File Coverage

deps/libgit2/src/libgit2/delta.h
Criterion Covered Total %
statement 0 10 0.0
branch 0 4 0.0
condition n/a
subroutine n/a
pod n/a
total 0 14 0.0


line stmt bran cond sub pod time code
1             /*
2             * diff-delta code taken from git.git. See diff-delta.c for details.
3             *
4             */
5             #ifndef INCLUDE_git_delta_h__
6             #define INCLUDE_git_delta_h__
7              
8             #include "common.h"
9              
10             #include "pack.h"
11              
12             typedef struct git_delta_index git_delta_index;
13              
14             /*
15             * git_delta_index_init: compute index data from given buffer
16             *
17             * This returns a pointer to a struct delta_index that should be passed to
18             * subsequent create_delta() calls, or to free_delta_index(). A NULL pointer
19             * is returned on failure. The given buffer must not be freed nor altered
20             * before free_delta_index() is called. The returned pointer must be freed
21             * using free_delta_index().
22             */
23             extern int git_delta_index_init(
24             git_delta_index **out, const void *buf, size_t bufsize);
25              
26             /*
27             * Free the index created by git_delta_index_init()
28             */
29             extern void git_delta_index_free(git_delta_index *index);
30              
31             /*
32             * Returns memory usage of delta index.
33             */
34             extern size_t git_delta_index_size(git_delta_index *index);
35              
36             /*
37             * create_delta: create a delta from given index for the given buffer
38             *
39             * This function may be called multiple times with different buffers using
40             * the same delta_index pointer. If max_delta_size is non-zero and the
41             * resulting delta is to be larger than max_delta_size then NULL is returned.
42             * On success, a non-NULL pointer to the buffer with the delta data is
43             * returned and *delta_size is updated with its size. The returned buffer
44             * must be freed by the caller.
45             */
46             extern int git_delta_create_from_index(
47             void **out,
48             size_t *out_size,
49             const struct git_delta_index *index,
50             const void *buf,
51             size_t bufsize,
52             size_t max_delta_size);
53              
54             /*
55             * diff_delta: create a delta from source buffer to target buffer
56             *
57             * If max_delta_size is non-zero and the resulting delta is to be larger
58             * than max_delta_size then GIT_EBUFS is returned. On success, a non-NULL
59             * pointer to the buffer with the delta data is returned and *delta_size is
60             * updated with its size. The returned buffer must be freed by the caller.
61             */
62 0           GIT_INLINE(int) git_delta(
63             void **out, size_t *out_len,
64             const void *src_buf, size_t src_bufsize,
65             const void *trg_buf, size_t trg_bufsize,
66             size_t max_delta_size)
67             {
68             git_delta_index *index;
69 0           int error = 0;
70              
71 0           *out = NULL;
72 0           *out_len = 0;
73              
74 0 0         if ((error = git_delta_index_init(&index, src_buf, src_bufsize)) < 0)
75 0           return error;
76              
77 0 0         if (index) {
78 0           error = git_delta_create_from_index(out, out_len,
79             index, trg_buf, trg_bufsize, max_delta_size);
80              
81 0           git_delta_index_free(index);
82             }
83              
84 0           return error;
85             }
86              
87             /* the smallest possible delta size is 4 bytes */
88             #define GIT_DELTA_SIZE_MIN 4
89              
90             /**
91             * Apply a git binary delta to recover the original content.
92             * The caller is responsible for freeing the returned buffer.
93             *
94             * @param out the output buffer
95             * @param out_len the length of the output buffer
96             * @param base the base to copy from during copy instructions.
97             * @param base_len number of bytes available at base.
98             * @param delta the delta to execute copy/insert instructions from.
99             * @param delta_len total number of bytes in the delta.
100             * @return 0 on success or an error code
101             */
102             extern int git_delta_apply(
103             void **out,
104             size_t *out_len,
105             const unsigned char *base,
106             size_t base_len,
107             const unsigned char *delta,
108             size_t delta_len);
109              
110             /**
111             * Read the header of a git binary delta.
112             *
113             * @param base_out pointer to store the base size field.
114             * @param result_out pointer to store the result size field.
115             * @param delta the delta to execute copy/insert instructions from.
116             * @param delta_len total number of bytes in the delta.
117             * @return 0 on success or an error code
118             */
119             extern int git_delta_read_header(
120             size_t *base_out,
121             size_t *result_out,
122             const unsigned char *delta,
123             size_t delta_len);
124              
125             /**
126             * Read the header of a git binary delta
127             *
128             * This variant reads just enough from the packfile stream to read the
129             * delta header.
130             */
131             extern int git_delta_read_header_fromstream(
132             size_t *base_out,
133             size_t *result_out,
134             git_packfile_stream *stream);
135              
136             #endif