-/* Memory layout of a ziplist, containing "foo", "bar", "quux":
- * <zlbytes><zllen><len>"foo"<len>"bar"<len>"quux"
+/* The ziplist is a specially encoded dually linked list that is designed
+ * to be very memory efficient. It stores both strings and integer values,
+ * where integers are encoded as actual integers instead of a series of
+ * characters. It allows push and pop operations on either side of the list
+ * in O(1) time. However, because every operation requires a reallocation of
+ * the memory used by the ziplist, the actual complexity is related to the
+ * amount of memory used by the ziplist.
*
- * <zlbytes> is an unsigned integer to hold the number of bytes that
- * the ziplist occupies. This is stored to not have to traverse the ziplist
- * to know the new length when pushing.
+ * ----------------------------------------------------------------------------
*
- * <zllen> is the number of items in the ziplist. When this value is
- * greater than 254, we need to traverse the entire list to know
- * how many items it holds.
+ * ZIPLIST OVERALL LAYOUT:
+ * The general layout of the ziplist is as follows:
+ * <zlbytes><zltail><zllen><entry><entry><zlend>
*
- * <len> is the number of bytes occupied by a single entry. When this
- * number is greater than 253, the length will occupy 5 bytes, where
- * the extra bytes contain an unsigned integer to hold the length.
+ * <zlbytes> is an unsigned integer to hold the number of bytes that the
+ * ziplist occupies. This value needs to be stored to be able to resize the
+ * entire structure without the need to traverse it first.
+ *
+ * <zltail> is the offset to the last entry in the list. This allows a pop
+ * operation on the far side of the list without the need for full traversal.
+ *
+ * <zllen> is the number of entries.When this value is larger than 2**16-2,
+ * we need to traverse the entire list to know how many items it holds.
+ *
+ * <zlend> is a single byte special value, equal to 255, which indicates the
+ * end of the list.
+ *
+ * ZIPLIST ENTRIES:
+ * Every entry in the ziplist is prefixed by a header that contains two pieces
+ * of information. First, the length of the previous entry is stored to be
+ * able to traverse the list from back to front. Second, the encoding with an
+ * optional string length of the entry itself is stored.
+ *
+ * The length of the previous entry is encoded in the following way:
+ * If this length is smaller than 254 bytes, it will only consume a single
+ * byte that takes the length as value. When the length is greater than or
+ * equal to 254, it will consume 5 bytes. The first byte is set to 254 to
+ * indicate a larger value is following. The remaining 4 bytes take the
+ * length of the previous entry as value.
+ *
+ * The other header field of the entry itself depends on the contents of the
+ * entry. When the entry is a string, the first 2 bits of this header will hold
+ * the type of encoding used to store the length of the string, followed by the
+ * actual length of the string. When the entry is an integer the first 2 bits
+ * are both set to 1. The following 2 bits are used to specify what kind of
+ * integer will be stored after this header. An overview of the different
+ * types and encodings is as follows:
+ *
+ * |00pppppp| - 1 byte
+ * String value with length less than or equal to 63 bytes (6 bits).
+ * |01pppppp|qqqqqqqq| - 2 bytes
+ * String value with length less than or equal to 16383 bytes (14 bits).
+ * |10______|qqqqqqqq|rrrrrrrr|ssssssss|tttttttt| - 5 bytes
+ * String value with length greater than or equal to 16384 bytes.
+ * |1100____| - 1 byte
+ * Integer encoded as int16_t (2 bytes).
+ * |1101____| - 1 byte
+ * Integer encoded as int32_t (4 bytes).
+ * |1110____| - 1 byte
+ * Integer encoded as int64_t (8 bytes).
