Refactor reading code into read.c

Makes hiredis reading functions easier to include in external projects

[fixed all merge conflicts against current version]

Closes #249

5 files changed, 646 insertions, 553 deletions

diff --git a/Makefile b/Makefile
index 09a6ef5..4133c9b 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,7 @@
 # Copyright (C) 2010-2011 Pieter Noordhuis <pcnoordhuis at gmail dot com>
 # This file is released under the BSD license, see the COPYING file
 
-OBJ=net.o hiredis.o sds.o async.o
+OBJ=net.o hiredis.o sds.o async.o read.o
 EXAMPLES=hiredis-example hiredis-example-libevent hiredis-example-libev hiredis-example-glib
 TESTS=hiredis-test
 LIBNAME=libhiredis
@@ -59,6 +59,7 @@ all: $(DYLIBNAME)
 # Deps (use make dep to generate this)
 net.o: net.c fmacros.h net.h hiredis.h
 async.o: async.c async.h hiredis.h sds.h dict.c dict.h
+read.o: read.c read.h
 hiredis.o: hiredis.c fmacros.h hiredis.h net.h sds.h
 sds.o: sds.c sds.h
 test.o: test.c hiredis.h
diff --git a/hiredis.c b/hiredis.c
index da3cd74..9a826ae 100644
--- a/hiredis.c
+++ b/hiredis.c
@@ -186,487 +186,6 @@ static void *createNilObject(const redisReadTask *task) {
     return r;
 }
 
