remove unnessory code

4 files changed, 567 insertions, 178 deletions

diff --git a/fmacros.h b/fmacros.h
index 19d7b21..82ff08d 100644
--- a/fmacros.h
+++ b/fmacros.h
@@ -14,7 +14,7 @@
 #define _XOPEN_SOURCE
 #endif
 
-#if __APPLE__ && __MACH__
+#if defined(__APPLE__) && defined(__MACH__)
 #define _OSX
 #endif
 
diff --git a/sds.c b/sds.c
index c57f614..b31ccf2 100644
--- a/sds.c
+++ b/sds.c
@@ -1,6 +1,8 @@
-/* SDS (Simple Dynamic Strings), A C dynamic strings library.
+/* SDSLib 2.0 -- A C dynamic strings library
  *
- * Copyright (c) 2006-2014, Salvatore Sanfilippo <antirez at gmail dot com>
+ * 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
@@ -33,8 +35,36 @@
 #include <string.h>
 #include <ctype.h>
 #include <assert.h>
-
 #include "sds.h"
+#include "sdsalloc.h"
+
+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 < 32)
+        return SDS_TYPE_5;
+    if (string_size < 0xff)
+        return SDS_TYPE_8;
+    if (string_size < 0xffff)
+        return SDS_TYPE_16;
+    if (string_size < 0xffffffff)
+        return SDS_TYPE_32;
+    return SDS_TYPE_64;
+}
 
 /* Create a new sds string with the content specified by the 'init' pointer
  * and 'initlen'.
@@ -43,26 +73,65 @@
  * 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");
+ * 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) {
-    struct sdshdr *sh;
-
-    if (init) {
-        sh = malloc(sizeof *sh+initlen+1);
-    } else {
-        sh = calloc(sizeof *sh+initlen+1,1);
-    }
+    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 (!init)
+        memset(sh, 0, hdrlen+initlen+1);
     if (sh == NULL) return NULL;
-    sh->len = initlen;
-    sh->free = 0;
+    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(sh->buf, init, initlen);
-    sh->buf[initlen] = '\0';
-    return (char*)sh->buf;
+        memcpy(s, init, initlen);
+    s[initlen] = '\0';
+    return s;
 }
 
 /* Create an empty (zero length) sds string. Even in this case the string
@@ -71,7 +140,7 @@ sds sdsempty(void) {
     return sdsnewlen("",0);
 }
 
-/* Create a new sds string starting from a null termined C string. */
+/* 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);
@@ -85,7 +154,7 @@ sds sdsdup(const sds s) {
 /* Free an sds string. No operation is performed if 's' is NULL. */
 void sdsfree(sds s) {
     if (s == NULL) return;
-    free(s-sizeof(struct sdshdr));
+    s_free((char*)s-sdsHdrSize(s[-1]));
 }
 
 /* Set the sds string length to the length as obtained with strlen(), so
@@ -103,21 +172,17 @@ void sdsfree(sds s) {
  * the output will be "6" as the string was modified but the logical length
  * remains 6 bytes. */
 void sdsupdatelen(sds s) {
-    struct sdshdr *sh = (void*) (s-sizeof *sh);
     int reallen = strlen(s);
-    sh->free += (sh->len-reallen);
-    sh->len = reallen;
+    sdssetlen(s, reallen);
 }
 
-/* Modify an sds string on-place to make it empty (zero length).
+/* 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) {
-    struct sdshdr *sh = (void*) (s-sizeof *sh);
-    sh->free += sh->len;
-    sh->len = 0;
-    sh->buf[0] = '\0';
+    sdssetlen(s, 0);
+    s[0] = '\0';
 }
 
 /* Enlarge the free space at the end of the sds string so that the caller
@@ -127,23 +192,48 @@ void sdsclear(sds s) {
  * 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) {
-    struct sdshdr *sh, *newsh;
-    size_t free = sdsavail(s);
+    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;
 
