summaryrefslogtreecommitdiffstats
path: root/src/ziplist.c
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-14 13:40:54 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-14 13:40:54 +0000
commit317c0644ccf108aa23ef3fd8358bd66c2840bfc0 (patch)
treec417b3d25c86b775989cb5ac042f37611b626c8a /src/ziplist.c
parentInitial commit. (diff)
downloadredis-317c0644ccf108aa23ef3fd8358bd66c2840bfc0.tar.xz
redis-317c0644ccf108aa23ef3fd8358bd66c2840bfc0.zip
Adding upstream version 5:7.2.4.upstream/5%7.2.4
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/ziplist.c')
-rw-r--r--src/ziplist.c2666
1 files changed, 2666 insertions, 0 deletions
diff --git a/src/ziplist.c b/src/ziplist.c
new file mode 100644
index 0000000..c891625
--- /dev/null
+++ b/src/ziplist.c
@@ -0,0 +1,2666 @@
+/* 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.
+ *
+ * ----------------------------------------------------------------------------
+ *
+ * ZIPLIST OVERALL LAYOUT
+ * ======================
+ *
+ * The general layout of the ziplist is as follows:
+ *
+ * <zlbytes> <zltail> <zllen> <entry> <entry> ... <entry> <zlend>
+ *
+ * NOTE: all fields are stored in little endian, if not specified otherwise.
+ *
+ * <uint32_t zlbytes> is an unsigned integer to hold the number of bytes that
+ * the ziplist occupies, including the four bytes of the zlbytes field itself.
+ * This value needs to be stored to be able to resize the entire structure
+ * without the need to traverse it first.
+ *
+ * <uint32_t 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.
+ *
+ * <uint16_t zllen> is the number of entries. When there are more than
+ * 2^16-2 entries, this value is set to 2^16-1 and we need to traverse the
+ * entire list to know how many items it holds.
+ *
+ * <uint8_t zlend> is a special entry representing the end of the ziplist.
+ * Is encoded as a single byte equal to 255. No other normal entry starts
+ * with a byte set to the value of 255.
+ *
+ * ZIPLIST ENTRIES
+ * ===============
+ *
+ * Every entry in the ziplist is prefixed by metadata 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 entry encoding is
+ * provided. It represents the entry type, integer or string, and in the case
+ * of strings it also represents the length of the string payload.
+ * So a complete entry is stored like this:
+ *
+ * <prevlen> <encoding> <entry-data>
+ *
+ * Sometimes the encoding represents the entry itself, like for small integers
+ * as we'll see later. In such a case the <entry-data> part is missing, and we
+ * could have just:
+ *
+ * <prevlen> <encoding>
+ *
+ * The length of the previous entry, <prevlen>, is encoded in the following way:
+ * If this length is smaller than 254 bytes, it will only consume a single
+ * byte representing the length as an unsigned 8 bit integer. When the length
+ * is greater than or equal to 254, it will consume 5 bytes. The first byte is
+ * set to 254 (FE) to indicate a larger value is following. The remaining 4
+ * bytes take the length of the previous entry as value.
+ *
+ * So practically an entry is encoded in the following way:
+ *
+ * <prevlen from 0 to 253> <encoding> <entry>
+ *
+ * Or alternatively if the previous entry length is greater than 253 bytes
+ * the following encoding is used:
+ *
+ * 0xFE <4 bytes unsigned little endian prevlen> <encoding> <entry>
+ *
+ * The encoding field of the entry depends on the content of the
+ * entry. When the entry is a string, the first 2 bits of the encoding first
+ * byte 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. The first byte is always enough
+ * to determine the kind of entry.
+ *
+ * |00pppppp| - 1 byte
+ * String value with length less than or equal to 63 bytes (6 bits).
+ * "pppppp" represents the unsigned 6 bit length.
+ * |01pppppp|qqqqqqqq| - 2 bytes
+ * String value with length less than or equal to 16383 bytes (14 bits).
+ * IMPORTANT: The 14 bit number is stored in big endian.
+ * |10000000|qqqqqqqq|rrrrrrrr|ssssssss|tttttttt| - 5 bytes
+ * String value with length greater than or equal to 16384 bytes.
+ * Only the 4 bytes following the first byte represents the length
+ * up to 2^32-1. The 6 lower bits of the first byte are not used and
+ * are set to zero.
+ * IMPORTANT: The 32 bit number is stored in big endian.
+ * |11000000| - 3 bytes
+ * Integer encoded as int16_t (2 bytes).
+ * |11010000| - 5 bytes
+ * Integer encoded as int32_t (4 bytes).
+ * |11100000| - 9 bytes
+ * Integer encoded as int64_t (8 bytes).
+ * |11110000| - 4 bytes
+ * Integer encoded as 24 bit signed (3 bytes).
+ * |11111110| - 2 bytes
+ * Integer encoded as 8 bit signed (1 byte).
+ * |1111xxxx| - (with xxxx between 0001 and 1101) immediate 4 bit integer.
+ * Unsigned integer from 0 to 12. The encoded value is actually from
+ * 1 to 13 because 0000 and 1111 can not be used, so 1 should be
+ * subtracted from the encoded 4 bit value to obtain the right value.
+ * |11111111| - End of ziplist special entry.
+ *
+ * Like for the ziplist header, all the integers are represented in little
+ * endian byte order, even when this code is compiled in big endian systems.
+ *
+ * EXAMPLES OF ACTUAL ZIPLISTS
+ * ===========================
+ *
+ * The following is a ziplist containing the two elements representing
+ * the strings "2" and "5". It is composed of 15 bytes, that we visually
+ * split into sections:
+ *
+ * [0f 00 00 00] [0c 00 00 00] [02 00] [00 f3] [02 f6] [ff]
+ * | | | | | |
+ * zlbytes zltail zllen "2" "5" end
+ *
+ * The first 4 bytes represent the number 15, that is the number of bytes
+ * the whole ziplist is composed of. The second 4 bytes are the offset
+ * at which the last ziplist entry is found, that is 12, in fact the
+ * last entry, that is "5", is at offset 12 inside the ziplist.
+ * The next 16 bit integer represents the number of elements inside the
+ * ziplist, its value is 2 since there are just two elements inside.
+ * Finally "00 f3" is the first entry representing the number 2. It is
+ * composed of the previous entry length, which is zero because this is
+ * our first entry, and the byte F3 which corresponds to the encoding
+ * |1111xxxx| with xxxx between 0001 and 1101. We need to remove the "F"
+ * higher order bits 1111, and subtract 1 from the "3", so the entry value
+ * is "2". The next entry has a prevlen of 02, since the first entry is
+ * composed of exactly two bytes. The entry itself, F6, is encoded exactly
+ * like the first entry, and 6-1 = 5, so the value of the entry is 5.
+ * Finally the special entry FF signals the end of the ziplist.
+ *
+ * Adding another element to the above string with the value "Hello World"
+ * allows us to show how the ziplist encodes small strings. We'll just show
+ * the hex dump of the entry itself. Imagine the bytes as following the
+ * entry that stores "5" in the ziplist above:
+ *
+ * [02] [0b] [48 65 6c 6c 6f 20 57 6f 72 6c 64]
+ *
+ * The first byte, 02, is the length of the previous entry. The next
+ * byte represents the encoding in the pattern |00pppppp| that means
+ * that the entry is a string of length <pppppp>, so 0B means that
+ * an 11 bytes string follows. From the third byte (48) to the last (64)
+ * there are just the ASCII characters for "Hello World".
+ *
+ * ----------------------------------------------------------------------------
+ *
+ * Copyright (c) 2009-2012, Pieter Noordhuis <pcnoordhuis at gmail dot com>
+ * Copyright (c) 2009-2017, Salvatore Sanfilippo <antirez at gmail dot com>
+ * Copyright (c) 2020, Redis Labs, Inc
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * * Neither the name of Redis nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <limits.h>
+#include "zmalloc.h"
+#include "util.h"
+#include "ziplist.h"
+#include "config.h"
+#include "endianconv.h"
+#include "redisassert.h"
+
+#define ZIP_END 255 /* Special "end of ziplist" entry. */
+#define ZIP_BIG_PREVLEN 254 /* ZIP_BIG_PREVLEN - 1 is the max number of bytes of
+ the previous entry, for the "prevlen" field prefixing
+ each entry, to be represented with just a single byte.
+ Otherwise it is represented as FE AA BB CC DD, where
+ AA BB CC DD are a 4 bytes unsigned integer
+ representing the previous entry len. */
+
+/* Different encoding/length possibilities */
+#define ZIP_STR_MASK 0xc0
+#define ZIP_INT_MASK 0x30
+#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)
+#define ZIP_INT_24B (0xc0 | 3<<4)
+#define ZIP_INT_8B 0xfe
+
+/* 4 bit integer immediate encoding |1111xxxx| with xxxx between
+ * 0001 and 1101. */
+#define ZIP_INT_IMM_MASK 0x0f /* Mask to extract the 4 bits value. To add
+ one is needed to reconstruct the value. */
+#define ZIP_INT_IMM_MIN 0xf1 /* 11110001 */
+#define ZIP_INT_IMM_MAX 0xfd /* 11111101 */
+
+#define INT24_MAX 0x7fffff
+#define INT24_MIN (-INT24_MAX - 1)
+
+/* Macro to determine if the entry is a string. String entries never start
+ * with "11" as most significant bits of the first byte. */
+#define ZIP_IS_STR(enc) (((enc) & ZIP_STR_MASK) < ZIP_STR_MASK)
+
+/* Utility macros.*/
+
+/* Return total bytes a ziplist is composed of. */
+#define ZIPLIST_BYTES(zl) (*((uint32_t*)(zl)))
+
+/* Return the offset of the last item inside the ziplist. */
+#define ZIPLIST_TAIL_OFFSET(zl) (*((uint32_t*)((zl)+sizeof(uint32_t))))
+
+/* Return the length of a ziplist, or UINT16_MAX if the length cannot be
+ * determined without scanning the whole ziplist. */
+#define ZIPLIST_LENGTH(zl) (*((uint16_t*)((zl)+sizeof(uint32_t)*2)))
+
+/* The size of a ziplist header: two 32 bit integers for the total
+ * bytes count and last item offset. One 16 bit integer for the number
+ * of items field. */
+#define ZIPLIST_HEADER_SIZE (sizeof(uint32_t)*2+sizeof(uint16_t))
+
+/* Size of the "end of ziplist" entry. Just one byte. */
+#define ZIPLIST_END_SIZE (sizeof(uint8_t))
+
+/* Return the pointer to the first entry of a ziplist. */
+#define ZIPLIST_ENTRY_HEAD(zl) ((zl)+ZIPLIST_HEADER_SIZE)
+
+/* Return the pointer to the last entry of a ziplist, using the
+ * last entry offset inside the ziplist header. */
+#define ZIPLIST_ENTRY_TAIL(zl) ((zl)+intrev32ifbe(ZIPLIST_TAIL_OFFSET(zl)))
+
+/* Return the pointer to the last byte of a ziplist, which is, the
+ * end of ziplist FF entry. */
+#define ZIPLIST_ENTRY_END(zl) ((zl)+intrev32ifbe(ZIPLIST_BYTES(zl))-ZIPLIST_END_SIZE)
+
+/* Increment the number of items field in the ziplist header. Note that this
+ * macro should never overflow the unsigned 16 bit integer, since entries are
+ * always pushed one at a time. When UINT16_MAX is reached we want the count
+ * to stay there to signal that a full scan is needed to get the number of
+ * items inside the ziplist. */
+#define ZIPLIST_INCR_LENGTH(zl,incr) { \
+ if (intrev16ifbe(ZIPLIST_LENGTH(zl)) < UINT16_MAX) \
+ ZIPLIST_LENGTH(zl) = intrev16ifbe(intrev16ifbe(ZIPLIST_LENGTH(zl))+incr); \
+}
+
+/* Don't let ziplists grow over 1GB in any case, don't wanna risk overflow in
+ * zlbytes */
+#define ZIPLIST_MAX_SAFETY_SIZE (1<<30)
+int ziplistSafeToAdd(unsigned char* zl, size_t add) {
+ size_t len = zl? ziplistBlobLen(zl): 0;
+ if (len + add > ZIPLIST_MAX_SAFETY_SIZE)
+ return 0;
+ return 1;
+}
+
+
+/* We use this function to receive information about a ziplist entry.
+ * Note that this is not how the data is actually encoded, is just what we
+ * get filled by a function in order to operate more easily. */
+typedef struct zlentry {
+ unsigned int prevrawlensize; /* Bytes used to encode the previous entry len*/
+ unsigned int prevrawlen; /* Previous entry len. */
+ unsigned int lensize; /* Bytes used to encode this entry type/len.
