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https://github.com/fluencelabs/redis
synced 2025-03-18 16:40:50 +00:00
partial revert of c80df5 because ziplist functions are starting to divert too much from zipmap functions
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29b14d5fac
commit
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108
zipmap.c
108
zipmap.c
@ -80,21 +80,54 @@
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#include <string.h>
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#include <assert.h>
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#include "zmalloc.h"
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#include "zip.c"
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#define ZIPMAP_BIGLEN 254
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#define ZIPMAP_END 255
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/* The following defines the max value for the <free> field described in the
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* comments above, that is, the max number of trailing bytes in a value. */
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#define ZIPMAP_VALUE_MAX_FREE 4
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/* The following macro returns the number of bytes needed to encode the length
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* for the integer value _l, that is, 1 byte for lengths < ZIPMAP_BIGLEN and
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* 5 bytes for all the other lengths. */
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#define ZIPMAP_LEN_BYTES(_l) (((_l) < ZIPMAP_BIGLEN) ? 1 : sizeof(unsigned int)+1)
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/* Create a new empty zipmap. */
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unsigned char *zipmapNew(void) {
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unsigned char *zm = zmalloc(2);
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zm[0] = 0; /* Length */
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zm[1] = ZIP_END;
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zm[1] = ZIPMAP_END;
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return zm;
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}
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/* Decode the encoded length pointed by 'p' */
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static unsigned int zipmapDecodeLength(unsigned char *p) {
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unsigned int len = *p;
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if (len < ZIPMAP_BIGLEN) return len;
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memcpy(&len,p+1,sizeof(unsigned int));
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return len;
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}
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/* Encode the length 'l' writing it in 'p'. If p is NULL it just returns
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* the amount of bytes required to encode such a length. */
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static unsigned int zipmapEncodeLength(unsigned char *p, unsigned int len) {
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if (p == NULL) {
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return ZIPMAP_LEN_BYTES(len);
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} else {
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if (len < ZIPMAP_BIGLEN) {
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p[0] = len;
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return 1;
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} else {
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p[0] = ZIPMAP_BIGLEN;
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memcpy(p+1,&len,sizeof(len));
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return 1+sizeof(len);
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}
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}
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}
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/* Search for a matching key, returning a pointer to the entry inside the
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* zipmap. Returns NULL if the key is not found.
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*
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@ -105,12 +138,12 @@ static unsigned char *zipmapLookupRaw(unsigned char *zm, unsigned char *key, uns
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unsigned char *p = zm+1, *k = NULL;
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unsigned int l,llen;
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while(*p != ZIP_END) {
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while(*p != ZIPMAP_END) {
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unsigned char free;
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/* Match or skip the key */
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l = zipDecodeLength(p);
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llen = zipEncodeLength(NULL,l);
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l = zipmapDecodeLength(p);
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llen = zipmapEncodeLength(NULL,l);
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if (k == NULL && l == klen && !memcmp(p+llen,key,l)) {
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/* Only return when the user doesn't care
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* for the total length of the zipmap. */
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@ -122,8 +155,8 @@ static unsigned char *zipmapLookupRaw(unsigned char *zm, unsigned char *key, uns
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}
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p += llen+l;
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/* Skip the value as well */
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l = zipDecodeLength(p);
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p += zipEncodeLength(NULL,l);
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l = zipmapDecodeLength(p);
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p += zipmapEncodeLength(NULL,l);
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free = p[0];
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p += l+1+free; /* +1 to skip the free byte */
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}
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@ -135,23 +168,24 @@ static unsigned long zipmapRequiredLength(unsigned int klen, unsigned int vlen)
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unsigned int l;
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l = klen+vlen+3;
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if (klen >= ZIP_BIGLEN) l += 4;
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if (vlen >= ZIP_BIGLEN) l += 4;
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if (klen >= ZIPMAP_BIGLEN) l += 4;
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if (vlen >= ZIPMAP_BIGLEN) l += 4;
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return l;
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}
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/* Return the total amount used by a key (encoded length + payload) */
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static unsigned int zipmapRawKeyLength(unsigned char *p) {
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return zipRawEntryLength(p);
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unsigned int l = zipmapDecodeLength(p);
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return zipmapEncodeLength(NULL,l) + l;
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}
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/* Return the total amount used by a value
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* (encoded length + single byte free count + payload) */
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static unsigned int zipmapRawValueLength(unsigned char *p) {
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unsigned int l = zipDecodeLength(p);
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unsigned int l = zipmapDecodeLength(p);
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unsigned int used;
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used = zipEncodeLength(NULL,l);
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used = zipmapEncodeLength(NULL,l);
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used += p[used] + 1 + l;
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return used;
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}
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@ -164,6 +198,12 @@ static unsigned int zipmapRawEntryLength(unsigned char *p) {
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return l + zipmapRawValueLength(p+l);
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}
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static inline unsigned char *zipmapResize(unsigned char *zm, unsigned int len) {
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zm = zrealloc(zm, len);
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zm[len-1] = ZIPMAP_END;
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return zm;
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}
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/* Set key to value, creating the key if it does not already exist.
