Merge branch 'js/pack-objects-delta-size-t'

The 'pack-objects' and delta-encoding code paths have been updated to
use 'size_t' instead of 'unsigned long' for object sizes and offset
limits, avoiding potential truncation issues on 64-bit Windows.

* js/pack-objects-delta-size-t:
  packfile: widen `unpack_object_header_buffer()` to `size_t`
  git-zlib: widen `git_deflate_bound()` to `size_t`
  t/helper/test-pack-deltas: widen `do_compress()`'s maxsize local to `size_t`
  http-push: widen `start_put()`'s size local from `ssize_t` to `size_t`
  diff: widen `deflate_it()`'s bound local from int to `size_t`
  archive-zip: widen `zlib_deflate_raw()`'s maxsize local to `size_t`
  packfile, git-zlib: widen `use_pack()` and zstream avail fields to `size_t`
  delta: widen `create_delta()` and `diff_delta()` to `size_t`
  pack-objects: widen `mem_usage` and `try_delta()`'s out-param to `size_t`
  pack-objects: widen `free_unpacked()` return to `size_t`
  pack-objects: widen delta-cache accounting to `size_t`
  delta: widen `create_delta_index()` parameter to `size_t`
  diff-delta: widen `struct delta_index`' size fields to `size_t`
main
Junio C Hamano 2026-08-24 13:17:51 -07:00
commit 781fd4ea83
19 changed files with 97 additions and 58 deletions

View File

@ -206,7 +206,7 @@ static void *zlib_deflate_raw(void *data, unsigned long size,
unsigned long *compressed_size) unsigned long *compressed_size)
{ {
git_zstream stream; git_zstream stream;
unsigned long maxsize; size_t maxsize;
void *buffer; void *buffer;
int result; int result;



View File

@ -980,7 +980,7 @@ static int store_object(
struct object_entry *e; struct object_entry *e;
unsigned char hdr[96]; unsigned char hdr[96];
struct object_id oid; struct object_id oid;
unsigned long hdrlen, deltalen; unsigned long hdrlen, deltalen = 0;
struct git_hash_ctx c; struct git_hash_ctx c;
git_zstream s; git_zstream s;
struct repo_config_values *cfg = repo_config_values(the_repository); struct repo_config_values *cfg = repo_config_values(the_repository);
@ -1016,11 +1016,13 @@ static int store_object(


if (last && last->data.len && last->data.buf && last->depth < max_depth if (last && last->data.len && last->data.buf && last->depth < max_depth
&& dat->len > the_hash_algo->rawsz) { && dat->len > the_hash_algo->rawsz) {
size_t deltalen_st;


delta_count_attempts_by_type[type]++; delta_count_attempts_by_type[type]++;
delta = diff_delta(last->data.buf, last->data.len, delta = diff_delta(last->data.buf, last->data.len,
dat->buf, dat->len, dat->buf, dat->len,
&deltalen, dat->len - the_hash_algo->rawsz); &deltalen_st, dat->len - the_hash_algo->rawsz);
deltalen = cast_size_t_to_ulong(deltalen_st);
} else } else
delta = NULL; delta = NULL;



View File

@ -261,8 +261,8 @@ static int exclude_promisor_objects_best_effort;


static int use_delta_islands; static int use_delta_islands;


static unsigned long delta_cache_size = 0; static size_t delta_cache_size = 0;
static unsigned long max_delta_cache_size = DEFAULT_DELTA_CACHE_SIZE; static size_t max_delta_cache_size = DEFAULT_DELTA_CACHE_SIZE;
static unsigned long cache_max_small_delta_size = 1000; static unsigned long cache_max_small_delta_size = 1000;


static unsigned long window_memory_limit = 0; static unsigned long window_memory_limit = 0;
@ -354,7 +354,8 @@ static void index_commit_for_bitmap(struct commit *commit)


static void *get_delta(struct object_entry *entry) static void *get_delta(struct object_entry *entry)
{ {
unsigned long size, base_size, delta_size; unsigned long size, base_size;
size_t delta_size;
void *buf, *base_buf, *delta_buf; void *buf, *base_buf, *delta_buf;
enum object_type type; enum object_type type;
size_t size_st = 0, base_size_st = 0; size_t size_st = 0, base_size_st = 0;
@ -488,7 +489,7 @@ static void copy_pack_data(struct hashfile *f,
off_t len) off_t len)
{ {
unsigned char *in; unsigned char *in;
unsigned long avail; size_t avail;


