diff options
Diffstat (limited to 'src/main/jni/giflib/gif_hash.h')
-rw-r--r-- | src/main/jni/giflib/gif_hash.h | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/src/main/jni/giflib/gif_hash.h b/src/main/jni/giflib/gif_hash.h new file mode 100644 index 000000000..ac20a43cb --- /dev/null +++ b/src/main/jni/giflib/gif_hash.h @@ -0,0 +1,39 @@ +/****************************************************************************** + +gif_hash.h - magfic constants and declarations for GIF LZW + +******************************************************************************/ + +#ifndef _GIF_HASH_H_ +#define _GIF_HASH_H_ + +#include <unistd.h> +#include <stdint.h> + +#define HT_SIZE 8192 /* 12bits = 4096 or twice as big! */ +#define HT_KEY_MASK 0x1FFF /* 13bits keys */ +#define HT_KEY_NUM_BITS 13 /* 13bits keys */ +#define HT_MAX_KEY 8191 /* 13bits - 1, maximal code possible */ +#define HT_MAX_CODE 4095 /* Biggest code possible in 12 bits. */ + +/* The 32 bits of the long are divided into two parts for the key & code: */ +/* 1. The code is 12 bits as our compression algorithm is limited to 12bits */ +/* 2. The key is 12 bits Prefix code + 8 bit new char or 20 bits. */ +/* The key is the upper 20 bits. The code is the lower 12. */ +#define HT_GET_KEY(l) (l >> 12) +#define HT_GET_CODE(l) (l & 0x0FFF) +#define HT_PUT_KEY(l) (l << 12) +#define HT_PUT_CODE(l) (l & 0x0FFF) + +typedef struct GifHashTableType { + uint32_t HTable[HT_SIZE]; +} GifHashTableType; + +GifHashTableType *_InitHashTable(void); +void _ClearHashTable(GifHashTableType *HashTable); +void _InsertHashTable(GifHashTableType *HashTable, uint32_t Key, int Code); +int _ExistsHashTable(GifHashTableType *HashTable, uint32_t Key); + +#endif /* _GIF_HASH_H_ */ + +/* end */ |