#define ZIPLIST_INCR_LENGTH(zl,incr) { \
if (ZIPLIST_LENGTH(zl) < ZIP_BIGLEN) ZIPLIST_LENGTH(zl)+=incr; }
+typedef struct zlentry {
+ unsigned int prevrawlensize, prevrawlen;
+ unsigned int lensize, len;
+ unsigned int headersize;
+ unsigned char encoding;
+ unsigned char *p;
+} zlentry;
+
/* Return bytes needed to store integer encoded by 'encoding' */
static unsigned int zipEncodingSize(char encoding) {
if (encoding == ZIP_ENC_SHORT) {
return ret;
}
-/* Return the total amount used by an entry (encoded length + payload). */
+/* Return a struct with all information about an entry. */
+static zlentry zipEntry(unsigned char *p) {
+ zlentry e;
+ e.prevrawlen = zipDecodeLength(p,&e.prevrawlensize);
+ e.len = zipDecodeLength(p+e.prevrawlensize,&e.lensize);
+ e.headersize = e.prevrawlensize+e.lensize;
+ e.encoding = ZIP_ENCODING(p+e.prevrawlensize);
+ e.p = p;
+ return e;
+}
+
+/* Return the total number of bytes used by the entry at "p". */
static unsigned int zipRawEntryLength(unsigned char *p) {
- unsigned int prevlensize, lensize, len;
- /* Byte-size of encoded length of previous entry */
- zipDecodeLength(p,&prevlensize);
- /* Encoded length of this entry's payload */
- len = zipDecodeLength(p+prevlensize, &lensize);
- return prevlensize+lensize+len;
+ zlentry e = zipEntry(p);
+ return e.headersize + e.len;
}
/* Create a new empty ziplist. */
p += zipRawEntryLength(p);
}
return q;
+
+/* Delete "num" entries, starting at "p". Returns pointer to the ziplist. */
+static unsigned char *__ziplistDelete(unsigned char *zl, unsigned char *p, int num) {
+ unsigned int i, totlen, deleted = 0;
+ int nextdiff = 0;
+ zlentry first = zipEntry(p);
+ for (i = 0; p[0] != ZIP_END && i < num; i++) {
+ p += zipRawEntryLength(p);
+ deleted++;
+ }
+
+ totlen = p-first.p;
+ if (totlen > 0) {
+ if (p[0] != ZIP_END) {
+ /* Tricky: storing the prevlen in this entry might reduce or
+ * increase the number of bytes needed, compared to the current
+ * prevlen. Note that we can always store this length because
+ * it was previously stored by an entry that is being deleted. */
+ nextdiff = zipPrevLenByteDiff(p,first.prevrawlen);
+ zipEncodeLength(p-nextdiff,ZIP_ENC_RAW,first.prevrawlen);
+
+ /* Update offset for tail */
+ ZIPLIST_TAIL_OFFSET(zl) -= totlen+nextdiff;
+
+ /* Move tail to the front of the ziplist */
+ memmove(first.p,p-nextdiff,ZIPLIST_BYTES(zl)-(p-zl)-1+nextdiff);
+ } else {
+ /* The entire tail was deleted. No need to move memory. */
+ ZIPLIST_TAIL_OFFSET(zl) = (first.p-zl)-first.prevrawlen;
+ }
+
+ /* Resize and update length */
+ zl = ziplistResize(zl, ZIPLIST_BYTES(zl)-totlen+nextdiff);
+ ZIPLIST_INCR_LENGTH(zl,-deleted);
+ }
+ return zl;
}
-unsigned char *ziplistPush(unsigned char *zl, unsigned char *entry, unsigned int elen, int where) {
- unsigned int curlen = ZIPLIST_BYTES(zl), reqlen, prevlen;
- unsigned char *p, *curtail;
+/* Insert item at "p". */
+static unsigned char *__ziplistInsert(unsigned char *zl, unsigned char *p, unsigned char *s, unsigned int slen) {
+ unsigned int curlen = ZIPLIST_BYTES(zl), reqlen, prevlen = 0;
+ unsigned int offset, nextdiff = 0;
+ unsigned char *tail;
char encoding = ZIP_ENC_RAW;
long long value;
+ zlentry entry;
- /* We need to store the length of the current tail when the list
- * is non-empty and we push at the tail. */
- curtail = zl+ZIPLIST_TAIL_OFFSET(zl);
- if (where == ZIPLIST_TAIL && curtail[0] != ZIP_END) {
- prevlen = zipRawEntryLength(curtail);
+ /* Find out prevlen for the entry that is inserted. */
+ if (p[0] != ZIP_END) {
+ entry = zipEntry(p);
+ prevlen = entry.prevrawlen;
} else {
- prevlen = 0;
+ tail = ziplistTail(zl);
+ if (tail[0] != ZIP_END) {
+ prevlen = zipRawEntryLength(tail);
