Convert LZW decompressor to use vector instead of static arraychromium/3230chromium/3229chromium/3228chromium/3227

Speciifically replacing what was called the "stack_", an array, with a
vector called "decompressed_". The fact that this data structure
wasn't actually a stack caused a lot of grief when refactoring.

BUG=pdfium:903

Change-Id: I056f8fc9183bcde67a03dc9de0dae9ddf9fb0f37
Reviewed-on: https://pdfium-review.googlesource.com/15092
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Ryan Harrison <rharrison@chromium.org>

1 files changed, 12 insertions, 2 deletions

diff --git a/core/fxcodec/gif/cfx_lzwdecompressor.h b/core/fxcodec/gif/cfx_lzwdecompressor.h
index 10c0a566d7..717c055973 100644
--- a/core/fxcodec/gif/cfx_lzwdecompressor.h
+++ b/core/fxcodec/gif/cfx_lzwdecompressor.h
@@ -29,11 +29,21 @@ class CFX_LZWDecompressor {
                              uint8_t* des_buf,
                              uint32_t* des_size);
 
+  // Used by unittests, should not be called in production code.
+  uint32_t ExtractDataForTest(uint8_t* des_buf, uint32_t des_size) {
+    return ExtractData(des_buf, des_size);
+  }
+
+  std::vector<uint8_t>* DecompressedForTest() { return &decompressed_; }
+
+  size_t* DecompressedNextForTest() { return &decompressed_next_; }
+
  private:
   CFX_LZWDecompressor(uint8_t color_exp, uint8_t code_exp);
   void ClearTable();
   void AddCode(uint16_t prefix_code, uint8_t append_char);
   bool DecodeString(uint16_t code);
+  uint32_t ExtractData(uint8_t* des_buf, uint32_t des_size);
 
   uint8_t code_size_;
   uint8_t code_size_cur_;
@@ -42,8 +52,8 @@ class CFX_LZWDecompressor {
   uint16_t code_end_;
   uint16_t code_next_;
   uint8_t code_first_;
-  uint8_t stack_[GIF_MAX_LZW_CODE];
-  size_t stack_size_;
+  std::vector<uint8_t> decompressed_;
+  size_t decompressed_next_;
   CodeEntry code_table_[GIF_MAX_LZW_CODE];
   uint16_t code_old_;
   uint8_t* next_in_;