diff --git a/diff-delta.c b/diff-delta.c
index 35e517d2d79002214988b57b476faa29f8292394..25a798d050c6319f3d524c9c605ab70ea35ae7a1 100644 (file)
--- a/diff-delta.c
+++ b/diff-delta.c
struct delta_index * create_delta_index(const void *buf, unsigned long bufsize)
{
struct delta_index * create_delta_index(const void *buf, unsigned long bufsize)
{
- unsigned int i, hsize, hmask, entries, *hash_count;
+ unsigned int i, hsize, hmask, entries, prev_val, *hash_count;
const unsigned char *data, *buffer = buf;
struct delta_index *index;
struct index_entry *entry, **hash;
void *mem;
const unsigned char *data, *buffer = buf;
struct delta_index *index;
struct index_entry *entry, **hash;
void *mem;
+ unsigned long memsize;
if (!buf || !bufsize)
return NULL;
if (!buf || !bufsize)
return NULL;
@@ -155,9 +156,10 @@ struct delta_index * create_delta_index(const void *buf, unsigned long bufsize)
hmask = hsize - 1;
/* allocate lookup index */
hmask = hsize - 1;
/* allocate lookup index */
- mem = malloc(sizeof(*index) +
- sizeof(*hash) * hsize +
- sizeof(*entry) * entries);
+ memsize = sizeof(*index) +
+ sizeof(*hash) * hsize +
+ sizeof(*entry) * entries;
+ mem = malloc(memsize);
if (!mem)
return NULL;
index = mem;
if (!mem)
return NULL;
index = mem;
@@ -179,18 +181,25 @@ struct delta_index * create_delta_index(const void *buf, unsigned long bufsize)
}
/* then populate the index */
}
/* then populate the index */
- data = buffer + entries * RABIN_WINDOW - RABIN_WINDOW;
- while (data >= buffer) {
+ prev_val = ~0;
+ for (data = buffer + entries * RABIN_WINDOW - RABIN_WINDOW;
+ data >= buffer;
+ data -= RABIN_WINDOW) {
unsigned int val = 0;
for (i = 1; i <= RABIN_WINDOW; i++)
val = ((val << 8) | data[i]) ^ T[val >> RABIN_SHIFT];
unsigned int val = 0;
for (i = 1; i <= RABIN_WINDOW; i++)
val = ((val << 8) | data[i]) ^ T[val >> RABIN_SHIFT];
- i = val & hmask;
- entry->ptr = data + RABIN_WINDOW;
- entry->val = val;
- entry->next = hash[i];
- hash[i] = entry++;
- hash_count[i]++;
- data -= RABIN_WINDOW;
+ if (val == prev_val) {
+ /* keep the lowest of consecutive identical blocks */
+ entry[-1].ptr = data + RABIN_WINDOW;
+ } else {
+ prev_val = val;
+ i = val & hmask;
+ entry->ptr = data + RABIN_WINDOW;
+ entry->val = val;
+ entry->next = hash[i];
+ hash[i] = entry++;
+ hash_count[i]++;
+ }
}
/*
}
/*
const void *trg_buf, unsigned long trg_size,
unsigned long *delta_size, unsigned long max_size)
{
const void *trg_buf, unsigned long trg_size,
unsigned long *delta_size, unsigned long max_size)
{
- unsigned int i, outpos, outsize, hash_mask, val;
+ unsigned int i, outpos, outsize, val;
int inscnt;
const unsigned char *ref_data, *ref_top, *data, *top;
unsigned char *out;
int inscnt;
const unsigned char *ref_data, *ref_top, *data, *top;
unsigned char *out;
ref_top = ref_data + index->src_size;
data = trg_buf;
top = trg_buf + trg_size;
ref_top = ref_data + index->src_size;
data = trg_buf;
top = trg_buf + trg_size;
- hash_mask = index->hash_mask;
outpos++;
val = 0;
outpos++;
val = 0;
struct index_entry *entry;
val ^= U[data[-RABIN_WINDOW]];
val = ((val << 8) | *data) ^ T[val >> RABIN_SHIFT];
struct index_entry *entry;
val ^= U[data[-RABIN_WINDOW]];
val = ((val << 8) | *data) ^ T[val >> RABIN_SHIFT];
- i = val & hash_mask;
+ i = val & index->hash_mask;
for (entry = index->hash[i]; entry; entry = entry->next) {
const unsigned char *ref = entry->ptr;
const unsigned char *src = data;
for (entry = index->hash[i]; entry; entry = entry->next) {
const unsigned char *ref = entry->ptr;
const unsigned char *src = data;