while (len) { while (len) {
in = use_pack(p, w_curs, offset, &avail); in = use_pack(p, w_curs, offset, &avail);
@ -2259,8 +2260,7 @@ static void check_object(struct object_entry *entry, uint32_t object_index)
int have_base = 0; int have_base = 0;
struct object_id base_ref; struct object_id base_ref;
struct object_entry *base_entry; struct object_entry *base_entry;
unsigned long used, used_0; size_t used, used_0, avail;
unsigned long avail;
off_t ofs; off_t ofs;
unsigned char *buf, c; unsigned char *buf, c;
enum object_type type; enum object_type type;
@ -2688,8 +2688,8 @@ struct unpacked {
unsigned depth; unsigned depth;
}; };


static int delta_cacheable(unsigned long src_size, unsigned long trg_size, static int delta_cacheable(size_t src_size, size_t trg_size,
unsigned long delta_size) size_t delta_size)
{ {
if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size) if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
return 0; return 0;
@ -2772,8 +2772,7 @@ size_t oe_get_size_slow(struct packing_data *pack,
struct pack_window *w_curs; struct pack_window *w_curs;
unsigned char *buf; unsigned char *buf;
enum object_type type; enum object_type type;
unsigned long used, avail; size_t used, avail, size;
size_t size;


if (e->type_ != OBJ_OFS_DELTA && e->type_ != OBJ_REF_DELTA) { if (e->type_ != OBJ_OFS_DELTA && e->type_ != OBJ_REF_DELTA) {
size_t sz; size_t sz;
@ -2804,11 +2803,12 @@ size_t oe_get_size_slow(struct packing_data *pack,
} }


static int try_delta(struct unpacked *trg, struct unpacked *src, static int try_delta(struct unpacked *trg, struct unpacked *src,
unsigned max_depth, unsigned long *mem_usage) unsigned max_depth, size_t *mem_usage)
{ {
struct object_entry *trg_entry = trg->entry; struct object_entry *trg_entry = trg->entry;
struct object_entry *src_entry = src->entry; struct object_entry *src_entry = src->entry;
unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz; unsigned long trg_size, src_size, sizediff, max_size, sz;
size_t delta_size;
unsigned ref_depth; unsigned ref_depth;
enum object_type type; enum object_type type;
void *delta_buf; void *delta_buf;
@ -2972,9 +2972,9 @@ static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
return m; return m;
} }


static unsigned long free_unpacked(struct unpacked *n) static size_t free_unpacked(struct unpacked *n)
{ {
unsigned long freed_mem = sizeof_delta_index(n->index); size_t freed_mem = sizeof_delta_index(n->index);
free_delta_index(n->index); free_delta_index(n->index);
n->index = NULL; n->index = NULL;
if (n->data) { if (n->data) {
@ -2991,7 +2991,7 @@ static void find_deltas(struct object_entry **list, unsigned *list_size,
{ {
uint32_t i, idx = 0, count = 0; uint32_t i, idx = 0, count = 0;
struct unpacked *array; struct unpacked *array;
unsigned long mem_usage = 0; size_t mem_usage = 0;


CALLOC_ARRAY(array, window); CALLOC_ARRAY(array, window);


@ -3701,7 +3701,7 @@ static int git_pack_config(const char *k, const char *v,
return 0; return 0;
} }
if (!strcmp(k, "pack.deltacachesize")) { if (!strcmp(k, "pack.deltacachesize")) {
max_delta_cache_size = git_config_int(k, v, ctx->kvi); max_delta_cache_size = git_config_size_t(k, v, ctx->kvi);
return 0; return 0;
} }
if (!strcmp(k, "pack.deltacachelimit")) { if (!strcmp(k, "pack.deltacachelimit")) {

View File

@ -1271,6 +1271,15 @@ ssize_t git_config_ssize_t(const char *name, const char *value,
return ret; return ret;
} }


size_t git_config_size_t(const char *name, const char *value,
const struct key_value_info *kvi)
{
size_t ret;
if (!git_parse_size_t(value, &ret))
die_bad_number(name, value, kvi);
return ret;
}

double git_config_double(const char *name, const char *value, double git_config_double(const char *name, const char *value,
const struct key_value_info *kvi) const struct key_value_info *kvi)
{ {