+ For example strings have a 1, 2 or 5 bytes
+ header. Integers always use a single byte.*/
+ unsigned int len; /* Bytes used to represent the actual entry.
+ For strings this is just the string length
+ while for integers it is 1, 2, 3, 4, 8 or
+ 0 (for 4 bit immediate) depending on the
+ number range. */
+ unsigned int headersize; /* prevrawlensize + lensize. */
+ unsigned char encoding; /* Set to ZIP_STR_* or ZIP_INT_* depending on
+ the entry encoding. However for 4 bits
+ immediate integers this can assume a range
+ of values and must be range-checked. */
+ unsigned char *p; /* Pointer to the very start of the entry, that
+ is, this points to prev-entry-len field. */
+} zlentry;
+
+#define ZIPLIST_ENTRY_ZERO(zle) { \
+ (zle)->prevrawlensize = (zle)->prevrawlen = 0; \
+ (zle)->lensize = (zle)->len = (zle)->headersize = 0; \
+ (zle)->encoding = 0; \
+ (zle)->p = NULL; \
+}
+
+/* Extract the encoding from the byte pointed by 'ptr' and set it into
+ * 'encoding' field of the zlentry structure. */
+#define ZIP_ENTRY_ENCODING(ptr, encoding) do { \
+ (encoding) = ((ptr)[0]); \
+ if ((encoding) < ZIP_STR_MASK) (encoding) &= ZIP_STR_MASK; \
+} while(0)
+
+#define ZIP_ENCODING_SIZE_INVALID 0xff
+/* Return the number of bytes required to encode the entry type + length.
+ * On error, return ZIP_ENCODING_SIZE_INVALID */
+static inline unsigned int zipEncodingLenSize(unsigned char encoding) {
+ if (encoding == ZIP_INT_16B || encoding == ZIP_INT_32B ||
+ encoding == ZIP_INT_24B || encoding == ZIP_INT_64B ||
+ encoding == ZIP_INT_8B)
+ return 1;
+ if (encoding >= ZIP_INT_IMM_MIN && encoding <= ZIP_INT_IMM_MAX)
+ return 1;
+ if (encoding == ZIP_STR_06B)
+ return 1;
+ if (encoding == ZIP_STR_14B)
+ return 2;
+ if (encoding == ZIP_STR_32B)
+ return 5;
+ return ZIP_ENCODING_SIZE_INVALID;
+}
+
+#define ZIP_ASSERT_ENCODING(encoding) do { \
+ assert(zipEncodingLenSize(encoding) != ZIP_ENCODING_SIZE_INVALID); \
+} while (0)
+
+/* Return bytes needed to store integer encoded by 'encoding' */
+static inline unsigned int zipIntSize(unsigned char encoding) {
+ switch(encoding) {
+ case ZIP_INT_8B: return 1;
+ case ZIP_INT_16B: return 2;
+ case ZIP_INT_24B: return 3;
+ case ZIP_INT_32B: return 4;
+ case ZIP_INT_64B: return 8;
+ }
+ if (encoding >= ZIP_INT_IMM_MIN && encoding <= ZIP_INT_IMM_MAX)
+ return 0; /* 4 bit immediate */
+ /* bad encoding, covered by a previous call to ZIP_ASSERT_ENCODING */
+ redis_unreachable();
+ return 0;
+}
+
+/* Write the encoding header of the entry in 'p'. If p is NULL it just returns
+ * the amount of bytes required to encode such a length. Arguments:
+ *
+ * 'encoding' is the encoding we are using for the entry. It could be
+ * ZIP_INT_* or ZIP_STR_* or between ZIP_INT_IMM_MIN and ZIP_INT_IMM_MAX
+ * for single-byte small immediate integers.
+ *
+ * 'rawlen' is only used for ZIP_STR_* encodings and is the length of the
+ * string that this entry represents.
+ *
+ * The function returns the number of bytes used by the encoding/length
+ * header stored in 'p'. */
+unsigned int zipStoreEntryEncoding(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;
+ buf[0] = ZIP_STR_06B | rawlen;
+ } else if (rawlen <= 0x3fff) {
+ len += 1;
+ if (!p) return len;
+ buf[0] = ZIP_STR_14B | ((rawlen >> 8) & 0x3f);
+ buf[1] = rawlen & 0xff;
+ } else {
+ len += 4;
+ if (!p) return len;
+ buf[0] = ZIP_STR_32B;
+ buf[1] = (rawlen >> 24) & 0xff;
+ buf[2] = (rawlen >> 16) & 0xff;
+ buf[3] = (rawlen >> 8) & 0xff;
+ buf[4] = rawlen & 0xff;
+ }
+ } else {
+ /* Implies integer encoding, so length is always 1. */
+ if (!p) return len;
+ buf[0] = encoding;
+ }
+
+ /* Store this length at p. */
+ memcpy(p,buf,len);
+ return len;
+}
+
+/* Decode the entry encoding type and data length (string length for strings,
+ * number of bytes used for the integer for integer entries) encoded in 'ptr'.
+ * The 'encoding' variable is input, extracted by the caller, the 'lensize'
+ * variable will hold the number of bytes required to encode the entry
+ * length, and the 'len' variable will hold the entry length.
+ * On invalid encoding error, lensize is set to 0. */
+#define ZIP_DECODE_LENGTH(ptr, encoding, lensize, len) do { \
+ if ((encoding) < ZIP_STR_MASK) { \
+ if ((encoding) == ZIP_STR_06B) { \
+ (lensize) = 1; \
+ (len) = (ptr)[0] & 0x3f; \
+ } else if ((encoding) == ZIP_STR_14B) { \
+ (lensize) = 2; \
+ (len) = (((ptr)[0] & 0x3f) << 8) | (ptr)[1]; \
+ } else if ((encoding) == ZIP_STR_32B) { \
+ (lensize) = 5; \
+ (len) = ((uint32_t)(ptr)[1] << 24) | \
+ ((uint32_t)(ptr)[2] << 16) | \
+ ((uint32_t)(ptr)[3] << 8) | \
+ ((uint32_t)(ptr)[4]); \
+ } else { \
+ (lensize) = 0; /* bad encoding, should be covered by a previous */ \
+ (len) = 0; /* ZIP_ASSERT_ENCODING / zipEncodingLenSize, or */ \
+ /* match the lensize after this macro with 0. */ \
+ } \
+ } else { \
+ (lensize) = 1; \
+ if ((encoding) == ZIP_INT_8B) (len) = 1; \
+ else if ((encoding) == ZIP_INT_16B) (len) = 2; \
+ else if ((encoding) == ZIP_INT_24B) (len) = 3; \
+ else if ((encoding) == ZIP_INT_32B) (len) = 4; \
+ else if ((encoding) == ZIP_INT_64B) (len) = 8; \
+ else if (encoding >= ZIP_INT_IMM_MIN && encoding <= ZIP_INT_IMM_MAX) \
+ (len) = 0; /* 4 bit immediate */ \
+ else \
+ (lensize) = (len) = 0; /* bad encoding */ \
+ } \
+} while(0)
+
+/* Encode the length of the previous entry and write it to "p". This only
+ * uses the larger encoding (required in __ziplistCascadeUpdate). */
+int zipStorePrevEntryLengthLarge(unsigned char *p, unsigned int len) {
+ uint32_t u32;
+ if (p != NULL) {
+ p[0] = ZIP_BIG_PREVLEN;
+ u32 = len;
+ memcpy(p+1,&u32,sizeof(u32));
+ memrev32ifbe(p+1);
+ }
+ return 1 + sizeof(uint32_t);
+}
+
+/* Encode the length of the previous entry and write it to "p". Return the
+ * number of bytes needed to encode this length if "p" is NULL. */
+unsigned int zipStorePrevEntryLength(unsigned char *p, unsigned int len) {
+ if (p == NULL) {
+ return (len < ZIP_BIG_PREVLEN) ? 1 : sizeof(uint32_t) + 1;
+ } else {
+ if (len < ZIP_BIG_PREVLEN) {
+ p[0] = len;
+ return 1;
+ } else {
+ return zipStorePrevEntryLengthLarge(p,len);
+ }
+ }
+}
+
+/* Return the number of bytes used to encode the length of the previous
+ * entry. The length is returned by setting the var 'prevlensize'. */
+#define ZIP_DECODE_PREVLENSIZE(ptr, prevlensize) do { \
+ if ((ptr)[0] < ZIP_BIG_PREVLEN) { \
+ (prevlensize) = 1; \
+ } else { \
+ (prevlensize) = 5; \
+ } \
+} while(0)
+
+/* Return the length of the previous element, and the number of bytes that
+ * are used in order to encode the previous element length.
+ * 'ptr' must point to the prevlen prefix of an entry (that encodes the
+ * length of the previous entry in order to navigate the elements backward).
+ * The length of the previous entry is stored in 'prevlen', the number of
+ * bytes needed to encode the previous entry length are stored in
+ * 'prevlensize'. */
+#define ZIP_DECODE_PREVLEN(ptr, prevlensize, prevlen) do { \
+ ZIP_DECODE_PREVLENSIZE(ptr, prevlensize); \
+ if ((prevlensize) == 1) { \
+ (prevlen) = (ptr)[0]; \
+ } else { /* prevlensize == 5 */ \
+ (prevlen) = ((ptr)[4] << 24) | \
+ ((ptr)[3] << 16) | \
+ ((ptr)[2] << 8) | \
+ ((ptr)[1]); \
+ } \
+} while(0)
+
+/* Given a pointer 'p' to the prevlen info that prefixes an entry, this
+ * function returns the difference in number of bytes needed to encode
+ * the prevlen if the previous entry changes of size.
+ *
+ * So if A is the number of bytes used right now to encode the 'prevlen'
+ * field.
+ *
+ * And B is the number of bytes that are needed in order to encode the
+ * 'prevlen' if the previous element will be updated to one of size 'len'.
+ *
+ * Then the function returns B - A
+ *
+ * So the function returns a positive number if more space is needed,
+ * a negative number if less space is needed, or zero if the same space
+ * is needed. */
+int zipPrevLenByteDiff(unsigned char *p, unsigned int len) {
+ unsigned int prevlensize;
+ ZIP_DECODE_PREVLENSIZE(p, prevlensize);
+ return zipStorePrevEntryLength(NULL, len) - prevlensize;
+}
+
+/* Check if string pointed to by 'entry' can be encoded as an integer.
+ * Stores the integer value in 'v' and its encoding in 'encoding'. */
+int zipTryEncoding(unsigned char *entry, unsigned int entrylen, long long *v, unsigned char *encoding) {
+ long long value;
+
+ if (entrylen >= 32 || entrylen == 0) return 0;
+ if (string2ll((char*)entry,entrylen,&value)) {
+ /* Great, the string can be encoded. Check what's the smallest
+ * of our encoding types that can hold this value. */
+ if (value >= 0 && value <= 12) {
+ *encoding = ZIP_INT_IMM_MIN+value;
+ } else if (value >= INT8_MIN && value <= INT8_MAX) {
+ *encoding = ZIP_INT_8B;
+ } else if (value >= INT16_MIN && value <= INT16_MAX) {
+ *encoding = ZIP_INT_16B;
+ } else if (value >= INT24_MIN && value <= INT24_MAX) {
+ *encoding = ZIP_INT_24B;
+ } else if (value >= INT32_MIN && value <= INT32_MAX) {
+ *encoding = ZIP_INT_32B;
+ } else {
+ *encoding = ZIP_INT_64B;
+ }
+ *v = value;
+ return 1;
+ }
+ return 0;
+}
+
+/* Store integer 'value' at 'p', encoded as 'encoding' */
+void zipSaveInteger(unsigned char *p, int64_t value, unsigned char encoding) {
+ int16_t i16;
+ int32_t i32;
+ int64_t i64;
+ if (encoding == ZIP_INT_8B) {
+ ((int8_t*)p)[0] = (int8_t)value;
+ } else if (encoding == ZIP_INT_16B) {
+ i16 = value;
+ memcpy(p,&i16,sizeof(i16));
+ memrev16ifbe(p);
+ } else if (encoding == ZIP_INT_24B) {
+ i32 = ((uint64_t)value)<<8;
+ memrev32ifbe(&i32);
+ memcpy(p,((uint8_t*)&i32)+1,sizeof(i32)-sizeof(uint8_t));
+ } else if (encoding == ZIP_INT_32B) {
+ i32 = value;
+ memcpy(p,&i32,sizeof(i32));
+ memrev32ifbe(p);
+ } else if (encoding == ZIP_INT_64B) {
+ i64 = value;
+ memcpy(p,&i64,sizeof(i64));
+ memrev64ifbe(p);
+ } else if (encoding >= ZIP_INT_IMM_MIN && encoding <= ZIP_INT_IMM_MAX) {
+ /* Nothing to do, the value is stored in the encoding itself. */
+ } else {
+ assert(NULL);
+ }
+}
+
+/* Read integer encoded as 'encoding' from 'p' */
+int64_t zipLoadInteger(unsigned char *p, unsigned char encoding) {
+ int16_t i16;
+ int32_t i32;
+ int64_t i64, ret = 0;
+ if (encoding == ZIP_INT_8B) {
+ ret = ((int8_t*)p)[0];
+ } else if (encoding == ZIP_INT_16B) {
+ memcpy(&i16,p,sizeof(i16));
+ memrev16ifbe(&i16);
+ ret = i16;
+ } else if (encoding == ZIP_INT_32B) {
+ memcpy(&i32,p,sizeof(i32));
+ memrev32ifbe(&i32);
+ ret = i32;
+ } else if (encoding == ZIP_INT_24B) {
+ i32 = 0;
+ memcpy(((uint8_t*)&i32)+1,p,sizeof(i32)-sizeof(uint8_t));
+ memrev32ifbe(&i32);
+ ret = i32>>8;
+ } else if (encoding == ZIP_INT_64B) {
+ memcpy(&i64,p,sizeof(i64));
+ memrev64ifbe(&i64);
+ ret = i64;
+ } else if (encoding >= ZIP_INT_IMM_MIN && encoding <= ZIP_INT_IMM_MAX) {
+ ret = (encoding & ZIP_INT_IMM_MASK)-1;
+ } else {
+ assert(NULL);
+ }
+ return ret;
+}
+
+/* Fills a struct with all information about an entry.
