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Add a 24bit integer to ziplists to save one byte for ints that can

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fit in 24 bits (thanks to antirez for catching and solving the two's compliment
bug).

Increment REDIS_RDB_VERSION to 6
This commit is contained in:
Grisha Trubetskoy 2012-04-20 10:38:42 -04:00 committed by antirez
parent 21661d7acc
commit 5a86ab4799
2 changed files with 17 additions and 1 deletions
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2
src/rdb.h
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@ -9,7 +9,7 @@
/* The current RDB version. When the format changes in a way that is no longer
* backward compatible this number gets incremented. */
#define REDIS_RDB_VERSION 5
#define REDIS_RDB_VERSION 6
/* Defines related to the dump file format. To store 32 bits lengths for short
* keys requires a lot of space, so we check the most significant 2 bits of

16
src/ziplist.c
View File

@ -83,6 +83,10 @@
#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 INT24_MAX 0x7fffff
#define INT24_MIN (-INT24_MAX - 1)
/* Macro to determine type */
#define ZIP_IS_STR(enc) (((enc) & ZIP_STR_MASK) < ZIP_STR_MASK)
@ -123,6 +127,7 @@ typedef struct zlentry {
static unsigned int zipIntSize(unsigned char encoding) {
switch(encoding) {
case ZIP_INT_16B: return sizeof(int16_t);
case ZIP_INT_24B: return sizeof(int32_t)-sizeof(int8_t);
case ZIP_INT_32B: return sizeof(int32_t);
case ZIP_INT_64B: return sizeof(int64_t);
}
@ -271,6 +276,8 @@ static int zipTryEncoding(unsigned char *entry, unsigned int entrylen, long long
* of our encoding types that can hold this value. */
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 {
@ -291,6 +298,10 @@ static void zipSaveInteger(unsigned char *p, int64_t value, unsigned char encodi
i16 = value;
memcpy(p,&i16,sizeof(i16));
memrev16ifbe(p);
} else if (encoding == ZIP_INT_24B) {
i32 = value<<8;
memrev32ifbe(&i32);
memcpy(p,((unsigned char*)&i32)+1,sizeof(i32)-sizeof(int8_t));
} else if (encoding == ZIP_INT_32B) {
i32 = value;
memcpy(p,&i32,sizeof(i32));
@ -317,6 +328,11 @@ static int64_t zipLoadInteger(unsigned char *p, unsigned char encoding) {
memcpy(&i32,p,sizeof(i32));
memrev32ifbe(&i32);
ret = i32;
} else if (encoding == ZIP_INT_24B) {
i32 = 0;
memcpy(((unsigned char*)&i32)+1,p,sizeof(i32)-sizeof(int8_t));
memrev32ifbe(&i32);
ret = i32>>8;
} else if (encoding == ZIP_INT_64B) {
memcpy(&i64,p,sizeof(i64));
memrev64ifbe(&i64);