-static void __redisReaderSetError(redisReader *r, int type, const char *str) {
-    size_t len;
-
-    if (r->reply != NULL && r->fn && r->fn->freeObject) {
-        r->fn->freeObject(r->reply);
-        r->reply = NULL;
-    }
-
-    /* Clear input buffer on errors. */
-    if (r->buf != NULL) {
-        sdsfree(r->buf);
-        r->buf = NULL;
-        r->pos = r->len = 0;
-    }
-
-    /* Reset task stack. */
-    r->ridx = -1;
-
-    /* Set error. */
-    r->err = type;
-    len = strlen(str);
-    len = len < (sizeof(r->errstr)-1) ? len : (sizeof(r->errstr)-1);
-    memcpy(r->errstr,str,len);
-    r->errstr[len] = '\0';
-}
-
-static size_t chrtos(char *buf, size_t size, char byte) {
-    size_t len = 0;
-
-    switch(byte) {
-    case '\\':
-    case '"':
-        len = snprintf(buf,size,"\"\\%c\"",byte);
-        break;
-    case '\n': len = snprintf(buf,size,"\"\\n\""); break;
-    case '\r': len = snprintf(buf,size,"\"\\r\""); break;
-    case '\t': len = snprintf(buf,size,"\"\\t\""); break;
-    case '\a': len = snprintf(buf,size,"\"\\a\""); break;
-    case '\b': len = snprintf(buf,size,"\"\\b\""); break;
-    default:
-        if (isprint(byte))
-            len = snprintf(buf,size,"\"%c\"",byte);
-        else
-            len = snprintf(buf,size,"\"\\x%02x\"",(unsigned char)byte);
-        break;
-    }
-
-    return len;
-}
-
-static void __redisReaderSetErrorProtocolByte(redisReader *r, char byte) {
-    char cbuf[8], sbuf[128];
-
-    chrtos(cbuf,sizeof(cbuf),byte);
-    snprintf(sbuf,sizeof(sbuf),
-        "Protocol error, got %s as reply type byte", cbuf);
-    __redisReaderSetError(r,REDIS_ERR_PROTOCOL,sbuf);
-}
-
-static void __redisReaderSetErrorOOM(redisReader *r) {
-    __redisReaderSetError(r,REDIS_ERR_OOM,"Out of memory");
-}
-
-static char *readBytes(redisReader *r, unsigned int bytes) {
-    char *p;
-    if (r->len-r->pos >= bytes) {
-        p = r->buf+r->pos;
-        r->pos += bytes;
-        return p;
-    }
-    return NULL;
-}
-
-/* Find pointer to \r\n. */
-static char *seekNewline(char *s, size_t len) {
-    int pos = 0;
-    int _len = len-1;
-
-    /* Position should be < len-1 because the character at "pos" should be
-     * followed by a \n. Note that strchr cannot be used because it doesn't
-     * allow to search a limited length and the buffer that is being searched
-     * might not have a trailing NULL character. */
-    while (pos < _len) {
-        while(pos < _len && s[pos] != '\r') pos++;
-        if (s[pos] != '\r') {
-            /* Not found. */
-            return NULL;
-        } else {
-            if (s[pos+1] == '\n') {
-                /* Found. */
-                return s+pos;
-            } else {
-                /* Continue searching. */
-                pos++;
-            }
-        }
-    }
-    return NULL;
-}
-
-/* Read a long long value starting at *s, under the assumption that it will be
- * terminated by \r\n. Ambiguously returns -1 for unexpected input. */
-static long long readLongLong(char *s) {
-    long long v = 0;
-    int dec, mult = 1;
-    char c;
-
-    if (*s == '-') {
-        mult = -1;
-        s++;
-    } else if (*s == '+') {
-        mult = 1;
-        s++;
-    }
-
-    while ((c = *(s++)) != '\r') {
-        dec = c - '0';
-        if (dec >= 0 && dec < 10) {
-            v *= 10;
-            v += dec;
-        } else {
-            /* Should not happen... */
-            return -1;
-        }
-    }
-
-    return mult*v;
-}
-
-static char *readLine(redisReader *r, int *_len) {
-    char *p, *s;
-    int len;
-
-    p = r->buf+r->pos;
-    s = seekNewline(p,(r->len-r->pos));
-    if (s != NULL) {
-        len = s-(r->buf+r->pos);
-        r->pos += len+2; /* skip \r\n */
-        if (_len) *_len = len;
-        return p;
-    }
-    return NULL;
-}
-
-static void moveToNextTask(redisReader *r) {
-    redisReadTask *cur, *prv;
-    while (r->ridx >= 0) {
-        /* Return a.s.a.p. when the stack is now empty. */
-        if (r->ridx == 0) {
-            r->ridx--;
-            return;
-        }
-
-        cur = &(r->rstack[r->ridx]);
-        prv = &(r->rstack[r->ridx-1]);
-        assert(prv->type == REDIS_REPLY_ARRAY);
-        if (cur->idx == prv->elements-1) {
-            r->ridx--;
-        } else {
-            /* Reset the type because the next item can be anything */
-            assert(cur->idx < prv->elements);
-            cur->type = -1;
-            cur->elements = -1;
-            cur->idx++;
-            return;
