Initial commit

3 files changed, 1616 insertions, 0 deletions

diff --git a/util/sds/sds.c b/util/sds/sds.c
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--- /dev/null
+++ b/util/sds/sds.c
@@ -0,0 +1,1300 @@
+/* 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.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <assert.h>
+#include <limits.h>
+#include "sds.h"
+#include "sdsalloc.h"
+
+const char *SDS_NOINIT = "SDS_NOINIT";
+
+static inline int sdsHdrSize(char type) {
+    switch(type&SDS_TYPE_MASK) {
+        case SDS_TYPE_5:
+            return sizeof(struct sdshdr5);
+        case SDS_TYPE_8:
+            return sizeof(struct sdshdr8);
+        case SDS_TYPE_16:
+            return sizeof(struct sdshdr16);
+        case SDS_TYPE_32:
+            return sizeof(struct sdshdr32);
+        case SDS_TYPE_64:
+            return sizeof(struct sdshdr64);
+    }
+    return 0;
+}
+
+static inline char sdsReqType(size_t string_size) {
+    if (string_size < 1<<5)
+        return SDS_TYPE_5;
+    if (string_size < 1<<8)
+        return SDS_TYPE_8;
+    if (string_size < 1<<16)
+        return SDS_TYPE_16;
+#if (LONG_MAX == LLONG_MAX)
+    if (string_size < 1ll<<32)
+        return SDS_TYPE_32;
+    return SDS_TYPE_64;
+#else
+    return SDS_TYPE_32;
+#endif
+}
+
+/* Create a new sds string with the content specified by the 'init' pointer
+ * and 'initlen'.
+ * If NULL is used for 'init' the string is initialized with zero bytes.
+ * If SDS_NOINIT is used, the buffer is left uninitialized;
+ *
+ * The string is always null-termined (all the sds strings are, always) so
+ * even if you create an sds string with:
+ *
+ * mystring = sdsnewlen("abc",3);
+ *
+ * You can print the string with printf() as there is an implicit \0 at the
+ * end of the string. However the string is binary safe and can contain
+ * \0 characters in the middle, as the length is stored in the sds header. */
+sds sdsnewlen(const void *init, size_t initlen) {
+    void *sh;
+    sds s;
+    char type = sdsReqType(initlen);
+    /* Empty strings are usually created in order to append. Use type 8
+     * since type 5 is not good at this. */
+    if (type == SDS_TYPE_5 && initlen == 0) type = SDS_TYPE_8;
+    int hdrlen = sdsHdrSize(type);
+    unsigned char *fp; /* flags pointer. */
+
+    sh = s_malloc(hdrlen+initlen+1);
+    if (sh == NULL) return NULL;
+    if (init==SDS_NOINIT)
+        init = NULL;
+    else if (!init)
+        memset(sh, 0, hdrlen+initlen+1);
+    s = (char*)sh+hdrlen;
+    fp = ((unsigned char*)s)-1;
+    switch(type) {
+        case SDS_TYPE_5: {
+            *fp = type | (initlen << SDS_TYPE_BITS);
+            break;
+        }
+        case SDS_TYPE_8: {
+            SDS_HDR_VAR(8,s);
+            sh->len = initlen;
+            sh->alloc = initlen;
+            *fp = type;
+            break;
+        }
+        case SDS_TYPE_16: {
+            SDS_HDR_VAR(16,s);
+            sh->len = initlen;
+            sh->alloc = initlen;
+            *fp = type;
+            break;
+        }
+        case SDS_TYPE_32: {
+            SDS_HDR_VAR(32,s);
+            sh->len = initlen;
+            sh->alloc = initlen;
+            *fp = type;
+            break;
+        }
+        case SDS_TYPE_64: {
+            SDS_HDR_VAR(64,s);
+            sh->len = initlen;
+            sh->alloc = initlen;
+            *fp = type;
+            break;
+        }
+    }
+    if (initlen && init)
+        memcpy(s, init, initlen);
+    s[initlen] = '\0';
+    return s;
+}
+
+/* Create an empty (zero length) sds string. Even in this case the string
+ * always has an implicit null term. */
+sds sdsempty(void) {
+    return sdsnewlen("",0);
+}
+
+/* Create a new sds string starting from a null terminated C string. */
+sds sdsnew(const char *init) {
+    size_t initlen = (init == NULL) ? 0 : strlen(init);
+    return sdsnewlen(init, initlen);
+}
+
+/* Duplicate an sds string. */
+sds sdsdup(const sds s) {
+    return sdsnewlen(s, sdslen(s));
+}
+
+/* Free an sds string. No operation is performed if 's' is NULL. */
+void sdsfree(sds s) {
+    if (s == NULL) return;
+    s_free((char*)s-sdsHdrSize(s[-1]));
+}
+
+/* Set the sds string length to the length as obtained with strlen(), so
+ * considering as content only up to the first null term character.
+ *
+ * This function is useful when the sds string is hacked manually in some
+ * way, like in the following example:
+ *
+ * s = sdsnew("foobar");
+ * s[2] = '\0';
+ * sdsupdatelen(s);
+ * printf("%d\n", sdslen(s));
+ *
+ * The output will be "2", but if we comment out the call to sdsupdatelen()
+ * the output will be "6" as the string was modified but the logical length
+ * remains 6 bytes. */
+void sdsupdatelen(sds s) {
+    size_t reallen = strlen(s);
+    sdssetlen(s, reallen);
+}
+
+/* Modify an sds string in-place to make it empty (zero length).
+ * However all the existing buffer is not discarded but set as free space
+ * so that next append operations will not require allocations up to the
+ * number of bytes previously available. */
+void sdsclear(sds s) {
+    sdssetlen(s, 0);
+    s[0] = '\0';
+}
+
+/* Enlarge the free space at the end of the sds string so that the caller
+ * is sure that after calling this function can overwrite up to addlen
+ * bytes after the end of the string, plus one more byte for nul term.
