP8LBitWriter* const src, VP8LBitWriter* const dst) { + const VP8LBitWriter tmp = *src; + *src = *dst; + *dst = tmp; +} + +void VP8LPutBitsFlushBits(VP8LBitWriter* const bw) { + // If needed, make some room by flushing some bits out. + if (bw->cur_ + VP8L_WRITER_BYTES > bw->end_) { + const uint64_t extra_size = (bw->end_ - bw->buf_) + MIN_EXTRA_SIZE; + if (!CheckSizeOverflow(extra_size) || + !VP8LBitWriterResize(bw, (size_t)extra_size)) { + bw->cur_ = bw->buf_; + bw->error_ = 1; + return; + } + } + *(vp8l_wtype_t*)bw->cur_ = (vp8l_wtype_t)WSWAP((vp8l_wtype_t)bw->bits_); + bw->cur_ += VP8L_WRITER_BYTES; + bw->bits_ >>= VP8L_WRITER_BITS; + bw->used_ -= VP8L_WRITER_BITS; +} + +void VP8LPutBitsInternal(VP8LBitWriter* const bw, uint32_t bits, int n_bits) { + assert(n_bits <= 32); + // That's the max we can handle: + assert(sizeof(vp8l_wtype_t) == 2); + if (n_bits > 0) { + vp8l_atype_t lbits = bw->bits_; + int used = bw->used_; + // Special case of overflow handling for 32bit accumulator (2-steps flush). +#if VP8L_WRITER_BITS == 16 + if (used + n_bits >= VP8L_WRITER_MAX_BITS) { + // Fill up all the VP8L_WRITER_MAX_BITS so it can be flushed out below. + const int shift = VP8L_WRITER_MAX_BITS - used; + lbits |= (vp8l_atype_t)bits << used; + used = VP8L_WRITER_MAX_BITS; + n_bits -= shift; + bits >>= shift; + assert(n_bits <= VP8L_WRITER_MAX_BITS); + } +#endif + // If needed, make some room by flushing some bits out. + while (used >= VP8L_WRITER_BITS) { + if (bw->cur_ + VP8L_WRITER_BYTES > bw->end_) { + const uint64_t extra_size = (bw->end_ - bw->buf_) + MIN_EXTRA_SIZE; + if (!CheckSizeOverflow(extra_size) || + !VP8LBitWriterResize(bw, (size_t)extra_size)) { + bw->cur_ = bw->buf_; + bw->error_ = 1; + return; + } + } + *(vp8l_wtype_t*)bw->cur_ = (vp8l_wtype_t)WSWAP((vp8l_wtype_t)lbits); + bw->cur_ += VP8L_WRITER_BYTES; + lbits >>= VP8L_WRITER_BITS; + used -= VP8L_WRITER_BITS; + } + bw->bits_ = lbits | ((vp8l_atype_t)bits << used); + bw->used_ = used + n_bits; + } +} + +uint8_t* VP8LBitWriterFinish(VP8LBitWriter* const bw) { + // flush leftover bits + if (VP8LBitWriterResize(bw, (bw->used_ + 7) >> 3)) { + while (bw->used_ > 0) { + *bw->cur_++ = (uint8_t)bw->bits_; + bw->bits_ >>= 8; + bw->used_ -= 8; + } + bw->used_ = 0; + } + return bw->buf_; +} + +//------------------------------------------------------------------------------ |