*/
#include <stdio.h>
int ll2string(char *s, size_t len, long long value);
-/* Important note: the ZIP_END value is used to depict the end of the
- * ziplist structure. When a pointer contains an entry, the first couple
- * of bytes contain the encoded length of the previous entry. This length
- * is encoded as ZIP_ENC_RAW length, so the first two bits will contain 00
- * and the byte will therefore never have a value of 255. */
#define ZIP_END 255
#define ZIP_BIGLEN 254
-/* Entry encoding */
-#define ZIP_ENC_RAW 0
-#define ZIP_ENC_INT16 1
-#define ZIP_ENC_INT32 2
-#define ZIP_ENC_INT64 3
-#define ZIP_ENCODING(p) ((p)[0] >> 6)
+/* Different encoding/length possibilities */
+#define ZIP_STR_06B (0 << 6)
+#define ZIP_STR_14B (1 << 6)
+#define ZIP_STR_32B (2 << 6)
+#define ZIP_INT_16B (0xc0 | 0<<4)
+#define ZIP_INT_32B (0xc0 | 1<<4)
+#define ZIP_INT_64B (0xc0 | 2<<4)
-/* Length encoding for raw entries */
-#define ZIP_LEN_INLINE 0
-#define ZIP_LEN_UINT16 1
-#define ZIP_LEN_UINT32 2
+/* Macro's to determine type */
+#define ZIP_IS_STR(enc) (((enc) & 0xc0) < 0xc0)
+#define ZIP_IS_INT(enc) (!ZIP_IS_STR(enc) && ((enc) & 0x30) < 0x30)
/* Utility macros */
#define ZIPLIST_BYTES(zl) (*((uint32_t*)(zl)))
unsigned char *p;
} zlentry;
+/* Return the encoding pointer to by 'p'. */
+static unsigned int zipEntryEncoding(unsigned char *p) {
+ /* String encoding: 2 MSBs */
+ unsigned char b = p[0] & 0xc0;
+ if (b < 0xc0) {
+ return b;
+ } else {
+ /* Integer encoding: 4 MSBs */
+ return p[0] & 0xf0;
+ }
+ assert(NULL);
+}
+
/* Return bytes needed to store integer encoded by 'encoding' */
-static unsigned int zipEncodingSize(unsigned char encoding) {
- if (encoding == ZIP_ENC_INT16) {
- return sizeof(int16_t);
- } else if (encoding == ZIP_ENC_INT32) {
- return sizeof(int32_t);
- } else if (encoding == ZIP_ENC_INT64) {
- return sizeof(int64_t);
+static unsigned int zipIntSize(unsigned char encoding) {
+ switch(encoding) {
+ case ZIP_INT_16B: return sizeof(int16_t);
+ case ZIP_INT_32B: return sizeof(int32_t);
+ case ZIP_INT_64B: return sizeof(int64_t);
}
assert(NULL);
}
/* Decode the encoded length pointed by 'p'. If a pointer to 'lensize' is
* provided, it is set to the number of bytes required to encode the length. */
static unsigned int zipDecodeLength(unsigned char *p, unsigned int *lensize) {
- unsigned char encoding = ZIP_ENCODING(p), lenenc;
+ unsigned char encoding = zipEntryEncoding(p);
unsigned int len;
- if (encoding == ZIP_ENC_RAW) {
- lenenc = (p[0] >> 4) & 0x3;
- if (lenenc == ZIP_LEN_INLINE) {
- len = p[0] & 0xf;
+ if (ZIP_IS_STR(encoding)) {
+ switch(encoding) {
+ case ZIP_STR_06B:
+ len = p[0] & 0x3f;
if (lensize) *lensize = 1;
- } else if (lenenc == ZIP_LEN_UINT16) {
- len = p[1] | (p[2] << 8);
- if (lensize) *lensize = 3;
- } else {
- len = p[1] | (p[2] << 8) | (p[3] << 16) | (p[4] << 24);
+ break;
+ case ZIP_STR_14B:
+ len = ((p[0] & 0x3f) << 6) | p[1];
+ if (lensize) *lensize = 2;
+ break;
+ case ZIP_STR_32B:
+ len = (p[1] << 24) | (p[2] << 16) | (p[3] << 8) | p[4];
if (lensize) *lensize = 5;
+ break;
+ default:
+ assert(NULL);
}
} else {
- len = zipEncodingSize(encoding);
+ len = zipIntSize(encoding);
if (lensize) *lensize = 1;
}
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 zipEncodeLength(unsigned char *p, char encoding, unsigned int rawlen) {
- unsigned char len = 1, lenenc, buf[5];
- if (encoding == ZIP_ENC_RAW) {
- if (rawlen <= 0xf) {
+static unsigned int zipEncodeLength(unsigned char *p, unsigned char encoding, unsigned int rawlen) {
+ unsigned char len = 1, buf[5];
+
+ if (ZIP_IS_STR(encoding)) {
+ /* Although encoding is given it may not be set for strings,
+ * so we determine it here using the raw length. */