+ *
+ * Note: this does not change the *length* of the sds string as returned
+ * by sdslen(), but only the free buffer space we have. */
+sds sdsMakeRoomFor(sds s, size_t addlen) {
+    void *sh, *newsh;
+    size_t avail = sdsavail(s);
+    size_t len, newlen;
+    char type, oldtype = s[-1] & SDS_TYPE_MASK;
+    int hdrlen;
+
+    /* Return ASAP if there is enough space left. */
+    if (avail >= addlen) return s;
+
+    len = sdslen(s);
+    sh = (char*)s-sdsHdrSize(oldtype);
+    newlen = (len+addlen);
+    if (newlen < SDS_MAX_PREALLOC)
+        newlen *= 2;
+    else
+        newlen += SDS_MAX_PREALLOC;
+
+    type = sdsReqType(newlen);
+
+    /* Don't use type 5: the user is appending to the string and type 5 is
+     * not able to remember empty space, so sdsMakeRoomFor() must be called
+     * at every appending operation. */
+    if (type == SDS_TYPE_5) type = SDS_TYPE_8;
+
+    hdrlen = sdsHdrSize(type);
+    if (oldtype==type) {
+        newsh = s_realloc(sh, hdrlen+newlen+1);
+        if (newsh == NULL) return NULL;
+        s = (char*)newsh+hdrlen;
+    } else {
+        /* Since the header size changes, need to move the string forward,
+         * and can't use realloc */
+        newsh = s_malloc(hdrlen+newlen+1);
+        if (newsh == NULL) return NULL;
+        memcpy((char*)newsh+hdrlen, s, len+1);
+        s_free(sh);
+        s = (char*)newsh+hdrlen;
+        s[-1] = type;
+        sdssetlen(s, len);
+    }
+    sdssetalloc(s, newlen);
+    return s;
+}
+
+/* Reallocate the sds string so that it has no free space at the end. The
+ * contained string remains not altered, but next concatenation operations
+ * will require a reallocation.
+ *
+ * After the call, the passed sds string is no longer valid and all the
+ * references must be substituted with the new pointer returned by the call. */
+sds sdsRemoveFreeSpace(sds s) {
+    void *sh, *newsh;
+    char type, oldtype = s[-1] & SDS_TYPE_MASK;
+    int hdrlen, oldhdrlen = sdsHdrSize(oldtype);
+    size_t len = sdslen(s);
+    size_t avail = sdsavail(s);
+    sh = (char*)s-oldhdrlen;
+
+    /* Return ASAP if there is no space left. */
+    if (avail == 0) return s;
+
+    /* Check what would be the minimum SDS header that is just good enough to
+     * fit this string. */
+    type = sdsReqType(len);
+    hdrlen = sdsHdrSize(type);
+
+    /* If the type is the same, or at least a large enough type is still
+     * required, we just realloc(), letting the allocator to do the copy
+     * only if really needed. Otherwise if the change is huge, we manually
+     * reallocate the string to use the different header type. */
+    if (oldtype==type || type > SDS_TYPE_8) {
+        newsh = s_realloc(sh, oldhdrlen+len+1);
+        if (newsh == NULL) return NULL;
+        s = (char*)newsh+oldhdrlen;
+    } else {
+        newsh = s_malloc(hdrlen+len+1);
+        if (newsh == NULL) return NULL;
+        memcpy((char*)newsh+hdrlen, s, len+1);
+        s_free(sh);
+        s = (char*)newsh+hdrlen;
+        s[-1] = type;
+        sdssetlen(s, len);
+    }
+    sdssetalloc(s, len);
+    return s;
+}
+
+/* Return the total size of the allocation of the specified sds string,
+ * including:
+ * 1) The sds header before the pointer.
+ * 2) The string.
+ * 3) The free buffer at the end if any.
+ * 4) The implicit null term.
+ */
+size_t sdsAllocSize(sds s) {
+    size_t alloc = sdsalloc(s);
+    return sdsHdrSize(s[-1])+alloc+1;
+}
+
+/* Return the pointer of the actual SDS allocation (normally SDS strings
+ * are referenced by the start of the string buffer). */
+void *sdsAllocPtr(sds s) {
+    return (void*) (s-sdsHdrSize(s[-1]));
+}
+
+/* Increment the sds length and decrements the left free space at the
+ * end of the string according to 'incr'. Also set the null term
+ * in the new end of the string.
+ *
+ * This function is used in order to fix the string length after the
+ * user calls sdsMakeRoomFor(), writes something after the end of
+ * the current string, and finally needs to set the new length.
+ *
+ * Note: it is possible to use a negative increment in order to
+ * right-trim the string.
+ *
+ * Usage example:
+ *
+ * Using sdsIncrLen() and sdsMakeRoomFor() it is possible to mount the
+ * following schema, to cat bytes coming from the kernel to the end of an
+ * sds string without copying into an intermediate buffer:
+ *
+ * oldlen = sdslen(s);
+ * s = sdsMakeRoomFor(s, BUFFER_SIZE);
+ * nread = read(fd, s+oldlen, BUFFER_SIZE);
+ * ... check for nread <= 0 and handle it ...
