GIFHASH.H

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/* --
OpenFX version >= 1.0 - Modelling, Animation and Rendering Package
-- */

/* file GIFHASH.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.           */
#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 {
    unsigned long HTable[HT_SIZE];
} GifHashTableType;

#ifdef _SUNSTYLE
GifHashTableType *_InitHashTable();
void _ClearHashTable();
void _InsertHashTable();
long _ExistsHashTable();
#else
GifHashTableType *_InitHashTable(void);
void _ClearHashTable(GifHashTableType *HashTable);
void _InsertHashTable(GifHashTableType *HashTable, unsigned long Key, long Code);
long _ExistsHashTable(GifHashTableType *HashTable, unsigned long Key);
#endif