Home | History | Annotate | Line # | Download | only in common 
      1 /* transforms is a part of ABI, but not API.
      2 
      3    It means that there are some functions that are supposed to be in "common"
      4    library, but header itself is not placed into include/brotli. This way,
      5    aforementioned functions will be available only to brotli internals.
      6  */
      7 
      8 #ifndef BROTLI_COMMON_TRANSFORM_H_
      9 #define BROTLI_COMMON_TRANSFORM_H_
     10 
     11 #include <brotli/port.h>
     12 #include <brotli/types.h>
     13 
     14 #if defined(__cplusplus) || defined(c_plusplus)
     15 extern "C" {
     16 #endif
     17 
     18 enum BrotliWordTransformType {
     19   BROTLI_TRANSFORM_IDENTITY = 0,
     20   BROTLI_TRANSFORM_OMIT_LAST_1 = 1,
     21   BROTLI_TRANSFORM_OMIT_LAST_2 = 2,
     22   BROTLI_TRANSFORM_OMIT_LAST_3 = 3,
     23   BROTLI_TRANSFORM_OMIT_LAST_4 = 4,
     24   BROTLI_TRANSFORM_OMIT_LAST_5 = 5,
     25   BROTLI_TRANSFORM_OMIT_LAST_6 = 6,
     26   BROTLI_TRANSFORM_OMIT_LAST_7 = 7,
     27   BROTLI_TRANSFORM_OMIT_LAST_8 = 8,
     28   BROTLI_TRANSFORM_OMIT_LAST_9 = 9,
     29   BROTLI_TRANSFORM_UPPERCASE_FIRST = 10,
     30   BROTLI_TRANSFORM_UPPERCASE_ALL = 11,
     31   BROTLI_TRANSFORM_OMIT_FIRST_1 = 12,
     32   BROTLI_TRANSFORM_OMIT_FIRST_2 = 13,
     33   BROTLI_TRANSFORM_OMIT_FIRST_3 = 14,
     34   BROTLI_TRANSFORM_OMIT_FIRST_4 = 15,
     35   BROTLI_TRANSFORM_OMIT_FIRST_5 = 16,
     36   BROTLI_TRANSFORM_OMIT_FIRST_6 = 17,
     37   BROTLI_TRANSFORM_OMIT_FIRST_7 = 18,
     38   BROTLI_TRANSFORM_OMIT_FIRST_8 = 19,
     39   BROTLI_TRANSFORM_OMIT_FIRST_9 = 20,
     40   BROTLI_TRANSFORM_SHIFT_FIRST = 21,
     41   BROTLI_TRANSFORM_SHIFT_ALL = 22,
     42   BROTLI_NUM_TRANSFORM_TYPES  /* Counts transforms, not a transform itself. */
     43 };
     44 
     45 #define BROTLI_TRANSFORMS_MAX_CUT_OFF BROTLI_TRANSFORM_OMIT_LAST_9
     46 
     47 typedef struct BrotliTransforms {
     48   uint16_t prefix_suffix_size;
     49   /* Last character must be null, so prefix_suffix_size must be at least 1. */
     50   const uint8_t* prefix_suffix;
     51   const uint16_t* prefix_suffix_map;
     52   uint32_t num_transforms;
     53   /* Each entry is a [prefix_id, transform, suffix_id] triplet. */
     54   const uint8_t* transforms;
     55   /* Shift for BROTLI_TRANSFORM_SHIFT_FIRST and BROTLI_TRANSFORM_SHIFT_ALL,
     56      must be NULL if and only if no such transforms are present. */
     57   const uint8_t* params;
     58   /* Indices of transforms like ["", BROTLI_TRANSFORM_OMIT_LAST_#, ""].
     59      0-th element corresponds to ["", BROTLI_TRANSFORM_IDENTITY, ""].
     60      -1, if cut-off transform does not exist. */
     61   int16_t cutOffTransforms[BROTLI_TRANSFORMS_MAX_CUT_OFF + 1];
     62 } BrotliTransforms;
     63 
     64 /* T is BrotliTransforms*; result is uint8_t. */
     65 #define BROTLI_TRANSFORM_PREFIX_ID(T, I) ((T)->transforms[((I) * 3) + 0])
     66 #define BROTLI_TRANSFORM_TYPE(T, I)      ((T)->transforms[((I) * 3) + 1])
     67 #define BROTLI_TRANSFORM_SUFFIX_ID(T, I) ((T)->transforms[((I) * 3) + 2])
     68 
     69 /* T is BrotliTransforms*; result is const uint8_t*. */
     70 #define BROTLI_TRANSFORM_PREFIX(T, I) (&(T)->prefix_suffix[ \
     71     (T)->prefix_suffix_map[BROTLI_TRANSFORM_PREFIX_ID(T, I)]])
     72 #define BROTLI_TRANSFORM_SUFFIX(T, I) (&(T)->prefix_suffix[ \
     73     (T)->prefix_suffix_map[BROTLI_TRANSFORM_SUFFIX_ID(T, I)]])
     74 
     75 BROTLI_COMMON_API const BrotliTransforms* BrotliGetTransforms(void);
     76 
     77 BROTLI_COMMON_API int BrotliTransformDictionaryWord(
     78     uint8_t* dst, const uint8_t* word, int len,
     79     const BrotliTransforms* transforms, int transform_idx);
     80 
     81 #if defined(__cplusplus) || defined(c_plusplus)
     82 }  /* extern "C" */
     83 #endif
     84 
     85 #endif  /* BROTLI_COMMON_TRANSFORM_H_ */
     86