+ }
}
/* See if the entry can be encoded */
- if (zipTryEncoding(entry,&value,&encoding)) {
+ if (zipTryEncoding(s,&value,&encoding)) {
reqlen = zipEncodingSize(encoding);
} else {
- reqlen = elen;
+ reqlen = slen;
}
/* We need space for both the length of the previous entry and
* the length of the payload. */
reqlen += zipEncodeLength(NULL,ZIP_ENC_RAW,prevlen);
- reqlen += zipEncodeLength(NULL,encoding,elen);
-
- /* Resize the ziplist and move if needed */
- zl = ziplistResize(zl,curlen+reqlen);
- if (where == ZIPLIST_HEAD) {
- p = zl+ZIPLIST_HEADER_SIZE;
- if (*p != ZIP_END) {
- /* Subtract one because of the ZIP_END bytes */
- memmove(p+reqlen,p,curlen-ZIPLIST_HEADER_SIZE-1);
- }
+ reqlen += zipEncodeLength(NULL,encoding,slen);
+
+ /* When the insert position is not equal to the tail, we need to
+ * make sure that the next entry can hold this entry's length in
+ * its prevlen field. */
+ nextdiff = p[0] != ZIP_END ? zipPrevLenByteDiff(p,reqlen) : 0;
+
+ /* Store offset because a realloc may change the address of zl. */
+ offset = p-zl;
+ zl = ziplistResize(zl,curlen+reqlen+nextdiff);
+ p = zl+offset;
+
+ /* Apply memory move when necessary and update tail offset. */
+ if (p[0] != ZIP_END) {
+ /* Subtract one because of the ZIP_END bytes */
+ memmove(p+reqlen,p-nextdiff,curlen-offset-1+nextdiff);
+ /* Encode this entry's raw length in the next entry. */
+ zipEncodeLength(p+reqlen,ZIP_ENC_RAW,reqlen);
+ /* Update offset for tail */
+ ZIPLIST_TAIL_OFFSET(zl) += reqlen+nextdiff;
} else {
- p = zl+curlen-1;
- }
-
- /* Update tail offset if this is not the first element */
- if (curtail[0] != ZIP_END) {
- if (where == ZIPLIST_HEAD) {
- ZIPLIST_TAIL_OFFSET(zl) += reqlen;
- } else {
- ZIPLIST_TAIL_OFFSET(zl) += prevlen;
- }
+ /* This element will be the new tail. */
+ ZIPLIST_TAIL_OFFSET(zl) = p-zl;
}
/* Write the entry */
p += zipEncodeLength(p,ZIP_ENC_RAW,prevlen);
- p += zipEncodeLength(p,encoding,elen);
+ p += zipEncodeLength(p,encoding,slen);
if (encoding != ZIP_ENC_RAW) {
zipSaveInteger(p,value,encoding);
} else {
- memcpy(p,entry,elen);
+ memcpy(p,s,slen);
}
ZIPLIST_INCR_LENGTH(zl,1);
return zl;
}
+unsigned char *ziplistPush(unsigned char *zl, unsigned char *s, unsigned int slen, int where) {
+ unsigned char *p;
+ p = (where == ZIPLIST_HEAD) ? ziplistHead(zl) : (zl+ZIPLIST_BYTES(zl)-1);
+ return __ziplistInsert(zl,p,s,slen);
+}
+
unsigned char *ziplistPop(unsigned char *zl, sds *target, int where) {
- unsigned int curlen = ZIPLIST_BYTES(zl), rawlen;
- unsigned int prevrawlensize, prevrawlen, lensize, len, headerlen;
- int nextdiff = 0;
- unsigned char encoding;
+ zlentry entry;
unsigned char *p;
long long value;
if (target) *target = NULL;
p = (where == ZIPLIST_HEAD) ? ziplistHead(zl) : ziplistTail(zl);
if (*p == ZIP_END) return zl;
- prevrawlen = zipDecodeLength(p,&prevrawlensize);
- len = zipDecodeLength(p+prevrawlensize,&lensize);
- headerlen = prevrawlensize+lensize;
- rawlen = headerlen+len;
+ entry = zipEntry(p);
if (target) {
- encoding = ZIP_ENCODING(p+prevrawlensize);
- if (encoding == ZIP_ENC_RAW) {
- *target = sdsnewlen(p+headerlen,len);
+ if (entry.encoding == ZIP_ENC_RAW) {
+ *target = sdsnewlen(p+entry.headersize,entry.len);
} else {
- value = zipLoadInteger(p+headerlen,encoding);
+ value = zipLoadInteger(p+entry.headersize,entry.encoding);
*target = sdscatprintf(sdsempty(), "%lld", value);
}
}
- if (where == ZIPLIST_HEAD) {
- /* The next entry will now be the head of the list */
- if (p[rawlen] != ZIP_END) {
- /* Tricky: storing the length of the previous entry in the next
- * entry (this previous length is always 0 when popping from the
- * head), might reduce the number of bytes needed.
