21
21
aggregate source */
24
/* result type for functions that have multiple failure modes */
26
DELTA_OK, /* Success */
27
DELTA_OUT_OF_MEMORY, /* Could not allocate required memory */
28
DELTA_INDEX_NEEDED, /* A delta_index must be passed */
29
DELTA_SOURCE_EMPTY, /* A source_info had no content */
30
DELTA_SOURCE_BAD, /* A source_info had invalid or corrupt content */
31
DELTA_BUFFER_EMPTY, /* A buffer pointer and size */
32
DELTA_SIZE_TOO_BIG, /* Delta data is larger than the max requested */
37
25
* create_delta_index: compute index data from given buffer
39
* Returns a delta_result status, when DELTA_OK then *fresh is set to a struct
40
* delta_index that should be passed to subsequent create_delta() calls, or to
41
* free_delta_index(). Other values are a failure, and *fresh is unset.
42
* The given buffer must not be freed nor altered before free_delta_index() is
43
* called. The resultant struct must be freed using free_delta_index().
45
* :param max_bytes_to_index: Limit the number of regions to sample to this
46
* amount of text. We will store at most max_bytes_to_index / RABIN_WINDOW
47
* pointers into the source text. Useful if src can be unbounded in size,
48
* and you are willing to trade match accuracy for peak memory.
27
* This returns a pointer to a struct delta_index that should be passed to
28
* subsequent create_delta() calls, or to free_delta_index(). A NULL pointer
29
* is returned on failure. The given buffer must not be freed nor altered
30
* before free_delta_index() is called. The returned pointer must be freed
31
* using free_delta_index().
33
extern struct delta_index *
51
34
create_delta_index(const struct source_info *src,
52
struct delta_index *old,
53
struct delta_index **fresh,
54
int max_bytes_to_index);
35
struct delta_index *old);
58
39
* create_delta_index_from_delta: compute index data from given buffer
60
* Returns a delta_result status, when DELTA_OK then *fresh is set to a struct
61
* delta_index that should be passed to subsequent create_delta() calls, or to
62
* free_delta_index(). Other values are a failure, and *fresh is unset.
41
* This returns a pointer to a struct delta_index that should be passed to
42
* subsequent create_delta() calls, or to free_delta_index(). A NULL pointer
43
* is returned on failure.
63
44
* The bytes must be in the form of a delta structure, as generated by
64
45
* create_delta(). The generated index will only index the insert bytes, and
65
46
* not any of the control structures.
48
extern struct delta_index *
68
49
create_delta_index_from_delta(const struct source_info *delta,
69
struct delta_index *old,
70
struct delta_index **fresh);
50
struct delta_index *old);
72
52
* free_delta_index: free the index created by create_delta_index()
88
68
* This function may be called multiple times with different buffers using
89
69
* the same delta_index pointer. If max_delta_size is non-zero and the
90
* resulting delta is to be larger than max_delta_size then DELTA_SIZE_TOO_BIG
91
* is returned. Otherwise on success, DELTA_OK is returned and *delta_data is
92
* set to a new buffer with the delta data and *delta_size is updated with its
93
* size. That buffer must be freed by the caller.
70
* resulting delta is to be larger than max_delta_size then NULL is returned.
71
* On success, a non-NULL pointer to the buffer with the delta data is
72
* returned and *delta_size is updated with its size. The returned buffer
73
* must be freed by the caller.
96
76
create_delta(const struct delta_index *index,
97
const void *buf, unsigned long bufsize,
98
unsigned long *delta_size, unsigned long max_delta_size,
77
const void *buf, unsigned long bufsize,
78
unsigned long *delta_size, unsigned long max_delta_size);
101
80
/* the smallest possible delta size is 3 bytes
102
81
* Target size, Copy command, Copy length
127
* Return the basic information about a given delta index.
128
* :param index: The delta_index object
129
* :param pos: The offset in the entry list. Start at 0, and walk until you get
130
* 0 as a return code.
131
* :param global_offset: return value, distance to the beginning of all sources
132
* :param hash_val: return value, the RABIN hash associated with this pointer
133
* :param hash_offset: Location for this entry in the hash array.
134
* :return: 1 if pos != -1 (there was data produced)
137
get_entry_summary(const struct delta_index *index, int pos,
138
unsigned int *text_offset, unsigned int *hash_val);
141
* Determine what entry index->hash[X] points to.
144
get_hash_offset(const struct delta_index *index, int pos,
145
unsigned int *entry_offset);
148
* Compute the rabin_hash of the given data, it is assumed the data is at least
149
* RABIN_WINDOW wide (16 bytes).
152
rabin_hash(const unsigned char *data);
added
removed
bzrlib/delta.h
