diff options
| -rw-r--r-- | src/quicklist.c | 3 | ||||
| -rw-r--r-- | src/t_hash.c | 7 | ||||
| -rw-r--r-- | src/ziplist.c | 71 | ||||
| -rw-r--r-- | src/ziplist.h | 1 |
4 files changed, 75 insertions, 7 deletions
diff --git a/src/quicklist.c b/src/quicklist.c index b2a406004..c8517414c 100644 --- a/src/quicklist.c +++ b/src/quicklist.c @@ -680,8 +680,7 @@ int quicklistReplaceAtIndex(quicklist *quicklist, long index, void *data, quicklistEntry entry; if (likely(quicklistIndex(quicklist, index, &entry))) { /* quicklistIndex provides an uncompressed node */ - entry.node->zl = ziplistDelete(entry.node->zl, &entry.zi); - entry.node->zl = ziplistInsert(entry.node->zl, entry.zi, data, sz); + entry.node->zl = ziplistReplace(entry.node->zl, entry.zi, data, sz); quicklistNodeUpdateSz(entry.node); quicklistCompress(quicklist, entry.node); return 1; diff --git a/src/t_hash.c b/src/t_hash.c index cae350566..15b57c1d7 100644 --- a/src/t_hash.c +++ b/src/t_hash.c @@ -215,11 +215,8 @@ int hashTypeSet(robj *o, sds field, sds value, int flags) { serverAssert(vptr != NULL); update = 1; - /* Delete value */ - zl = ziplistDelete(zl, &vptr); - - /* Insert new value */ - zl = ziplistInsert(zl, vptr, (unsigned char*)value, + /* Replace value */ + zl = ziplistReplace(zl, vptr, (unsigned char*)value, sdslen(value)); } } diff --git a/src/ziplist.c b/src/ziplist.c index 35a0f283a..b66f97ef8 100644 --- a/src/ziplist.c +++ b/src/ziplist.c @@ -1265,6 +1265,42 @@ unsigned char *ziplistDeleteRange(unsigned char *zl, int index, unsigned int num return (p == NULL) ? zl : __ziplistDelete(zl,p,num); } +/* Replaces the entry at p. This is equivalent to a delete and an insert, + * but avoids some overhead when replacing a value of the same size. */ +unsigned char *ziplistReplace(unsigned char *zl, unsigned char *p, unsigned char *s, unsigned int slen) { + + /* get metadata of the current entry */ + zlentry entry; + zipEntry(p, &entry); + + /* compute length of entry to store, excluding prevlen */ + unsigned int reqlen; + unsigned char encoding = 0; + long long value = 123456789; /* initialized to avoid warning. */ + if (zipTryEncoding(s,slen,&value,&encoding)) { + reqlen = zipIntSize(encoding); /* encoding is set */ + } else { + reqlen = slen; /* encoding == 0 */ + } + reqlen += zipStoreEntryEncoding(NULL,encoding,slen); + + if (reqlen == entry.lensize + entry.len) { + /* Simply overwrite the element. */ + p += entry.prevrawlensize; + p += zipStoreEntryEncoding(p,encoding,slen); + if (ZIP_IS_STR(encoding)) { + memcpy(p,s,slen); + } else { + zipSaveInteger(p,value,encoding); + } + } else { + /* Fallback. */ + zl = ziplistDelete(zl,&p); + zl = ziplistInsert(zl,p,s,slen); + } + return zl; +} + /* Compare entry pointer to by 'p' with 'sstr' of length 'slen'. */ /* Return 1 if equal. */ unsigned int ziplistCompare(unsigned char *p, unsigned char *sstr, unsigned int slen) { @@ -2070,6 +2106,41 @@ int ziplistTest(int argc, char **argv) { zfree(zl); } + printf("Replace with same size:\n"); + { + zl = createList(); /* "hello", "foo", "quux", "1024" */ + unsigned char *orig_zl = zl; + p = ziplistIndex(zl, 0); + zl = ziplistReplace(zl, p, (unsigned char*)"zoink", 5); + p = ziplistIndex(zl, 3); + zl = ziplistReplace(zl, p, (unsigned char*)"yy", 2); + p = ziplistIndex(zl, 1); + zl = ziplistReplace(zl, p, (unsigned char*)"65536", 5); + p = ziplistIndex(zl, 0); + assert(!memcmp((char*)p, + "\x00\x05zoink" + "\x07\xf0\x00\x00\x01" /* 65536 as int24 */ + "\x05\x04quux" "\x06\x02yy" "\xff", + 23)); + assert(zl == orig_zl); /* no reallocations have happened */ + zfree(zl); + printf("SUCCESS\n\n"); + } + + printf("Replace with different size:\n"); + { + zl = createList(); /* "hello", "foo", "quux", "1024" */ + p = ziplistIndex(zl, 1); + zl = ziplistReplace(zl, p, (unsigned char*)"squirrel", 8); + p = ziplistIndex(zl, 0); + assert(!strncmp((char*)p, + "\x00\x05hello" "\x07\x08squirrel" "\x0a\x04quux" + "\x06\xc0\x00\x04" "\xff", + 28)); + zfree(zl); + printf("SUCCESS\n\n"); + } + printf("Regression test for >255 byte strings:\n"); { char v1[257] = {0}, v2[257] = {0}; diff --git a/src/ziplist.h b/src/ziplist.h index fff334cbd..9dc1061b0 100644 --- a/src/ziplist.h +++ b/src/ziplist.h @@ -53,6 +53,7 @@ unsigned int ziplistGet(unsigned char *p, unsigned char **sval, unsigned int *sl unsigned char *ziplistInsert(unsigned char *zl, unsigned char *p, unsigned char *s, unsigned int slen); unsigned char *ziplistDelete(unsigned char *zl, unsigned char **p); unsigned char *ziplistDeleteRange(unsigned char *zl, int index, unsigned int num); +unsigned char *ziplistReplace(unsigned char *zl, unsigned char *p, unsigned char *s, unsigned int slen); unsigned int ziplistCompare(unsigned char *p, unsigned char *s, unsigned int slen); unsigned char *ziplistFind(unsigned char *zl, unsigned char *p, unsigned char *vstr, unsigned int vlen, unsigned int skip); unsigned int ziplistLen(unsigned char *zl); |