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delta: refactor git_delta functions for consistency
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Refactor the git_delta functions to have consistent naming and
parameters with the rest of the library.
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@ethomson
ethomson authored and Edward Thomson committed May 26, 2016
1 parent 6a2d2f8 commit 1cd6599
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Showing 4 changed files with 138 additions and 144 deletions.
135 changes: 72 additions & 63 deletions src/delta.c
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Original file line number Diff line number Diff line change
Expand Up @@ -114,7 +114,7 @@ struct index_entry {
struct git_delta_index {
unsigned long memsize;
const void *src_buf;
unsigned long src_size;
size_t src_size;
unsigned int hash_mask;
struct index_entry *hash[GIT_FLEX_ARRAY];
};
Expand Down Expand Up @@ -142,8 +142,8 @@ static int lookup_index_alloc(
return 0;
}

struct git_delta_index *
git_delta_create_index(const void *buf, unsigned long bufsize)
int git_delta_index_init(
git_delta_index **out, const void *buf, size_t bufsize)
{
unsigned int i, hsize, hmask, entries, prev_val, *hash_count;
const unsigned char *data, *buffer = buf;
Expand All @@ -152,8 +152,10 @@ git_delta_create_index(const void *buf, unsigned long bufsize)
void *mem;
unsigned long memsize;

*out = NULL;

if (!buf || !bufsize)
return NULL;
return 0;

/* Determine index hash size. Note that indexing skips the
first byte to allow for optimizing the rabin polynomial
Expand All @@ -172,7 +174,7 @@ git_delta_create_index(const void *buf, unsigned long bufsize)
hmask = hsize - 1;

if (lookup_index_alloc(&mem, &memsize, entries, hsize) < 0)
return NULL;
return -1;

index = mem;
mem = index->hash;
Expand All @@ -190,7 +192,7 @@ git_delta_create_index(const void *buf, unsigned long bufsize)
hash_count = git__calloc(hsize, sizeof(*hash_count));
if (!hash_count) {
git__free(index);
return NULL;
return -1;
}

/* then populate the index */
Expand Down Expand Up @@ -243,20 +245,20 @@ git_delta_create_index(const void *buf, unsigned long bufsize)
}
git__free(hash_count);

return index;
*out = index;
return 0;
}

void git_delta_free_index(struct git_delta_index *index)
void git_delta_index_free(git_delta_index *index)
{
git__free(index);
}

unsigned long git_delta_sizeof_index(struct git_delta_index *index)
size_t git_delta_index_size(git_delta_index *index)
{
if (index)
return index->memsize;
else
return 0;
assert(index);

return index->memsize;
}

/*
Expand All @@ -265,55 +267,57 @@ unsigned long git_delta_sizeof_index(struct git_delta_index *index)
*/
#define MAX_OP_SIZE (5 + 5 + 1 + RABIN_WINDOW + 7)

void *
git_delta_create(
int git_delta_create_from_index(
void **out,
size_t *out_len,
const struct git_delta_index *index,
const void *trg_buf,
unsigned long trg_size,
unsigned long *delta_size,
unsigned long max_size)
size_t trg_size,
size_t max_size)
{
unsigned int i, outpos, outsize, moff, msize, val;
unsigned int i, bufpos, bufsize, moff, msize, val;
int inscnt;
const unsigned char *ref_data, *ref_top, *data, *top;
unsigned char *out;
unsigned char *buf;

*out = NULL;
*out_len = 0;

if (!trg_buf || !trg_size)
return NULL;
return 0;

outpos = 0;
outsize = 8192;
if (max_size && outsize >= max_size)
outsize = (unsigned int)(max_size + MAX_OP_SIZE + 1);
out = git__malloc(outsize);
if (!out)
return NULL;
bufpos = 0;
bufsize = 8192;
if (max_size && bufsize >= max_size)
bufsize = (unsigned int)(max_size + MAX_OP_SIZE + 1);
buf = git__malloc(bufsize);
GITERR_CHECK_ALLOC(buf);

/* store reference buffer size */
i = index->src_size;
while (i >= 0x80) {
out[outpos++] = i | 0x80;
buf[bufpos++] = i | 0x80;
i >>= 7;
}
out[outpos++] = i;
buf[bufpos++] = i;