+ * This function is the "unsafe" alternative to the one below.
+ * Generally, all function that return a pointer to an element in the ziplist
+ * will assert that this element is valid, so it can be freely used.
+ * Generally functions such ziplistGet assume the input pointer is already
+ * validated (since it's the return value of another function). */
+static inline void zipEntry(unsigned char *p, zlentry *e) {
+ ZIP_DECODE_PREVLEN(p, e->prevrawlensize, e->prevrawlen);
+ ZIP_ENTRY_ENCODING(p + e->prevrawlensize, e->encoding);
+ ZIP_DECODE_LENGTH(p + e->prevrawlensize, e->encoding, e->lensize, e->len);
+ assert(e->lensize != 0); /* check that encoding was valid. */
+ e->headersize = e->prevrawlensize + e->lensize;
+ e->p = p;
+}
+
+/* Fills a struct with all information about an entry.
+ * This function is safe to use on untrusted pointers, it'll make sure not to
+ * try to access memory outside the ziplist payload.
+ * Returns 1 if the entry is valid, and 0 otherwise. */
+static inline int zipEntrySafe(unsigned char* zl, size_t zlbytes, unsigned char *p, zlentry *e, int validate_prevlen) {
+ unsigned char *zlfirst = zl + ZIPLIST_HEADER_SIZE;
+ unsigned char *zllast = zl + zlbytes - ZIPLIST_END_SIZE;
+#define OUT_OF_RANGE(p) (unlikely((p) < zlfirst || (p) > zllast))
+
+ /* If there's no possibility for the header to reach outside the ziplist,
+ * take the fast path. (max lensize and prevrawlensize are both 5 bytes) */
+ if (p >= zlfirst && p + 10 < zllast) {
+ ZIP_DECODE_PREVLEN(p, e->prevrawlensize, e->prevrawlen);
+ ZIP_ENTRY_ENCODING(p + e->prevrawlensize, e->encoding);
+ ZIP_DECODE_LENGTH(p + e->prevrawlensize, e->encoding, e->lensize, e->len);
+ e->headersize = e->prevrawlensize + e->lensize;
+ e->p = p;
+ /* We didn't call ZIP_ASSERT_ENCODING, so we check lensize was set to 0. */
+ if (unlikely(e->lensize == 0))
+ return 0;
+ /* Make sure the entry doesn't reach outside the edge of the ziplist */
+ if (OUT_OF_RANGE(p + e->headersize + e->len))
+ return 0;
+ /* Make sure prevlen doesn't reach outside the edge of the ziplist */
+ if (validate_prevlen && OUT_OF_RANGE(p - e->prevrawlen))
+ return 0;
+ return 1;
+ }
+
+ /* Make sure the pointer doesn't reach outside the edge of the ziplist */
+ if (OUT_OF_RANGE(p))
+ return 0;
+
+ /* Make sure the encoded prevlen header doesn't reach outside the allocation */
+ ZIP_DECODE_PREVLENSIZE(p, e->prevrawlensize);
+ if (OUT_OF_RANGE(p + e->prevrawlensize))
+ return 0;
+
+ /* Make sure encoded entry header is valid. */
+ ZIP_ENTRY_ENCODING(p + e->prevrawlensize, e->encoding);
+ e->lensize = zipEncodingLenSize(e->encoding);
+ if (unlikely(e->lensize == ZIP_ENCODING_SIZE_INVALID))
+ return 0;
+
+ /* Make sure the encoded entry header doesn't reach outside the allocation */
+ if (OUT_OF_RANGE(p + e->prevrawlensize + e->lensize))
+ return 0;
+
+ /* Decode the prevlen and entry len headers. */
+ ZIP_DECODE_PREVLEN(p, e->prevrawlensize, e->prevrawlen);
+ ZIP_DECODE_LENGTH(p + e->prevrawlensize, e->encoding, e->lensize, e->len);
+ e->headersize = e->prevrawlensize + e->lensize;
+
+ /* Make sure the entry doesn't reach outside the edge of the ziplist */
+ if (OUT_OF_RANGE(p + e->headersize + e->len))
+ return 0;
+
+ /* Make sure prevlen doesn't reach outside the edge of the ziplist */
+ if (validate_prevlen && OUT_OF_RANGE(p - e->prevrawlen))
+ return 0;
+
+ e->p = p;
+ return 1;
+#undef OUT_OF_RANGE
+}
+
+/* Return the total number of bytes used by the entry pointed to by 'p'. */
+static inline unsigned int zipRawEntryLengthSafe(unsigned char* zl, size_t zlbytes, unsigned char *p) {
+ zlentry e;
+ assert(zipEntrySafe(zl, zlbytes, p, &e, 0));
+ return e.headersize + e.len;
+}
+
+/* Return the total number of bytes used by the entry pointed to by 'p'. */
+static inline unsigned int zipRawEntryLength(unsigned char *p) {
+ zlentry e;
+ zipEntry(p, &e);
+ return e.headersize + e.len;
+}
+
+/* Validate that the entry doesn't reach outside the ziplist allocation. */
+static inline void zipAssertValidEntry(unsigned char* zl, size_t zlbytes, unsigned char *p) {
+ zlentry e;
+ assert(zipEntrySafe(zl, zlbytes, p, &e, 1));
+}
+
+/* Create a new empty ziplist. */
+unsigned char *ziplistNew(void) {
+ unsigned int bytes = ZIPLIST_HEADER_SIZE+ZIPLIST_END_SIZE;
+ unsigned char *zl = zmalloc(bytes);
+ ZIPLIST_BYTES(zl) = intrev32ifbe(bytes);
+ ZIPLIST_TAIL_OFFSET(zl) = intrev32ifbe(ZIPLIST_HEADER_SIZE);
+ ZIPLIST_LENGTH(zl) = 0;
+ zl[bytes-1] = ZIP_END;
+ return zl;
+}
+
+/* Resize the ziplist. */
+unsigned char *ziplistResize(unsigned char *zl, size_t len) {
+ assert(len < UINT32_MAX);
+ zl = zrealloc(zl,len);
+ ZIPLIST_BYTES(zl) = intrev32ifbe(len);
+ zl[len-1] = ZIP_END;
+ 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_BIG_PREVLEN, 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. */
+unsigned char *__ziplistCascadeUpdate(unsigned char *zl, unsigned char *p) {
+ zlentry cur;
+ size_t prevlen, prevlensize, prevoffset; /* Informat of the last changed entry. */
+ size_t firstentrylen; /* Used to handle insert at head. */
+ size_t rawlen, curlen = intrev32ifbe(ZIPLIST_BYTES(zl));
+ size_t extra = 0, cnt = 0, offset;
+ size_t delta = 4; /* Extra bytes needed to update a entry's prevlen (5-1). */
+ unsigned char *tail = zl + intrev32ifbe(ZIPLIST_TAIL_OFFSET(zl));
+
+ /* Empty ziplist */
+ if (p[0] == ZIP_END) return zl;
+
+ zipEntry(p, &cur); /* no need for "safe" variant since the input pointer was validated by the function that returned it. */
+ firstentrylen = prevlen = cur.headersize + cur.len;
+ prevlensize = zipStorePrevEntryLength(NULL, prevlen);
+ prevoffset = p - zl;
+ p += prevlen;
+
+ /* Iterate ziplist to find out how many extra bytes do we need to update it. */
+ while (p[0] != ZIP_END) {
+ assert(zipEntrySafe(zl, curlen, p, &cur, 0));
+
+ /* Abort when "prevlen" has not changed. */
+ if (cur.prevrawlen == prevlen) break;
+
+ /* Abort when entry's "prevlensize" is big enough. */
+ if (cur.prevrawlensize >= prevlensize) {
+ if (cur.prevrawlensize == prevlensize) {
+ zipStorePrevEntryLength(p, prevlen);
+ } else {
+ /* This would result in shrinking, which we want to avoid.
+ * So, set "prevlen" in the available bytes. */
+ zipStorePrevEntryLengthLarge(p, prevlen);
+ }
+ break;
+ }
+
+ /* cur.prevrawlen means cur is the former head entry. */
+ assert(cur.prevrawlen == 0 || cur.prevrawlen + delta == prevlen);
+
+ /* Update prev entry's info and advance the cursor. */
+ rawlen = cur.headersize + cur.len;
+ prevlen = rawlen + delta;
+ prevlensize = zipStorePrevEntryLength(NULL, prevlen);
+ prevoffset = p - zl;
+ p += rawlen;
+ extra += delta;
+ cnt++;
+ }
+
+ /* Extra bytes is zero all update has been done(or no need to update). */
+ if (extra == 0) return zl;
+
+ /* Update tail offset after loop. */
+ if (tail == zl + prevoffset) {
+ /* When the last entry we need to update is also the tail, update tail offset
+ * unless this is the only entry that was updated (so the tail offset didn't change). */
+ if (extra - delta != 0) {
+ ZIPLIST_TAIL_OFFSET(zl) =
+ intrev32ifbe(intrev32ifbe(ZIPLIST_TAIL_OFFSET(zl))+extra-delta);
+ }
+ } else {
+ /* Update the tail offset in cases where the last entry we updated is not the tail. */
+ ZIPLIST_TAIL_OFFSET(zl) =
+ intrev32ifbe(intrev32ifbe(ZIPLIST_TAIL_OFFSET(zl))+extra);
+ }
+
+ /* Now "p" points at the first unchanged byte in original ziplist,
+ * move data after that to new ziplist. */
+ offset = p - zl;
+ zl = ziplistResize(zl, curlen + extra);
+ p = zl + offset;
+ memmove(p + extra, p, curlen - offset - 1);
+ p += extra;
+
+ /* Iterate all entries that need to be updated tail to head. */
+ while (cnt) {
+ zipEntry(zl + prevoffset, &cur); /* no need for "safe" variant since we already iterated on all these entries above. */
+ rawlen = cur.headersize + cur.len;
+ /* Move entry to tail and reset prevlen. */
+ memmove(p - (rawlen - cur.prevrawlensize),
+ zl + prevoffset + cur.prevrawlensize,
+ rawlen - cur.prevrawlensize);
+ p -= (rawlen + delta);
+ if (cur.prevrawlen == 0) {
+ /* "cur" is the previous head entry, update its prevlen with firstentrylen. */
+ zipStorePrevEntryLength(p, firstentrylen);
+ } else {
+ /* An entry's prevlen can only increment 4 bytes. */
+ zipStorePrevEntryLength(p, cur.prevrawlen+delta);
+ }
+ /* Forward to previous entry. */
+ prevoffset -= cur.prevrawlen;
+ cnt--;
+ }
+ return zl;
+}
+
+/* Delete "num" entries, starting at "p". Returns pointer to the ziplist. */
+unsigned char *__ziplistDelete(unsigned char *zl, unsigned char *p, unsigned int num) {
+ unsigned int i, totlen, deleted = 0;
+ size_t offset;
+ int nextdiff = 0;
+ zlentry first, tail;
+ size_t zlbytes = intrev32ifbe(ZIPLIST_BYTES(zl));
+
+ zipEntry(p, &first); /* no need for "safe" variant since the input pointer was validated by the function that returned it. */
+ for (i = 0; p[0] != ZIP_END && i < num; i++) {
+ p += zipRawEntryLengthSafe(zl, zlbytes, p);
+ deleted++;
+ }
+
+ assert(p >= first.p);
+ totlen = p-first.p; /* Bytes taken by the element(s) to delete. */
+ if (totlen > 0) {
+ uint32_t set_tail;
+ if (p[0] != ZIP_END) {
+ /* Storing `prevrawlen` in this entry may increase or decrease the
+ * number of bytes required compare to the current `prevrawlen`.