+ if (rawlen <= 0x3f) {
if (!p) return len;
- lenenc = ZIP_LEN_INLINE;
- buf[0] = rawlen;
- } else if (rawlen <= 0xffff) {
- len += 2;
+ buf[0] = ZIP_STR_06B | rawlen;
+ } else if (rawlen <= 0x3fff) {
+ len += 1;
if (!p) return len;
- lenenc = ZIP_LEN_UINT16;
- buf[1] = (rawlen ) & 0xff;
- buf[2] = (rawlen >> 8) & 0xff;
+ buf[0] = ZIP_STR_14B | ((rawlen >> 8) & 0x3f);
+ buf[1] = rawlen & 0xff;
} else {
len += 4;
if (!p) return len;
- lenenc = ZIP_LEN_UINT32;
- buf[1] = (rawlen ) & 0xff;
- buf[2] = (rawlen >> 8) & 0xff;
- buf[3] = (rawlen >> 16) & 0xff;
- buf[4] = (rawlen >> 24) & 0xff;
+ buf[0] = ZIP_STR_32B;
+ buf[1] = (rawlen >> 24) & 0xff;
+ buf[2] = (rawlen >> 16) & 0xff;
+ buf[3] = (rawlen >> 8) & 0xff;
+ buf[4] = rawlen & 0xff;
}
- buf[0] = (lenenc << 4) | (buf[0] & 0xf);
+ } else {
+ /* Implies integer encoding, so length is always 1. */
+ if (!p) return len;
+ buf[0] = encoding;
}
- if (!p) return len;
- /* Apparently we need to store the length in 'p' */
- buf[0] = (encoding << 6) | (buf[0] & 0x3f);
+ /* Store this length at p */
memcpy(p,buf,len);
return len;
}
}
}
+/* Encode the length of the previous entry and write it to "p". This only
+ * uses the larger encoding (required in __ziplistCascadeUpdate). */
+static void zipPrevEncodeLengthForceLarge(unsigned char *p, unsigned int len) {
+ if (p == NULL) return;
+ p[0] = ZIP_BIGLEN;
+ memcpy(p+1,&len,sizeof(len));
+}
+
/* Return the difference in number of bytes needed to store the new length
* "len" on the entry pointed to by "p". */
static int zipPrevLenByteDiff(unsigned char *p, unsigned int len) {
/* Great, the string can be encoded. Check what's the smallest
* of our encoding types that can hold this value. */
if (value >= INT16_MIN && value <= INT16_MAX) {
- *encoding = ZIP_ENC_INT16;
+ *encoding = ZIP_INT_16B;
} else if (value >= INT32_MIN && value <= INT32_MAX) {
- *encoding = ZIP_ENC_INT32;
+ *encoding = ZIP_INT_32B;
} else {
- *encoding = ZIP_ENC_INT64;
+ *encoding = ZIP_INT_64B;
}
*v = value;
return 1;
int16_t i16;
int32_t i32;
int64_t i64;
- if (encoding == ZIP_ENC_INT16) {
+ if (encoding == ZIP_INT_16B) {
i16 = value;
memcpy(p,&i16,sizeof(i16));
- } else if (encoding == ZIP_ENC_INT32) {
+ } else if (encoding == ZIP_INT_32B) {
i32 = value;
memcpy(p,&i32,sizeof(i32));
- } else if (encoding == ZIP_ENC_INT64) {
+ } else if (encoding == ZIP_INT_64B) {
i64 = value;
memcpy(p,&i64,sizeof(i64));
} else {
int16_t i16;
int32_t i32;
int64_t i64, ret;
- if (encoding == ZIP_ENC_INT16) {
+ if (encoding == ZIP_INT_16B) {
memcpy(&i16,p,sizeof(i16));
ret = i16;
- } else if (encoding == ZIP_ENC_INT32) {
+ } else if (encoding == ZIP_INT_32B) {
memcpy(&i32,p,sizeof(i32));
ret = i32;
- } else if (encoding == ZIP_ENC_INT64) {
+ } else if (encoding == ZIP_INT_64B) {
memcpy(&i64,p,sizeof(i64));
ret = i64;
} else {
e.prevrawlen = zipPrevDecodeLength(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.encoding = zipEntryEncoding(p+e.prevrawlensize);
e.p = p;
return e;
}
return zl;
}
+/* When an entry is inserted, we need to set the prevlen field of the next
+ * entry to equal the length of the inserted entry. It can occur that this
+ * length cannot be encoded in 1 byte and the next entry needs to be grow
+ * a bit larger to hold the 5-byte encoded prevlen. This can be done for free,
+ * because this only happens when an entry is already being inserted (which
+ * causes a realloc and memmove). However, encoding the prevlen may require
+ * that this entry is grown as well. This effect may cascade throughout
+ * the ziplist when there are consecutive entries with a size close to
+ * ZIP_BIGLEN, so we need to check that the prevlen can be encoded in every
+ * consecutive entry.