/* store target buffer size */
i = trg_size;
while (i >= 0x80) {
out[outpos++] = i | 0x80;
buf[bufpos++] = i | 0x80;
i >>= 7;
}
out[outpos++] = i;
buf[bufpos++] = i;

ref_data = index->src_buf;
ref_top = ref_data + index->src_size;
data = trg_buf;
top = (const unsigned char *) trg_buf + trg_size;

outpos++;
bufpos++;
val = 0;
for (i = 0; i < RABIN_WINDOW && data < top; i++, data++) {
out[outpos++] = *data;
buf[bufpos++] = *data;
val = ((val << 8) | *data) ^ T[val >> RABIN_SHIFT];
}
inscnt = i;
Expand Down Expand Up @@ -350,11 +354,11 @@ git_delta_create(

if (msize < 4) {
if (!inscnt)
outpos++;
out[outpos++] = *data++;
bufpos++;
buf[bufpos++] = *data++;
inscnt++;
if (inscnt == 0x7f) {
out[outpos - inscnt - 1] = inscnt;
buf[bufpos - inscnt - 1] = inscnt;
inscnt = 0;
}
msize = 0;
Expand All @@ -368,37 +372,37 @@ git_delta_create(
msize++;
moff--;
data--;
outpos--;
bufpos--;
if (--inscnt)
continue;
outpos--; /* remove count slot */
bufpos--; /* remove count slot */
inscnt--; /* make it -1 */
break;
}
out[outpos - inscnt - 1] = inscnt;
buf[bufpos - inscnt - 1] = inscnt;
inscnt = 0;
}

/* A copy op is currently limited to 64KB (pack v2) */
left = (msize < 0x10000) ? 0 : (msize - 0x10000);
msize -= left;

op = out + outpos++;
op = buf + bufpos++;
i = 0x80;

if (moff & 0x000000ff)
out[outpos++] = moff >> 0, i |= 0x01;
buf[bufpos++] = moff >> 0, i |= 0x01;
if (moff & 0x0000ff00)
out[outpos++] = moff >> 8, i |= 0x02;
buf[bufpos++] = moff >> 8, i |= 0x02;
if (moff & 0x00ff0000)
out[outpos++] = moff >> 16, i |= 0x04;
buf[bufpos++] = moff >> 16, i |= 0x04;
if (moff & 0xff000000)
out[outpos++] = moff >> 24, i |= 0x08;
buf[bufpos++] = moff >> 24, i |= 0x08;

if (msize & 0x00ff)
out[outpos++] = msize >> 0, i |= 0x10;
buf[bufpos++] = msize >> 0, i |= 0x10;
if (msize & 0xff00)
out[outpos++] = msize >> 8, i |= 0x20;
buf[bufpos++] = msize >> 8, i |= 0x20;

*op = i;

Expand All @@ -415,31 +419,33 @@ git_delta_create(
}
}

if (outpos >= outsize - MAX_OP_SIZE) {
void *tmp = out;
outsize = outsize * 3 / 2;
if (max_size && outsize >= max_size)
outsize = max_size + MAX_OP_SIZE + 1;
if (max_size && outpos > max_size)
if (bufpos >= bufsize - MAX_OP_SIZE) {
void *tmp = buf;
bufsize = bufsize * 3 / 2;
if (max_size && bufsize >= max_size)
bufsize = max_size + MAX_OP_SIZE + 1;
if (max_size && bufpos > max_size)
break;
out = git__realloc(out, outsize);
if (!out) {
buf = git__realloc(buf, bufsize);
if (!buf) {
git__free(tmp);
return NULL;
return -1;
}
}
}

if (inscnt)
out[outpos - inscnt - 1] = inscnt;
buf[bufpos - inscnt - 1] = inscnt;

if (max_size && outpos > max_size) {
git__free(out);
return NULL;
if (max_size && bufpos > max_size) {
giterr_set(GITERR_NOMEMORY, "delta would be larger than maximum size");
git__free(buf);
return GIT_EBUFS;
}

*delta_size = outpos;
return out;
*out_len = bufpos;
*out = buf;
return 0;
}

/*
Expand All @@ -459,8 +465,11 @@ static int hdr_sz(
unsigned int c, shift = 0;

do {
if (d == end)
if (d == end) {
giterr_set(GITERR_INVALID, "truncated delta");
return -1;
}

c = *d++;
r |= (c & 0x7f) << shift;
shift += 7;
Expand Down
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