- *
- * In this special case (new length is 0), we know that the
- * byte difference to store is always <= 0, which means that
- * we always have space to store it. */
- nextdiff = zipPrevLenByteDiff(p+rawlen,0);
- zipEncodeLength(p+rawlen-nextdiff,ZIP_ENC_RAW,0);
- }
- /* Move list to the front */
- memmove(p,p+rawlen-nextdiff,curlen-ZIPLIST_HEADER_SIZE-rawlen+nextdiff);
-
- /* Subtract the gained space from the tail offset */
- ZIPLIST_TAIL_OFFSET(zl) -= rawlen+nextdiff;
- } else {
- /* Subtract the length of the previous element from the tail offset. */
- ZIPLIST_TAIL_OFFSET(zl) -= prevrawlen;
- }
-
- /* Resize and update length */
- zl = ziplistResize(zl,curlen-rawlen+nextdiff);
- ZIPLIST_INCR_LENGTH(zl,-1);
+ zl = __ziplistDelete(zl,p,1);
return zl;
}
* on the encoding of the entry. 'e' is always set to NULL to be able
* to find out whether the string pointer or the integer value was set.
* Return 0 if 'p' points to the end of the zipmap, 1 otherwise. */
-unsigned int ziplistGet(unsigned char *p, unsigned char **e, unsigned int *elen, long long *v) {
- unsigned int prevrawlensize, lensize, len, headerlen;
+unsigned int ziplistGet(unsigned char *p, unsigned char **sstr, unsigned int *slen, long long *sval) {
+ zlentry entry;
if (*p == ZIP_END) return 0;
- if (e) *e = NULL;
-
- zipDecodeLength(p,&prevrawlensize);
- len = zipDecodeLength(p+prevrawlensize,&lensize);
- headerlen = prevrawlensize+lensize;
- if (ZIP_ENCODING(p+prevrawlensize) == ZIP_ENC_RAW) {
- if (e) {
- *elen = len;
- *e = p+headerlen;
+ if (sstr) *sstr = NULL;
+
+ entry = zipEntry(p);
+ if (entry.encoding == ZIP_ENC_RAW) {
+ if (sstr) {
+ *slen = entry.len;
+ *sstr = p+entry.headersize;
}
} else {
- if (v) {
- *v = zipLoadInteger(p+headerlen,ZIP_ENCODING(p+prevrawlensize));
+ if (sval) {
+ *sval = zipLoadInteger(p+entry.headersize,entry.encoding);
}
}
return 1;
/* Delete a range of entries from the ziplist. */
unsigned char *ziplistDeleteRange(unsigned char *zl, unsigned int index, unsigned int num) {
- unsigned char *p, *first = ziplistIndex(zl, index);
- unsigned int i, totlen, deleted = 0;
- for (p = first, i = 0; *p != ZIP_END && i < num; i++) {
- p += zipRawEntryLength(p);
- deleted++;
- }
-
- totlen = p-first;
- if (totlen > 0) {
- /* Move current tail to the new tail when there *is* a tail */
- if (*p != ZIP_END) memmove(first,p,ZIPLIST_BYTES(zl)-(p-zl)-1);
-
- /* Resize and update length */
- zl = ziplistResize(zl, ZIPLIST_BYTES(zl)-totlen);
- ZIPLIST_INCR_LENGTH(zl,-deleted);
- }
- return zl;
+ unsigned char *p = ziplistIndex(zl,index);
+ return __ziplistDelete(zl,p,num);
}
/* Delete a single entry from the ziplist, pointed to by *p.