+ * sdsIncrLen(s, nread);
+ */
+void sdsIncrLen(sds s, ssize_t incr) {
+    unsigned char flags = s[-1];
+    size_t len;
+    switch(flags&SDS_TYPE_MASK) {
+        case SDS_TYPE_5: {
+            unsigned char *fp = ((unsigned char*)s)-1;
+            unsigned char oldlen = SDS_TYPE_5_LEN(flags);
+            assert((incr > 0 && oldlen+incr < 32) || (incr < 0 && oldlen >= (unsigned int)(-incr)));
+            *fp = SDS_TYPE_5 | ((oldlen+incr) << SDS_TYPE_BITS);
+            len = oldlen+incr;
+            break;
+        }
+        case SDS_TYPE_8: {
+            SDS_HDR_VAR(8,s);
+            assert((incr >= 0 && sh->alloc-sh->len >= incr) || (incr < 0 && sh->len >= (unsigned int)(-incr)));
+            len = (sh->len += incr);
+            break;
+        }
+        case SDS_TYPE_16: {
+            SDS_HDR_VAR(16,s);
+            assert((incr >= 0 && sh->alloc-sh->len >= incr) || (incr < 0 && sh->len >= (unsigned int)(-incr)));
+            len = (sh->len += incr);
+            break;
+        }
+        case SDS_TYPE_32: {
+            SDS_HDR_VAR(32,s);
+            assert((incr >= 0 && sh->alloc-sh->len >= (unsigned int)incr) || (incr < 0 && sh->len >= (unsigned int)(-incr)));
+            len = (sh->len += incr);
+            break;
+        }
+        case SDS_TYPE_64: {
+            SDS_HDR_VAR(64,s);
+            assert((incr >= 0 && sh->alloc-sh->len >= (uint64_t)incr) || (incr < 0 && sh->len >= (uint64_t)(-incr)));
+            len = (sh->len += incr);
+            break;
+        }
+        default: len = 0; /* Just to avoid compilation warnings. */
+    }
+    s[len] = '\0';
+}
+
+/* Grow the sds to have the specified length. Bytes that were not part of
+ * the original length of the sds will be set to zero.
+ *
+ * if the specified length is smaller than the current length, no operation
+ * is performed. */
+sds sdsgrowzero(sds s, size_t len) {
+    size_t curlen = sdslen(s);
+
+    if (len <= curlen) return s;
+    s = sdsMakeRoomFor(s,len-curlen);
+    if (s == NULL) return NULL;
+
+    /* Make sure added region doesn't contain garbage */
+    memset(s+curlen,0,(len-curlen+1)); /* also set trailing \0 byte */
+    sdssetlen(s, len);
+    return s;
+}
+
+/* Append the specified binary-safe string pointed by 't' of 'len' bytes to the
+ * end of the specified sds string 's'.
+ *
+ * After the call, the passed sds string is no longer valid and all the
+ * references must be substituted with the new pointer returned by the call. */
+sds sdscatlen(sds s, const void *t, size_t len) {
+    size_t curlen = sdslen(s);
+
+    s = sdsMakeRoomFor(s,len);
+    if (s == NULL) return NULL;
+    memcpy(s+curlen, t, len);
+    sdssetlen(s, curlen+len);
+    s[curlen+len] = '\0';
+    return s;
+}
+
+/* Append the specified null termianted C string to the sds string 's'.
+ *
+ * After the call, the passed sds string is no longer valid and all the
+ * references must be substituted with the new pointer returned by the call. */
+sds sdscat(sds s, const char *t) {
+    return sdscatlen(s, t, strlen(t));
+}
+
+/* Append the specified sds 't' to the existing sds 's'.
+ *
+ * After the call, the modified sds string is no longer valid and all the
+ * references must be substituted with the new pointer returned by the call. */
+sds sdscatsds(sds s, const sds t) {
+    return sdscatlen(s, t, sdslen(t));
+}
+
+/* Destructively modify the sds string 's' to hold the specified binary
+ * safe string pointed by 't' of length 'len' bytes. */
+sds sdscpylen(sds s, const char *t, size_t len) {
+    if (sdsalloc(s) < len) {
+        s = sdsMakeRoomFor(s,len-sdslen(s));
+        if (s == NULL) return NULL;
+    }
+    memcpy(s, t, len);
+    s[len] = '\0';
+    sdssetlen(s, len);
+    return s;
+}
+
+/* Like sdscpylen() but 't' must be a null-termined string so that the length
+ * of the string is obtained with strlen(). */
+sds sdscpy(sds s, const char *t) {
+    return sdscpylen(s, t, strlen(t));
+}
+
+/* Helper for sdscatlonglong() doing the actual number -> string
+ * conversion. 's' must point to a string with room for at least
+ * SDS_LLSTR_SIZE bytes.
+ *
+ * The function returns the length of the null-terminated string
+ * representation stored at 's'. */
+#define SDS_LLSTR_SIZE 21
+int sdsll2str(char *s, long long value) {
+    char *p, aux;
+    unsigned long long v;
+    size_t l;
+
+    /* Generate the string representation, this method produces
+     * an reversed string. */
+    v = (value < 0) ? -value : value;
+    p = s;
+    do {
+        *p++ = '0'+(v%10);
+        v /= 10;
+    } while(v);
+    if (value < 0) *p++ = '-';
+
+    /* Compute length and add null term. */
+    l = p-s;
+    *p = '\0';
+
+    /* Reverse the string. */
+    p--;
+    while(s < p) {
+        aux = *s;
+        *s = *p;
+        *p = aux;
+        s++;
+        p--;
+    }
+    return l;
+}
+
+/* Identical sdsll2str(), but for unsigned long long type. */
+int sdsull2str(char *s, unsigned long long v) {
+    char *p, aux;
+    size_t l;
+
+    /* Generate the string representation, this method produces
+     * an reversed string. */
+    p = s;
+    do {
+        *p++ = '0'+(v%10);
+        v /= 10;
+    } while(v);
+
+    /* Compute length and add null term. */
+    l = p-s;
+    *p = '\0';
+
+    /* Reverse the string. */
+    p--;
+    while(s < p) {
+        aux = *s;
+        *s = *p;
+        *p = aux;
+        s++;
+        p--;
+    }
+    return l;
+}
+
+/* Create an sds string from a long long value. It is much faster than:
+ *
+ * sdscatprintf(sdsempty(),"%lld\n", value);
+ */
+sds sdsfromlonglong(long long value) {
+    char buf[SDS_LLSTR_SIZE];
+    int len = sdsll2str(buf,value);
+
+    return sdsnewlen(buf,len);
+}
+
+/* Like sdscatprintf() but gets va_list instead of being variadic. */
+sds sdscatvprintf(sds s, const char *fmt, va_list ap) {
+    va_list cpy;
+    char staticbuf[1024], *buf = staticbuf, *t;
+    size_t buflen = strlen(fmt)*2;
+
+    /* We try to start using a static buffer for speed.