+ * There always is room to store this, because it was previously
+ * stored by an entry that is now being deleted. */
+ nextdiff = zipPrevLenByteDiff(p,first.prevrawlen);
+
+ /* Note that there is always space when p jumps backward: if
+ * the new previous entry is large, one of the deleted elements
+ * had a 5 bytes prevlen header, so there is for sure at least
+ * 5 bytes free and we need just 4. */
+ p -= nextdiff;
+ assert(p >= first.p && p<zl+zlbytes-1);
+ zipStorePrevEntryLength(p,first.prevrawlen);
+
+ /* Update offset for tail */
+ set_tail = intrev32ifbe(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. */
+ assert(zipEntrySafe(zl, zlbytes, p, &tail, 1));
+ if (p[tail.headersize+tail.len] != ZIP_END) {
+ set_tail = set_tail + nextdiff;
+ }
+
+ /* Move tail to the front of the ziplist */
+ /* since we asserted that p >= first.p. we know totlen >= 0,
+ * so we know that p > first.p and this is guaranteed not to reach
+ * beyond the allocation, even if the entries lens are corrupted. */
+ size_t bytes_to_move = zlbytes-(p-zl)-1;
+ memmove(first.p,p,bytes_to_move);
+ } else {
+ /* The entire tail was deleted. No need to move memory. */
+ set_tail = (first.p-zl)-first.prevrawlen;
+ }
+
+ /* Resize the ziplist */
+ offset = first.p-zl;
+ zlbytes -= totlen - nextdiff;
+ zl = ziplistResize(zl, zlbytes);
+ p = zl+offset;
+
+ /* Update record count */
+ ZIPLIST_INCR_LENGTH(zl,-deleted);
+
+ /* Set the tail offset computed above */
+ assert(set_tail <= zlbytes - ZIPLIST_END_SIZE);
+ ZIPLIST_TAIL_OFFSET(zl) = intrev32ifbe(set_tail);
+
+ /* 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;
+}
+
+/* Insert item at "p". */
+unsigned char *__ziplistInsert(unsigned char *zl, unsigned char *p, unsigned char *s, unsigned int slen) {
+ size_t curlen = intrev32ifbe(ZIPLIST_BYTES(zl)), reqlen, newlen;
+ unsigned int prevlensize, prevlen = 0;
+ size_t offset;
+ int nextdiff = 0;
+ unsigned char encoding = 0;
+ long long value = 123456789; /* initialized to avoid warning. Using a value
+ that is easy to see if for some reason
+ we use it uninitialized. */
+ zlentry tail;
+
+ /* Find out prevlen for the entry that is inserted. */
+ if (p[0] != ZIP_END) {
+ ZIP_DECODE_PREVLEN(p, prevlensize, prevlen);
+ } else {
+ unsigned char *ptail = ZIPLIST_ENTRY_TAIL(zl);
+ if (ptail[0] != ZIP_END) {
+ prevlen = zipRawEntryLengthSafe(zl, curlen, ptail);
+ }
+ }
+
+ /* See if the entry can be encoded */
+ if (zipTryEncoding(s,slen,&value,&encoding)) {
+ /* 'encoding' is set to the appropriate integer encoding */
+ reqlen = zipIntSize(encoding);
+ } else {
+ /* 'encoding' is untouched, however zipStoreEntryEncoding 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 += zipStorePrevEntryLength(NULL,prevlen);
+ reqlen += zipStoreEntryEncoding(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. */
+ int forcelarge = 0;
+ nextdiff = (p[0] != ZIP_END) ? zipPrevLenByteDiff(p,reqlen) : 0;
+ if (nextdiff == -4 && reqlen < 4) {
+ nextdiff = 0;
+ forcelarge = 1;
+ }
+
+ /* Store offset because a realloc may change the address of zl. */
+ offset = p-zl;
+ newlen = curlen+reqlen+nextdiff;
+ zl = ziplistResize(zl,newlen);
+ 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. */
+ if (forcelarge)
+ zipStorePrevEntryLengthLarge(p+reqlen,reqlen);
+ else
+ zipStorePrevEntryLength(p+reqlen,reqlen);
+
+ /* Update offset for tail */
+ ZIPLIST_TAIL_OFFSET(zl) =
+ intrev32ifbe(intrev32ifbe(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. */
+ assert(zipEntrySafe(zl, newlen, p+reqlen, &tail, 1));
+ if (p[reqlen+tail.headersize+tail.len] != ZIP_END) {
+ ZIPLIST_TAIL_OFFSET(zl) =
+ intrev32ifbe(intrev32ifbe(ZIPLIST_TAIL_OFFSET(zl))+nextdiff);
+ }
+ } else {
+ /* This element will be the new tail. */
+ ZIPLIST_TAIL_OFFSET(zl) = intrev32ifbe(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 += zipStorePrevEntryLength(p,prevlen);
+ p += zipStoreEntryEncoding(p,encoding,slen);
+ if (ZIP_IS_STR(encoding)) {
+ memcpy(p,s,slen);
+ } else {
+ zipSaveInteger(p,value,encoding);
+ }
+ ZIPLIST_INCR_LENGTH(zl,1);
+ return zl;
+}
+
+/* Merge ziplists 'first' and 'second' by appending 'second' to 'first'.
+ *
+ * NOTE: The larger ziplist is reallocated to contain the new merged ziplist.
+ * Either 'first' or 'second' can be used for the result. The parameter not
+ * used will be free'd and set to NULL.
+ *
+ * After calling this function, the input parameters are no longer valid since
+ * they are changed and free'd in-place.
+ *
+ * The result ziplist is the contents of 'first' followed by 'second'.
+ *
+ * On failure: returns NULL if the merge is impossible.
+ * On success: returns the merged ziplist (which is expanded version of either
+ * 'first' or 'second', also frees the other unused input ziplist, and sets the
+ * input ziplist argument equal to newly reallocated ziplist return value. */
+unsigned char *ziplistMerge(unsigned char **first, unsigned char **second) {
+ /* If any params are null, we can't merge, so NULL. */
+ if (first == NULL || *first == NULL || second == NULL || *second == NULL)
+ return NULL;
+
+ /* Can't merge same list into itself. */
+ if (*first == *second)
+ return NULL;
+
+ size_t first_bytes = intrev32ifbe(ZIPLIST_BYTES(*first));
+ size_t first_len = intrev16ifbe(ZIPLIST_LENGTH(*first));
+
+ size_t second_bytes = intrev32ifbe(ZIPLIST_BYTES(*second));
+ size_t second_len = intrev16ifbe(ZIPLIST_LENGTH(*second));
+
+ int append;
+ unsigned char *source, *target;
+ size_t target_bytes, source_bytes;
+ /* Pick the largest ziplist so we can resize easily in-place.
+ * We must also track if we are now appending or prepending to
+ * the target ziplist. */
+ if (first_len >= second_len) {
+ /* retain first, append second to first. */
+ target = *first;
+ target_bytes = first_bytes;
+ source = *second;
+ source_bytes = second_bytes;
+ append = 1;
+ } else {
+ /* else, retain second, prepend first to second. */
+ target = *second;
+ target_bytes = second_bytes;
+ source = *first;
+ source_bytes = first_bytes;
+ append = 0;
+ }
+
+ /* Calculate final bytes (subtract one pair of metadata) */
+ size_t zlbytes = first_bytes + second_bytes -
+ ZIPLIST_HEADER_SIZE - ZIPLIST_END_SIZE;
+ size_t zllength = first_len + second_len;
+
+ /* Combined zl length should be limited within UINT16_MAX */
+ zllength = zllength < UINT16_MAX ? zllength : UINT16_MAX;
+
+ /* larger values can't be stored into ZIPLIST_BYTES */
+ assert(zlbytes < UINT32_MAX);
+
+ /* Save offset positions before we start ripping memory apart. */
+ size_t first_offset = intrev32ifbe(ZIPLIST_TAIL_OFFSET(*first));
+ size_t second_offset = intrev32ifbe(ZIPLIST_TAIL_OFFSET(*second));
+
+ /* Extend target to new zlbytes then append or prepend source. */
+ target = zrealloc(target, zlbytes);
+ if (append) {
+ /* append == appending to target */
+ /* Copy source after target (copying over original [END]):
+ * [TARGET - END, SOURCE - HEADER] */
+ memcpy(target + target_bytes - ZIPLIST_END_SIZE,
+ source + ZIPLIST_HEADER_SIZE,
+ source_bytes - ZIPLIST_HEADER_SIZE);
+ } else {
+ /* !append == prepending to target */
+ /* Move target *contents* exactly size of (source - [END]),
+ * then copy source into vacated space (source - [END]):
+ * [SOURCE - END, TARGET - HEADER] */
+ memmove(target + source_bytes - ZIPLIST_END_SIZE,
+ target + ZIPLIST_HEADER_SIZE,
+ target_bytes - ZIPLIST_HEADER_SIZE);
+ memcpy(target, source, source_bytes - ZIPLIST_END_SIZE);
+ }
+
+ /* Update header metadata. */
+ ZIPLIST_BYTES(target) = intrev32ifbe(zlbytes);
+ ZIPLIST_LENGTH(target) = intrev16ifbe(zllength);
+ /* New tail offset is:
+ * + N bytes of first ziplist
+ * - 1 byte for [END] of first ziplist
+ * + M bytes for the offset of the original tail of the second ziplist
+ * - J bytes for HEADER because second_offset keeps no header. */
+ ZIPLIST_TAIL_OFFSET(target) = intrev32ifbe(
+ (first_bytes - ZIPLIST_END_SIZE) +
+ (second_offset - ZIPLIST_HEADER_SIZE));
+
+ /* __ziplistCascadeUpdate just fixes the prev length values until it finds a
+ * correct prev length value (then it assumes the rest of the list is okay).
+ * We tell CascadeUpdate to start at the first ziplist's tail element to fix
+ * the merge seam. */
+ target = __ziplistCascadeUpdate(target, target+first_offset);
+
+ /* Now free and NULL out what we didn't realloc */
+ if (append) {
+ zfree(*second);
+ *second = NULL;
+ *first = target;
+ } else {
+ zfree(*first);
+ *first = NULL;
+ *second = target;
+ }
+ return target;
+}
+
+unsigned char *ziplistPush(unsigned char *zl, unsigned char *s, unsigned int slen, int where) {
+ unsigned char *p;
+ p = (where == ZIPLIST_HEAD) ? ZIPLIST_ENTRY_HEAD(zl) : ZIPLIST_ENTRY_END(zl);
+ return __ziplistInsert(zl,p,s,slen);
+}
+
+/* Returns an offset to use for iterating with ziplistNext. When the given
+ * index is negative, the list is traversed back to front. When the list
+ * doesn't contain an element at the provided index, NULL is returned. */
+unsigned char *ziplistIndex(unsigned char *zl, int index) {
+ unsigned char *p;
+ unsigned int prevlensize, prevlen = 0;
+ size_t zlbytes = intrev32ifbe(ZIPLIST_BYTES(zl));
+ if (index < 0) {
+ index = (-index)-1;
+ p = ZIPLIST_ENTRY_TAIL(zl);
+ if (p[0] != ZIP_END) {
+ /* No need for "safe" check: when going backwards, we know the header
+ * we're parsing is in the range, we just need to assert (below) that
+ * the size we take doesn't cause p to go outside the allocation. */
+ ZIP_DECODE_PREVLENSIZE(p, prevlensize);
+ assert(p + prevlensize < zl + zlbytes - ZIPLIST_END_SIZE);
+ ZIP_DECODE_PREVLEN(p, prevlensize, prevlen);
+ while (prevlen > 0 && index--) {
+ p -= prevlen;
+ assert(p >= zl + ZIPLIST_HEADER_SIZE && p < zl + zlbytes - ZIPLIST_END_SIZE);
+ ZIP_DECODE_PREVLEN(p, prevlensize, prevlen);
+ }
+ }
+ } else {
+ p = ZIPLIST_ENTRY_HEAD(zl);
+ while (index--) {
+ /* Use the "safe" length: When we go forward, we need to be careful
+ * not to decode an entry header if it's past the ziplist allocation. */
+ p += zipRawEntryLengthSafe(zl, zlbytes, p);
+ if (p[0] == ZIP_END)
+ break;
+ }
+ }
+ if (p[0] == ZIP_END || index > 0)
+ return NULL;
+ zipAssertValidEntry(zl, zlbytes, p);
+ return p;
+}
+
+/* Return pointer to next entry in ziplist.