-    if (free >= addlen) return s;
     len = sdslen(s);
-    sh = (void*) (s-sizeof *sh);
+    sh = (char*)s-sdsHdrSize(oldtype);
     newlen = (len+addlen);
     if (newlen < SDS_MAX_PREALLOC)
         newlen *= 2;
     else
         newlen += SDS_MAX_PREALLOC;
-    newsh = realloc(sh, sizeof *newsh+newlen+1);
-    if (newsh == NULL) return NULL;
 
-    newsh->free = newlen - len;
-    return newsh->buf;
+    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
@@ -153,12 +243,29 @@ sds sdsMakeRoomFor(sds s, size_t addlen) {
  * 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) {
-    struct sdshdr *sh;
-
-    sh = (void*) (s-sizeof *sh);
-    sh = realloc(sh, sizeof *sh+sh->len+1);
-    sh->free = 0;
-    return sh->buf;
+    void *sh, *newsh;
+    char type, oldtype = s[-1] & SDS_TYPE_MASK;
+    int hdrlen;
+    size_t len = sdslen(s);
+    sh = (char*)s-sdsHdrSize(oldtype);
+
+    type = sdsReqType(len);
+    hdrlen = sdsHdrSize(type);
+    if (oldtype==type) {
+        newsh = s_realloc(sh, hdrlen+len+1);
+        if (newsh == NULL) return NULL;
+        s = (char*)newsh+hdrlen;
+    } 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 specifed sds string,
@@ -169,9 +276,14 @@ sds sdsRemoveFreeSpace(sds s) {
  * 4) The implicit null term.
  */
 size_t sdsAllocSize(sds s) {
-    struct sdshdr *sh = (void*) (s-sizeof *sh);
+    size_t alloc = sdsalloc(s);
+    return sdsHdrSize(s[-1])+alloc+1;
+}
 
-    return sizeof(*sh)+sh->len+sh->free+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
@@ -198,13 +310,44 @@ size_t sdsAllocSize(sds s) {
  * sdsIncrLen(s, nread);
  */
 void sdsIncrLen(sds s, int incr) {
-    struct sdshdr *sh = (void*) (s-sizeof *sh);
-
-    assert(sh->free >= incr);
-    sh->len += incr;
-    sh->free -= incr;
-    assert(sh->free >= 0);
-    s[sh->len] = '\0';
+    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
@@ -213,19 +356,15 @@ void sdsIncrLen(sds s, int incr) {
  * if the specified length is smaller than the current length, no operation
  * is performed. */
 sds sdsgrowzero(sds s, size_t len) {
-    struct sdshdr *sh = (void*) (s-sizeof *sh);
-    size_t totlen, curlen = sh->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 */
-    sh = (void*)(s-sizeof *sh);
     memset(s+curlen,0,(len-curlen+1)); /* also set trailing \0 byte */
-    totlen = sh->len+sh->free;
-    sh->len = len;
-    sh->free = totlen-sh->len;
+    sdssetlen(s, len);
     return s;
 }
 
@@ -235,15 +374,12 @@ sds sdsgrowzero(sds s, size_t len) {
  * 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) {
-    struct sdshdr *sh;
     size_t curlen = sdslen(s);
 
     s = sdsMakeRoomFor(s,len);
     if (s == NULL) return NULL;
-    sh = (void*) (s-sizeof *sh);
     memcpy(s+curlen, t, len);
-    sh->len = curlen+len;
-    sh->free = sh->free-len;
+    sdssetlen(s, curlen+len);
     s[curlen+len] = '\0';
     return s;
 }
@@ -267,19 +403,13 @@ sds sdscatsds(sds s, const sds 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) {
-    struct sdshdr *sh = (void*) (s-sizeof *sh);
-    size_t totlen = sh->free+sh->len;
-
-    if (totlen < len) {
-        s = sdsMakeRoomFor(s,len-sh->len);
+    if (sdsalloc(s) < len) {
+        s = sdsMakeRoomFor(s,len-sdslen(s));
         if (s == NULL) return NULL;
-        sh = (void*) (s-sizeof *sh);
-        totlen = sh->free+sh->len;
     }
     memcpy(s, t, len);
     s[len] = '\0';
-    sh->len = len;
-    sh->free = totlen-len;
+    sdssetlen(s, len);
     return s;
 }
 
@@ -356,27 +486,52 @@ int sdsull2str(char *s, unsigned long long v) {
     return l;
 }
 