+     * If not possible we revert to heap allocation. */
+    if (buflen > sizeof(staticbuf)) {
+        buf = s_malloc(buflen);
+        if (buf == NULL) return NULL;
+    } else {
+        buflen = sizeof(staticbuf);
+    }
+
+    /* Try with buffers two times bigger every time we fail to
+     * fit the string in the current buffer size. */
+    while(1) {
+        buf[buflen-2] = '\0';
+        va_copy(cpy,ap);
+        vsnprintf(buf, buflen, fmt, cpy);
+        va_end(cpy);
+        if (buf[buflen-2] != '\0') {
+            if (buf != staticbuf) s_free(buf);
+            buflen *= 2;
+            buf = s_malloc(buflen);
+            if (buf == NULL) return NULL;
+            continue;
+        }
+        break;
+    }
+
+    /* Finally concat the obtained string to the SDS string and return it. */
+    t = sdscat(s, buf);
+    if (buf != staticbuf) s_free(buf);
+    return t;
+}
+
+/* Append to the sds string 's' a string obtained using printf-alike format
+ * specifier.
+ *
+ * After the call, the modified sds string is no longer valid and all the
+ * references must be substituted with the new pointer returned by the call.
+ *
+ * Example:
+ *
+ * s = sdsnew("Sum is: ");
+ * s = sdscatprintf(s,"%d+%d = %d",a,b,a+b).
+ *
+ * Often you need to create a string from scratch with the printf-alike
+ * format. When this is the need, just use sdsempty() as the target string:
+ *
+ * s = sdscatprintf(sdsempty(), "... your format ...", args);
+ */
+sds sdscatprintf(sds s, const char *fmt, ...) {
+    va_list ap;
+    char *t;
+    va_start(ap, fmt);
+    t = sdscatvprintf(s,fmt,ap);
+    va_end(ap);
+    return t;
+}
+
+/* This function is similar to sdscatprintf, but much faster as it does
+ * not rely on sprintf() family functions implemented by the libc that
+ * are often very slow. Moreover directly handling the sds string as
+ * new data is concatenated provides a performance improvement.
+ *
+ * However this function only handles an incompatible subset of printf-alike
+ * format specifiers:
+ *
+ * %s - C String
+ * %S - SDS string
+ * %i - signed int
+ * %I - 64 bit signed integer (long long, int64_t)
+ * %u - unsigned int
+ * %U - 64 bit unsigned integer (unsigned long long, uint64_t)
+ * %% - Verbatim "%" character.
+ */
+sds sdscatfmt(sds s, char const *fmt, ...) {
+    size_t initlen = sdslen(s);
+    const char *f = fmt;
+    long i;
+    va_list ap;
+
+    /* To avoid continuous reallocations, let's start with a buffer that
+     * can hold at least two times the format string itself. It's not the
+     * best heuristic but seems to work in practice. */
+    s = sdsMakeRoomFor(s, initlen + strlen(fmt)*2);
+    va_start(ap,fmt);
+    f = fmt;    /* Next format specifier byte to process. */
+    i = initlen; /* Position of the next byte to write to dest str. */
+    while(*f) {
+        char next, *str;
+        size_t l;
+        long long num;
+        unsigned long long unum;
+
+        /* Make sure there is always space for at least 1 char. */
+        if (sdsavail(s)==0) {
+            s = sdsMakeRoomFor(s,1);
+        }
+
+        switch(*f) {
+        case '%':
+            next = *(f+1);
+            f++;
+            switch(next) {
+            case 's':
+            case 'S':
+                str = va_arg(ap,char*);
+                l = (next == 's') ? strlen(str) : sdslen(str);
+                if (sdsavail(s) < l) {
+                    s = sdsMakeRoomFor(s,l);
+                }
+                memcpy(s+i,str,l);
+                sdsinclen(s,l);
+                i += l;
+                break;
+            case 'i':
+            case 'I':
+                if (next == 'i')
+                    num = va_arg(ap,int);
+                else
+                    num = va_arg(ap,long long);
+                {
+                    char buf[SDS_LLSTR_SIZE];
+                    l = sdsll2str(buf,num);
+                    if (sdsavail(s) < l) {
+                        s = sdsMakeRoomFor(s,l);
+                    }
+                    memcpy(s+i,buf,l);
+                    sdsinclen(s,l);
+                    i += l;
+                }
+                break;
+            case 'u':
+            case 'U':
+                if (next == 'u')
+                    unum = va_arg(ap,unsigned int);
+                else
+                    unum = va_arg(ap,unsigned long long);
+                {
+                    char buf[SDS_LLSTR_SIZE];
+                    l = sdsull2str(buf,unum);
+                    if (sdsavail(s) < l) {
+                        s = sdsMakeRoomFor(s,l);
+                    }
+                    memcpy(s+i,buf,l);
+                    sdsinclen(s,l);
+                    i += l;
+                }
+                break;
+            default: /* Handle %% and generally %<unknown>. */
+                s[i++] = next;
+                sdsinclen(s,1);
+                break;
+            }
+            break;
+        default:
+            s[i++] = *f;
+            sdsinclen(s,1);
+            break;
+        }
+        f++;
+    }
+    va_end(ap);
+
+    /* Add null-term */
+    s[i] = '\0';
+    return s;
+}
+
+/* Remove the part of the string from left and from right composed just of
+ * contiguous characters found in 'cset', that is a null terminted C string.