View File

@ -282,6 +282,9 @@ unsigned long git_config_ulong(const char *, const char *,
ssize_t git_config_ssize_t(const char *, const char *, ssize_t git_config_ssize_t(const char *, const char *,
const struct key_value_info *); const struct key_value_info *);


size_t git_config_size_t(const char *, const char *,
const struct key_value_info *);

/** /**
* Identically to `git_config_double`, but for double-precision floating point * Identically to `git_config_double`, but for double-precision floating point
* values. * values.

14
delta.h
View File

@ -14,7 +14,7 @@ struct delta_index;
* using free_delta_index(). * using free_delta_index().
*/ */
struct delta_index * struct delta_index *
create_delta_index(const void *buf, unsigned long bufsize); create_delta_index(const void *buf, size_t bufsize);


/* /*
* free_delta_index: free the index created by create_delta_index() * free_delta_index: free the index created by create_delta_index()
@ -28,7 +28,7 @@ void free_delta_index(struct delta_index *index);
* *
* Given pointer must be what create_delta_index() returned, or NULL. * Given pointer must be what create_delta_index() returned, or NULL.
*/ */
unsigned long sizeof_delta_index(struct delta_index *index); size_t sizeof_delta_index(struct delta_index *index);


/* /*
* create_delta: create a delta from given index for the given buffer * create_delta: create a delta from given index for the given buffer
@ -42,8 +42,8 @@ unsigned long sizeof_delta_index(struct delta_index *index);
*/ */
void * void *
create_delta(const struct delta_index *index, create_delta(const struct delta_index *index,
const void *buf, unsigned long bufsize, const void *buf, size_t bufsize,
unsigned long *delta_size, unsigned long max_delta_size); size_t *delta_size, size_t max_delta_size);


/* /*
* diff_delta: create a delta from source buffer to target buffer * diff_delta: create a delta from source buffer to target buffer
@ -54,9 +54,9 @@ create_delta(const struct delta_index *index,
* updated with its size. The returned buffer must be freed by the caller. * updated with its size. The returned buffer must be freed by the caller.
*/ */
static inline void * static inline void *
diff_delta(const void *src_buf, unsigned long src_bufsize, diff_delta(const void *src_buf, size_t src_bufsize,
const void *trg_buf, unsigned long trg_bufsize, const void *trg_buf, size_t trg_bufsize,
unsigned long *delta_size, unsigned long max_delta_size) size_t *delta_size, size_t max_delta_size)
{ {
struct delta_index *index = create_delta_index(src_buf, src_bufsize); struct delta_index *index = create_delta_index(src_buf, src_bufsize);
if (index) { if (index) {

View File

@ -125,14 +125,14 @@ struct unpacked_index_entry {
}; };


struct delta_index { struct delta_index {
unsigned long memsize; size_t memsize;
const void *src_buf; const void *src_buf;
unsigned long src_size; size_t src_size;
unsigned int hash_mask; unsigned int hash_mask;
struct index_entry *hash[FLEX_ARRAY]; struct index_entry *hash[FLEX_ARRAY];
}; };


struct delta_index * create_delta_index(const void *buf, unsigned long bufsize) struct delta_index * create_delta_index(const void *buf, size_t bufsize)
{ {
unsigned int i, hsize, hmask, entries, prev_val, *hash_count; unsigned int i, hsize, hmask, entries, prev_val, *hash_count;
const unsigned char *data, *buffer = buf; const unsigned char *data, *buffer = buf;
@ -140,7 +140,7 @@ struct delta_index * create_delta_index(const void *buf, unsigned long bufsize)
struct unpacked_index_entry *entry, **hash; struct unpacked_index_entry *entry, **hash;
struct index_entry *packed_entry, **packed_hash; struct index_entry *packed_entry, **packed_hash;
void *mem; void *mem;
unsigned long memsize; size_t memsize;


if (!buf || !bufsize) if (!buf || !bufsize)
return NULL; return NULL;
@ -302,7 +302,7 @@ void free_delta_index(struct delta_index *index)
free(index); free(index);
} }