-/* Like sdscatpritf() but gets va_list instead of being variadic. */
+/* 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 *buf, *t;
-    size_t buflen = 16;
+    char staticbuf[1024], *buf = staticbuf, *t;
+    size_t buflen = strlen(fmt)*2;
 
-    while(1) {
-        buf = malloc(buflen);
+    /* 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') {
-            free(buf);
+            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);
-    free(buf);
+    if (buf != staticbuf) s_free(buf);
     return t;
 }
 
@@ -389,7 +544,7 @@ sds sdscatvprintf(sds s, const char *fmt, va_list ap) {
  * Example:
  *
  * s = sdsnew("Sum is: ");
- * s = sdscatprintf(s,"%d+%d = %d",a,b,a+b);
+ * 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:
@@ -419,11 +574,9 @@ sds sdscatprintf(sds s, const char *fmt, ...) {
  * %I - 64 bit signed integer (long long, int64_t)
  * %u - unsigned int
  * %U - 64 bit unsigned integer (unsigned long long, uint64_t)
- * %T - A size_t variable.
  * %% - Verbatim "%" character.
  */
 sds sdscatfmt(sds s, char const *fmt, ...) {
-    struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr)));
     const char *f = fmt;
     int i;
     va_list ap;
@@ -432,14 +585,13 @@ sds sdscatfmt(sds s, char const *fmt, ...) {
     i = sdslen(s); /* Position of the next byte to write to dest str. */
     while(*f) {
         char next, *str;
-        int l;
+        size_t l;
         long long num;
         unsigned long long unum;
 
         /* Make sure there is always space for at least 1 char. */
-        if (sh->free == 0) {
+        if (sdsavail(s)==0) {
             s = sdsMakeRoomFor(s,1);
-            sh = (void*) (s-(sizeof(struct sdshdr)));
         }
 
         switch(*f) {
@@ -451,13 +603,11 @@ sds sdscatfmt(sds s, char const *fmt, ...) {
             case 'S':
                 str = va_arg(ap,char*);
                 l = (next == 's') ? strlen(str) : sdslen(str);
-                if (sh->free < l) {
+                if (sdsavail(s) < l) {
                     s = sdsMakeRoomFor(s,l);
-                    sh = (void*) (s-(sizeof(struct sdshdr)));
                 }
                 memcpy(s+i,str,l);
-                sh->len += l;
-                sh->free -= l;
+                sdsinclen(s,l);
                 i += l;
                 break;
             case 'i':
@@ -469,49 +619,40 @@ sds sdscatfmt(sds s, char const *fmt, ...) {
                 {
                     char buf[SDS_LLSTR_SIZE];
                     l = sdsll2str(buf,num);
-                    if (sh->free < l) {
+                    if (sdsavail(s) < l) {
                         s = sdsMakeRoomFor(s,l);
-                        sh = (void*) (s-(sizeof(struct sdshdr)));
                     }
                     memcpy(s+i,buf,l);
-                    sh->len += l;
-                    sh->free -= l;
+                    sdsinclen(s,l);
                     i += l;
                 }
                 break;
             case 'u':
             case 'U':
-            case 'T':
                 if (next == 'u')
                     unum = va_arg(ap,unsigned int);
-                else if(next == 'U')
-                    unum = va_arg(ap,unsigned long long);
                 else
-                    unum = (unsigned long long)va_arg(ap,size_t);
+                    unum = va_arg(ap,unsigned long long);
                 {
                     char buf[SDS_LLSTR_SIZE];
                     l = sdsull2str(buf,unum);
-                    if (sh->free < l) {
+                    if (sdsavail(s) < l) {
                         s = sdsMakeRoomFor(s,l);
-                        sh = (void*) (s-(sizeof(struct sdshdr)));
                     }
                     memcpy(s+i,buf,l);
-                    sh->len += l;
-                    sh->free -= l;
+                    sdsinclen(s,l);
                     i += l;
                 }
                 break;
             default: /* Handle %% and generally %<unknown>. */
                 s[i++] = next;
-                sh->len += 1;
-                sh->free -= 1;
+                sdsinclen(s,1);
                 break;
             }
             break;
         default:
             s[i++] = *f;
-            sh->len += 1;
-            sh->free -= 1;
+            sdsinclen(s,1);
             break;
         }
         f++;
@@ -523,7 +664,6 @@ sds sdscatfmt(sds s, char const *fmt, ...) {
     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.
  *
@@ -533,25 +673,24 @@ sds sdscatfmt(sds s, char const *fmt, ...) {
  * Example:
  *
  * s = sdsnew("AA...AA.a.aa.aHelloWorld     :::");
- * s = sdstrim(s,"A. :");
+ * s = sdstrim(s,"Aa. :");
  * printf("%s\n", s);
  *
  * Output will be just "Hello World".
  */
-void sdstrim(sds s, const char *cset) {
-    struct sdshdr *sh = (void*) (s-sizeof *sh);
+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 > start && strchr(cset, *ep)) ep--;
+    while(ep > sp && strchr(cset, *ep)) ep--;
     len = (sp > ep) ? 0 : ((ep-sp)+1);
-    if (sh->buf != sp) memmove(sh->buf, sp, len);
-    sh->buf[len] = '\0';
-    sh->free = sh->free+(sh->len-len);
-    sh->len = len;
+    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
@@ -571,7 +710,6 @@ void sdstrim(sds s, const char *cset) {
  * sdsrange(s,1,-1); => "ello World"
  */
 void sdsrange(sds s, int start, int end) {
-    struct sdshdr *sh = (void*) (s-sizeof *sh);
     size_t newlen, len = sdslen(s);
 