-        }
-    }
-}
-
-static int processLineItem(redisReader *r) {
-    redisReadTask *cur = &(r->rstack[r->ridx]);
-    void *obj;
-    char *p;
-    int len;
-
-    if ((p = readLine(r,&len)) != NULL) {
-        if (cur->type == REDIS_REPLY_INTEGER) {
-            if (r->fn && r->fn->createInteger)
-                obj = r->fn->createInteger(cur,readLongLong(p));
-            else
-                obj = (void*)REDIS_REPLY_INTEGER;
-        } else {
-            /* Type will be error or status. */
-            if (r->fn && r->fn->createString)
-                obj = r->fn->createString(cur,p,len);
-            else
-                obj = (void*)(size_t)(cur->type);
-        }
-
-        if (obj == NULL) {
-            __redisReaderSetErrorOOM(r);
-            return REDIS_ERR;
-        }
-
-        /* Set reply if this is the root object. */
-        if (r->ridx == 0) r->reply = obj;
-        moveToNextTask(r);
-        return REDIS_OK;
-    }
-
-    return REDIS_ERR;
-}
-
-static int processBulkItem(redisReader *r) {
-    redisReadTask *cur = &(r->rstack[r->ridx]);
-    void *obj = NULL;
-    char *p, *s;
-    long len;
-    unsigned long bytelen;
-    int success = 0;
-
-    p = r->buf+r->pos;
-    s = seekNewline(p,r->len-r->pos);
-    if (s != NULL) {
-        p = r->buf+r->pos;
-        bytelen = s-(r->buf+r->pos)+2; /* include \r\n */
-        len = readLongLong(p);
-
-        if (len < 0) {
-            /* The nil object can always be created. */
-            if (r->fn && r->fn->createNil)
-                obj = r->fn->createNil(cur);
-            else
-                obj = (void*)REDIS_REPLY_NIL;
-            success = 1;
-        } else {
-            /* Only continue when the buffer contains the entire bulk item. */
-            bytelen += len+2; /* include \r\n */
-            if (r->pos+bytelen <= r->len) {
-                if (r->fn && r->fn->createString)
-                    obj = r->fn->createString(cur,s+2,len);
-                else
-                    obj = (void*)REDIS_REPLY_STRING;
-                success = 1;
-            }
-        }
-
-        /* Proceed when obj was created. */
-        if (success) {
-            if (obj == NULL) {
-                __redisReaderSetErrorOOM(r);
-                return REDIS_ERR;
-            }
-
-            r->pos += bytelen;
-
-            /* Set reply if this is the root object. */
-            if (r->ridx == 0) r->reply = obj;
-            moveToNextTask(r);
-            return REDIS_OK;
-        }
-    }
-
-    return REDIS_ERR;
-}
-
-static int processMultiBulkItem(redisReader *r) {
-    redisReadTask *cur = &(r->rstack[r->ridx]);
-    void *obj;
-    char *p;
-    long elements;
-    int root = 0;
-
-    /* Set error for nested multi bulks with depth > 7 */
-    if (r->ridx == 8) {
-        __redisReaderSetError(r,REDIS_ERR_PROTOCOL,
-            "No support for nested multi bulk replies with depth > 7");
-        return REDIS_ERR;
-    }
-
-    if ((p = readLine(r,NULL)) != NULL) {
-        elements = readLongLong(p);
-        root = (r->ridx == 0);
-
-        if (elements == -1) {
-            if (r->fn && r->fn->createNil)
-                obj = r->fn->createNil(cur);
-            else
-                obj = (void*)REDIS_REPLY_NIL;
-
-            if (obj == NULL) {
-                __redisReaderSetErrorOOM(r);
-                return REDIS_ERR;
-            }
-
-            moveToNextTask(r);
-        } else {
-            if (r->fn && r->fn->createArray)
-                obj = r->fn->createArray(cur,elements);
-            else
-                obj = (void*)REDIS_REPLY_ARRAY;
-
-            if (obj == NULL) {
-                __redisReaderSetErrorOOM(r);
-                return REDIS_ERR;
-            }
-
-            /* Modify task stack when there are more than 0 elements. */
-            if (elements > 0) {
-                cur->elements = elements;
-                cur->obj = obj;
-                r->ridx++;
-                r->rstack[r->ridx].type = -1;
-                r->rstack[r->ridx].elements = -1;
-                r->rstack[r->ridx].idx = 0;
-                r->rstack[r->ridx].obj = NULL;
-                r->rstack[r->ridx].parent = cur;
-                r->rstack[r->ridx].privdata = r->privdata;
-            } else {
-                moveToNextTask(r);
-            }
-        }
-
-        /* Set reply if this is the root object. */
-        if (root) r->reply = obj;
-        return REDIS_OK;
-    }
-
-    return REDIS_ERR;
-}
-