+ *
+ * Note that this effect can also happen in reverse, where the bytes required
+ * to encode the prevlen field can shrink. This effect is deliberately ignored,
+ * because it can cause a "flapping" effect where a chain prevlen fields is
+ * first grown and then shrunk again after consecutive inserts. Rather, the
+ * field is allowed to stay larger than necessary, because a large prevlen
+ * field implies the ziplist is holding large entries anyway.
+ *
+ * The pointer "p" points to the first entry that does NOT need to be
+ * updated, i.e. consecutive fields MAY need an update. */
+static unsigned char *__ziplistCascadeUpdate(unsigned char *zl, unsigned char *p) {
+ unsigned int curlen = ZIPLIST_BYTES(zl), rawlen, rawlensize;
+ unsigned int offset, noffset, extra;
+ unsigned char *np;
+ zlentry cur, next;
+
+ while (p[0] != ZIP_END) {
+ cur = zipEntry(p);
+ rawlen = cur.headersize + cur.len;
+ rawlensize = zipPrevEncodeLength(NULL,rawlen);
+
+ /* Abort if there is no next entry. */
+ if (p[rawlen] == ZIP_END) break;
+ next = zipEntry(p+rawlen);
+
+ /* Abort when "prevlen" has not changed. */
+ if (next.prevrawlen == rawlen) break;
+
+ if (next.prevrawlensize < rawlensize) {
+ /* The "prevlen" field of "next" needs more bytes to hold
+ * the raw length of "cur". */
+ offset = p-zl;
+ extra = rawlensize-next.prevrawlensize;
+ zl = ziplistResize(zl,curlen+extra);
+ ZIPLIST_TAIL_OFFSET(zl) += extra;
+ p = zl+offset;
+
+ /* Move the tail to the back. */
+ np = p+rawlen;
+ noffset = np-zl;
+ memmove(np+rawlensize,
+ np+next.prevrawlensize,
+ curlen-noffset-next.prevrawlensize-1);
+ zipPrevEncodeLength(np,rawlen);
+
+ /* Advance the cursor */
+ p += rawlen;
+ } else {
+ if (next.prevrawlensize > rawlensize) {
+ /* This would result in shrinking, which we want to avoid.
+ * So, set "rawlen" in the available bytes. */
+ zipPrevEncodeLengthForceLarge(p+rawlen,rawlen);
+ } else {
+ zipPrevEncodeLength(p+rawlen,rawlen);
+ }
+
+ /* Stop here, as the raw length of "next" has not changed. */
+ break;
+ }
+ }
+ return zl;
+}
+
/* Delete "num" entries, starting at "p". Returns pointer to the ziplist. */
static unsigned char *__ziplistDelete(unsigned char *zl, unsigned char *p, unsigned int num) {
unsigned int i, totlen, deleted = 0;
- int nextdiff = 0;
- zlentry first = zipEntry(p);
+ int offset, nextdiff = 0;
+ zlentry first, tail;
+
+ first = zipEntry(p);
for (i = 0; p[0] != ZIP_END && i < num; i++) {
p += zipRawEntryLength(p);
deleted++;
zipPrevEncodeLength(p-nextdiff,first.prevrawlen);
/* Update offset for tail */
- ZIPLIST_TAIL_OFFSET(zl) -= totlen+nextdiff;
+ ZIPLIST_TAIL_OFFSET(zl) -= totlen;
+
+ /* When the tail contains more than one entry, we need to take
+ * "nextdiff" in account as well. Otherwise, a change in the
+ * size of prevlen doesn't have an effect on the *tail* offset. */
+ tail = zipEntry(p);
+ if (p[tail.headersize+tail.len] != ZIP_END)
+ ZIPLIST_TAIL_OFFSET(zl) += nextdiff;
/* Move tail to the front of the ziplist */