unsigned long sizeof_delta_index(struct delta_index *index) size_t sizeof_delta_index(struct delta_index *index)
{ {
if (index) if (index)
return index->memsize; return index->memsize;
@ -318,8 +318,8 @@ unsigned long sizeof_delta_index(struct delta_index *index)


void * void *
create_delta(const struct delta_index *index, create_delta(const struct delta_index *index,
const void *trg_buf, unsigned long trg_size, const void *trg_buf, size_t trg_size,
unsigned long *delta_size, unsigned long max_size) size_t *delta_size, size_t max_size)
{ {
unsigned int i, val; unsigned int i, val;
off_t outpos, moff; off_t outpos, moff;

6
diff.c
View File

@ -3586,7 +3586,7 @@ static unsigned char *deflate_it(char *data,
unsigned long size, unsigned long size,
unsigned long *result_size) unsigned long *result_size)
{ {
int bound; size_t bound;
unsigned char *deflated; unsigned char *deflated;
git_zstream stream; git_zstream stream;
struct repo_config_values *cfg = repo_config_values(the_repository); struct repo_config_values *cfg = repo_config_values(the_repository);
@ -3624,9 +3624,11 @@ static void emit_binary_diff_body(struct diff_options *o,
delta = NULL; delta = NULL;
deflated = deflate_it(two->ptr, two->size, &deflate_size); deflated = deflate_it(two->ptr, two->size, &deflate_size);
if (one->size && two->size) { if (one->size && two->size) {
size_t delta_size_st = 0;
delta = diff_delta(one->ptr, one->size, delta = diff_delta(one->ptr, one->size,
two->ptr, two->size, two->ptr, two->size,
&delta_size, deflate_size); &delta_size_st, deflate_size);
delta_size = cast_size_t_to_ulong(delta_size_st);
if (delta) { if (delta) {
void *to_free = delta; void *to_free = delta;
orig_size = delta_size; orig_size = delta_size;

View File

@ -33,7 +33,7 @@ static const char *zerr_to_string(int status)


/* uLong is 32-bit on Windows, even on 64-bit systems */ /* uLong is 32-bit on Windows, even on 64-bit systems */
#define ULONG_MAX_VALUE maximum_unsigned_value_of_type(uLong) #define ULONG_MAX_VALUE maximum_unsigned_value_of_type(uLong)
static inline uInt zlib_buf_cap(unsigned long len) static inline uInt zlib_buf_cap(size_t len)
{ {
return (ZLIB_BUF_MAX < len) ? ZLIB_BUF_MAX : len; return (ZLIB_BUF_MAX < len) ? ZLIB_BUF_MAX : len;
} }
@ -167,9 +167,21 @@ int git_inflate(git_zstream *strm, int flush)
return status; return status;
} }


unsigned long git_deflate_bound(git_zstream *strm, unsigned long size) size_t git_deflate_bound(git_zstream *strm, size_t size)
{ {
return deflateBound(&strm->z, size); #if SIZE_MAX > ULONG_MAX
if (size > maximum_unsigned_value_of_type(uLong))
/*
* deflateBound() takes uLong, which is 32-bit on
* Windows. For inputs above that range, return zlib's
* stored-block formula (the conservative path it would
* itself use for an unknown stream state) plus the
* worst-case wrapper overhead.
*/
return size + (size >> 5) + (size >> 7) + (size >> 11)
+ 7 + 18;
#endif
return deflateBound(&strm->z, (uLong)size);
} }


void git_deflate_init(git_zstream *strm, int level) void git_deflate_init(git_zstream *strm, int level)

View File

@ -5,8 +5,8 @@


typedef struct git_zstream { typedef struct git_zstream {
struct z_stream_s z; struct z_stream_s z;
unsigned long avail_in; size_t avail_in;
unsigned long avail_out; size_t avail_out;
size_t total_in; size_t total_in;
size_t total_out; size_t total_out;
unsigned char *next_in; unsigned char *next_in;
@ -25,6 +25,6 @@ void git_deflate_end(git_zstream *);
int git_deflate_abort(git_zstream *); int git_deflate_abort(git_zstream *);
int git_deflate_end_gently(git_zstream *); int git_deflate_end_gently(git_zstream *);
int git_deflate(git_zstream *, int flush); int git_deflate(git_zstream *, int flush);
unsigned long git_deflate_bound(git_zstream *, unsigned long); size_t git_deflate_bound(git_zstream *, size_t);