+ *
+ * zl is the pointer to the ziplist
+ * p is the pointer to the current element
+ *
+ * The element after 'p' is returned, otherwise NULL if we are at the end. */
+unsigned char *ziplistNext(unsigned char *zl, unsigned char *p) {
+ ((void) zl);
+ size_t zlbytes = intrev32ifbe(ZIPLIST_BYTES(zl));
+
+ /* "p" could be equal to ZIP_END, caused by ziplistDelete,
+ * and we should return NULL. Otherwise, we should return NULL
+ * when the *next* element is ZIP_END (there is no next entry). */
+ if (p[0] == ZIP_END) {
+ return NULL;
+ }
+
+ p += zipRawEntryLength(p);
+ if (p[0] == ZIP_END) {
+ return NULL;
+ }
+
+ zipAssertValidEntry(zl, zlbytes, p);
+ return p;
+}
+
+/* Return pointer to previous entry in ziplist. */
+unsigned char *ziplistPrev(unsigned char *zl, unsigned char *p) {
+ unsigned int prevlensize, prevlen = 0;
+
+ /* Iterating backwards from ZIP_END should return the tail. When "p" is
+ * equal to the first element of the list, we're already at the head,
+ * and should return NULL. */
+ if (p[0] == ZIP_END) {
+ p = ZIPLIST_ENTRY_TAIL(zl);
+ return (p[0] == ZIP_END) ? NULL : p;
+ } else if (p == ZIPLIST_ENTRY_HEAD(zl)) {
+ return NULL;
+ } else {
+ ZIP_DECODE_PREVLEN(p, prevlensize, prevlen);
+ assert(prevlen > 0);
+ p-=prevlen;
+ size_t zlbytes = intrev32ifbe(ZIPLIST_BYTES(zl));
+ zipAssertValidEntry(zl, zlbytes, p);
+ return p;
+ }
+}
+
+/* Get entry pointed to by 'p' and store in either '*sstr' or 'sval' depending
+ * on the encoding of the entry. '*sstr' 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 ziplist, 1 otherwise. */
+unsigned int ziplistGet(unsigned char *p, unsigned char **sstr, unsigned int *slen, long long *sval) {
+ zlentry entry;
+ if (p == NULL || p[0] == ZIP_END) return 0;
+ if (sstr) *sstr = NULL;
+
+ zipEntry(p, &entry); /* no need for "safe" variant since the input pointer was validated by the function that returned it. */
+ if (ZIP_IS_STR(entry.encoding)) {
+ if (sstr) {
+ *slen = entry.len;
+ *sstr = p+entry.headersize;
+ }
+ } else {
+ if (sval) {
+ *sval = zipLoadInteger(p+entry.headersize,entry.encoding);
+ }
+ }
+ return 1;
+}
+
+/* Insert an entry at "p". */
+unsigned char *ziplistInsert(unsigned char *zl, unsigned char *p, unsigned char *s, unsigned int slen) {
+ return __ziplistInsert(zl,p,s,slen);
+}
+
+/* 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) {
+ size_t offset = *p-zl;
+ zl = __ziplistDelete(zl,*p,1);
+
+ /* Store pointer to current element in p, because ziplistDelete will
+ * do a realloc which might result in a different "zl"-pointer.
+ * When the delete direction is back to front, we might delete the last
+ * entry and end up with "p" pointing to ZIP_END, so check this. */
+ *p = zl+offset;
+ return zl;
+}
+
+/* Delete a range of entries from the ziplist. */
+unsigned char *ziplistDeleteRange(unsigned char *zl, int index, unsigned int num) {
+ unsigned char *p = ziplistIndex(zl,index);
+ 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) {
+ zlentry entry;
+ unsigned char sencoding;
+ long long zval, sval;
+ if (p[0] == ZIP_END) return 0;
+
+ zipEntry(p, &entry); /* no need for "safe" variant since the input pointer was validated by the function that returned it. */
+ if (ZIP_IS_STR(entry.encoding)) {
+ /* Raw compare */
+ if (entry.len == slen) {
+ return memcmp(p+entry.headersize,sstr,slen) == 0;
+ } else {
+ return 0;
+ }
+ } else {
+ /* Try to compare encoded values. Don't compare encoding because
+ * different implementations may encoded integers differently. */
+ if (zipTryEncoding(sstr,slen,&sval,&sencoding)) {
+ zval = zipLoadInteger(p+entry.headersize,entry.encoding);
+ return zval == sval;
+ }
+ }
+ return 0;
+}
+
+/* Find pointer to the entry equal to the specified entry. Skip 'skip' entries
+ * between every comparison. Returns NULL when the field could not be found. */
+unsigned char *ziplistFind(unsigned char *zl, unsigned char *p, unsigned char *vstr, unsigned int vlen, unsigned int skip) {
+ int skipcnt = 0;
+ unsigned char vencoding = 0;
+ long long vll = 0;
+ size_t zlbytes = ziplistBlobLen(zl);
+
+ while (p[0] != ZIP_END) {
+ struct zlentry e;
+ unsigned char *q;
+
+ assert(zipEntrySafe(zl, zlbytes, p, &e, 1));
+ q = p + e.prevrawlensize + e.lensize;
+
+ if (skipcnt == 0) {
+ /* Compare current entry with specified entry */
+ if (ZIP_IS_STR(e.encoding)) {
+ if (e.len == vlen && memcmp(q, vstr, vlen) == 0) {
+ return p;
+ }
+ } else {
+ /* Find out if the searched field can be encoded. Note that
+ * we do it only the first time, once done vencoding is set
+ * to non-zero and vll is set to the integer value. */
+ if (vencoding == 0) {
+ if (!zipTryEncoding(vstr, vlen, &vll, &vencoding)) {
+ /* If the entry can't be encoded we set it to
+ * UCHAR_MAX so that we don't retry again the next
+ * time. */
+ vencoding = UCHAR_MAX;
+ }
+ /* Must be non-zero by now */
+ assert(vencoding);
+ }
+
+ /* Compare current entry with specified entry, do it only
+ * if vencoding != UCHAR_MAX because if there is no encoding
+ * possible for the field it can't be a valid integer. */
+ if (vencoding != UCHAR_MAX) {
+ long long ll = zipLoadInteger(q, e.encoding);
+ if (ll == vll) {
+ return p;
+ }
+ }
+ }
+
+ /* Reset skip count */
+ skipcnt = skip;
+ } else {
+ /* Skip entry */
+ skipcnt--;
+ }
+
+ /* Move to next entry */
+ p = q + e.len;
+ }
+
+ return NULL;
+}
+
+/* Return length of ziplist. */
+unsigned int ziplistLen(unsigned char *zl) {
+ unsigned int len = 0;
+ if (intrev16ifbe(ZIPLIST_LENGTH(zl)) < UINT16_MAX) {
+ len = intrev16ifbe(ZIPLIST_LENGTH(zl));
+ } else {
+ unsigned char *p = zl+ZIPLIST_HEADER_SIZE;
+ size_t zlbytes = intrev32ifbe(ZIPLIST_BYTES(zl));
+ while (*p != ZIP_END) {
+ p += zipRawEntryLengthSafe(zl, zlbytes, p);
+ len++;
+ }
+
+ /* Re-store length if small enough */
+ if (len < UINT16_MAX) ZIPLIST_LENGTH(zl) = intrev16ifbe(len);
+ }
+ return len;
+}
+
+/* Return ziplist blob size in bytes. */
+size_t ziplistBlobLen(unsigned char *zl) {
+ return intrev32ifbe(ZIPLIST_BYTES(zl));
+}
+
+void ziplistRepr(unsigned char *zl) {
+ unsigned char *p;
+ int index = 0;
+ zlentry entry;
+ size_t zlbytes = ziplistBlobLen(zl);
+
+ printf(
+ "{total bytes %u} "
+ "{num entries %u}\n"
+ "{tail offset %u}\n",
+ intrev32ifbe(ZIPLIST_BYTES(zl)),
+ intrev16ifbe(ZIPLIST_LENGTH(zl)),
+ intrev32ifbe(ZIPLIST_TAIL_OFFSET(zl)));
+ p = ZIPLIST_ENTRY_HEAD(zl);
+ while(*p != ZIP_END) {
+ assert(zipEntrySafe(zl, zlbytes, p, &entry, 1));
+ printf(
+ "{\n"
+ "\taddr 0x%08lx,\n"
+ "\tindex %2d,\n"
+ "\toffset %5lu,\n"
+ "\thdr+entry len: %5u,\n"
+ "\thdr len%2u,\n"
+ "\tprevrawlen: %5u,\n"
+ "\tprevrawlensize: %2u,\n"
+ "\tpayload %5u\n",
+ (long unsigned)p,
+ index,
+ (unsigned long) (p-zl),
+ entry.headersize+entry.len,
+ entry.headersize,
+ entry.prevrawlen,
+ entry.prevrawlensize,
+ entry.len);
+ printf("\tbytes: ");
+ for (unsigned int i = 0; i < entry.headersize+entry.len; i++) {
+ printf("%02x|",p[i]);
+ }
+ printf("\n");
+ p += entry.headersize;
+ if (ZIP_IS_STR(entry.encoding)) {
+ printf("\t[str]");
+ if (entry.len > 40) {
+ if (fwrite(p,40,1,stdout) == 0) perror("fwrite");
+ printf("...");
+ } else {
+ if (entry.len &&
+ fwrite(p,entry.len,1,stdout) == 0) perror("fwrite");
+ }
+ } else {
+ printf("\t[int]%lld", (long long) zipLoadInteger(p,entry.encoding));
+ }
+ printf("\n}\n");
+ p += entry.len;
+ index++;
+ }
+ printf("{end}\n\n");
+}
+
+/* Validate the integrity of the data structure.
+ * when `deep` is 0, only the integrity of the header is validated.
+ * when `deep` is 1, we scan all the entries one by one. */
+int ziplistValidateIntegrity(unsigned char *zl, size_t size, int deep,
+ ziplistValidateEntryCB entry_cb, void *cb_userdata) {
+ /* check that we can actually read the header. (and ZIP_END) */
+ if (size < ZIPLIST_HEADER_SIZE + ZIPLIST_END_SIZE)
+ return 0;
+
+ /* check that the encoded size in the header must match the allocated size. */
+ size_t bytes = intrev32ifbe(ZIPLIST_BYTES(zl));
+ if (bytes != size)
+ return 0;
+
+ /* the last byte must be the terminator. */
+ if (zl[size - ZIPLIST_END_SIZE] != ZIP_END)
+ return 0;
+
+ /* make sure the tail offset isn't reaching outside the allocation. */
+ if (intrev32ifbe(ZIPLIST_TAIL_OFFSET(zl)) > size - ZIPLIST_END_SIZE)
+ return 0;
+
+ if (!deep)
+ return 1;
+
+ unsigned int count = 0;
+ unsigned int header_count = intrev16ifbe(ZIPLIST_LENGTH(zl));
+ unsigned char *p = ZIPLIST_ENTRY_HEAD(zl);
+ unsigned char *prev = NULL;
+ size_t prev_raw_size = 0;
+ while(*p != ZIP_END) {
+ struct zlentry e;
+ /* Decode the entry headers and fail if invalid or reaches outside the allocation */
+ if (!zipEntrySafe(zl, size, p, &e, 1))
+ return 0;
+
+ /* Make sure the record stating the prev entry size is correct. */
+ if (e.prevrawlen != prev_raw_size)
+ return 0;
+
+ /* Optionally let the caller validate the entry too. */
+ if (entry_cb && !entry_cb(p, header_count, cb_userdata))
+ return 0;
+
+ /* Move to the next entry */
+ prev_raw_size = e.headersize + e.len;
+ prev = p;
+ p += e.headersize + e.len;
+ count++;
+ }
+
+ /* Make sure 'p' really does point to the end of the ziplist. */
+ if (p != zl + bytes - ZIPLIST_END_SIZE)
+ return 0;
+
+ /* Make sure the <zltail> entry really do point to the start of the last entry. */
+ if (prev != NULL && prev != ZIPLIST_ENTRY_TAIL(zl))
+ return 0;
+
+ /* Check that the count in the header is correct */
+ if (header_count != UINT16_MAX && count != header_count)
+ return 0;
+
+ return 1;
+}
+
+/* Randomly select a pair of key and value.
