diff options
Diffstat (limited to 'core/fxcodec/gif/cfx_lzwdecompressor.cpp')
| -rw-r--r-- | core/fxcodec/gif/cfx_lzwdecompressor.cpp | 196 |
1 files changed, 0 insertions, 196 deletions
diff --git a/core/fxcodec/gif/cfx_lzwdecompressor.cpp b/core/fxcodec/gif/cfx_lzwdecompressor.cpp deleted file mode 100644 index 12e0d89df..000000000 --- a/core/fxcodec/gif/cfx_lzwdecompressor.cpp +++ /dev/null @@ -1,196 +0,0 @@ -// Copyright 2017 PDFium Authors. All rights reserved. -// Use of this source code is governed by a BSD-style license that can be -// found in the LICENSE file. - -// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com - -#include "core/fxcodec/gif/cfx_lzwdecompressor.h" - -#include <algorithm> -#include <cstring> -#include <memory> -#include <utility> - -#include "core/fxcrt/fx_safe_types.h" -#include "third_party/base/numerics/safe_math.h" - -std::unique_ptr<CFX_LZWDecompressor> CFX_LZWDecompressor::Create( - uint8_t color_exp, - uint8_t code_exp) { - // color_exp generates 2^(n + 1) codes, where as the code_exp reserves 2^n. - // This is a quirk of the GIF spec. - if (code_exp > GIF_MAX_LZW_EXP || code_exp < color_exp + 1) - return nullptr; - return std::unique_ptr<CFX_LZWDecompressor>( - new CFX_LZWDecompressor(color_exp, code_exp)); -} - -CFX_LZWDecompressor::CFX_LZWDecompressor(uint8_t color_exp, uint8_t code_exp) - : code_size_(code_exp), - code_size_cur_(0), - code_color_end_(static_cast<uint16_t>(1 << (color_exp + 1))), - code_clear_(static_cast<uint16_t>(1 << code_exp)), - code_end_(static_cast<uint16_t>((1 << code_exp) + 1)), - code_next_(0), - code_first_(0), - code_old_(0), - next_in_(nullptr), - avail_in_(0), - bits_left_(0), - code_store_(0) {} - -CFX_LZWDecompressor::~CFX_LZWDecompressor() {} - -CFX_GifDecodeStatus CFX_LZWDecompressor::Decode(const uint8_t* src_buf, - uint32_t src_size, - uint8_t* dest_buf, - uint32_t* dest_size) { - if (!src_buf || src_size == 0 || !dest_buf || !dest_size) - return CFX_GifDecodeStatus::Error; - - if (*dest_size == 0) - return CFX_GifDecodeStatus::InsufficientDestSize; - - next_in_ = src_buf; - avail_in_ = src_size; - - ClearTable(); - - uint32_t i = 0; - if (decompressed_next_ != 0) { - uint32_t extracted_size = ExtractData(dest_buf, *dest_size); - if (decompressed_next_ != 0) - return CFX_GifDecodeStatus::InsufficientDestSize; - - dest_buf += extracted_size; - i += extracted_size; - } - - while (i <= *dest_size && (avail_in_ > 0 || bits_left_ >= code_size_cur_)) { - if (code_size_cur_ > GIF_MAX_LZW_EXP) - return CFX_GifDecodeStatus::Error; - - if (avail_in_ > 0) { - if (bits_left_ > 31) - return CFX_GifDecodeStatus::Error; - - FX_SAFE_UINT32 safe_code = *next_in_++; - safe_code <<= bits_left_; - safe_code |= code_store_; - if (!safe_code.IsValid()) - return CFX_GifDecodeStatus::Error; - - code_store_ = safe_code.ValueOrDie(); - --avail_in_; - bits_left_ += 8; - } - - while (bits_left_ >= code_size_cur_) { - uint16_t code = - static_cast<uint16_t>(code_store_) & ((1 << code_size_cur_) - 1); - code_store_ >>= code_size_cur_; - bits_left_ -= code_size_cur_; - if (code == code_clear_) { - ClearTable(); - continue; - } - if (code == code_end_) { - *dest_size = i; - return CFX_GifDecodeStatus::Success; - } - - if (code_old_ != static_cast<uint16_t>(-1)) { - if (code_next_ < GIF_MAX_LZW_CODE) { - if (code == code_next_) { - AddCode(code_old_, code_first_); - if (!DecodeString(code)) - return CFX_GifDecodeStatus::Error; - } else if (code > code_next_) { - return CFX_GifDecodeStatus::Error; - } else { - if (!DecodeString(code)) - return CFX_GifDecodeStatus::Error; - - uint8_t append_char = decompressed_[decompressed_next_ - 1]; - AddCode(code_old_, append_char); - } - } - } else { - if (!DecodeString(code)) - return CFX_GifDecodeStatus::Error; - } - - code_old_ = code; - uint32_t extracted_size = ExtractData(dest_buf, *dest_size - i); - if (decompressed_next_ != 0) - return CFX_GifDecodeStatus::InsufficientDestSize; - - dest_buf += extracted_size; - i += extracted_size; - } - } - - if (avail_in_ != 0) - return CFX_GifDecodeStatus::Error; - - *dest_size = i; - return CFX_GifDecodeStatus::Unfinished; -} - -void CFX_LZWDecompressor::ClearTable() { - code_size_cur_ = code_size_ + 1; - code_next_ = code_end_ + 1; - code_old_ = static_cast<uint16_t>(-1); - memset(code_table_, 0, sizeof(code_table_)); - for (uint16_t i = 0; i < code_clear_; i++) - code_table_[i].suffix = static_cast<uint8_t>(i); - decompressed_.resize(code_next_ - code_clear_ + 1); - decompressed_next_ = 0; -} - -void CFX_LZWDecompressor::AddCode(uint16_t prefix_code, uint8_t append_char) { - if (code_next_ == GIF_MAX_LZW_CODE) - return; - - code_table_[code_next_].prefix = prefix_code; - code_table_[code_next_].suffix = append_char; - if (++code_next_ < GIF_MAX_LZW_CODE) { - if (code_next_ >> code_size_cur_) - code_size_cur_++; - } -} - -bool CFX_LZWDecompressor::DecodeString(uint16_t code) { - decompressed_.resize(code_next_ - code_clear_ + 1); - decompressed_next_ = 0; - - while (code >= code_clear_ && code <= code_next_) { - if (code == code_table_[code].prefix || - decompressed_next_ >= decompressed_.size()) - return false; - - decompressed_[decompressed_next_++] = code_table_[code].suffix; - code = code_table_[code].prefix; - } - - if (code >= code_color_end_) - return false; - - decompressed_[decompressed_next_++] = static_cast<uint8_t>(code); - code_first_ = static_cast<uint8_t>(code); - return true; -} - -uint32_t CFX_LZWDecompressor::ExtractData(uint8_t* dest_buf, - uint32_t dest_size) { - if (dest_size == 0) - return 0; - - uint32_t copy_size = dest_size <= decompressed_next_ - ? dest_size - : static_cast<uint32_t>(decompressed_next_); - std::reverse_copy(decompressed_.data() + decompressed_next_ - copy_size, - decompressed_.data() + decompressed_next_, dest_buf); - decompressed_next_ -= copy_size; - return copy_size; -} |