-static int processItem(redisReader *r) {
-    redisReadTask *cur = &(r->rstack[r->ridx]);
-    char *p;
-
-    /* check if we need to read type */
-    if (cur->type < 0) {
-        if ((p = readBytes(r,1)) != NULL) {
-            switch (p[0]) {
-            case '-':
-                cur->type = REDIS_REPLY_ERROR;
-                break;
-            case '+':
-                cur->type = REDIS_REPLY_STATUS;
-                break;
-            case ':':
-                cur->type = REDIS_REPLY_INTEGER;
-                break;
-            case '$':
-                cur->type = REDIS_REPLY_STRING;
-                break;
-            case '*':
-                cur->type = REDIS_REPLY_ARRAY;
-                break;
-            default:
-                __redisReaderSetErrorProtocolByte(r,*p);
-                return REDIS_ERR;
-            }
-        } else {
-            /* could not consume 1 byte */
-            return REDIS_ERR;
-        }
-    }
-
-    /* process typed item */
-    switch(cur->type) {
-    case REDIS_REPLY_ERROR:
-    case REDIS_REPLY_STATUS:
-    case REDIS_REPLY_INTEGER:
-        return processLineItem(r);
-    case REDIS_REPLY_STRING:
-        return processBulkItem(r);
-    case REDIS_REPLY_ARRAY:
-        return processMultiBulkItem(r);
-    default:
-        assert(NULL);
-        return REDIS_ERR; /* Avoid warning. */
-    }
-}
-
-redisReader *redisReaderCreate(void) {
-    redisReader *r;
-
-    r = calloc(1,sizeof(redisReader));
-    if (r == NULL)
-        return NULL;
-
-    r->err = 0;
-    r->errstr[0] = '\0';
-    r->fn = &defaultFunctions;
-    r->buf = sdsempty();
-    r->maxbuf = REDIS_READER_MAX_BUF;
-    if (r->buf == NULL) {
-        free(r);
-        return NULL;
-    }
-
-    r->ridx = -1;
-    return r;
-}
-
-void redisReaderFree(redisReader *r) {
-    if (r->reply != NULL && r->fn && r->fn->freeObject)
-        r->fn->freeObject(r->reply);
-    if (r->buf != NULL)
-        sdsfree(r->buf);
-    free(r);
-}
-
-int redisReaderFeed(redisReader *r, const char *buf, size_t len) {
-    sds newbuf;
-
-    /* Return early when this reader is in an erroneous state. */
-    if (r->err)
-        return REDIS_ERR;
-
-    /* Copy the provided buffer. */
-    if (buf != NULL && len >= 1) {
-        /* Destroy internal buffer when it is empty and is quite large. */
-        if (r->len == 0 && r->maxbuf != 0 && sdsavail(r->buf) > r->maxbuf) {
-            sdsfree(r->buf);
-            r->buf = sdsempty();
-            r->pos = 0;
-
-            /* r->buf should not be NULL since we just free'd a larger one. */
-            assert(r->buf != NULL);
-        }
-
-        newbuf = sdscatlen(r->buf,buf,len);
-        if (newbuf == NULL) {
-            __redisReaderSetErrorOOM(r);
-            return REDIS_ERR;
-        }
-
-        r->buf = newbuf;
-        r->len = sdslen(r->buf);
-    }
-
-    return REDIS_OK;
-}
-
-int redisReaderGetReply(redisReader *r, void **reply) {
-    /* Default target pointer to NULL. */
-    if (reply != NULL)
-        *reply = NULL;
-
-    /* Return early when this reader is in an erroneous state. */
-    if (r->err)
-        return REDIS_ERR;
-
-    /* When the buffer is empty, there will never be a reply. */
-    if (r->len == 0)
-        return REDIS_OK;
-
-    /* Set first item to process when the stack is empty. */
-    if (r->ridx == -1) {
-        r->rstack[0].type = -1;
-        r->rstack[0].elements = -1;
-        r->rstack[0].idx = -1;
-        r->rstack[0].obj = NULL;
-        r->rstack[0].parent = NULL;
-        r->rstack[0].privdata = r->privdata;
-        r->ridx = 0;
-    }
-
-    /* Process items in reply. */
-    while (r->ridx >= 0)
-        if (processItem(r) != REDIS_OK)
-            break;
-
-    /* Return ASAP when an error occurred. */
-    if (r->err)
-        return REDIS_ERR;
-
-    /* Discard part of the buffer when we've consumed at least 1k, to avoid
-     * doing unnecessary calls to memmove() in sds.c. */
-    if (r->pos >= 1024) {
-        sdsrange(r->buf,r->pos,-1);
-        r->pos = 0;
-        r->len = sdslen(r->buf);
-    }
-
-    /* Emit a reply when there is one. */
-    if (r->ridx == -1) {
-        if (reply != NULL)
-            *reply = r->reply;
-        r->reply = NULL;
-    }
-    return REDIS_OK;
-}
-
 /* Calculate the number of bytes needed to represent an integer as string. */
 static int intlen(int i) {
     int len = 0;
@@ -1064,6 +583,10 @@ void __redisSetError(redisContext *c, int type, const char *str) {
     }
 }
 