#endif /* GIT_ZLIB_H */ #endif /* GIT_ZLIB_H */

View File

@ -367,7 +367,7 @@ static void start_put(struct transfer_request *request)
void *unpacked; void *unpacked;
size_t len; size_t len;
int hdrlen; int hdrlen;
ssize_t size; size_t size;
git_zstream stream; git_zstream stream;
struct repo_config_values *cfg = repo_config_values(the_repository); struct repo_config_values *cfg = repo_config_values(the_repository);



View File

@ -9,7 +9,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
size_t len; size_t len;


unpack_object_header_buffer((const unsigned char *)data, unpack_object_header_buffer((const unsigned char *)data,
(unsigned long)size, &type, &len); size, &type, &len);


return 0; return 0;
} }

View File

@ -34,7 +34,7 @@ int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
uint32_t data_crc = crc32(0, NULL, 0); uint32_t data_crc = crc32(0, NULL, 0);


do { do {
unsigned long avail; size_t avail;
void *data = use_pack(p, w_curs, offset, &avail); void *data = use_pack(p, w_curs, offset, &avail);
if (avail > len) if (avail > len)
avail = len; avail = len;
@ -71,7 +71,7 @@ static int verify_packfile(struct repository *r,


git_hash_init(&ctx, r->hash_algo); git_hash_init(&ctx, r->hash_algo);
do { do {
unsigned long remaining; size_t remaining;
unsigned char *in = use_pack(p, w_curs, offset, &remaining); unsigned char *in = use_pack(p, w_curs, offset, &remaining);
offset += remaining; offset += remaining;
if (!pack_sig_ofs) if (!pack_sig_ofs)

View File

@ -620,7 +620,7 @@ static int in_window(struct repository *r, struct pack_window *win,
unsigned char *use_pack(struct packed_git *p, unsigned char *use_pack(struct packed_git *p,
struct pack_window **w_cursor, struct pack_window **w_cursor,
off_t offset, off_t offset,
unsigned long *left) size_t *left)
{ {
struct pack_window *win = *w_cursor; struct pack_window *win = *w_cursor;


@ -866,12 +866,11 @@ struct packfile_list_entry *packfile_store_get_packs(struct odb_source_packed *s
return store->packs.head; return store->packs.head;
} }


unsigned long unpack_object_header_buffer(const unsigned char *buf, size_t unpack_object_header_buffer(const unsigned char *buf, size_t len,
unsigned long len, enum object_type *type, size_t *sizep) enum object_type *type, size_t *sizep)
{ {
unsigned shift; unsigned shift;
size_t size, c; size_t size, c, used = 0;
unsigned long used = 0;


c = buf[used++]; c = buf[used++];
*type = (c >> 4) & 7; *type = (c >> 4) & 7;
@ -960,8 +959,7 @@ int unpack_object_header(struct packed_git *p,
size_t *sizep) size_t *sizep)
{ {
unsigned char *base; unsigned char *base;
unsigned long left; size_t left, used;
unsigned long used;
enum object_type type; enum object_type type;


/* use_pack() assures us we have [base, base + 20) available /* use_pack() assures us we have [base, base + 20) available

View File

@ -240,7 +240,8 @@ uint32_t get_pack_fanout(struct packed_git *p, uint32_t value);


struct object_database; struct object_database;


unsigned char *use_pack(struct packed_git *, struct pack_window **, off_t, unsigned long *); unsigned char *use_pack(struct packed_git *, struct pack_window **, off_t,
size_t *);
void close_pack_windows(struct packed_git *); void close_pack_windows(struct packed_git *);
void close_pack(struct packed_git *); void close_pack(struct packed_git *);
void unuse_pack(struct pack_window **); void unuse_pack(struct pack_window **);
@ -299,7 +300,8 @@ int packfile_fill_entry(struct packed_git *p,
int is_pack_valid(struct packed_git *); int is_pack_valid(struct packed_git *);
void *unpack_entry(struct repository *r, struct packed_git *, off_t, void *unpack_entry(struct repository *r, struct packed_git *, off_t,
enum object_type *, size_t *); enum object_type *, size_t *);
unsigned long unpack_object_header_buffer(const unsigned char *buf, unsigned long len, enum object_type *type, size_t *sizep); size_t unpack_object_header_buffer(const unsigned char *buf, size_t len,
enum object_type *type, size_t *sizep);
size_t get_size_from_delta(struct packed_git *, struct pack_window **, off_t); size_t get_size_from_delta(struct packed_git *, struct pack_window **, off_t);
int unpack_object_header(struct packed_git *, struct pack_window **, off_t *, size_t *); int unpack_object_header(struct packed_git *, struct pack_window **, off_t *, size_t *);
off_t get_delta_base(struct packed_git *p, struct pack_window **w_curs, off_t get_delta_base(struct packed_git *p, struct pack_window **w_curs,