+ *
+ * After the call, the modified sds string is no longer valid and all the
+ * references must be substituted with the new pointer returned by the call.
+ *
+ * Example:
+ *
+ * s = sdsnew("AA...AA.a.aa.aHelloWorld     :::");
+ * s = sdstrim(s,"Aa. :");
+ * printf("%s\n", s);
+ *
+ * Output will be just "HelloWorld".
+ */
+sds sdstrim(sds s, const char *cset) {
+    char *start, *end, *sp, *ep;
+    size_t len;
+
+    sp = start = s;
+    ep = end = s+sdslen(s)-1;
+    while(sp <= end && strchr(cset, *sp)) sp++;
+    while(ep > sp && strchr(cset, *ep)) ep--;
+    len = (sp > ep) ? 0 : ((ep-sp)+1);
+    if (s != sp) memmove(s, sp, len);
+    s[len] = '\0';
+    sdssetlen(s,len);
+    return s;
+}
+
+/* Turn the string into a smaller (or equal) string containing only the
+ * substring specified by the 'start' and 'end' indexes.
+ *
+ * start and end can be negative, where -1 means the last character of the
+ * string, -2 the penultimate character, and so forth.
+ *
+ * The interval is inclusive, so the start and end characters will be part
+ * of the resulting string.
+ *
+ * The string is modified in-place.
+ *
+ * Example:
+ *
+ * s = sdsnew("Hello World");
+ * sdsrange(s,1,-1); => "ello World"
+ */
+void sdsrange(sds s, ssize_t start, ssize_t end) {
+    size_t newlen, len = sdslen(s);
+
+    if (len == 0) return;
+    if (start < 0) {
+        start = len+start;
+        if (start < 0) start = 0;
+    }
+    if (end < 0) {
+        end = len+end;
+        if (end < 0) end = 0;
+    }
+    newlen = (start > end) ? 0 : (end-start)+1;
+    if (newlen != 0) {
+        if (start >= (ssize_t)len) {
+            newlen = 0;
+        } else if (end >= (ssize_t)len) {
+            end = len-1;
+            newlen = (start > end) ? 0 : (end-start)+1;
+        }
+    } else {
+        start = 0;
+    }
+    if (start && newlen) memmove(s, s+start, newlen);
+    s[newlen] = 0;
+    sdssetlen(s,newlen);
+}
+
+/* Apply tolower() to every character of the sds string 's'. */
+void sdstolower(sds s) {
+    size_t len = sdslen(s), j;
+
+    for (j = 0; j < len; j++) s[j] = tolower(s[j]);
+}
+
+/* Apply toupper() to every character of the sds string 's'. */
+void sdstoupper(sds s) {
+    size_t len = sdslen(s), j;
+
+    for (j = 0; j < len; j++) s[j] = toupper(s[j]);
+}
+
+/* Compare two sds strings s1 and s2 with memcmp().
+ *
+ * Return value:
+ *
+ *     positive if s1 > s2.
+ *     negative if s1 < s2.
+ *     0 if s1 and s2 are exactly the same binary string.
+ *
+ * If two strings share exactly the same prefix, but one of the two has
+ * additional characters, the longer string is considered to be greater than
+ * the smaller one. */
+int sdscmp(const sds s1, const sds s2) {
+    size_t l1, l2, minlen;
+    int cmp;
+
+    l1 = sdslen(s1);
+    l2 = sdslen(s2);
+    minlen = (l1 < l2) ? l1 : l2;
+    cmp = memcmp(s1,s2,minlen);
+    if (cmp == 0) return l1>l2? 1: (l1<l2? -1: 0);
+    return cmp;
+}
+
+/* Split 's' with separator in 'sep'. An array
+ * of sds strings is returned. *count will be set
+ * by reference to the number of tokens returned.
+ *
+ * On out of memory, zero length string, zero length
+ * separator, NULL is returned.
+ *
+ * Note that 'sep' is able to split a string using
+ * a multi-character separator. For example
+ * sdssplit("foo_-_bar","_-_"); will return two
+ * elements "foo" and "bar".
+ *
+ * This version of the function is binary-safe but
+ * requires length arguments. sdssplit() is just the
+ * same function but for zero-terminated strings.
+ */
+sds *sdssplitlen(const char *s, ssize_t len, const char *sep, int seplen, int *count) {
+    int elements = 0, slots = 5;
+    long start = 0, j;
+    sds *tokens;
+
+    if (seplen < 1 || len < 0) return NULL;
+
+    tokens = s_malloc(sizeof(sds)*slots);
+    if (tokens == NULL) return NULL;
+
+    if (len == 0) {
+        *count = 0;
+        return tokens;
+    }
+    for (j = 0; j < (len-(seplen-1)); j++) {
+        /* make sure there is room for the next element and the final one */
+        if (slots < elements+2) {
+            sds *newtokens;
+
+            slots *= 2;
+            newtokens = s_realloc(tokens,sizeof(sds)*slots);
+            if (newtokens == NULL) goto cleanup;
+            tokens = newtokens;
+        }
+        /* search the separator */
+        if ((seplen == 1 && *(s+j) == sep[0]) || (memcmp(s+j,sep,seplen) == 0)) {
+            tokens[elements] = sdsnewlen(s+start,j-start);
+            if (tokens[elements] == NULL) goto cleanup;
+            elements++;
+            start = j+seplen;
+            j = j+seplen-1; /* skip the separator */
+        }
+    }
+    /* Add the final element. We are sure there is room in the tokens array. */
+    tokens[elements] = sdsnewlen(s+start,len-start);
+    if (tokens[elements] == NULL) goto cleanup;
+    elements++;
+    *count = elements;
+    return tokens;
+
+cleanup:
+    {
+        int i;
+        for (i = 0; i < elements; i++) sdsfree(tokens[i]);
+        s_free(tokens);
+        *count = 0;
+        return NULL;
+    }
+}
+
+/* Free the result returned by sdssplitlen(), or do nothing if 'tokens' is NULL. */
+void sdsfreesplitres(sds *tokens, int count) {
+    if (!tokens) return;
+    while(count--)
+        sdsfree(tokens[count]);
+    s_free(tokens);
+}
+
+/* Append to the sds string "s" an escaped string representation where
+ * all the non-printable characters (tested with isprint()) are turned into
+ * escapes in the form "\n\r\a...." or "\x<hex-number>".