+redisReader *redisReaderCreate(void) {
+    return redisReaderCreateWithFunctions(&defaultFunctions);
+}
+
 static redisContext *redisContextInit(void) {
     redisContext *c;
 
diff --git a/hiredis.h b/hiredis.h
index 114b9ae..f01b1ca 100644
--- a/hiredis.h
+++ b/hiredis.h
@@ -31,7 +31,7 @@
 
 #ifndef __HIREDIS_H
 #define __HIREDIS_H
-#include <stdio.h> /* for size_t */
+#include "read.h"
 #include <stdarg.h> /* for va_list */
 #include <sys/time.h> /* for struct timeval */
 #include "sds.h" /* for sds */
@@ -40,19 +40,6 @@
 #define HIREDIS_MINOR 11
 #define HIREDIS_PATCH 0
 
-#define REDIS_ERR -1
-#define REDIS_OK 0
-
-/* When an error occurs, the err flag in a context is set to hold the type of
- * error that occured. REDIS_ERR_IO means there was an I/O error and you
- * should use the "errno" variable to find out what is wrong.
- * For other values, the "errstr" field will hold a description. */
-#define REDIS_ERR_IO 1 /* Error in read or write */
-#define REDIS_ERR_EOF 3 /* End of file */
-#define REDIS_ERR_PROTOCOL 4 /* Protocol error */
-#define REDIS_ERR_OOM 5 /* Out of memory */
-#define REDIS_ERR_OTHER 2 /* Everything else... */
-
 /* Connection type can be blocking or non-blocking and is set in the
  * least significant bit of the flags field in redisContext. */
 #define REDIS_BLOCK 0x1
@@ -83,15 +70,6 @@
 /* Flag that is set when we should set SO_REUSEADDR before calling bind() */
 #define REDIS_REUSEADDR 0x80
 
-#define REDIS_REPLY_STRING 1
-#define REDIS_REPLY_ARRAY 2
-#define REDIS_REPLY_INTEGER 3
-#define REDIS_REPLY_NIL 4
-#define REDIS_REPLY_STATUS 5
-#define REDIS_REPLY_ERROR 6
-
-#define REDIS_READER_MAX_BUF (1024*16)  /* Default max unused reader buffer. */
-
 #define REDIS_KEEPALIVE_INTERVAL 15 /* seconds */
 
 /* number of times we retry to connect in the case of EADDRNOTAVAIL and
@@ -112,55 +90,7 @@ typedef struct redisReply {
     struct redisReply **element; /* elements vector for REDIS_REPLY_ARRAY */
 } redisReply;
 
-typedef struct redisReadTask {
-    int type;
-    int elements; /* number of elements in multibulk container */
-    int idx; /* index in parent (array) object */
-    void *obj; /* holds user-generated value for a read task */
-    struct redisReadTask *parent; /* parent task */
-    void *privdata; /* user-settable arbitrary field */
-} redisReadTask;
-
-typedef struct redisReplyObjectFunctions {
-    void *(*createString)(const redisReadTask*, char*, size_t);
-    void *(*createArray)(const redisReadTask*, int);
-    void *(*createInteger)(const redisReadTask*, long long);
-    void *(*createNil)(const redisReadTask*);
-    void (*freeObject)(void*);
-} redisReplyObjectFunctions;
-
-/* State for the protocol parser */
-typedef struct redisReader {
-    int err; /* Error flags, 0 when there is no error */
-    char errstr[128]; /* String representation of error when applicable */
-
-    char *buf; /* Read buffer */
-    size_t pos; /* Buffer cursor */
-    size_t len; /* Buffer length */
-    size_t maxbuf; /* Max length of unused buffer */
-
-    redisReadTask rstack[9];
-    int ridx; /* Index of current read task */
-    void *reply; /* Temporary reply pointer */
-
-    redisReplyObjectFunctions *fn;
-    void *privdata;
-} redisReader;
-
-/* Public API for the protocol parser. */
 redisReader *redisReaderCreate(void);
-void redisReaderFree(redisReader *r);
-int redisReaderFeed(redisReader *r, const char *buf, size_t len);
-int redisReaderGetReply(redisReader *r, void **reply);
-
-/* Backwards compatibility, can be removed on big version bump. */
-#define redisReplyReaderCreate redisReaderCreate
-#define redisReplyReaderFree redisReaderFree
-#define redisReplyReaderFeed redisReaderFeed
-#define redisReplyReaderGetReply redisReaderGetReply
-#define redisReplyReaderSetPrivdata(_r, _p) (int)(((redisReader*)(_r))->privdata = (_p))
-#define redisReplyReaderGetObject(_r) (((redisReader*)(_r))->reply)
-#define redisReplyReaderGetError(_r) (((redisReader*)(_r))->errstr)
 