View File

@ -134,6 +134,15 @@ int git_parse_ssize_t(const char *value, ssize_t *ret)
return 1; return 1;
} }


int git_parse_size_t(const char *value, size_t *ret)
{
uintmax_t tmp;
if (!git_parse_unsigned(value, &tmp, maximum_signed_value_of_type(size_t)))
return 0;
*ret = tmp;
return 1;
}

int git_parse_double(const char *value, double *ret) int git_parse_double(const char *value, double *ret)
{ {
char *end; char *end;

View File

@ -4,6 +4,7 @@
int git_parse_signed(const char *value, intmax_t *ret, intmax_t max); int git_parse_signed(const char *value, intmax_t *ret, intmax_t max);
int git_parse_unsigned(const char *value, uintmax_t *ret, uintmax_t max); int git_parse_unsigned(const char *value, uintmax_t *ret, uintmax_t max);
int git_parse_ssize_t(const char *, ssize_t *); int git_parse_ssize_t(const char *, ssize_t *);
int git_parse_size_t(const char *, size_t *);
int git_parse_ulong(const char *, unsigned long *); int git_parse_ulong(const char *, unsigned long *);
int git_parse_uint(const char *value, unsigned int *ret); int git_parse_uint(const char *value, unsigned int *ret);
int git_parse_int(const char *value, int *ret); int git_parse_int(const char *value, int *ret);

View File

@ -32,7 +32,7 @@ int cmd__delta(int argc, const char **argv)
die_errno("unable to read '%s'", argv[3]); die_errno("unable to read '%s'", argv[3]);


if (argv[1][1] == 'd') { if (argv[1][1] == 'd') {
unsigned long delta_size; size_t delta_size;
out_buf = diff_delta(from.buf, from.len, out_buf = diff_delta(from.buf, from.len,
data.buf, data.len, data.buf, data.len,
&delta_size, 0); &delta_size, 0);

View File

@ -22,7 +22,7 @@ static unsigned long do_compress(void **pptr, unsigned long size)
{ {
git_zstream stream; git_zstream stream;
void *in, *out; void *in, *out;
unsigned long maxsize; size_t maxsize;


git_deflate_init(&stream, 1); git_deflate_init(&stream, 1);
maxsize = git_deflate_bound(&stream, size); maxsize = git_deflate_bound(&stream, size);
@ -49,7 +49,7 @@ static void write_ref_delta(struct hashfile *f,
{ {
unsigned char header[MAX_PACK_OBJECT_HEADER]; unsigned char header[MAX_PACK_OBJECT_HEADER];
unsigned long delta_size, compressed_size, hdrlen; unsigned long delta_size, compressed_size, hdrlen;
size_t size, base_size; size_t size, base_size, delta_size_st = 0;
enum object_type type; enum object_type type;
void *base_buf, *delta_buf; void *base_buf, *delta_buf;
void *buf = odb_read_object(the_repository->objects, void *buf = odb_read_object(the_repository->objects,
@ -65,7 +65,8 @@ static void write_ref_delta(struct hashfile *f,
die("unable to read %s", oid_to_hex(base)); die("unable to read %s", oid_to_hex(base));


delta_buf = diff_delta(base_buf, base_size, delta_buf = diff_delta(base_buf, base_size,
buf, size, &delta_size, 0); buf, size, &delta_size_st, 0);
delta_size = cast_size_t_to_ulong(delta_size_st);


compressed_size = do_compress(&delta_buf, delta_size); compressed_size = do_compress(&delta_buf, delta_size);