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* If 'update' is not NULL, *update is set to 1 if the key was
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* already preset, otherwise to 0. */
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@ -178,12 +218,12 @@ unsigned char *zipmapSet(unsigned char *zm, unsigned char *key, unsigned int kle
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p = zipmapLookupRaw(zm,key,klen,&zmlen);
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if (p == NULL) {
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/* Key not found: enlarge */
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zm = zipResize(zm, zmlen+reqlen);
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zm = zipmapResize(zm, zmlen+reqlen);
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p = zm+zmlen-1;
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zmlen = zmlen+reqlen;
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/* Increase zipmap length (this is an insert) */
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if (zm[0] < ZIP_BIGLEN) zm[0]++;
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if (zm[0] < ZIPMAP_BIGLEN) zm[0]++;
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} else {
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/* Key found. Is there enough space for the new value? */
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/* Compute the total length: */
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@ -194,7 +234,7 @@ unsigned char *zipmapSet(unsigned char *zm, unsigned char *key, unsigned int kle
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* it can be resized. Then, move the tail backwards so this
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* pair fits at the current position. */
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offset = p-zm;
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zm = zipResize(zm, zmlen-freelen+reqlen);
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zm = zipmapResize(zm, zmlen-freelen+reqlen);
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p = zm+offset;
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/* The +1 in the number of bytes to be moved is caused by the
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@ -216,7 +256,7 @@ unsigned char *zipmapSet(unsigned char *zm, unsigned char *key, unsigned int kle
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offset = p-zm;
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memmove(p+reqlen, p+freelen, zmlen-(offset+freelen+1));
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zmlen -= empty;
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zm = zipResize(zm, zmlen);
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zm = zipmapResize(zm, zmlen);
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p = zm+offset;
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vempty = 0;
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} else {
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@ -225,11 +265,11 @@ unsigned char *zipmapSet(unsigned char *zm, unsigned char *key, unsigned int kle
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/* Just write the key + value and we are done. */
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/* Key: */
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p += zipEncodeLength(p,klen);
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p += zipmapEncodeLength(p,klen);
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memcpy(p,key,klen);
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p += klen;
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/* Value: */
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p += zipEncodeLength(p,vlen);
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p += zipmapEncodeLength(p,vlen);
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*p++ = vempty;
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memcpy(p,val,vlen);
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return zm;
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@ -243,10 +283,10 @@ unsigned char *zipmapDel(unsigned char *zm, unsigned char *key, unsigned int kle
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if (p) {
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freelen = zipmapRawEntryLength(p);
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memmove(p, p+freelen, zmlen-((p-zm)+freelen+1));
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zm = zipResize(zm, zmlen-freelen);
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zm = zipmapResize(zm, zmlen-freelen);
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/* Decrease zipmap length */
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if (zm[0] < ZIP_BIGLEN) zm[0]--;
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if (zm[0] < ZIPMAP_BIGLEN) zm[0]--;
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if (deleted) *deleted = 1;
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} else {
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@ -272,17 +312,17 @@ unsigned char *zipmapRewind(unsigned char *zm) {
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* }
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*/
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unsigned char *zipmapNext(unsigned char *zm, unsigned char **key, unsigned int *klen, unsigned char **value, unsigned int *vlen) {
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if (zm[0] == ZIP_END) return NULL;
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if (zm[0] == ZIPMAP_END) return NULL;
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if (key) {
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*key = zm;
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*klen = zipDecodeLength(zm);
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*key += ZIP_LEN_BYTES(*klen);
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*klen = zipmapDecodeLength(zm);
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*key += ZIPMAP_LEN_BYTES(*klen);
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}
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zm += zipmapRawKeyLength(zm);
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if (value) {
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*value = zm+1;
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*vlen = zipDecodeLength(zm);
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*value += ZIP_LEN_BYTES(*vlen);
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*vlen = zipmapDecodeLength(zm);
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*value += ZIPMAP_LEN_BYTES(*vlen);
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}
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zm += zipmapRawValueLength(zm);
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return zm;
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@ -295,8 +335,8 @@ int zipmapGet(unsigned char *zm, unsigned char *key, unsigned int klen, unsigned
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if ((p = zipmapLookupRaw(zm,key,klen,NULL)) == NULL) return 0;
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p += zipmapRawKeyLength(p);
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*vlen = zipDecodeLength(p);
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*value = p + ZIP_LEN_BYTES(*vlen) + 1;
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*vlen = zipmapDecodeLength(p);
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*value = p + ZIPMAP_LEN_BYTES(*vlen) + 1;
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return 1;
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}
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@ -308,14 +348,14 @@ int zipmapExists(unsigned char *zm, unsigned char *key, unsigned int klen) {
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/* Return the number of entries inside a zipmap */
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unsigned int zipmapLen(unsigned char *zm) {
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unsigned int len = 0;
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if (zm[0] < ZIP_BIGLEN) {
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if (zm[0] < ZIPMAP_BIGLEN) {
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len = zm[0];
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} else {
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unsigned char *p = zipmapRewind(zm);
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while((p = zipmapNext(p,NULL,NULL,NULL,NULL)) != NULL) len++;
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/* Re-store length if small enough */
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if (len < ZIP_BIGLEN) zm[0] = len;
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if (len < ZIPMAP_BIGLEN) zm[0] = len;
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}
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return len;
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}
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@ -325,21 +365,21 @@ void zipmapRepr(unsigned char *p) {
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printf("{status %u}",*p++);
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while(1) {
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if (p[0] == ZIP_END) {
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if (p[0] == ZIPMAP_END) {
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printf("{end}");
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break;
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} else {
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unsigned char e;
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l = zipDecodeLength(p);
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l = zipmapDecodeLength(p);
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printf("{key %u}",l);
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p += zipEncodeLength(NULL,l);
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p += zipmapEncodeLength(NULL,l);
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fwrite(p,l,1,stdout);
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p += l;
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l = zipDecodeLength(p);
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l = zipmapDecodeLength(p);
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printf("{value %u}",l);
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p += zipEncodeLength(NULL,l);
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p += zipmapEncodeLength(NULL,l);
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e = *p++;
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fwrite(p,l,1,stdout);
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p += l+e;
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