     if (len == 0) return;
@@ -594,10 +732,9 @@ void sdsrange(sds s, int start, int end) {
     } else {
         start = 0;
     }
-    if (start && newlen) memmove(sh->buf, sh->buf+start, newlen);
-    sh->buf[newlen] = 0;
-    sh->free = sh->free+(sh->len-newlen);
-    sh->len = newlen;
+    if (start && newlen) memmove(s, s+start, newlen);
+    s[newlen] = 0;
+    sdssetlen(s,newlen);
 }
 
 /* Apply tolower() to every character of the sds string 's'. */
@@ -618,8 +755,8 @@ void sdstoupper(sds s) {
  *
  * Return value:
  *
- *     1 if s1 > s2.
- *    -1 if s1 < s2.
+ *     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
@@ -659,7 +796,7 @@ sds *sdssplitlen(const char *s, int len, const char *sep, int seplen, int *count
 
     if (seplen < 1 || len < 0) return NULL;
 
-    tokens = malloc(sizeof(sds)*slots);
+    tokens = s_malloc(sizeof(sds)*slots);
     if (tokens == NULL) return NULL;
 
     if (len == 0) {
@@ -672,7 +809,7 @@ sds *sdssplitlen(const char *s, int len, const char *sep, int seplen, int *count
             sds *newtokens;
 
             slots *= 2;
-            newtokens = realloc(tokens,sizeof(sds)*slots);
+            newtokens = s_realloc(tokens,sizeof(sds)*slots);
             if (newtokens == NULL) goto cleanup;
             tokens = newtokens;
         }
@@ -696,7 +833,7 @@ cleanup:
     {
         int i;
         for (i = 0; i < elements; i++) sdsfree(tokens[i]);
-        free(tokens);
+        s_free(tokens);
         *count = 0;
         return NULL;
     }
@@ -707,26 +844,7 @@ void sdsfreesplitres(sds *tokens, int count) {
     if (!tokens) return;
     while(count--)
         sdsfree(tokens[count]);
-    free(tokens);
-}
-
-/* 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[32], *p;
-    unsigned long long v;
-
-    v = (value < 0) ? -value : value;
-    p = buf+31; /* point to the last character */
-    do {
-        *p-- = '0'+(v%10);
-        v /= 10;
-    } while(v);
-    if (value < 0) *p-- = '-';
-    p++;
-    return sdsnewlen(p,32-(p-buf));
+    s_free(tokens);
 }
 