 /* Function to free the reply objects hiredis returns by default. */
 void freeReplyObject(void *reply);
diff --git a/read.c b/read.c
new file mode 100644
index 0000000..457ac68
--- /dev/null
+++ b/read.c
@@ -0,0 +1,523 @@
+/*
+ * Copyright (c) 2009-2011, Salvatore Sanfilippo <antirez at gmail dot com>
+ * Copyright (c) 2010-2011, Pieter Noordhuis <pcnoordhuis at gmail dot com>
+ *
+ * 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 "fmacros.h"
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <ctype.h>
+
+#include "read.h"
+#include "sds.h"
+
+static void __redisReaderSetError(redisReader *r, int type, const char *str) {
+    size_t len;
+
+    if (r->reply != NULL && r->fn && r->fn->freeObject) {
+        r->fn->freeObject(r->reply);
+        r->reply = NULL;
+    }
+
+    /* Clear input buffer on errors. */
+    if (r->buf != NULL) {
+        sdsfree(r->buf);
+        r->buf = NULL;
+        r->pos = r->len = 0;
+    }
+
+    /* Reset task stack. */
+    r->ridx = -1;
+
+    /* Set error. */
+    r->err = type;
+    len = strlen(str);
+    len = len < (sizeof(r->errstr)-1) ? len : (sizeof(r->errstr)-1);
+    memcpy(r->errstr,str,len);
+    r->errstr[len] = '\0';
+}
+
+static size_t chrtos(char *buf, size_t size, char byte) {
+    size_t len = 0;
+
+    switch(byte) {
+    case '\\':
+    case '"':
+        len = snprintf(buf,size,"\"\\%c\"",byte);
+        break;
+    case '\n': len = snprintf(buf,size,"\"\\n\""); break;
+    case '\r': len = snprintf(buf,size,"\"\\r\""); break;
+    case '\t': len = snprintf(buf,size,"\"\\t\""); break;
+    case '\a': len = snprintf(buf,size,"\"\\a\""); break;
+    case '\b': len = snprintf(buf,size,"\"\\b\""); break;
+    default:
+        if (isprint(byte))
+            len = snprintf(buf,size,"\"%c\"",byte);
+        else
+            len = snprintf(buf,size,"\"\\x%02x\"",(unsigned char)byte);
+        break;
+    }
+
+    return len;
+}
+
+static void __redisReaderSetErrorProtocolByte(redisReader *r, char byte) {
+    char cbuf[8], sbuf[128];
+
+    chrtos(cbuf,sizeof(cbuf),byte);
+    snprintf(sbuf,sizeof(sbuf),
+        "Protocol error, got %s as reply type byte", cbuf);
+    __redisReaderSetError(r,REDIS_ERR_PROTOCOL,sbuf);
+}
+
+static void __redisReaderSetErrorOOM(redisReader *r) {
+    __redisReaderSetError(r,REDIS_ERR_OOM,"Out of memory");
+}
+
+static char *readBytes(redisReader *r, unsigned int bytes) {
+    char *p;
+    if (r->len-r->pos >= bytes) {
+        p = r->buf+r->pos;
+        r->pos += bytes;
+        return p;
+    }
+    return NULL;
+}
+
+/* Find pointer to \r\n. */
+static char *seekNewline(char *s, size_t len) {
+    int pos = 0;
+    int _len = len-1;
+
+    /* Position should be < len-1 because the character at "pos" should be
+     * followed by a \n. Note that strchr cannot be used because it doesn't
+     * allow to search a limited length and the buffer that is being searched
+     * might not have a trailing NULL character. */
+    while (pos < _len) {
+        while(pos < _len && s[pos] != '\r') pos++;
+        if (s[pos] != '\r') {
+            /* Not found. */
+            return NULL;
+        } else {
+            if (s[pos+1] == '\n') {
+                /* Found. */
+                return s+pos;
+            } else {
+                /* Continue searching. */
+                pos++;
+            }
+        }
+    }
+    return NULL;
+}
+
+/* Read a long long value starting at *s, under the assumption that it will be
+ * terminated by \r\n. Ambiguously returns -1 for unexpected input. */
+static long long readLongLong(char *s) {
+    long long v = 0;
+    int dec, mult = 1;
+    char c;
+
+    if (*s == '-') {
+        mult = -1;
+        s++;
+    } else if (*s == '+') {
+        mult = 1;
+        s++;
+    }
+
+    while ((c = *(s++)) != '\r') {
+        dec = c - '0';
+        if (dec >= 0 && dec < 10) {
+            v *= 10;
+            v += dec;
+        } else {
+            /* Should not happen... */
+            return -1;
+        }
+    }
+
+    return mult*v;
+}
+
+static char *readLine(redisReader *r, int *_len) {
+    char *p, *s;
+    int len;
+
+    p = r->buf+r->pos;
+    s = seekNewline(p,(r->len-r->pos));
+    if (s != NULL) {
+        len = s-(r->buf+r->pos);
+        r->pos += len+2; /* skip \r\n */
+        if (_len) *_len = len;
+        return p;
+    }
+    return NULL;
+}
+
+static void moveToNextTask(redisReader *r) {
+    redisReadTask *cur, *prv;
+    while (r->ridx >= 0) {
+        /* Return a.s.a.p. when the stack is now empty. */
+        if (r->ridx == 0) {
+            r->ridx--;
+            return;
+        }
+
+        cur = &(r->rstack[r->ridx]);
+        prv = &(r->rstack[r->ridx-1]);
+        assert(prv->type == REDIS_REPLY_ARRAY);
+        if (cur->idx == prv->elements-1) {
+            r->ridx--;
+        } else {
+            /* Reset the type because the next item can be anything */
+            assert(cur->idx < prv->elements);
+            cur->type = -1;
+            cur->elements = -1;
+            cur->idx++;
+            return;
+        }
+    }
+}
+
+static int processLineItem(redisReader *r) {
+    redisReadTask *cur = &(r->rstack[r->ridx]);
+    void *obj;
+    char *p;
+    int len;
+
+    if ((p = readLine(r,&len)) != NULL) {
+        if (cur->type == REDIS_REPLY_INTEGER) {
+            if (r->fn && r->fn->createInteger)
+                obj = r->fn->createInteger(cur,readLongLong(p));
+            else
+                obj = (void*)REDIS_REPLY_INTEGER;
+        } else {
+            /* Type will be error or status. */
+            if (r->fn && r->fn->createString)
+                obj = r->fn->createString(cur,p,len);
+            else
+                obj = (void*)(size_t)(cur->type);