memmove(first.p,p-nextdiff,ZIPLIST_BYTES(zl)-(p-zl)-1+nextdiff);
}
/* Resize and update length */
+ offset = first.p-zl;
zl = ziplistResize(zl, ZIPLIST_BYTES(zl)-totlen+nextdiff);
ZIPLIST_INCR_LENGTH(zl,-deleted);
+ p = zl+offset;
+
+ /* When nextdiff != 0, the raw length of the next entry has changed, so
+ * we need to cascade the update throughout the ziplist */
+ if (nextdiff != 0)
+ zl = __ziplistCascadeUpdate(zl,p);
}
return zl;
}
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;
- unsigned char encoding = ZIP_ENC_RAW;
+ unsigned char encoding = 0;
long long value;
- zlentry entry;
+ zlentry entry, tail;
/* Find out prevlen for the entry that is inserted. */
if (p[0] != ZIP_END) {
entry = zipEntry(p);
prevlen = entry.prevrawlen;
} else {
- tail = ZIPLIST_ENTRY_TAIL(zl);
- if (tail[0] != ZIP_END) {
- prevlen = zipRawEntryLength(tail);
+ unsigned char *ptail = ZIPLIST_ENTRY_TAIL(zl);
+ if (ptail[0] != ZIP_END) {
+ prevlen = zipRawEntryLength(ptail);
}
}
/* See if the entry can be encoded */
if (zipTryEncoding(s,slen,&value,&encoding)) {
- reqlen = zipEncodingSize(encoding);
+ /* 'encoding' is set to the appropriate integer encoding */
+ reqlen = zipIntSize(encoding);
} else {
+ /* 'encoding' is untouched, however zipEncodeLength will use the
+ * string length to figure out how to encode it. */
reqlen = slen;
}
-
/* We need space for both the length of the previous entry and
* the length of the payload. */
reqlen += zipPrevEncodeLength(NULL,prevlen);
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. */
zipPrevEncodeLength(p+reqlen,reqlen);
+
/* Update offset for tail */
- ZIPLIST_TAIL_OFFSET(zl) += reqlen+nextdiff;
+ ZIPLIST_TAIL_OFFSET(zl) += reqlen;
+
+ /* When the tail contains more than one entry, we need to take
+ * "nextdiff" in account as well. Otherwise, a change in the
+ * size of prevlen doesn't have an effect on the *tail* offset. */
+ tail = zipEntry(p+reqlen);
+ if (p[reqlen+tail.headersize+tail.len] != ZIP_END)
+ ZIPLIST_TAIL_OFFSET(zl) += nextdiff;
} else {
/* This element will be the new tail. */
ZIPLIST_TAIL_OFFSET(zl) = p-zl;
}
+ /* When nextdiff != 0, the raw length of the next entry has changed, so
+ * we need to cascade the update throughout the ziplist */
+ if (nextdiff != 0) {
+ offset = p-zl;
+ zl = __ziplistCascadeUpdate(zl,p+reqlen);
+ p = zl+offset;
+ }
+
/* Write the entry */
p += zipPrevEncodeLength(p,prevlen);
p += zipEncodeLength(p,encoding,slen);
- if (encoding != ZIP_ENC_RAW) {
- zipSaveInteger(p,value,encoding);
- } else {
+ if (ZIP_IS_STR(encoding)) {
memcpy(p,s,slen);
+ } else {
+ zipSaveInteger(p,value,encoding);
}
ZIPLIST_INCR_LENGTH(zl,1);
return zl;
return NULL;
} else {
entry = zipEntry(p);
+ assert(entry.prevrawlen > 0);
return p-entry.prevrawlen;
}
}
if (sstr) *sstr = NULL;
entry = zipEntry(p);
- if (entry.encoding == ZIP_ENC_RAW) {
+ if (ZIP_IS_STR(entry.encoding)) {
if (sstr) {
*slen = entry.len;
*sstr = p+entry.headersize;
if (p[0] == ZIP_END) return 0;
entry = zipEntry(p);