+ * total_count is a pre-computed length/2 of the ziplist (to avoid calls to ziplistLen)
+ * 'key' and 'val' are used to store the result key value pair.
+ * 'val' can be NULL if the value is not needed. */
+void ziplistRandomPair(unsigned char *zl, unsigned long total_count, ziplistEntry *key, ziplistEntry *val) {
+ int ret;
+ unsigned char *p;
+
+ /* Avoid div by zero on corrupt ziplist */
+ assert(total_count);
+
+ /* Generate even numbers, because ziplist saved K-V pair */
+ int r = (rand() % total_count) * 2;
+ p = ziplistIndex(zl, r);
+ ret = ziplistGet(p, &key->sval, &key->slen, &key->lval);
+ assert(ret != 0);
+
+ if (!val)
+ return;
+ p = ziplistNext(zl, p);
+ ret = ziplistGet(p, &val->sval, &val->slen, &val->lval);
+ assert(ret != 0);
+}
+
+/* int compare for qsort */
+int uintCompare(const void *a, const void *b) {
+ return (*(unsigned int *) a - *(unsigned int *) b);
+}
+
+/* Helper method to store a string into from val or lval into dest */
+static inline void ziplistSaveValue(unsigned char *val, unsigned int len, long long lval, ziplistEntry *dest) {
+ dest->sval = val;
+ dest->slen = len;
+ dest->lval = lval;
+}
+
+/* Randomly select count of key value pairs and store into 'keys' and
+ * 'vals' args. The order of the picked entries is random, and the selections
+ * are non-unique (repetitions are possible).
+ * The 'vals' arg can be NULL in which case we skip these. */
+void ziplistRandomPairs(unsigned char *zl, unsigned int count, ziplistEntry *keys, ziplistEntry *vals) {
+ unsigned char *p, *key, *value;
+ unsigned int klen = 0, vlen = 0;
+ long long klval = 0, vlval = 0;
+
+ /* Notice: the index member must be first due to the use in uintCompare */
+ typedef struct {
+ unsigned int index;
+ unsigned int order;
+ } rand_pick;
+ rand_pick *picks = zmalloc(sizeof(rand_pick)*count);
+ unsigned int total_size = ziplistLen(zl)/2;
+
+ /* Avoid div by zero on corrupt ziplist */
+ assert(total_size);
+
+ /* create a pool of random indexes (some may be duplicate). */
+ for (unsigned int i = 0; i < count; i++) {
+ picks[i].index = (rand() % total_size) * 2; /* Generate even indexes */
+ /* keep track of the order we picked them */
+ picks[i].order = i;
+ }
+
+ /* sort by indexes. */
+ qsort(picks, count, sizeof(rand_pick), uintCompare);
+
+ /* fetch the elements form the ziplist into a output array respecting the original order. */
+ unsigned int zipindex = picks[0].index, pickindex = 0;
+ p = ziplistIndex(zl, zipindex);
+ while (ziplistGet(p, &key, &klen, &klval) && pickindex < count) {
+ p = ziplistNext(zl, p);
+ assert(ziplistGet(p, &value, &vlen, &vlval));
+ while (pickindex < count && zipindex == picks[pickindex].index) {
+ int storeorder = picks[pickindex].order;
+ ziplistSaveValue(key, klen, klval, &keys[storeorder]);
+ if (vals)
+ ziplistSaveValue(value, vlen, vlval, &vals[storeorder]);
+ pickindex++;
+ }
+ zipindex += 2;
+ p = ziplistNext(zl, p);
+ }
+
+ zfree(picks);
+}
+
+/* Randomly select count of key value pairs and store into 'keys' and
+ * 'vals' args. The selections are unique (no repetitions), and the order of
+ * the picked entries is NOT-random.
+ * The 'vals' arg can be NULL in which case we skip these.
+ * The return value is the number of items picked which can be lower than the
+ * requested count if the ziplist doesn't hold enough pairs. */
+unsigned int ziplistRandomPairsUnique(unsigned char *zl, unsigned int count, ziplistEntry *keys, ziplistEntry *vals) {
+ unsigned char *p, *key;
+ unsigned int klen = 0;
+ long long klval = 0;
+ unsigned int total_size = ziplistLen(zl)/2;
+ unsigned int index = 0;
+ if (count > total_size)
+ count = total_size;
+
+ /* To only iterate once, every time we try to pick a member, the probability
+ * we pick it is the quotient of the count left we want to pick and the
+ * count still we haven't visited in the dict, this way, we could make every
+ * member be equally picked.*/
+ p = ziplistIndex(zl, 0);
+ unsigned int picked = 0, remaining = count;
+ while (picked < count && p) {
+ double randomDouble = ((double)rand()) / RAND_MAX;
+ double threshold = ((double)remaining) / (total_size - index);
+ if (randomDouble <= threshold) {
+ assert(ziplistGet(p, &key, &klen, &klval));
+ ziplistSaveValue(key, klen, klval, &keys[picked]);
+ p = ziplistNext(zl, p);
+ assert(p);
+ if (vals) {
+ assert(ziplistGet(p, &key, &klen, &klval));
+ ziplistSaveValue(key, klen, klval, &vals[picked]);
+ }
+ remaining--;
+ picked++;
+ } else {
+ p = ziplistNext(zl, p);
+ assert(p);
+ }
+ p = ziplistNext(zl, p);
+ index++;
+ }
+ return picked;
+}
+
+#ifdef REDIS_TEST
+#include <sys/time.h>
+#include "adlist.h"
+#include "sds.h"
+#include "testhelp.h"
+
+#define debug(f, ...) { if (DEBUG) printf(f, __VA_ARGS__); }
+
+static unsigned char *createList(void) {
+ unsigned char *zl = ziplistNew();
+ zl = ziplistPush(zl, (unsigned char*)"foo", 3, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)"quux", 4, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)"hello", 5, ZIPLIST_HEAD);
+ zl = ziplistPush(zl, (unsigned char*)"1024", 4, ZIPLIST_TAIL);
+ return zl;
+}
+
+static unsigned char *createIntList(void) {
+ unsigned char *zl = ziplistNew();
+ char buf[32];
+
+ snprintf(buf, sizeof(buf), "100");
+ zl = ziplistPush(zl, (unsigned char*)buf, strlen(buf), ZIPLIST_TAIL);
+ snprintf(buf, sizeof(buf), "128000");
+ zl = ziplistPush(zl, (unsigned char*)buf, strlen(buf), ZIPLIST_TAIL);
+ snprintf(buf, sizeof(buf), "-100");
+ zl = ziplistPush(zl, (unsigned char*)buf, strlen(buf), ZIPLIST_HEAD);
+ snprintf(buf, sizeof(buf), "4294967296");
+ zl = ziplistPush(zl, (unsigned char*)buf, strlen(buf), ZIPLIST_HEAD);
+ snprintf(buf, sizeof(buf), "non integer");
+ zl = ziplistPush(zl, (unsigned char*)buf, strlen(buf), ZIPLIST_TAIL);
+ snprintf(buf,sizeof(buf), "much much longer non integer");
+ zl = ziplistPush(zl, (unsigned char*)buf, strlen(buf), ZIPLIST_TAIL);
+ return zl;
+}
+
+static long long usec(void) {
+ struct timeval tv;
+ gettimeofday(&tv,NULL);
+ return (((long long)tv.tv_sec)*1000000)+tv.tv_usec;
+}
+
+static void stress(int pos, int num, int maxsize, int dnum) {
+ int i,j,k;
+ unsigned char *zl;
+ char posstr[2][5] = { "HEAD", "TAIL" };
+ long long start;
+ for (i = 0; i < maxsize; i+=dnum) {
+ zl = ziplistNew();
+ for (j = 0; j < i; j++) {
+ zl = ziplistPush(zl,(unsigned char*)"quux",4,ZIPLIST_TAIL);
+ }
+
+ /* Do num times a push+pop from pos */
+ start = usec();
+ for (k = 0; k < num; k++) {
+ zl = ziplistPush(zl,(unsigned char*)"quux",4,pos);
+ zl = ziplistDeleteRange(zl,0,1);
+ }
+ printf("List size: %8d, bytes: %8d, %dx push+pop (%s): %6lld usec\n",
+ i,intrev32ifbe(ZIPLIST_BYTES(zl)),num,posstr[pos],usec()-start);
+ zfree(zl);
+ }
+}
+
+static unsigned char *pop(unsigned char *zl, int where) {
+ unsigned char *p, *vstr;
+ unsigned int vlen;
+ long long vlong = 0;
+
+ p = ziplistIndex(zl,where == ZIPLIST_HEAD ? 0 : -1);
+ if (ziplistGet(p,&vstr,&vlen,&vlong)) {
+ if (where == ZIPLIST_HEAD)
+ printf("Pop head: ");
+ else
+ printf("Pop tail: ");
+
+ if (vstr) {
+ if (vlen && fwrite(vstr,vlen,1,stdout) == 0) perror("fwrite");
+ }
+ else {
+ printf("%lld", vlong);
+ }
+
+ printf("\n");
+ return ziplistDelete(zl,&p);
+ } else {
+ printf("ERROR: Could not pop\n");
+ exit(1);
+ }
+}
+
+static int randstring(char *target, unsigned int min, unsigned int max) {
+ int p = 0;
+ int len = min+rand()%(max-min+1);
+ int minval, maxval;
+ switch(rand() % 3) {
+ case 0:
+ minval = 0;
+ maxval = 255;
+ break;
+ case 1:
+ minval = 48;
+ maxval = 122;
+ break;
+ case 2:
+ minval = 48;
+ maxval = 52;
+ break;
+ default:
+ assert(NULL);
+ }
+
+ while(p < len)
+ target[p++] = minval+rand()%(maxval-minval+1);
+ return len;
+}
+
+static void verify(unsigned char *zl, zlentry *e) {
+ int len = ziplistLen(zl);
+ zlentry _e;
+
+ ZIPLIST_ENTRY_ZERO(&_e);
+
+ for (int i = 0; i < len; i++) {
+ memset(&e[i], 0, sizeof(zlentry));
+ zipEntry(ziplistIndex(zl, i), &e[i]);
+
+ memset(&_e, 0, sizeof(zlentry));
+ zipEntry(ziplistIndex(zl, -len+i), &_e);
+
+ assert(memcmp(&e[i], &_e, sizeof(zlentry)) == 0);
+ }
+}
+
+static unsigned char *insertHelper(unsigned char *zl, char ch, size_t len, unsigned char *pos) {
+ assert(len <= ZIP_BIG_PREVLEN);
+ unsigned char data[ZIP_BIG_PREVLEN] = {0};
+ memset(data, ch, len);
+ return ziplistInsert(zl, pos, data, len);
+}
+
+static int compareHelper(unsigned char *zl, char ch, size_t len, int index) {
+ assert(len <= ZIP_BIG_PREVLEN);
+ unsigned char data[ZIP_BIG_PREVLEN] = {0};
+ memset(data, ch, len);
+ unsigned char *p = ziplistIndex(zl, index);
+ assert(p != NULL);
+ return ziplistCompare(p, data, len);
+}
+
+static size_t strEntryBytesSmall(size_t slen) {
+ return slen + zipStorePrevEntryLength(NULL, 0) + zipStoreEntryEncoding(NULL, 0, slen);
+}
+
+static size_t strEntryBytesLarge(size_t slen) {
+ return slen + zipStorePrevEntryLength(NULL, ZIP_BIG_PREVLEN) + zipStoreEntryEncoding(NULL, 0, slen);
+}
+
+/* ./redis-server test ziplist <randomseed> */
+int ziplistTest(int argc, char **argv, int flags) {
+ int accurate = (flags & REDIS_TEST_ACCURATE);
+ unsigned char *zl, *p;
+ unsigned char *entry;
+ unsigned int elen;
+ long long value;
+ int iteration;
+
+ /* If an argument is given, use it as the random seed. */
+ if (argc >= 4)
+ srand(atoi(argv[3]));
+
+ zl = createIntList();
+ ziplistRepr(zl);
+
+ zfree(zl);
+
+ zl = createList();
+ ziplistRepr(zl);
+
+ zl = pop(zl,ZIPLIST_TAIL);
+ ziplistRepr(zl);
+
+ zl = pop(zl,ZIPLIST_HEAD);
+ ziplistRepr(zl);
+
+ zl = pop(zl,ZIPLIST_TAIL);
+ ziplistRepr(zl);
+
+ zl = pop(zl,ZIPLIST_TAIL);
+ ziplistRepr(zl);
+
+ zfree(zl);
+
+ printf("Get element at index 3:\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, 3);
+ if (!ziplistGet(p, &entry, &elen, &value)) {
+ printf("ERROR: Could not access index 3\n");
+ return 1;
+ }
+ if (entry) {
+ if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
+ printf("\n");
+ } else {
+ printf("%lld\n", value);
+ }
+ printf("\n");
+ zfree(zl);
+ }
+
+ printf("Get element at index 4 (out of range):\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, 4);
+ if (p == NULL) {
+ printf("No entry\n");
+ } else {
+ printf("ERROR: Out of range index should return NULL, returned offset: %ld\n", (long)(p-zl));
+ return 1;
+ }
+ printf("\n");
+ zfree(zl);
+ }
+
+ printf("Get element at index -1 (last element):\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, -1);
+ if (!ziplistGet(p, &entry, &elen, &value)) {
+ printf("ERROR: Could not access index -1\n");
+ return 1;
+ }
+ if (entry) {
+ if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
+ printf("\n");
+ } else {
+ printf("%lld\n", value);
+ }
+ printf("\n");
+ zfree(zl);
+ }
+
+ printf("Get element at index -4 (first element):\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, -4);
+ if (!ziplistGet(p, &entry, &elen, &value)) {
+ printf("ERROR: Could not access index -4\n");
+ return 1;
+ }
+ if (entry) {
+ if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
+ printf("\n");
+ } else {
+ printf("%lld\n", value);
+ }
+ printf("\n");
+ zfree(zl);
+ }
+
+ printf("Get element at index -5 (reverse out of range):\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, -5);
+ if (p == NULL) {
+ printf("No entry\n");
+ } else {
+ printf("ERROR: Out of range index should return NULL, returned offset: %ld\n", (long)(p-zl));
+ return 1;
+ }
+ printf("\n");
+ zfree(zl);
+ }
+
+ printf("Iterate list from 0 to end:\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, 0);
+ while (ziplistGet(p, &entry, &elen, &value)) {
+ printf("Entry: ");
+ if (entry) {
+ if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
+ } else {
+ printf("%lld", value);
+ }
+ p = ziplistNext(zl,p);
+ printf("\n");
+ }
+ printf("\n");
+ zfree(zl);
+ }
+
+ printf("Iterate list from 1 to end:\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, 1);
+ while (ziplistGet(p, &entry, &elen, &value)) {
+ printf("Entry: ");
+ if (entry) {
+ if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
+ } else {
+ printf("%lld", value);
+ }
+ p = ziplistNext(zl,p);
+ printf("\n");
+ }
+ printf("\n");
+ zfree(zl);
+ }
+
+ printf("Iterate list from 2 to end:\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, 2);
+ while (ziplistGet(p, &entry, &elen, &value)) {
+ printf("Entry: ");
+ if (entry) {
+ if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
+ } else {
+ printf("%lld", value);
+ }
+ p = ziplistNext(zl,p);
+ printf("\n");
+ }
+ printf("\n");
+ zfree(zl);
+ }
+
+ printf("Iterate starting out of range:\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, 4);
+ if (!ziplistGet(p, &entry, &elen, &value)) {
+ printf("No entry\n");
+ } else {
+ printf("ERROR\n");
+ }
+ printf("\n");
+ zfree(zl);
+ }
+
+ printf("Iterate from back to front:\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, -1);
+ while (ziplistGet(p, &entry, &elen, &value)) {
+ printf("Entry: ");
+ if (entry) {
+ if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
+ } else {
+ printf("%lld", value);
+ }
+ p = ziplistPrev(zl,p);
+ printf("\n");
+ }
+ printf("\n");
+ zfree(zl);
+ }
+
+ printf("Iterate from back to front, deleting all items:\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, -1);
+ while (ziplistGet(p, &entry, &elen, &value)) {
+ printf("Entry: ");
+ if (entry) {
+ if (elen && fwrite(entry,elen,1,stdout) == 0) perror("fwrite");
+ } else {
+ printf("%lld", value);
+ }
+ zl = ziplistDelete(zl,&p);
+ p = ziplistPrev(zl,p);
+ printf("\n");
+ }
+ printf("\n");
+ zfree(zl);
+ }
+
+ printf("Delete inclusive range 0,0:\n");
+ {
+ zl = createList();
+ zl = ziplistDeleteRange(zl, 0, 1);
+ ziplistRepr(zl);
+ zfree(zl);
+ }
+
+ printf("Delete inclusive range 0,1:\n");
+ {
+ zl = createList();
+ zl = ziplistDeleteRange(zl, 0, 2);
+ ziplistRepr(zl);
+ zfree(zl);
+ }
+
+ printf("Delete inclusive range 1,2:\n");
+ {
+ zl = createList();
+ zl = ziplistDeleteRange(zl, 1, 2);
+ ziplistRepr(zl);
+ zfree(zl);
+ }
+
+ printf("Delete with start index out of range:\n");
+ {
+ zl = createList();
+ zl = ziplistDeleteRange(zl, 5, 1);
+ ziplistRepr(zl);
+ zfree(zl);
+ }
+
+ printf("Delete with num overflow:\n");
+ {
+ zl = createList();
+ zl = ziplistDeleteRange(zl, 1, 5);
+ ziplistRepr(zl);
+ zfree(zl);
+ }
+
+ printf("Delete foo while iterating:\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl,0);
+ while (ziplistGet(p,&entry,&elen,&value)) {
+ if (entry && strncmp("foo",(char*)entry,elen) == 0) {
+ printf("Delete foo\n");
+ zl = ziplistDelete(zl,&p);
+ } else {
+ printf("Entry: ");
+ if (entry) {
+ if (elen && fwrite(entry,elen,1,stdout) == 0)
+ perror("fwrite");
+ } else {
+ printf("%lld",value);
+ }
+ p = ziplistNext(zl,p);
+ printf("\n");
+ }
+ }
+ printf("\n");
+ ziplistRepr(zl);
+ 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};
+ memset(v1,'x',256);
+ memset(v2,'y',256);
+ zl = ziplistNew();
+ zl = ziplistPush(zl,(unsigned char*)v1,strlen(v1),ZIPLIST_TAIL);
+ zl = ziplistPush(zl,(unsigned char*)v2,strlen(v2),ZIPLIST_TAIL);
+
+ /* Pop values again and compare their value. */
+ p = ziplistIndex(zl,0);
+ assert(ziplistGet(p,&entry,&elen,&value));
+ assert(strncmp(v1,(char*)entry,elen) == 0);
+ p = ziplistIndex(zl,1);
+ assert(ziplistGet(p,&entry,&elen,&value));
+ assert(strncmp(v2,(char*)entry,elen) == 0);
+ printf("SUCCESS\n\n");
+ zfree(zl);
+ }
+
+ printf("Regression test deleting next to last entries:\n");
+ {
+ char v[3][257] = {{0}};
+ zlentry e[3] = {{.prevrawlensize = 0, .prevrawlen = 0, .lensize = 0,
+ .len = 0, .headersize = 0, .encoding = 0, .p = NULL}};
+ size_t i;
+
+ for (i = 0; i < (sizeof(v)/sizeof(v[0])); i++) {
+ memset(v[i], 'a' + i, sizeof(v[0]));
+ }
+
+ v[0][256] = '\0';
+ v[1][ 1] = '\0';
+ v[2][256] = '\0';
+
+ zl = ziplistNew();
+ for (i = 0; i < (sizeof(v)/sizeof(v[0])); i++) {
+ zl = ziplistPush(zl, (unsigned char *) v[i], strlen(v[i]), ZIPLIST_TAIL);
+ }
+
+ verify(zl, e);
+
+ assert(e[0].prevrawlensize == 1);
+ assert(e[1].prevrawlensize == 5);
+ assert(e[2].prevrawlensize == 1);
+
+ /* Deleting entry 1 will increase `prevrawlensize` for entry 2 */
+ unsigned char *p = e[1].p;
+ zl = ziplistDelete(zl, &p);
+
+ verify(zl, e);
+
+ assert(e[0].prevrawlensize == 1);
+ assert(e[1].prevrawlensize == 5);
+
+ printf("SUCCESS\n\n");
+ zfree(zl);
+ }
+
+ printf("Create long list and check indices:\n");
+ {
+ unsigned long long start = usec();
+ zl = ziplistNew();
+ char buf[32];
+ int i,len;
+ for (i = 0; i < 1000; i++) {
+ len = snprintf(buf,sizeof(buf),"%d",i);
+ zl = ziplistPush(zl,(unsigned char*)buf,len,ZIPLIST_TAIL);
+ }
+ for (i = 0; i < 1000; i++) {
+ p = ziplistIndex(zl,i);
+ assert(ziplistGet(p,NULL,NULL,&value));
+ assert(i == value);
+
+ p = ziplistIndex(zl,-i-1);
+ assert(ziplistGet(p,NULL,NULL,&value));
+ assert(999-i == value);
+ }
+ printf("SUCCESS. usec=%lld\n\n", usec()-start);
+ zfree(zl);
+ }
+
+ printf("Compare strings with ziplist entries:\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl,0);
+ if (!ziplistCompare(p,(unsigned char*)"hello",5)) {
+ printf("ERROR: not \"hello\"\n");
+ return 1;
+ }
+ if (ziplistCompare(p,(unsigned char*)"hella",5)) {
+ printf("ERROR: \"hella\"\n");
+ return 1;
+ }
+
+ p = ziplistIndex(zl,3);
+ if (!ziplistCompare(p,(unsigned char*)"1024",4)) {
+ printf("ERROR: not \"1024\"\n");
+ return 1;
+ }
+ if (ziplistCompare(p,(unsigned char*)"1025",4)) {
+ printf("ERROR: \"1025\"\n");
+ return 1;
+ }
+ printf("SUCCESS\n\n");
+ zfree(zl);
+ }
+
+ printf("Merge test:\n");
+ {
+ /* create list gives us: [hello, foo, quux, 1024] */
+ zl = createList();
+ unsigned char *zl2 = createList();
+
+ unsigned char *zl3 = ziplistNew();
+ unsigned char *zl4 = ziplistNew();
+
+ if (ziplistMerge(&zl4, &zl4)) {
+ printf("ERROR: Allowed merging of one ziplist into itself.\n");
+ return 1;
+ }
+
+ /* Merge two empty ziplists, get empty result back. */
+ zl4 = ziplistMerge(&zl3, &zl4);
+ ziplistRepr(zl4);
+ if (ziplistLen(zl4)) {
+ printf("ERROR: Merging two empty ziplists created entries.\n");
+ return 1;
+ }
+ zfree(zl4);
+
+ zl2 = ziplistMerge(&zl, &zl2);
+ /* merge gives us: [hello, foo, quux, 1024, hello, foo, quux, 1024] */
+ ziplistRepr(zl2);
+
+ if (ziplistLen(zl2) != 8) {
+ printf("ERROR: Merged length not 8, but: %u\n", ziplistLen(zl2));
+ return 1;
+ }
+
+ p = ziplistIndex(zl2,0);
+ if (!ziplistCompare(p,(unsigned char*)"hello",5)) {
+ printf("ERROR: not \"hello\"\n");
+ return 1;
+ }
+ if (ziplistCompare(p,(unsigned char*)"hella",5)) {
+ printf("ERROR: \"hella\"\n");
+ return 1;
+ }
+
+ p = ziplistIndex(zl2,3);
+ if (!ziplistCompare(p,(unsigned char*)"1024",4)) {
+ printf("ERROR: not \"1024\"\n");
+ return 1;
+ }
+ if (ziplistCompare(p,(unsigned char*)"1025",4)) {
+ printf("ERROR: \"1025\"\n");
+ return 1;
+ }
+
+ p = ziplistIndex(zl2,4);
+ if (!ziplistCompare(p,(unsigned char*)"hello",5)) {
+ printf("ERROR: not \"hello\"\n");
+ return 1;
+ }
+ if (ziplistCompare(p,(unsigned char*)"hella",5)) {
+ printf("ERROR: \"hella\"\n");
+ return 1;
+ }
+
+ p = ziplistIndex(zl2,7);
+ if (!ziplistCompare(p,(unsigned char*)"1024",4)) {
+ printf("ERROR: not \"1024\"\n");
+ return 1;
+ }
+ if (ziplistCompare(p,(unsigned char*)"1025",4)) {
+ printf("ERROR: \"1025\"\n");
+ return 1;
+ }
+ printf("SUCCESS\n\n");
+ zfree(zl);
+ }
+
+ printf("Stress with random payloads of different encoding:\n");
+ {
+ unsigned long long start = usec();
+ int i,j,len,where;
+ unsigned char *p;
+ char buf[1024];
+ int buflen;
+ list *ref;
+ listNode *refnode;
+
+ /* Hold temp vars from ziplist */
+ unsigned char *sstr;
+ unsigned int slen;
+ long long sval;
+
+ iteration = accurate ? 20000 : 20;
+ for (i = 0; i < iteration; i++) {
+ zl = ziplistNew();
+ ref = listCreate();
+ listSetFreeMethod(ref,(void (*)(void*))sdsfree);
+ len = rand() % 256;
+
+ /* Create lists */
+ for (j = 0; j < len; j++) {
+ where = (rand() & 1) ? ZIPLIST_HEAD : ZIPLIST_TAIL;
+ if (rand() % 2) {
+ buflen = randstring(buf,1,sizeof(buf)-1);
+ } else {
+ switch(rand() % 3) {
+ case 0:
+ buflen = snprintf(buf,sizeof(buf),"%lld",(0LL + rand()) >> 20);
+ break;
+ case 1:
+ buflen = snprintf(buf,sizeof(buf),"%lld",(0LL + rand()));
+ break;
+ case 2:
+ buflen = snprintf(buf,sizeof(buf),"%lld",(0LL + rand()) << 20);
+ break;
+ default:
+ assert(NULL);
+ }
+ }
+
+ /* Add to ziplist */
+ zl = ziplistPush(zl, (unsigned char*)buf, buflen, where);
+
+ /* Add to reference list */
+ if (where == ZIPLIST_HEAD) {
+ listAddNodeHead(ref,sdsnewlen(buf, buflen));
+ } else if (where == ZIPLIST_TAIL) {
+ listAddNodeTail(ref,sdsnewlen(buf, buflen));
+ } else {
+ assert(NULL);
+ }
+ }
+
+ assert(listLength(ref) == ziplistLen(zl));
+ for (j = 0; j < len; j++) {
+ /* Naive way to get elements, but similar to the stresser
+ * executed from the Tcl test suite. */
+ p = ziplistIndex(zl,j);
+ refnode = listIndex(ref,j);
+
+ assert(ziplistGet(p,&sstr,&slen,&sval));
+ if (sstr == NULL) {
+ buflen = snprintf(buf,sizeof(buf),"%lld",sval);
+ } else {
+ buflen = slen;
+ memcpy(buf,sstr,buflen);
+ buf[buflen] = '\0';
+ }
+ assert(memcmp(buf,listNodeValue(refnode),buflen) == 0);
+ }
+ zfree(zl);
+ listRelease(ref);
+ }
+ printf("Done. usec=%lld\n\n", usec()-start);
+ }
+
+ printf("Stress with variable ziplist size:\n");
+ {
+ unsigned long long start = usec();
+ int maxsize = accurate ? 16384 : 16;
+ stress(ZIPLIST_HEAD,100000,maxsize,256);
+ stress(ZIPLIST_TAIL,100000,maxsize,256);
+ printf("Done. usec=%lld\n\n", usec()-start);
+ }
+
+ /* Benchmarks */
+ {
+ zl = ziplistNew();
+ iteration = accurate ? 100000 : 100;
+ for (int i=0; i<iteration; i++) {
+ char buf[4096] = "asdf";
+ zl = ziplistPush(zl, (unsigned char*)buf, 4, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)buf, 40, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)buf, 400, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)buf, 4000, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)"1", 1, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)"10", 2, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)"100", 3, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)"1000", 4, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)"10000", 5, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)"100000", 6, ZIPLIST_TAIL);
+ }
+
+ printf("Benchmark ziplistFind:\n");
+ {
+ unsigned long long start = usec();
+ for (int i = 0; i < 2000; i++) {
+ unsigned char *fptr = ziplistIndex(zl, ZIPLIST_HEAD);
+ fptr = ziplistFind(zl, fptr, (unsigned char*)"nothing", 7, 1);
+ }
+ printf("%lld\n", usec()-start);
+ }
+
+ printf("Benchmark ziplistIndex:\n");
+ {
+ unsigned long long start = usec();
+ for (int i = 0; i < 2000; i++) {
+ ziplistIndex(zl, 99999);
+ }
+ printf("%lld\n", usec()-start);
+ }
+
+ printf("Benchmark ziplistValidateIntegrity:\n");
+ {
+ unsigned long long start = usec();
+ for (int i = 0; i < 2000; i++) {
+ ziplistValidateIntegrity(zl, ziplistBlobLen(zl), 1, NULL, NULL);
+ }
+ printf("%lld\n", usec()-start);
+ }
+
+ printf("Benchmark ziplistCompare with string\n");
+ {
+ unsigned long long start = usec();
+ for (int i = 0; i < 2000; i++) {
+ unsigned char *eptr = ziplistIndex(zl,0);
+ while (eptr != NULL) {
+ ziplistCompare(eptr,(unsigned char*)"nothing",7);
+ eptr = ziplistNext(zl,eptr);
+ }
+ }
+ printf("Done. usec=%lld\n", usec()-start);
+ }
+
+ printf("Benchmark ziplistCompare with number\n");
+ {
+ unsigned long long start = usec();
+ for (int i = 0; i < 2000; i++) {
+ unsigned char *eptr = ziplistIndex(zl,0);
+ while (eptr != NULL) {
+ ziplistCompare(eptr,(unsigned char*)"99999",5);
+ eptr = ziplistNext(zl,eptr);
+ }
+ }
+ printf("Done. usec=%lld\n", usec()-start);
+ }
+
+ zfree(zl);
+ }
+
+ printf("Stress __ziplistCascadeUpdate:\n");
+ {
+ char data[ZIP_BIG_PREVLEN];
+ zl = ziplistNew();
+ iteration = accurate ? 100000 : 100;
+ for (int i = 0; i < iteration; i++) {
+ zl = ziplistPush(zl, (unsigned char*)data, ZIP_BIG_PREVLEN-4, ZIPLIST_TAIL);
+ }
+ unsigned long long start = usec();
+ zl = ziplistPush(zl, (unsigned char*)data, ZIP_BIG_PREVLEN-3, ZIPLIST_HEAD);
+ printf("Done. usec=%lld\n\n", usec()-start);
+ zfree(zl);
+ }
+
+ printf("Edge cases of __ziplistCascadeUpdate:\n");
+ {
+ /* Inserting a entry with data length greater than ZIP_BIG_PREVLEN-4
+ * will leads to cascade update. */
+ size_t s1 = ZIP_BIG_PREVLEN-4, s2 = ZIP_BIG_PREVLEN-3;
+ zl = ziplistNew();
+
+ zlentry e[4] = {{.prevrawlensize = 0, .prevrawlen = 0, .lensize = 0,
+ .len = 0, .headersize = 0, .encoding = 0, .p = NULL}};
+
+ zl = insertHelper(zl, 'a', s1, ZIPLIST_ENTRY_HEAD(zl));
+ verify(zl, e);
+
+ assert(e[0].prevrawlensize == 1 && e[0].prevrawlen == 0);
+ assert(compareHelper(zl, 'a', s1, 0));
+ ziplistRepr(zl);
+
+ /* No expand. */
+ zl = insertHelper(zl, 'b', s1, ZIPLIST_ENTRY_HEAD(zl));
+ verify(zl, e);
+
+ assert(e[0].prevrawlensize == 1 && e[0].prevrawlen == 0);
+ assert(compareHelper(zl, 'b', s1, 0));
+
+ assert(e[1].prevrawlensize == 1 && e[1].prevrawlen == strEntryBytesSmall(s1));
+ assert(compareHelper(zl, 'a', s1, 1));
+
+ ziplistRepr(zl);
+
+ /* Expand(tail included). */
+ zl = insertHelper(zl, 'c', s2, ZIPLIST_ENTRY_HEAD(zl));
+ verify(zl, e);
+
+ assert(e[0].prevrawlensize == 1 && e[0].prevrawlen == 0);
+ assert(compareHelper(zl, 'c', s2, 0));
+
+ assert(e[1].prevrawlensize == 5 && e[1].prevrawlen == strEntryBytesSmall(s2));
+ assert(compareHelper(zl, 'b', s1, 1));
+
+ assert(e[2].prevrawlensize == 5 && e[2].prevrawlen == strEntryBytesLarge(s1));
+ assert(compareHelper(zl, 'a', s1, 2));
+
+ ziplistRepr(zl);
+
+ /* Expand(only previous head entry). */
+ zl = insertHelper(zl, 'd', s2, ZIPLIST_ENTRY_HEAD(zl));
+ verify(zl, e);
+
+ assert(e[0].prevrawlensize == 1 && e[0].prevrawlen == 0);
+ assert(compareHelper(zl, 'd', s2, 0));
+
+ assert(e[1].prevrawlensize == 5 && e[1].prevrawlen == strEntryBytesSmall(s2));
+ assert(compareHelper(zl, 'c', s2, 1));
+
+ assert(e[2].prevrawlensize == 5 && e[2].prevrawlen == strEntryBytesLarge(s2));
+ assert(compareHelper(zl, 'b', s1, 2));
+
+ assert(e[3].prevrawlensize == 5 && e[3].prevrawlen == strEntryBytesLarge(s1));
+ assert(compareHelper(zl, 'a', s1, 3));
+
+ ziplistRepr(zl);
+
+ /* Delete from mid. */
+ unsigned char *p = ziplistIndex(zl, 2);
+ zl = ziplistDelete(zl, &p);
+ verify(zl, e);
+
+ assert(e[0].prevrawlensize == 1 && e[0].prevrawlen == 0);
+ assert(compareHelper(zl, 'd', s2, 0));
+
+ assert(e[1].prevrawlensize == 5 && e[1].prevrawlen == strEntryBytesSmall(s2));
+ assert(compareHelper(zl, 'c', s2, 1));
+
+ assert(e[2].prevrawlensize == 5 && e[2].prevrawlen == strEntryBytesLarge(s2));
+ assert(compareHelper(zl, 'a', s1, 2));
+
+ ziplistRepr(zl);
+
+ zfree(zl);
+ }
+
+ printf("__ziplistInsert nextdiff == -4 && reqlen < 4 (issue #7170):\n");
+ {
+ zl = ziplistNew();
+
+ /* We set some values to almost reach the critical point - 254 */
+ char A_252[253] = {0}, A_250[251] = {0};
+ memset(A_252, 'A', 252);
+ memset(A_250, 'A', 250);
+
+ /* After the rpush, the list look like: [one two A_252 A_250 three 10] */
+ zl = ziplistPush(zl, (unsigned char*)"one", 3, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)"two", 3, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)A_252, strlen(A_252), ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)A_250, strlen(A_250), ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)"three", 5, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, (unsigned char*)"10", 2, ZIPLIST_TAIL);
+ ziplistRepr(zl);
+
+ p = ziplistIndex(zl, 2);
+ if (!ziplistCompare(p, (unsigned char*)A_252, strlen(A_252))) {
+ printf("ERROR: not \"A_252\"\n");
+ return 1;
+ }
+
+ /* When we remove A_252, the list became: [one two A_250 three 10]
+ * A_250's prev node became node two, because node two quite small
+ * So A_250's prevlenSize shrink to 1, A_250's total size became 253(1+2+250)
+ * The prev node of node three is still node A_250.
+ * We will not shrink the node three's prevlenSize, keep it at 5 bytes */
+ zl = ziplistDelete(zl, &p);
+ ziplistRepr(zl);
+
+ p = ziplistIndex(zl, 3);
+ if (!ziplistCompare(p, (unsigned char*)"three", 5)) {
+ printf("ERROR: not \"three\"\n");
+ return 1;
+ }
+
+ /* We want to insert a node after A_250, the list became: [one two A_250 10 three 10]
+ * Because the new node is quite small, node three prevlenSize will shrink to 1 */
+ zl = ziplistInsert(zl, p, (unsigned char*)"10", 2);
+ ziplistRepr(zl);
+
+ /* Last element should equal 10 */
+ p = ziplistIndex(zl, -1);
+ if (!ziplistCompare(p, (unsigned char*)"10", 2)) {
+ printf("ERROR: not \"10\"\n");
+ return 1;
+ }
+
+ zfree(zl);
+ }
+
+ printf("ALL TESTS PASSED!\n");
+ return 0;
+}
+#endif