modules/brotli/common/transform.h

   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_ */