+        }
+
+        if (obj == NULL) {
+            __redisReaderSetErrorOOM(r);
+            return REDIS_ERR;
+        }
+
+        /* Set reply if this is the root object. */
+        if (r->ridx == 0) r->reply = obj;
+        moveToNextTask(r);
+        return REDIS_OK;
+    }
+
+    return REDIS_ERR;
+}
+
+static int processBulkItem(redisReader *r) {
+    redisReadTask *cur = &(r->rstack[r->ridx]);
+    void *obj = NULL;
+    char *p, *s;
+    long len;
+    unsigned long bytelen;
+    int success = 0;
+
+    p = r->buf+r->pos;
+    s = seekNewline(p,r->len-r->pos);
+    if (s != NULL) {
+        p = r->buf+r->pos;
+        bytelen = s-(r->buf+r->pos)+2; /* include \r\n */
+        len = readLongLong(p);
+
+        if (len < 0) {
+            /* The nil object can always be created. */
+            if (r->fn && r->fn->createNil)
+                obj = r->fn->createNil(cur);
+            else
+                obj = (void*)REDIS_REPLY_NIL;
+            success = 1;
+        } else {
+            /* Only continue when the buffer contains the entire bulk item. */
+            bytelen += len+2; /* include \r\n */
+            if (r->pos+bytelen <= r->len) {
+                if (r->fn && r->fn->createString)
+                    obj = r->fn->createString(cur,s+2,len);
+                else
+                    obj = (void*)REDIS_REPLY_STRING;
+                success = 1;
+            }
+        }
+
+        /* Proceed when obj was created. */
+        if (success) {
+            if (obj == NULL) {
+                __redisReaderSetErrorOOM(r);
+                return REDIS_ERR;
+            }
+
+            r->pos += bytelen;
+
+            /* Set reply if this is the root object. */
+            if (r->ridx == 0) r->reply = obj;
+            moveToNextTask(r);
+            return REDIS_OK;
+        }
+    }
+
+    return REDIS_ERR;
+}
+
+static int processMultiBulkItem(redisReader *r) {
+    redisReadTask *cur = &(r->rstack[r->ridx]);
+    void *obj;
+    char *p;
+    long elements;
+    int root = 0;
+
+    /* Set error for nested multi bulks with depth > 7 */
+    if (r->ridx == 8) {
+        __redisReaderSetError(r,REDIS_ERR_PROTOCOL,
+            "No support for nested multi bulk replies with depth > 7");
+        return REDIS_ERR;
+    }
+
+    if ((p = readLine(r,NULL)) != NULL) {
+        elements = readLongLong(p);
+        root = (r->ridx == 0);
+
+        if (elements == -1) {
+            if (r->fn && r->fn->createNil)
+                obj = r->fn->createNil(cur);
+            else
+                obj = (void*)REDIS_REPLY_NIL;
+
+            if (obj == NULL) {
+                __redisReaderSetErrorOOM(r);
+                return REDIS_ERR;
+            }
+
+            moveToNextTask(r);
+        } else {
+            if (r->fn && r->fn->createArray)
+                obj = r->fn->createArray(cur,elements);
+            else
+                obj = (void*)REDIS_REPLY_ARRAY;
+
+            if (obj == NULL) {
+                __redisReaderSetErrorOOM(r);
+                return REDIS_ERR;
+            }
+
+            /* Modify task stack when there are more than 0 elements. */
+            if (elements > 0) {
+                cur->elements = elements;
+                cur->obj = obj;
+                r->ridx++;
+                r->rstack[r->ridx].type = -1;
+                r->rstack[r->ridx].elements = -1;
+                r->rstack[r->ridx].idx = 0;
+                r->rstack[r->ridx].obj = NULL;
+                r->rstack[r->ridx].parent = cur;
+                r->rstack[r->ridx].privdata = r->privdata;
+            } else {
+                moveToNextTask(r);
+            }
+        }
+
+        /* Set reply if this is the root object. */
+        if (root) r->reply = obj;
+        return REDIS_OK;
+    }
+
+    return REDIS_ERR;
+}
+
+static int processItem(redisReader *r) {
+    redisReadTask *cur = &(r->rstack[r->ridx]);
+    char *p;
+
+    /* check if we need to read type */
+    if (cur->type < 0) {
+        if ((p = readBytes(r,1)) != NULL) {
+            switch (p[0]) {
+            case '-':
+                cur->type = REDIS_REPLY_ERROR;
+                break;
+            case '+':
+                cur->type = REDIS_REPLY_STATUS;
+                break;
+            case ':':
+                cur->type = REDIS_REPLY_INTEGER;
+                break;
+            case '$':
+                cur->type = REDIS_REPLY_STRING;
+                break;
+            case '*':
+                cur->type = REDIS_REPLY_ARRAY;
+                break;
+            default:
+                __redisReaderSetErrorProtocolByte(r,*p);
+                return REDIS_ERR;
+            }
+        } else {
+            /* could not consume 1 byte */
+            return REDIS_ERR;
+        }
+    }
+
+    /* process typed item */
+    switch(cur->type) {
+    case REDIS_REPLY_ERROR:
+    case REDIS_REPLY_STATUS:
+    case REDIS_REPLY_INTEGER:
+        return processLineItem(r);
+    case REDIS_REPLY_STRING:
+        return processBulkItem(r);
+    case REDIS_REPLY_ARRAY:
+        return processMultiBulkItem(r);
+    default:
+        assert(NULL);
+        return REDIS_ERR; /* Avoid warning. */
+    }
+}
+
+redisReader *redisReaderCreateWithFunctions(redisReplyObjectFunctions *fn) {
+    redisReader *r;
+
+    r = calloc(sizeof(redisReader),1);
+    if (r == NULL)
+        return NULL;
+
+    r->err = 0;
+    r->errstr[0] = '\0';
+    r->fn = fn;
+    r->buf = sdsempty();
+    r->maxbuf = REDIS_READER_MAX_BUF;
+    if (r->buf == NULL) {
+        free(r);
+        return NULL;
+    }
+
+    r->ridx = -1;
+    return r;
+}
+
+void redisReaderFree(redisReader *r) {
+    if (r->reply != NULL && r->fn && r->fn->freeObject)
