/* SDSLib 2.0 -- A C dynamic strings library
 *
 * Copyright (c) 2006-2015, Salvatore Sanfilippo <antirez at gmail dot com>
 * Copyright (c) 2015, Oran Agra
 * Copyright (c) 2015, 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.
 */

#ifndef __SDS_H
#define __SDS_H

#define SDS_MAX_PREALLOC (1024 * 1024)

#include <sys/types.h>
#include <stdarg.h>
#include <stdint.h>

typedef char* sds;

/* 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)
{
    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)
{
    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);
sds sdsdup(const sds s);
void sdsfree(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);
sds sdscatsds(sds s, const sds t);
sds sdscpylen(sds s, const char* t, size_t len);
sds sdscpy(sds s, const char* t);

sds sdscatvprintf(sds s, const char* fmt, va_list ap);
#ifdef __GNUC__
sds sdscatprintf(sds s, const char* fmt, ...)
__attribute__((format(printf, 2, 3)));
#else
sds sdscatprintf(sds s, const char* fmt, ...);
#endif

sds sdscatfmt(sds s, char const* fmt, ...);
sds sdstrim(sds s, const char* cset);
void sdsrange(sds s, int start, int end);
void sdsupdatelen(sds s);
void sdsclear(sds s);
int sdscmp(const sds s1, const sds s2);
sds* sdssplitlen(
    const char* s, int len, const char* sep, int seplen, int* count);
void sdsfreesplitres(sds* tokens, int count);
void sdstolower(sds s);
void sdstoupper(sds s);
sds sdsfromlonglong(long long value);
sds sdscatrepr(sds s, const char* p, size_t len);
sds* sdssplitargs(const char* line, int* argc);
sds sdsmapchars(sds s, const char* from, const char* to, size_t setlen);
sds sdsjoin(char** argv, int argc, char* sep);
sds sdsjoinsds(sds* argv, int argc, const char* sep, size_t seplen);

/* Low level functions exposed to the user API */
sds sdsMakeRoomFor(sds s, size_t addlen);
void sdsIncrLen(sds s, int incr);
sds sdsRemoveFreeSpace(sds s);
size_t sdsAllocSize(sds s);
void* sdsAllocPtr(sds s);

#ifdef REDIS_TEST
int sdsTest(int argc, char* argv[]);
#endif

#endif