diff options
Diffstat (limited to 'src/sds.h')
| -rw-r--r-- | src/sds.h | 175 |
1 files changed, 166 insertions, 9 deletions
@@ -35,32 +35,188 @@ #include <sys/types.h> #include <stdarg.h> +#include <stdint.h> typedef char *sds; -struct sdshdr { - unsigned int len; - unsigned int free; +/* Note: sdshdr5 is never used, we just access the flags byte directly. + * However is here to document the layout of type 5 SDS strings. */ +struct __attribute__ ((__packed__)) sdshdr5 { + unsigned char flags; /* 3 lsb of type, and 5 msb of string length */ char buf[]; }; +struct __attribute__ ((__packed__)) sdshdr8 { + uint8_t len; /* used */ + uint8_t alloc; /* excluding the header and null terminator */ + unsigned char flags; /* 3 lsb of type, 5 unused bits */ + char buf[]; +}; +struct __attribute__ ((__packed__)) sdshdr16 { + uint16_t len; /* used */ + uint16_t alloc; /* excluding the header and null terminator */ + unsigned char flags; /* 3 lsb of type, 5 unused bits */ + char buf[]; +}; +struct __attribute__ ((__packed__)) sdshdr32 { + uint32_t len; /* used */ + uint32_t alloc; /* excluding the header and null terminator */ + unsigned char flags; /* 3 lsb of type, 5 unused bits */ + char buf[]; +}; +struct __attribute__ ((__packed__)) sdshdr64 { + uint64_t len; /* used */ + uint64_t alloc; /* excluding the header and null terminator */ + unsigned char flags; /* 3 lsb of type, 5 unused bits */ + char buf[]; +}; + +#define SDS_TYPE_5 0 +#define SDS_TYPE_8 1 +#define SDS_TYPE_16 2 +#define SDS_TYPE_32 3 +#define SDS_TYPE_64 4 +#define SDS_TYPE_MASK 7 +#define SDS_TYPE_BITS 3 +#define SDS_HDR_VAR(T,s) struct sdshdr##T *sh = (void*)((s)-(sizeof(struct sdshdr##T))); +#define SDS_HDR(T,s) ((struct sdshdr##T *)((s)-(sizeof(struct sdshdr##T)))) +#define SDS_TYPE_5_LEN(f) ((f)>>SDS_TYPE_BITS) static inline size_t sdslen(const sds s) { - struct sdshdr *sh = (void*)(s-(sizeof(struct sdshdr))); - return sh->len; + unsigned char flags = s[-1]; + switch(flags&SDS_TYPE_MASK) { + case SDS_TYPE_5: + return SDS_TYPE_5_LEN(flags); + case SDS_TYPE_8: + return SDS_HDR(8,s)->len; + case SDS_TYPE_16: + return SDS_HDR(16,s)->len; + case SDS_TYPE_32: + return SDS_HDR(32,s)->len; + case SDS_TYPE_64: + return SDS_HDR(64,s)->len; + } + return 0; } static inline size_t sdsavail(const sds s) { - struct sdshdr *sh = (void*)(s-(sizeof(struct sdshdr))); - return sh->free; + unsigned char flags = s[-1]; + switch(flags&SDS_TYPE_MASK) { + case SDS_TYPE_5: { + return 0; + } + case SDS_TYPE_8: { + SDS_HDR_VAR(8,s); + return sh->alloc - sh->len; + } + case SDS_TYPE_16: { + SDS_HDR_VAR(16,s); + return sh->alloc - sh->len; + } + case SDS_TYPE_32: { + SDS_HDR_VAR(32,s); + return sh->alloc - sh->len; + } + case SDS_TYPE_64: { + SDS_HDR_VAR(64,s); + return sh->alloc - sh->len; + } + } + return 0; +} + +static inline void sdssetlen(sds s, size_t newlen) { + unsigned char flags = s[-1]; + switch(flags&SDS_TYPE_MASK) { + case SDS_TYPE_5: + { + unsigned char *fp = ((unsigned char*)s)-1; + *fp = SDS_TYPE_5 | (newlen << SDS_TYPE_BITS); + } + break; + case SDS_TYPE_8: + SDS_HDR(8,s)->len = newlen; + break; + case SDS_TYPE_16: + SDS_HDR(16,s)->len = newlen; + break; + case SDS_TYPE_32: + SDS_HDR(32,s)->len = newlen; + break; + case SDS_TYPE_64: + SDS_HDR(64,s)->len = newlen; + break; + } +} + +static inline void sdsinclen(sds s, size_t inc) { + unsigned char flags = s[-1]; + switch(flags&SDS_TYPE_MASK) { + case SDS_TYPE_5: + { + unsigned char *fp = ((unsigned char*)s)-1; + unsigned char newlen = SDS_TYPE_5_LEN(flags)+inc; + *fp = SDS_TYPE_5 | (newlen << SDS_TYPE_BITS); + } + break; + case SDS_TYPE_8: + SDS_HDR(8,s)->len += inc; + break; + case SDS_TYPE_16: + SDS_HDR(16,s)->len += inc; + break; + case SDS_TYPE_32: + SDS_HDR(32,s)->len += inc; + break; + case SDS_TYPE_64: + SDS_HDR(64,s)->len += inc; + break; + } +} + +/* sdsalloc() = sdsavail() + sdslen() */ +static inline size_t sdsalloc(const sds s) { + unsigned char flags = s[-1]; + switch(flags&SDS_TYPE_MASK) { + case SDS_TYPE_5: + return SDS_TYPE_5_LEN(flags); + case SDS_TYPE_8: + return SDS_HDR(8,s)->alloc; + case SDS_TYPE_16: + return SDS_HDR(16,s)->alloc; + case SDS_TYPE_32: + return SDS_HDR(32,s)->alloc; + case SDS_TYPE_64: + return SDS_HDR(64,s)->alloc; + } + return 0; +} + +static inline void sdssetalloc(sds s, size_t newlen) { + unsigned char flags = s[-1]; + switch(flags&SDS_TYPE_MASK) { + case SDS_TYPE_5: + /* Nothing to do, this type has no total allocation info. */ + break; + case SDS_TYPE_8: + SDS_HDR(8,s)->alloc = newlen; + break; + case SDS_TYPE_16: + SDS_HDR(16,s)->alloc = newlen; + break; + case SDS_TYPE_32: + SDS_HDR(32,s)->alloc = newlen; + break; + case SDS_TYPE_64: + SDS_HDR(64,s)->alloc = newlen; + break; + } } sds sdsnewlen(const void *init, size_t initlen); sds sdsnew(const char *init); sds sdsempty(void); -size_t sdslen(const sds s); sds sdsdup(const sds s); void sdsfree(sds s); -size_t sdsavail(const sds s); sds sdsgrowzero(sds s, size_t len); sds sdscatlen(sds s, const void *t, size_t len); sds sdscat(sds s, const char *t); @@ -97,6 +253,7 @@ sds sdsMakeRoomFor(sds s, size_t addlen); void sdsIncrLen(sds s, int incr); sds sdsRemoveFreeSpace(sds s); size_t sdsAllocSize(sds s); +size_t sdsZmallocSize(sds s); #ifdef REDIS_TEST int sdsTest(int argc, char *argv[]); 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