+        r->fn->freeObject(r->reply);
+    if (r->buf != NULL)
+        sdsfree(r->buf);
+    free(r);
+}
+
+int redisReaderFeed(redisReader *r, const char *buf, size_t len) {
+    sds newbuf;
+
+    /* Return early when this reader is in an erroneous state. */
+    if (r->err)
+        return REDIS_ERR;
+
+    /* Copy the provided buffer. */
+    if (buf != NULL && len >= 1) {
+        /* Destroy internal buffer when it is empty and is quite large. */
+        if (r->len == 0 && r->maxbuf != 0 && sdsavail(r->buf) > r->maxbuf) {
+            sdsfree(r->buf);
+            r->buf = sdsempty();
+            r->pos = 0;
+
+            /* r->buf should not be NULL since we just free'd a larger one. */
+            assert(r->buf != NULL);
+        }
+
+        newbuf = sdscatlen(r->buf,buf,len);
+        if (newbuf == NULL) {
+            __redisReaderSetErrorOOM(r);
+            return REDIS_ERR;
+        }
+
+        r->buf = newbuf;
+        r->len = sdslen(r->buf);
+    }
+
+    return REDIS_OK;
+}
+
+int redisReaderGetReply(redisReader *r, void **reply) {
+    /* Default target pointer to NULL. */
+    if (reply != NULL)
+        *reply = NULL;
+
+    /* Return early when this reader is in an erroneous state. */
+    if (r->err)
+        return REDIS_ERR;
+
+    /* When the buffer is empty, there will never be a reply. */
+    if (r->len == 0)
+        return REDIS_OK;
+
+    /* Set first item to process when the stack is empty. */
+    if (r->ridx == -1) {
+        r->rstack[0].type = -1;
+        r->rstack[0].elements = -1;
+        r->rstack[0].idx = -1;
+        r->rstack[0].obj = NULL;
+        r->rstack[0].parent = NULL;
+        r->rstack[0].privdata = r->privdata;
+        r->ridx = 0;
+    }
+
+    /* Process items in reply. */
+    while (r->ridx >= 0)
+        if (processItem(r) != REDIS_OK)
+            break;
+
+    /* Return ASAP when an error occurred. */
+    if (r->err)
+        return REDIS_ERR;
+
+    /* Discard part of the buffer when we've consumed at least 1k, to avoid
+     * doing unnecessary calls to memmove() in sds.c. */
+    if (r->pos >= 1024) {
+        sdsrange(r->buf,r->pos,-1);
+        r->pos = 0;
+        r->len = sdslen(r->buf);
+    }
+
+    /* Emit a reply when there is one. */
+    if (r->ridx == -1) {
+        if (reply != NULL)
+            *reply = r->reply;
+        r->reply = NULL;
+    }
+    return REDIS_OK;
+}
diff --git a/read.h b/read.h
new file mode 100644
index 0000000..635a872
--- /dev/null
+++ b/read.h
@@ -0,0 +1,116 @@
+/*
+ * Copyright (c) 2009-2011, Salvatore Sanfilippo <antirez at gmail dot com>
+ * Copyright (c) 2010-2011, Pieter Noordhuis <pcnoordhuis at gmail dot com>
+ *
+ * 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 __HIREDIS_READ_H
+#define __HIREDIS_READ_H
+#include <stdio.h> /* for size_t */
+
+#define REDIS_ERR -1
+#define REDIS_OK 0
+
+/* When an error occurs, the err flag in a context is set to hold the type of
+ * error that occured. REDIS_ERR_IO means there was an I/O error and you
+ * should use the "errno" variable to find out what is wrong.
+ * For other values, the "errstr" field will hold a description. */
+#define REDIS_ERR_IO 1 /* Error in read or write */
+#define REDIS_ERR_EOF 3 /* End of file */
+#define REDIS_ERR_PROTOCOL 4 /* Protocol error */
+#define REDIS_ERR_OOM 5 /* Out of memory */
+#define REDIS_ERR_OTHER 2 /* Everything else... */
+
+#define REDIS_REPLY_STRING 1
+#define REDIS_REPLY_ARRAY 2
+#define REDIS_REPLY_INTEGER 3
+#define REDIS_REPLY_NIL 4
+#define REDIS_REPLY_STATUS 5
+#define REDIS_REPLY_ERROR 6
+
+#define REDIS_READER_MAX_BUF (1024*16)  /* Default max unused reader buffer. */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct redisReadTask {
+    int type;
+    int elements; /* number of elements in multibulk container */
+    int idx; /* index in parent (array) object */
+    void *obj; /* holds user-generated value for a read task */
+    struct redisReadTask *parent; /* parent task */
+    void *privdata; /* user-settable arbitrary field */
+} redisReadTask;
+
+typedef struct redisReplyObjectFunctions {
+    void *(*createString)(const redisReadTask*, char*, size_t);
+    void *(*createArray)(const redisReadTask*, int);
+    void *(*createInteger)(const redisReadTask*, long long);
+    void *(*createNil)(const redisReadTask*);
+    void (*freeObject)(void*);
+} redisReplyObjectFunctions;
+
+typedef struct redisReader {
+    int err; /* Error flags, 0 when there is no error */
+    char errstr[128]; /* String representation of error when applicable */
+
+    char *buf; /* Read buffer */
+    size_t pos; /* Buffer cursor */
+    size_t len; /* Buffer length */
+    size_t maxbuf; /* Max length of unused buffer */
+
+    redisReadTask rstack[9];
+    int ridx; /* Index of current read task */
+    void *reply; /* Temporary reply pointer */
+
+    redisReplyObjectFunctions *fn;
+    void *privdata;
+} redisReader;
+
+/* Public API for the protocol parser. */
+redisReader *redisReaderCreateWithFunctions(redisReplyObjectFunctions *fn);
+void redisReaderFree(redisReader *r);
+int redisReaderFeed(redisReader *r, const char *buf, size_t len);
+int redisReaderGetReply(redisReader *r, void **reply);
+
+/* Backwards compatibility, can be removed on big version bump. */
+#define redisReplyReaderCreate redisReaderCreate
+#define redisReplyReaderFree redisReaderFree
+#define redisReplyReaderFeed redisReaderFeed
+#define redisReplyReaderGetReply redisReaderGetReply
+#define redisReplyReaderSetPrivdata(_r, _p) (int)(((redisReader*)(_r))->privdata = (_p))
+#define redisReplyReaderGetObject(_r) (((redisReader*)(_r))->reply)
+#define redisReplyReaderGetError(_r) (((redisReader*)(_r))->errstr)
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif