#include <string.h>
#include <assert.h>
#include "zmalloc.h"
-
-#define ZIPMAP_BIGLEN 254
-#define ZIPMAP_END 255
+#include "zip.c"
/* The following defines the max value for the <free> field described in the
* comments above, that is, the max number of trailing bytes in a value. */
#define ZIPMAP_VALUE_MAX_FREE 4
-/* The following macro returns the number of bytes needed to encode the length
- * for the integer value _l, that is, 1 byte for lengths < ZIPMAP_BIGLEN and
- * 5 bytes for all the other lengths. */
-#define ZIPMAP_LEN_BYTES(_l) (((_l) < ZIPMAP_BIGLEN) ? 1 : sizeof(unsigned int)+1)
-
/* Create a new empty zipmap. */
unsigned char *zipmapNew(void) {
unsigned char *zm = zmalloc(2);
zm[0] = 0; /* Length */
- zm[1] = ZIPMAP_END;
+ zm[1] = ZIP_END;
return zm;
}
-/* Decode the encoded length pointed by 'p' */
-static unsigned int zipmapDecodeLength(unsigned char *p) {
- unsigned int len = *p;
-
- if (len < ZIPMAP_BIGLEN) return len;
- memcpy(&len,p+1,sizeof(unsigned int));
- return len;
-}
-
-/* Encode the length 'l' writing it in 'p'. If p is NULL it just returns
- * the amount of bytes required to encode such a length. */
-static unsigned int zipmapEncodeLength(unsigned char *p, unsigned int len) {
- if (p == NULL) {
- return ZIPMAP_LEN_BYTES(len);
- } else {
- if (len < ZIPMAP_BIGLEN) {
- p[0] = len;
- return 1;
- } else {
- p[0] = ZIPMAP_BIGLEN;
- memcpy(p+1,&len,sizeof(len));
- return 1+sizeof(len);
- }
- }
-}
-
/* Search for a matching key, returning a pointer to the entry inside the
* zipmap. Returns NULL if the key is not found.
*
* reallocate the original zipmap to make room for more entries. */
static unsigned char *zipmapLookupRaw(unsigned char *zm, unsigned char *key, unsigned int klen, unsigned int *totlen) {
unsigned char *p = zm+1, *k = NULL;
- unsigned int l;
+ unsigned int l,llen;
- while(*p != ZIPMAP_END) {
+ while(*p != ZIP_END) {
unsigned char free;
/* Match or skip the key */
- l = zipmapDecodeLength(p);
- if (k == NULL && l == klen && !memcmp(p+1,key,l)) {
+ l = zipDecodeLength(p);
+ llen = zipEncodeLength(NULL,l);
+ if (k == NULL && l == klen && !memcmp(p+llen,key,l)) {
/* Only return when the user doesn't care
* for the total length of the zipmap. */
if (totlen != NULL) {
return p;
}
}
- p += zipmapEncodeLength(NULL,l) + l;
+ p += llen+l;
/* Skip the value as well */
- l = zipmapDecodeLength(p);
- p += zipmapEncodeLength(NULL,l);
+ l = zipDecodeLength(p);
+ p += zipEncodeLength(NULL,l);
free = p[0];
p += l+1+free; /* +1 to skip the free byte */
}
unsigned int l;
l = klen+vlen+3;
- if (klen >= ZIPMAP_BIGLEN) l += 4;
- if (vlen >= ZIPMAP_BIGLEN) l += 4;
+ if (klen >= ZIP_BIGLEN) l += 4;
+ if (vlen >= ZIP_BIGLEN) l += 4;
return l;
}
/* Return the total amount used by a key (encoded length + payload) */
static unsigned int zipmapRawKeyLength(unsigned char *p) {
- unsigned int l = zipmapDecodeLength(p);
-
- return zipmapEncodeLength(NULL,l) + l;
+ return zipRawEntryLength(p);
}
/* Return the total amount used by a value
* (encoded length + single byte free count + payload) */
static unsigned int zipmapRawValueLength(unsigned char *p) {
- unsigned int l = zipmapDecodeLength(p);
+ unsigned int l = zipDecodeLength(p);
unsigned int used;
- used = zipmapEncodeLength(NULL,l);
+ used = zipEncodeLength(NULL,l);
used += p[used] + 1 + l;
return used;
}
return l + zipmapRawValueLength(p+l);
}
-static inline unsigned char *zipmapResize(unsigned char *zm, unsigned int len) {
- zm = zrealloc(zm, len);
- zm[len-1] = ZIPMAP_END;
- return zm;
-}
-
/* Set key to value, creating the key if it does not already exist.
* If 'update' is not NULL, *update is set to 1 if the key was
* already preset, otherwise to 0. */
unsigned char *zipmapSet(unsigned char *zm, unsigned char *key, unsigned int klen, unsigned char *val, unsigned int vlen, int *update) {
- unsigned int zmlen;
+ unsigned int zmlen, offset;
unsigned int freelen, reqlen = zipmapRequiredLength(klen,vlen);
unsigned int empty, vempty;
unsigned char *p;
p = zipmapLookupRaw(zm,key,klen,&zmlen);
if (p == NULL) {
/* Key not found: enlarge */
- zm = zipmapResize(zm, zmlen+reqlen);
+ zm = zipResize(zm, zmlen+reqlen);
p = zm+zmlen-1;
zmlen = zmlen+reqlen;
/* Increase zipmap length (this is an insert) */
- if (zm[0] < ZIPMAP_BIGLEN) zm[0]++;
+ if (zm[0] < ZIP_BIGLEN) zm[0]++;
} else {
/* Key found. Is there enough space for the new value? */
/* Compute the total length: */
if (update) *update = 1;
freelen = zipmapRawEntryLength(p);
if (freelen < reqlen) {
- /* Move remaining entries to the current position, so this
- * pair can be appended. Note: the +1 in memmove is caused
- * by the end-of-zipmap byte. */
- memmove(p, p+freelen, zmlen-((p-zm)+freelen+1));
- zm = zipmapResize(zm, zmlen-freelen+reqlen);
- p = zm+zmlen-1-freelen;
- zmlen = zmlen-1-freelen+reqlen;
+ /* Store the offset of this key within the current zipmap, so
+ * it can be resized. Then, move the tail backwards so this
+ * pair fits at the current position. */
+ offset = p-zm;
+ zm = zipResize(zm, zmlen-freelen+reqlen);
+ p = zm+offset;
+
+ /* The +1 in the number of bytes to be moved is caused by the
+ * end-of-zipmap byte. Note: the *original* zmlen is used. */
+ memmove(p+reqlen, p+freelen, zmlen-(offset+freelen+1));
+ zmlen = zmlen-freelen+reqlen;
freelen = reqlen;
}
}
- /* Ok we have a suitable block where to write the new key/value
- * entry. */
+ /* We now have a suitable block where the key/value entry can
+ * be written. If there is too much free space, move the tail
+ * of the zipmap a few bytes to the front and shrink the zipmap,
+ * as we want zipmaps to be very space efficient. */
empty = freelen-reqlen;
- /* If there is too much free space mark it as a free block instead
- * of adding it as trailing empty space for the value, as we want
- * zipmaps to be very space efficient. */
if (empty >= ZIPMAP_VALUE_MAX_FREE) {
- memmove(p+reqlen, p+freelen, zmlen-((p-zm)+freelen+1));
+ /* First, move the tail <empty> bytes to the front, then resize
+ * the zipmap to be <empty> bytes smaller. */
+ offset = p-zm;
+ memmove(p+reqlen, p+freelen, zmlen-(offset+freelen+1));
zmlen -= empty;
- zm = zipmapResize(zm, zmlen);
+ zm = zipResize(zm, zmlen);
+ p = zm+offset;
vempty = 0;
} else {
vempty = empty;
/* Just write the key + value and we are done. */
/* Key: */
- p += zipmapEncodeLength(p,klen);
+ p += zipEncodeLength(p,klen);
memcpy(p,key,klen);
p += klen;
/* Value: */
- p += zipmapEncodeLength(p,vlen);
+ p += zipEncodeLength(p,vlen);
*p++ = vempty;
memcpy(p,val,vlen);
return zm;
if (p) {
freelen = zipmapRawEntryLength(p);
memmove(p, p+freelen, zmlen-((p-zm)+freelen+1));
- zm = zipmapResize(zm, zmlen-freelen);
+ zm = zipResize(zm, zmlen-freelen);
/* Decrease zipmap length */
- if (zm[0] < ZIPMAP_BIGLEN) zm[0]--;
+ if (zm[0] < ZIP_BIGLEN) zm[0]--;
if (deleted) *deleted = 1;
} else {
* }
*/
unsigned char *zipmapNext(unsigned char *zm, unsigned char **key, unsigned int *klen, unsigned char **value, unsigned int *vlen) {
- if (zm[0] == ZIPMAP_END) return NULL;
+ if (zm[0] == ZIP_END) return NULL;
if (key) {
*key = zm;
- *klen = zipmapDecodeLength(zm);
- *key += ZIPMAP_LEN_BYTES(*klen);
+ *klen = zipDecodeLength(zm);
+ *key += ZIP_LEN_BYTES(*klen);
}
zm += zipmapRawKeyLength(zm);
if (value) {
*value = zm+1;
- *vlen = zipmapDecodeLength(zm);
- *value += ZIPMAP_LEN_BYTES(*vlen);
+ *vlen = zipDecodeLength(zm);
+ *value += ZIP_LEN_BYTES(*vlen);
}
zm += zipmapRawValueLength(zm);
return zm;
if ((p = zipmapLookupRaw(zm,key,klen,NULL)) == NULL) return 0;
p += zipmapRawKeyLength(p);
- *vlen = zipmapDecodeLength(p);
- *value = p + ZIPMAP_LEN_BYTES(*vlen) + 1;
+ *vlen = zipDecodeLength(p);
+ *value = p + ZIP_LEN_BYTES(*vlen) + 1;
return 1;
}
/* Return the number of entries inside a zipmap */
unsigned int zipmapLen(unsigned char *zm) {
unsigned int len = 0;
- if (zm[0] < ZIPMAP_BIGLEN) {
+ if (zm[0] < ZIP_BIGLEN) {
len = zm[0];
} else {
unsigned char *p = zipmapRewind(zm);
while((p = zipmapNext(p,NULL,NULL,NULL,NULL)) != NULL) len++;
/* Re-store length if small enough */
- if (len < ZIPMAP_BIGLEN) zm[0] = len;
+ if (len < ZIP_BIGLEN) zm[0] = len;
}
return len;
}
printf("{status %u}",*p++);
while(1) {
- if (p[0] == ZIPMAP_END) {
+ if (p[0] == ZIP_END) {
printf("{end}");
break;
} else {
unsigned char e;
- l = zipmapDecodeLength(p);
+ l = zipDecodeLength(p);
printf("{key %u}",l);
- p += zipmapEncodeLength(NULL,l);
+ p += zipEncodeLength(NULL,l);
fwrite(p,l,1,stdout);
p += l;
- l = zipmapDecodeLength(p);
+ l = zipDecodeLength(p);
printf("{value %u}",l);
- p += zipmapEncodeLength(NULL,l);
+ p += zipEncodeLength(NULL,l);
e = *p++;
fwrite(p,l,1,stdout);
p += l+e;
zm = zipmapSet(zm,(unsigned char*) "surname",7, (unsigned char*) "foo",3,NULL);
zm = zipmapSet(zm,(unsigned char*) "age",3, (unsigned char*) "foo",3,NULL);
zipmapRepr(zm);
- exit(1);
zm = zipmapSet(zm,(unsigned char*) "hello",5, (unsigned char*) "world!",6,NULL);
zm = zipmapSet(zm,(unsigned char*) "foo",3, (unsigned char*) "bar",3,NULL);
zipmapRepr(zm);
zm = zipmapDel(zm,(unsigned char*) "new",3,NULL);
zipmapRepr(zm);
+
+ printf("\nLook up large key:\n");
+ {
+ unsigned char buf[512];
+ unsigned char *value;
+ unsigned int vlen, i;
+ for (i = 0; i < 512; i++) buf[i] = 'a';
+
+ zm = zipmapSet(zm,buf,512,(unsigned char*) "long",4,NULL);
+ if (zipmapGet(zm,buf,512,&value,&vlen)) {
+ printf(" <long key> is associated to the %d bytes value: %.*s\n",
+ vlen, vlen, value);
+ }
+ }
+
printf("\nPerform a direct lookup:\n");
{
unsigned char *value;
projects / redis.git / blobdiff