read-cache: use get_be32 instead of hand-rolled ntoh_l
Commit d60c49c (read-cache.c: allow unaligned mapping of the index file, 2012-04-03) introduced helpers to access unaligned data. However, we already have get_be32, which has a few advantages: 1. It's already written, so we avoid duplication. 2. It's probably faster, since it does the endian conversion and the alignment fix at the same time. 3. The get_be32 code is well-tested, having been in block-sha1 for a long time. By contrast, our custom helpers were probably almost never used, since the user needed to manually define a macro to enable them. We have to add a get_be16 implementation to the existing get_be32, but that is very simple to do. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Jeff King committed
Jan 23, 2014 at 16:26 UTC
c3d8da571f11b0146e60591c040da399d411c3f2
2 files changed
+16
-32
compat/bswap.h
+4
@@ -136,11 +136,15 @@ static inline uint64_t git_bswap64(uint64_t x)
136
defined(__powerpc__) || defined(__powerpc64__) || \
137
defined(__s390__) || defined(__s390x__)
138
139
+#define get_be16(p) ntohs(*(unsigned short *)(p))
140
#define get_be32(p) ntohl(*(unsigned int *)(p))
141
#define put_be32(p, v) do { *(unsigned int *)(p) = htonl(v); } while (0)
142
143
#else
144
145
+#define get_be16(p) ( \
146
+ (*((unsigned char *)(p) + 0) << 8) | \
147
+ (*((unsigned char *)(p) + 1) << 0) )
148
#define get_be32(p) ( \
149
(*((unsigned char *)(p) + 0) << 24) | \
150
(*((unsigned char *)(p) + 1) << 16) | \
read-cache.c
+12
-32
@@ -1313,26 +1313,6 @@ int read_index(struct index_state *istate)
1313
return read_index_from(istate, get_index_file());
1314
}
1315
1316
-#ifndef NEEDS_ALIGNED_ACCESS
1317
-#define ntoh_s(var) ntohs(var)
1318
-#define ntoh_l(var) ntohl(var)
1319
-#else
1320
-static inline uint16_t ntoh_s_force_align(void *p)
1321
-{
1322
- uint16_t x;
1323
- memcpy(&x, p, sizeof(x));
1324
- return ntohs(x);
1325
-}
1326
-static inline uint32_t ntoh_l_force_align(void *p)
1327
-{
1328
- uint32_t x;
1329
- memcpy(&x, p, sizeof(x));
1330
- return ntohl(x);
1331
-}
1332
-#define ntoh_s(var) ntoh_s_force_align(&(var))
1333
-#define ntoh_l(var) ntoh_l_force_align(&(var))
1334
-#endif
1335
-
1316
static struct cache_entry *cache_entry_from_ondisk(struct ondisk_cache_entry *ondisk,
1317
unsigned int flags,
1318
const char *name,
@@ -1340,16 +1320,16 @@ static struct cache_entry *cache_entry_from_ondisk(struct ondisk_cache_entry *on
1320
{
1321
struct cache_entry *ce = xmalloc(cache_entry_size(len));
1322
1343
- ce->ce_stat_data.sd_ctime.sec = ntoh_l(ondisk->ctime.sec);
1344
- ce->ce_stat_data.sd_mtime.sec = ntoh_l(ondisk->mtime.sec);
1345
- ce->ce_stat_data.sd_ctime.nsec = ntoh_l(ondisk->ctime.nsec);
1346
- ce->ce_stat_data.sd_mtime.nsec = ntoh_l(ondisk->mtime.nsec);
1347
- ce->ce_stat_data.sd_dev = ntoh_l(ondisk->dev);
1348
- ce->ce_stat_data.sd_ino = ntoh_l(ondisk->ino);
1349
- ce->ce_mode = ntoh_l(ondisk->mode);
1350
- ce->ce_stat_data.sd_uid = ntoh_l(ondisk->uid);
1351
- ce->ce_stat_data.sd_gid = ntoh_l(ondisk->gid);
1352
- ce->ce_stat_data.sd_size = ntoh_l(ondisk->size);
1323
+ ce->ce_stat_data.sd_ctime.sec = get_be32(&ondisk->ctime.sec);
1324
+ ce->ce_stat_data.sd_mtime.sec = get_be32(&ondisk->mtime.sec);
1325
+ ce->ce_stat_data.sd_ctime.nsec = get_be32(&ondisk->ctime.nsec);
1326
+ ce->ce_stat_data.sd_mtime.nsec = get_be32(&ondisk->mtime.nsec);
1327
+ ce->ce_stat_data.sd_dev = get_be32(&ondisk->dev);
1328
+ ce->ce_stat_data.sd_ino = get_be32(&ondisk->ino);
1329
+ ce->ce_mode = get_be32(&ondisk->mode);
1330
+ ce->ce_stat_data.sd_uid = get_be32(&ondisk->uid);
1331
+ ce->ce_stat_data.sd_gid = get_be32(&ondisk->gid);
1332
+ ce->ce_stat_data.sd_size = get_be32(&ondisk->size);
1333
ce->ce_flags = flags & ~CE_NAMEMASK;
1334
ce->ce_namelen = len;
1335
hashcpy(ce->sha1, ondisk->sha1);
@@ -1389,14 +1369,14 @@ static struct cache_entry *create_from_disk(struct ondisk_cache_entry *ondisk,
1369
unsigned int flags;
1370
1371
/* On-disk flags are just 16 bits */
1392
- flags = ntoh_s(ondisk->flags);
1372
+ flags = get_be16(&ondisk->flags);
1373
len = flags & CE_NAMEMASK;
1374
1375
if (flags & CE_EXTENDED) {
1376
struct ondisk_cache_entry_extended *ondisk2;
1377
int extended_flags;
1378
ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
1399
- extended_flags = ntoh_s(ondisk2->flags2) << 16;
1379
+ extended_flags = get_be16(&ondisk2->flags2) << 16;
1380
/* We do not yet understand any bit out of CE_EXTENDED_FLAGS */
1381
if (extended_flags & ~CE_EXTENDED_FLAGS)
1382
die("Unknown index entry format %08x", extended_flags);