d6a09e795d
This introduces an additional guard for platforms where `unsigned long` and `size_t` are not of the same size. If the size of an object in the database would overflow `unsigned long`, instead we now exit with an error. A complete fix will have to update _many_ other functions throughout the codebase to use `size_t` instead of `unsigned long`. It will have to be implemented at some stage. This commit puts in a stop-gap for the time being. Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Matt Cooper <vtbassmatt@gmail.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
105 lines
3.4 KiB
C
105 lines
3.4 KiB
C
#ifndef DELTA_H
|
|
#define DELTA_H
|
|
|
|
/* opaque object for delta index */
|
|
struct delta_index;
|
|
|
|
/*
|
|
* create_delta_index: compute index data from given buffer
|
|
*
|
|
* This returns a pointer to a struct delta_index that should be passed to
|
|
* subsequent create_delta() calls, or to free_delta_index(). A NULL pointer
|
|
* is returned on failure. The given buffer must not be freed or altered
|
|
* before free_delta_index() is called. The returned pointer must be freed
|
|
* using free_delta_index().
|
|
*/
|
|
struct delta_index *
|
|
create_delta_index(const void *buf, unsigned long bufsize);
|
|
|
|
/*
|
|
* free_delta_index: free the index created by create_delta_index()
|
|
*
|
|
* Given pointer must be what create_delta_index() returned, or NULL.
|
|
*/
|
|
void free_delta_index(struct delta_index *index);
|
|
|
|
/*
|
|
* sizeof_delta_index: returns memory usage of delta index
|
|
*
|
|
* Given pointer must be what create_delta_index() returned, or NULL.
|
|
*/
|
|
unsigned long sizeof_delta_index(struct delta_index *index);
|
|
|
|
/*
|
|
* create_delta: create a delta from given index for the given buffer
|
|
*
|
|
* This function may be called multiple times with different buffers using
|
|
* the same delta_index pointer. If max_delta_size is non-zero and the
|
|
* resulting delta is to be larger than max_delta_size then NULL is returned.
|
|
* On success, a non-NULL pointer to the buffer with the delta data is
|
|
* returned and *delta_size is updated with its size. The returned buffer
|
|
* must be freed by the caller.
|
|
*/
|
|
void *
|
|
create_delta(const struct delta_index *index,
|
|
const void *buf, unsigned long bufsize,
|
|
unsigned long *delta_size, unsigned long max_delta_size);
|
|
|
|
/*
|
|
* diff_delta: create a delta from source buffer to target buffer
|
|
*
|
|
* If max_delta_size is non-zero and the resulting delta is to be larger
|
|
* than max_delta_size then NULL is returned. On success, a non-NULL
|
|
* pointer to the buffer with the delta data is returned and *delta_size is
|
|
* updated with its size. The returned buffer must be freed by the caller.
|
|
*/
|
|
static inline void *
|
|
diff_delta(const void *src_buf, unsigned long src_bufsize,
|
|
const void *trg_buf, unsigned long trg_bufsize,
|
|
unsigned long *delta_size, unsigned long max_delta_size)
|
|
{
|
|
struct delta_index *index = create_delta_index(src_buf, src_bufsize);
|
|
if (index) {
|
|
void *delta = create_delta(index, trg_buf, trg_bufsize,
|
|
delta_size, max_delta_size);
|
|
free_delta_index(index);
|
|
return delta;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* patch_delta: recreate target buffer given source buffer and delta data
|
|
*
|
|
* On success, a non-NULL pointer to the target buffer is returned and
|
|
* *trg_bufsize is updated with its size. On failure a NULL pointer is
|
|
* returned. The returned buffer must be freed by the caller.
|
|
*/
|
|
void *patch_delta(const void *src_buf, unsigned long src_size,
|
|
const void *delta_buf, unsigned long delta_size,
|
|
unsigned long *dst_size);
|
|
|
|
/* the smallest possible delta size is 4 bytes */
|
|
#define DELTA_SIZE_MIN 4
|
|
|
|
/*
|
|
* This must be called twice on the delta data buffer, first to get the
|
|
* expected source buffer size, and again to get the target buffer size.
|
|
*/
|
|
static inline unsigned long get_delta_hdr_size(const unsigned char **datap,
|
|
const unsigned char *top)
|
|
{
|
|
const unsigned char *data = *datap;
|
|
size_t cmd, size = 0;
|
|
int i = 0;
|
|
do {
|
|
cmd = *data++;
|
|
size |= st_left_shift(cmd & 0x7f, i);
|
|
i += 7;
|
|
} while (cmd & 0x80 && data < top);
|
|
*datap = data;
|
|
return cast_size_t_to_ulong(size);
|
|
}
|
|
|
|
#endif
|