- if (entry.encoding == ZIP_ENC_RAW) {
+ if (ZIP_IS_STR(entry.encoding)) {
/* Raw compare */
if (entry.len == slen) {
return memcmp(p+entry.headersize,sstr,slen) == 0;
void ziplistRepr(unsigned char *zl) {
unsigned char *p;
+ int index = 0;
zlentry entry;
- printf("{total bytes %d} {length %u}\n",ZIPLIST_BYTES(zl), ZIPLIST_LENGTH(zl));
+ printf(
+ "{total bytes %d} "
+ "{length %u}\n"
+ "{tail offset %u}\n",
+ ZIPLIST_BYTES(zl),
+ ZIPLIST_LENGTH(zl),
+ ZIPLIST_TAIL_OFFSET(zl));
p = ZIPLIST_ENTRY_HEAD(zl);
while(*p != ZIP_END) {
entry = zipEntry(p);
- printf("{offset %ld, header %u, payload %u} ",p-zl,entry.headersize,entry.len);
+ printf(
+ "{"
+ "addr 0x%08lx, "
+ "index %2d, "
+ "offset %5ld, "
+ "rl: %5u, "
+ "hs %2u, "
+ "pl: %5u, "
+ "pls: %2u, "
+ "payload %5u"
+ "} ",
+ (long unsigned int)p,
+ index,
+ p-zl,
+ entry.headersize+entry.len,
+ entry.headersize,
+ entry.prevrawlen,
+ entry.prevrawlensize,
+ entry.len);
p += entry.headersize;
- if (entry.encoding == ZIP_ENC_RAW) {
- fwrite(p,entry.len,1,stdout);
+ if (ZIP_IS_STR(entry.encoding)) {
+ if (entry.len > 40) {
+ fwrite(p,40,1,stdout);
+ printf("...");
+ } else {
+ fwrite(p,entry.len,1,stdout);
+ }
} else {
printf("%lld", (long long) zipLoadInteger(p,entry.encoding));
}
printf("\n");
p += entry.len;
+ index++;
}
printf("{end}\n\n");
}
unsigned int elen;
long long value;
+ /* If an argument is given, use it as the random seed. */
+ if (argc == 2)
+ srand(atoi(argv[1]));
+
zl = createIntList();
ziplistRepr(zl);
printf("ERROR: \"1025\"\n");
return 1;
}
- printf("SUCCESS\n");
+ printf("SUCCESS\n\n");
+ }
+
+ printf("Stress with random payloads of different encoding:\n");
+ {
+ int i, idx, where, len;
+ long long v;
+ unsigned char *p;
+ char buf[0x4041]; /* max length of generated string */
+ zl = ziplistNew();
+ for (i = 0; i < 100000; i++) {
+ where = (rand() & 1) ? ZIPLIST_HEAD : ZIPLIST_TAIL;
+ if (rand() & 1) {
+ /* equally likely create a 16, 32 or 64 bit int */
+ v = (rand() & INT16_MAX) + ((1ll << 32) >> ((rand() % 3)*16));
+ v *= 2*(rand() & 1)-1; /* randomly flip sign */
+ sprintf(buf, "%lld", v);
+ zl = ziplistPush(zl, (unsigned char*)buf, strlen(buf), where);
+ } else {
+ /* equally likely generate 6, 14 or >14 bit length */
+ v = rand() & 0x3f;
+ v += 0x4000 >> ((rand() % 3)*8);
+ memset(buf, 'x', v);
+ zl = ziplistPush(zl, (unsigned char*)buf, v, where);
+ }
+
+ /* delete a random element */
+ if ((len = ziplistLen(zl)) >= 10) {
+ idx = rand() % len;
+ // printf("Delete index %d\n", idx);
+ // ziplistRepr(zl);
+ ziplistDeleteRange(zl, idx, 1);
+ // ziplistRepr(zl);
+ len--;
+ }
+
+ /* iterate from front to back */
+ idx = 0;
+ p = ziplistIndex(zl, 0);
+ while((p = ziplistNext(zl,p)))
+ idx++;
+ assert(len == idx+1);
+
+ /* iterate from back to front */
+ idx = 0;
+ p = ziplistIndex(zl, -1);
+ while((p = ziplistPrev(zl,p)))
+ idx++;
+ assert(len == idx+1);
+ }
+ printf("SUCCESS\n\n");
}
printf("Stress with variable ziplist size:\n");
projects / redis.git / commitdiff