* Also update *p in place, to be able to iterate over the
* ziplist, while deleting entries. */
unsigned char *ziplistDelete(unsigned char *zl, unsigned char **p) {
- unsigned int offset = *p-zl, tail, len;
- len = zipRawEntryLength(*p);
- tail = ZIPLIST_BYTES(zl)-offset-len-1;
-
- /* Move current tail to the new tail when there *is* a tail */
- if (tail > 0) memmove(*p,*p+len,tail);
-
- /* Resize and update length */
- zl = ziplistResize(zl, ZIPLIST_BYTES(zl)-len);
- ZIPLIST_INCR_LENGTH(zl,-1);
+ unsigned int offset = *p-zl;
+ zl = __ziplistDelete(zl,*p,1);
- /* Store new pointer to current element in p.
- * This needs to be done because zl can change on realloc. */
+ /* Store pointer to current element in p, because ziplistDelete will
+ * do a realloc which might result in a different "zl"-pointer. */
*p = zl+offset;
return zl;
}
/* Compare entry pointer to by 'p' with 'entry'. Return 1 if equal. */
-unsigned int ziplistCompare(unsigned char *p, unsigned char *entry, unsigned int elen) {
- unsigned int prevrawlensize, lensize, len, headerlen;
- char encoding;
- long long val, eval;
+unsigned int ziplistCompare(unsigned char *p, unsigned char *sstr, unsigned int slen) {
+ zlentry entry;
+ unsigned char sencoding;
+ long long val, sval;
if (*p == ZIP_END) return 0;
- zipDecodeLength(p,&prevrawlensize);
- len = zipDecodeLength(p+prevrawlensize,&lensize);
- headerlen = prevrawlensize+lensize;
- if (ZIP_ENCODING(p+prevrawlensize) == ZIP_ENC_RAW) {
+ entry = zipEntry(p);
+ if (entry.encoding == ZIP_ENC_RAW) {
/* Raw compare */
- if (len == elen) {
- return memcmp(p+headerlen,entry,elen) == 0;
+ if (entry.len == slen) {
+ return memcmp(p+entry.headersize,sstr,slen) == 0;
} else {
return 0;
}
} else {
- if (zipTryEncoding(entry,&eval,&encoding)) {
- /* Do integer compare */
- val = zipLoadInteger(p+headerlen,ZIP_ENCODING(p+prevrawlensize));
- return val == eval;
- } else {
- /* Ziplist entry is integer encoded, but given entry is not. */
+ /* Try to compare encoded values */
+ if (zipTryEncoding(sstr,&sval,&sencoding)) {
+ if (entry.encoding == sencoding) {
+ val = zipLoadInteger(p+entry.headersize,entry.encoding);
+ return val == sval;
+ }
}
}
return 0;
}
void ziplistRepr(unsigned char *zl) {
- unsigned char *p, encoding;
- unsigned int prevrawlensize, prevrawlen, lensize, len;
+ unsigned char *p;
+ zlentry entry;
printf("{total bytes %d} {length %u}\n",ZIPLIST_BYTES(zl), ZIPLIST_LENGTH(zl));
p = ziplistHead(zl);
while(*p != ZIP_END) {
- prevrawlen = zipDecodeLength(p,&prevrawlensize);
- len = zipDecodeLength(p+prevrawlensize,&lensize);
- printf("{offset %ld, header %u, payload %u} ",p-zl,prevrawlensize+lensize,len);
- encoding = ZIP_ENCODING(p+prevrawlensize);
- p += prevrawlensize+lensize;
- if (encoding == ZIP_ENC_RAW) {
- fwrite(p,len,1,stdout);
+ entry = zipEntry(p);
+ printf("{offset %ld, header %u, payload %u} ",p-zl,entry.headersize,entry.len);
+ p += entry.headersize;
+ if (entry.encoding == ZIP_ENC_RAW) {
+ fwrite(p,entry.len,1,stdout);
} else {
- printf("%lld", zipLoadInteger(p,encoding));
+ printf("%lld", zipLoadInteger(p,entry.encoding));
}
printf("\n");
- p += len;
+ p += entry.len;
}
printf("{end}\n\n");
}
projects / redis.git / blobdiff