 /* Append to the sds string "s" an escaped string representation where
@@ -900,13 +1018,13 @@ sds *sdssplitargs(const char *line, int *argc) {
                 if (*p) p++;
             }
             /* add the token to the vector */
-            vector = realloc(vector,((*argc)+1)*sizeof(char*));
+            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 = malloc(sizeof(void*));
+            if (vector == NULL) vector = s_malloc(sizeof(void*));
             return vector;
         }
     }
@@ -914,7 +1032,7 @@ sds *sdssplitargs(const char *line, int *argc) {
 err:
     while((*argc)--)
         sdsfree(vector[*argc]);
-    free(vector);
+    s_free(vector);
     if (current) sdsfree(current);
     *argc = 0;
     return NULL;
@@ -945,13 +1063,13 @@ sds sdsmapchars(sds s, const char *from, const char *to, size_t setlen) {
 
 /* 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, size_t seplen) {
+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 = sdscatlen(join,sep,seplen);
+        if (j != argc-1) join = sdscat(join,sep);
     }
     return join;
 }
@@ -968,13 +1086,23 @@ sds sdsjoinsds(sds *argv, int argc, const char *sep, size_t seplen) {
     return join;
 }
 
-#ifdef SDS_TEST_MAIN
+/* 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"
 
-int main(void) {
+#define UNUSED(x) (void)(x)
+int sdsTest(void) {
     {
-        struct sdshdr *sh;
         sds x = sdsnew("foo"), y;
 
         test_cond("Create a string and obtain the length",
@@ -1001,7 +1129,35 @@ int main(void) {
         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)
+            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");
@@ -1070,24 +1226,47 @@ int main(void) {
             memcmp(y,"\"\\a\\n\\x00foo\\r\"",15) == 0)
 
         {
-            int oldfree;
+            unsigned int oldfree;
+            char *p;
+            int step = 10, j, i;
 
             sdsfree(x);
+            sdsfree(y);
             x = sdsnew("0");
-            sh = (void*) (x-(sizeof(struct sdshdr)));
-            test_cond("sdsnew() free/len buffers", sh->len == 1 && sh->free == 0);
-            x = sdsMakeRoomFor(x,1);
-            sh = (void*) (x-(sizeof(struct sdshdr)));
-            test_cond("sdsMakeRoomFor()", sh->len == 1 && sh->free > 0);
-            oldfree = sh->free;
-            x[1] = '1';
-            sdsIncrLen(x,1);
-            test_cond("sdsIncrLen() -- content", x[0] == '0' && x[1] == '1');
-            test_cond("sdsIncrLen() -- len", sh->len == 2);
-            test_cond("sdsIncrLen() -- free", sh->free == oldfree-1);
+            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/sds.h b/sds.h
index 19a2abd..394f8b5 100644
--- a/sds.h
+++ b/sds.h
@@ -1,6 +1,8 @@
-/* SDS (Simple Dynamic Strings), A C dynamic strings library.
+/* SDSLib 2.0 -- A C dynamic strings library
  *
- * Copyright (c) 2006-2014, Salvatore Sanfilippo <antirez at gmail dot com>
+ * 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
@@ -35,35 +37,188 @@
 
 #include <sys/types.h>
 #include <stdarg.h>
-#ifdef _MSC_VER
-#include "win32.h"
-#endif
+#include <stdint.h>
 
 typedef char *sds;
 
-struct sdshdr {
-    int len;
-    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 = (struct sdshdr *)(s-sizeof *sh);
-    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 = (struct sdshdr *)(s-sizeof *sh);
-    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);
@@ -80,7 +235,7 @@ sds sdscatprintf(sds s, const char *fmt, ...);
 #endif
 
 sds sdscatfmt(sds s, char const *fmt, ...);
-void sdstrim(sds s, const char *cset);
+sds sdstrim(sds s, const char *cset);
 void sdsrange(sds s, int start, int end);
 void sdsupdatelen(sds s);
 void sdsclear(sds s);
@@ -93,7 +248,7 @@ 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, size_t seplen);
+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 */
@@ -101,5 +256,18 @@ 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);
+
+/* 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/sdsalloc.h b/sdsalloc.h
new file mode 100644
index 0000000..f43023c
--- /dev/null
+++ b/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