+ *
+ * After the call, the modified sds string is no longer valid and all the
+ * references must be substituted with the new pointer returned by the call. */
+sds sdscatrepr(sds s, const char *p, size_t len) {
+    s = sdscatlen(s,"\"",1);
+    while(len--) {
+        switch(*p) {
+        case '\\':
+        case '"':
+            s = sdscatprintf(s,"\\%c",*p);
+            break;
+        case '\n': s = sdscatlen(s,"\\n",2); break;
+        case '\r': s = sdscatlen(s,"\\r",2); break;
+        case '\t': s = sdscatlen(s,"\\t",2); break;
+        case '\a': s = sdscatlen(s,"\\a",2); break;
+        case '\b': s = sdscatlen(s,"\\b",2); break;
+        default:
+            if (isprint(*p))
+                s = sdscatprintf(s,"%c",*p);
+            else
+                s = sdscatprintf(s,"\\x%02x",(unsigned char)*p);
+            break;
+        }
+        p++;
+    }
+    return sdscatlen(s,"\"",1);
+}
+
+/* Helper function for sdssplitargs() that returns non zero if 'c'
+ * is a valid hex digit. */
+int is_hex_digit(char c) {
+    return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') ||
+           (c >= 'A' && c <= 'F');
+}
+
+/* Helper function for sdssplitargs() that converts a hex digit into an
+ * integer from 0 to 15 */
+int hex_digit_to_int(char c) {
+    switch(c) {
+    case '0': return 0;
+    case '1': return 1;
+    case '2': return 2;
+    case '3': return 3;
+    case '4': return 4;
+    case '5': return 5;
+    case '6': return 6;
+    case '7': return 7;
+    case '8': return 8;
+    case '9': return 9;
+    case 'a': case 'A': return 10;
+    case 'b': case 'B': return 11;
+    case 'c': case 'C': return 12;
+    case 'd': case 'D': return 13;
+    case 'e': case 'E': return 14;
+    case 'f': case 'F': return 15;
+    default: return 0;
+    }
+}
+
+/* Split a line into arguments, where every argument can be in the
+ * following programming-language REPL-alike form:
+ *
+ * foo bar "newline are supported\n" and "\xff\x00otherstuff"
+ *
+ * The number of arguments is stored into *argc, and an array
+ * of sds is returned.
+ *
+ * The caller should free the resulting array of sds strings with
+ * sdsfreesplitres().
+ *
+ * Note that sdscatrepr() is able to convert back a string into
+ * a quoted string in the same format sdssplitargs() is able to parse.
+ *
+ * The function returns the allocated tokens on success, even when the
+ * input string is empty, or NULL if the input contains unbalanced
+ * quotes or closed quotes followed by non space characters
+ * as in: "foo"bar or "foo'
+ */
+sds *sdssplitargs(const char *line, int *argc) {
+    const char *p = line;
+    char *current = NULL;
+    char **vector = NULL;
+
+    *argc = 0;
+    while(1) {
+        /* skip blanks */
+        while(*p && isspace(*p)) p++;
+        if (*p) {
+            /* get a token */
+            int inq=0;  /* set to 1 if we are in "quotes" */
+            int insq=0; /* set to 1 if we are in 'single quotes' */
+            int done=0;
+
+            if (current == NULL) current = sdsempty();
+            while(!done) {
+                if (inq) {
+                    if (*p == '\\' && *(p+1) == 'x' &&
+                                             is_hex_digit(*(p+2)) &&
+                                             is_hex_digit(*(p+3)))
+                    {
+                        unsigned char byte;
+
+                        byte = (hex_digit_to_int(*(p+2))*16)+
+                                hex_digit_to_int(*(p+3));
+                        current = sdscatlen(current,(char*)&byte,1);
+                        p += 3;
+                    } else if (*p == '\\' && *(p+1)) {
+                        char c;
+
+                        p++;
+                        switch(*p) {
+                        case 'n': c = '\n'; break;
+                        case 'r': c = '\r'; break;
+                        case 't': c = '\t'; break;
+                        case 'b': c = '\b'; break;
+                        case 'a': c = '\a'; break;
+                        default: c = *p; break;
+                        }
+                        current = sdscatlen(current,&c,1);
+                    } else if (*p == '"') {
+                        /* closing quote must be followed by a space or
+                         * nothing at all. */
+                        if (*(p+1) && !isspace(*(p+1))) goto err;
+                        done=1;
+                    } else if (!*p) {
+                        /* unterminated quotes */
+                        goto err;
+                    } else {
+                        current = sdscatlen(current,p,1);
+                    }
+                } else if (insq) {
+                    if (*p == '\\' && *(p+1) == '\'') {
+                        p++;
+                        current = sdscatlen(current,"'",1);
+                    } else if (*p == '\'') {
+                        /* closing quote must be followed by a space or
+                         * nothing at all. */
+                        if (*(p+1) && !isspace(*(p+1))) goto err;
+                        done=1;
+                    } else if (!*p) {
+                        /* unterminated quotes */
+                        goto err;
+                    } else {
+                        current = sdscatlen(current,p,1);
+                    }
+                } else {
+                    switch(*p) {
+                    case ' ':
+                    case '\n':
+                    case '\r':
+                    case '\t':
+                    case '\0':
+                        done=1;
+                        break;
+                    case '"':
+                        inq=1;
+                        break;
+                    case '\'':
+                        insq=1;
+                        break;
+                    default:
+                        current = sdscatlen(current,p,1);
+                        break;
+                    }
+                }
+                if (*p) p++;
+            }
+            /* add the token to the vector */
+            vector = s_realloc(vector,((*argc)+1)*sizeof(char*));
+            vector[*argc] = current;
+            (*argc)++;
+            current = NULL;
+        } else {
+            /* Even on empty input string return something not NULL. */
+            if (vector == NULL) vector = s_malloc(sizeof(void*));
+            return vector;
+        }
+    }
+
+err:
+    while((*argc)--)
+        sdsfree(vector[*argc]);
+    s_free(vector);
+    if (current) sdsfree(current);
+    *argc = 0;
+    return NULL;
+}
+
+/* Modify the string substituting all the occurrences of the set of
+ * characters specified in the 'from' string to the corresponding character
+ * in the 'to' array.
+ *
+ * For instance: sdsmapchars(mystring, "ho", "01", 2)
+ * will have the effect of turning the string "hello" into "0ell1".
+ *
+ * The function returns the sds string pointer, that is always the same
+ * as the input pointer since no resize is needed. */
+sds sdsmapchars(sds s, const char *from, const char *to, size_t setlen) {
+    size_t j, i, l = sdslen(s);
+
+    for (j = 0; j < l; j++) {
+        for (i = 0; i < setlen; i++) {
+            if (s[j] == from[i]) {
+                s[j] = to[i];
+                break;
+            }
+        }
+    }
+    return s;
+}
+
+/* Join an array of C strings using the specified separator (also a C string).
+ * Returns the result as an sds string. */
+sds sdsjoin(char **argv, int argc, char *sep) {
+    sds join = sdsempty();
+    int j;
+
+    for (j = 0; j < argc; j++) {
+        join = sdscat(join, argv[j]);
+        if (j != argc-1) join = sdscat(join,sep);
+    }
+    return join;
+}
+
+/* Like sdsjoin, but joins an array of SDS strings. */
+sds sdsjoinsds(sds *argv, int argc, const char *sep, size_t seplen) {
+    sds join = sdsempty();
+    int j;
+
+    for (j = 0; j < argc; j++) {
+        join = sdscatsds(join, argv[j]);
+        if (j != argc-1) join = sdscatlen(join,sep,seplen);
+    }
+    return join;
+}
+
+/* Wrappers to the allocators used by SDS. Note that SDS will actually
+ * just use the macros defined into sdsalloc.h in order to avoid to pay
+ * the overhead of function calls. Here we define these wrappers only for
+ * the programs SDS is linked to, if they want to touch the SDS internals
+ * even if they use a different allocator. */
+void *sds_malloc(size_t size) { return s_malloc(size); }
+void *sds_realloc(void *ptr, size_t size) { return s_realloc(ptr,size); }
+void sds_free(void *ptr) { s_free(ptr); }
+
+#if defined(SDS_TEST_MAIN)
+#include <stdio.h>
+#include "testhelp.h"
+#include "limits.h"
+
+#define UNUSED(x) (void)(x)
+int sdsTest(void) {
+    {
+        sds x = sdsnew("foo"), y;
+
+        test_cond("Create a string and obtain the length",
+            sdslen(x) == 3 && memcmp(x,"foo\0",4) == 0)
+
+        sdsfree(x);
+        x = sdsnewlen("foo",2);
+        test_cond("Create a string with specified length",
+            sdslen(x) == 2 && memcmp(x,"fo\0",3) == 0)
+
+        x = sdscat(x,"bar");
+        test_cond("Strings concatenation",
+            sdslen(x) == 5 && memcmp(x,"fobar\0",6) == 0);
+
+        x = sdscpy(x,"a");
+        test_cond("sdscpy() against an originally longer string",
+            sdslen(x) == 1 && memcmp(x,"a\0",2) == 0)
+
+        x = sdscpy(x,"xyzxxxxxxxxxxyyyyyyyyyykkkkkkkkkk");
+        test_cond("sdscpy() against an originally shorter string",
+            sdslen(x) == 33 &&
+            memcmp(x,"xyzxxxxxxxxxxyyyyyyyyyykkkkkkkkkk\0",33) == 0)
+
+        sdsfree(x);
+        x = sdscatprintf(sdsempty(),"%d",123);
+        test_cond("sdscatprintf() seems working in the base case",
+            sdslen(x) == 3 && memcmp(x,"123\0",4) == 0)
+
+        sdsfree(x);
+        x = sdsnew("--");
+        x = sdscatfmt(x, "Hello %s World %I,%I--", "Hi!", LLONG_MIN,LLONG_MAX);
+        test_cond("sdscatfmt() seems working in the base case",
+            sdslen(x) == 60 &&
+            memcmp(x,"--Hello Hi! World -9223372036854775808,"
+                     "9223372036854775807--",60) == 0)
+        printf("[%s]\n",x);
+
+        sdsfree(x);
+        x = sdsnew("--");
+        x = sdscatfmt(x, "%u,%U--", UINT_MAX, ULLONG_MAX);
+        test_cond("sdscatfmt() seems working with unsigned numbers",
+            sdslen(x) == 35 &&
+            memcmp(x,"--4294967295,18446744073709551615--",35) == 0)
+
+        sdsfree(x);
+        x = sdsnew(" x ");
+        sdstrim(x," x");
+        test_cond("sdstrim() works when all chars match",
+            sdslen(x) == 0)
+
+        sdsfree(x);
+        x = sdsnew(" x ");
+        sdstrim(x," ");
+        test_cond("sdstrim() works when a single char remains",
+            sdslen(x) == 1 && x[0] == 'x')
+
+        sdsfree(x);
+        x = sdsnew("xxciaoyyy");
+        sdstrim(x,"xy");
+        test_cond("sdstrim() correctly trims characters",
+            sdslen(x) == 4 && memcmp(x,"ciao\0",5) == 0)
+
+        y = sdsdup(x);
+        sdsrange(y,1,1);
+        test_cond("sdsrange(...,1,1)",
+            sdslen(y) == 1 && memcmp(y,"i\0",2) == 0)
+
+        sdsfree(y);
+        y = sdsdup(x);
+        sdsrange(y,1,-1);
+        test_cond("sdsrange(...,1,-1)",
+            sdslen(y) == 3 && memcmp(y,"iao\0",4) == 0)
+
+        sdsfree(y);
+        y = sdsdup(x);
+        sdsrange(y,-2,-1);
+        test_cond("sdsrange(...,-2,-1)",
+            sdslen(y) == 2 && memcmp(y,"ao\0",3) == 0)
+
+        sdsfree(y);
+        y = sdsdup(x);
+        sdsrange(y,2,1);
+        test_cond("sdsrange(...,2,1)",
+            sdslen(y) == 0 && memcmp(y,"\0",1) == 0)
+
+        sdsfree(y);
+        y = sdsdup(x);
+        sdsrange(y,1,100);
+        test_cond("sdsrange(...,1,100)",
+            sdslen(y) == 3 && memcmp(y,"iao\0",4) == 0)
+
+        sdsfree(y);
+        y = sdsdup(x);
+        sdsrange(y,100,100);
+        test_cond("sdsrange(...,100,100)",
+            sdslen(y) == 0 && memcmp(y,"\0",1) == 0)
+
+        sdsfree(y);
+        sdsfree(x);
+        x = sdsnew("foo");
+        y = sdsnew("foa");
+        test_cond("sdscmp(foo,foa)", sdscmp(x,y) > 0)
+
+        sdsfree(y);
+        sdsfree(x);
+        x = sdsnew("bar");
+        y = sdsnew("bar");
+        test_cond("sdscmp(bar,bar)", sdscmp(x,y) == 0)
+
+        sdsfree(y);
+        sdsfree(x);
+        x = sdsnew("aar");
+        y = sdsnew("bar");
+        test_cond("sdscmp(bar,bar)", sdscmp(x,y) < 0)
+
+        sdsfree(y);
+        sdsfree(x);
+        x = sdsnewlen("\a\n\0foo\r",7);
+        y = sdscatrepr(sdsempty(),x,sdslen(x));
+        test_cond("sdscatrepr(...data...)",
+            memcmp(y,"\"\\a\\n\\x00foo\\r\"",15) == 0)
+
+        {
+            unsigned int oldfree;
+            char *p;
+            int step = 10, j, i;
+
+            sdsfree(x);
+            sdsfree(y);
+            x = sdsnew("0");
+            test_cond("sdsnew() free/len buffers", sdslen(x) == 1 && sdsavail(x) == 0);
+
+            /* Run the test a few times in order to hit the first two
+             * SDS header types. */
+            for (i = 0; i < 10; i++) {
+                int oldlen = sdslen(x);
+                x = sdsMakeRoomFor(x,step);
+                int type = x[-1]&SDS_TYPE_MASK;
+
+                test_cond("sdsMakeRoomFor() len", sdslen(x) == oldlen);
+                if (type != SDS_TYPE_5) {
+                    test_cond("sdsMakeRoomFor() free", sdsavail(x) >= step);
+                    oldfree = sdsavail(x);
+                }
+                p = x+oldlen;
+                for (j = 0; j < step; j++) {
+                    p[j] = 'A'+j;
+                }
+                sdsIncrLen(x,step);
+            }
+            test_cond("sdsMakeRoomFor() content",
+                memcmp("0ABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJ",x,101) == 0);
+            test_cond("sdsMakeRoomFor() final length",sdslen(x)==101);
+
+            sdsfree(x);
+        }
+    }
+    test_report()
+    return 0;
+}
+#endif
+
+#ifdef SDS_TEST_MAIN
+int main(void) {
+    return sdsTest();
+}
+#endif
diff --git a/util/sds/sds.h b/util/sds/sds.h
new file mode 100644
index 0000000..adcc12c
--- /dev/null
+++ b/util/sds/sds.h
@@ -0,0 +1,274 @@
+/* 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)
+extern const char *SDS_NOINIT;
+
+#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, ssize_t start, ssize_t end);
+void sdsupdatelen(sds s);
+void sdsclear(sds s);
+int sdscmp(const sds s1, const sds s2);
+sds *sdssplitlen(const char *s, ssize_t 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, ssize_t incr);
+sds sdsRemoveFreeSpace(sds s);
+size_t sdsAllocSize(sds s);
+void *sdsAllocPtr(sds s);
+
+/* Export the allocator used by SDS to the program using SDS.
+ * Sometimes the program SDS is linked to, may use a different set of
+ * allocators, but may want to allocate or free things that SDS will
+ * respectively free or allocate. */
+void *sds_malloc(size_t size);
+void *sds_realloc(void *ptr, size_t size);
+void sds_free(void *ptr);
+
+#ifdef REDIS_TEST
+int sdsTest(int argc, char *argv[]);
+#endif
+
+#endif
diff --git a/util/sds/sdsalloc.h b/util/sds/sdsalloc.h
new file mode 100644
index 0000000..f43023c
--- /dev/null
+++ b/util/sds/sdsalloc.h
@@ -0,0 +1,42 @@
+/* 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.
+ */
+
+/* SDS allocator selection.
+ *
+ * This file is used in order to change the SDS allocator at compile time.
+ * Just define the following defines to what you want to use. Also add
+ * the include of your alternate allocator if needed (not needed in order
+ * to use the default libc allocator). */
+
+#define s_malloc malloc
+#define s_realloc realloc
+#define s_free free