add dec/vp8l{i.h,.c} from experimental

Pulled from 5529a2e^.
The history of this and related files is a bit entangled so rather
trying to split the changes and introduce some noise in master's history
we'll start with a fresh snapshot.
The file progression is still available in the experimental branch.

Change-Id: I490a49cb0084d556a29d7c5257c986ea695ce60c

src/dec/vp8li.h

@@ -0,0 +1,134 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// This code is licensed under the same terms as WebM:
+//  Software License Agreement:  http://www.webmproject.org/license/software/
+//  Additional IP Rights Grant:  http://www.webmproject.org/license/additional/
+// -----------------------------------------------------------------------------
+//
+// Lossless decoder: internal header.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+//         Vikas Arora(vikaas.arora@gmail.com)
+
+#ifndef WEBP_DEC_VP8LI_H_
+#define WEBP_DEC_VP8LI_H_
+
+#include <string.h>     // for memcpy()
+#include "./webpi.h"
+#include "../utils/bit_reader.h"
+#include "../utils/color_cache.h"
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+#define NUM_TRANSFORMS               8
+#define HUFFMAN_CODES_PER_META_CODE  5
+#define ARGB_BLACK                   0xff000000
+#define NUM_LITERAL_CODES            256
+#define NUM_ARGB_CACHE_ROWS          16
+#define LOSSLESS_MAGIC_BYTE          0x64
+#define LOSSLESS_MAGIC_BYTE_RSVD     0x65
+
+struct HuffmanTree;
+
+typedef enum {
+  READ_DATA = 0,
+  READ_HDR = 1,
+  READ_DIM = 2
+} VP8LDecodeState;
+
+typedef enum {
+  PREDICTOR_TRANSFORM      = 0,
+  CROSS_COLOR_TRANSFORM    = 1,
+  SUBTRACT_GREEN           = 2,
+  COLOR_INDEXING_TRANSFORM = 3
+} VP8LImageTransformType;
+
+typedef struct VP8LTransform VP8LTransform;
+struct VP8LTransform {
+  VP8LImageTransformType type_;   // transform type.
+  int                    bits_;   // subsampling bits defining transform window.
+  size_t                 xsize_;  // transform window X index.
+  size_t                 ysize_;  // transform window Y index.
+  uint32_t              *data_;   // transform data.
+};
+
+typedef struct {
+  int             color_cache_size_;
+  VP8LColorCache *color_cache_;
+
+  int             num_huffman_trees_;
+  int             huffman_mask_;
+  int             huffman_subsample_bits_;
+  int             huffman_xsize_;
+  uint32_t       *meta_codes_;
+  uint32_t       *huffman_image_;
+  struct HuffmanTree *htrees_;
+  struct HuffmanTree *meta_htrees_[HUFFMAN_CODES_PER_META_CODE];
+} VP8LMetadata;
+
+typedef struct {
+  VP8StatusCode    status_;
+  VP8LDecodeState  action_;
+  VP8LDecodeState  state_;
+  VP8Io           *io_;
+
+  uint32_t        *argb_;          // Internal data: always in BGRA color mode.
+  uint32_t        *argb_cache_;    // Scratch buffer for temporary BGRA storage.
+
+  BitReader        br_;
+  uint32_t         br_offset_;
+
+  int              width_;
+  int              height_;
+  int              last_row_;      // last input row decoded so far.
+  int              last_out_row_;  // last row output so far.
+
+  VP8LMetadata     hdr_;
+
+  int              next_transform_;
+  VP8LTransform    transforms_[NUM_TRANSFORMS];
+
+  uint8_t         *rescaler_memory;  // Working memory for rescaling work.
+  WebPRescaler    *rescaler;         // Common rescaler for all channels.
+} VP8LDecoder;
+
+//------------------------------------------------------------------------------
+// internal functions. Not public.
+
+// in vp8l.c
+
+// Validates the VP8L data-header and retrieves basic header information viz
+// width and height. Returns 0 in case of formatting error. width/height
+// can be passed NULL.
+int VP8LGetInfo(const uint8_t* data,
+                int data_size,    // data available so far
+                int *width, int *height);
+
+// Allocates and initialize a new lossless decoder instance.
+VP8LDecoder* VP8LNew(void);
+
+// Initializes the decoder object.
+void VP8LInitDecoder(VP8LDecoder* const dec);
+
+// Decodes the image header. Returns false in case of error.
+int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io);
+
+// Decodes an image. It's required to decode the lossless header before calling
+// this function. Returns false in case of error, with updated dec->status_.
+int VP8LDecodeImage(VP8LDecoder* const dec);
+
+// Resets the decoder in its initial state, reclaiming memory.
+void VP8LClear(VP8LDecoder* const dec);
+
+// Clears and deallocate a lossless decoder instance.
+void VP8LDelete(VP8LDecoder* const dec);
+
+//------------------------------------------------------------------------------
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}    // extern "C"
+#endif
+
+#endif  /* WEBP_DEC_VP8LI_H_ */