lua: adds bufferlist and msgpack libraries

Adds basic Lua wrappers around ceph::bufferlist, the cmsgpack Lua
library, and builds Lua as a noinst shared library.

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>

6 files changed, 942 insertions, 2 deletions

diff --git a/configure.ac b/configure.ac
index 38b6782a46a..b95d136fc9b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -602,6 +602,7 @@ AC_CONFIG_FILES([Makefile
 	src/ocf/ceph
 	src/ocf/rbd
 	src/java/Makefile
+	src/liblua/Makefile
 	man/Makefile
 	ceph.spec])
 AC_OUTPUT
diff --git a/src/Makefile.am b/src/Makefile.am
index 4b09c23e872..421179eda72 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,6 +1,6 @@
 AUTOMAKE_OPTIONS = gnu
-SUBDIRS = ocf java
-DIST_SUBDIRS = gtest ocf libs3 java
+SUBDIRS = ocf java liblua
+DIST_SUBDIRS = gtest ocf libs3 java liblua
 
 EXTRA_DIST = \
 	libs3/COPYING \
diff --git a/src/liblua/Makefile.am b/src/liblua/Makefile.am
new file mode 100644
index 00000000000..04c47ad6f29
--- /dev/null
+++ b/src/liblua/Makefile.am
@@ -0,0 +1,59 @@
+noinst_LTLIBRARIES = liblua.la
+
+liblua_la_SOURCES = \
+	src/print.c \
+	src/lmem.c \
+	src/lbaselib.c \
+	src/lauxlib.c \
+	src/ltm.c \
+	src/loadlib.c \
+	src/lobject.c \
+	src/lzio.c \
+	src/ldebug.c \
+	src/lundump.c \
+	src/lcode.c \
+	src/liolib.c \
+	src/loslib.c \
+	src/ldblib.c \
+	src/llex.c \
+	src/lopcodes.c \
+	src/lstate.c \
+	src/lstring.c \
+	src/ldo.c \
+	src/ltable.c \
+	src/linit.c \
+	src/lapi.c \
+	src/ldump.c \
+	src/lparser.c \
+	src/lstrlib.c \
+	src/ltablib.c \
+	src/lvm.c \
+	src/lmathlib.c \
+	src/lgc.c \
+	src/lfunc.c \
+	src/lua_cmsgpack.c \
+	src/lua_bufferlist.cc \
+	src/lualib.h \
+	src/luaconf.h \
+	src/llimits.h \
+	src/lua.h \
+	src/ltm.h \
+	src/lvm.h \
+	src/lapi.h \
+	src/lauxlib.h \
+	src/lparser.h \
+	src/lstring.h \
+	src/lobject.h \
+	src/ldebug.h \
+	src/lundump.h \
+	src/ltable.h \
+	src/lstate.h \
+	src/lfunc.h \
+	src/lzio.h \
+	src/lmem.h \
+	src/lgc.h \
+	src/lcode.h \
+	src/ldo.h \
+	src/lopcodes.h \
+	src/llex.h \
+	lua.hpp
diff --git a/src/liblua/lua.hpp b/src/liblua/lua.hpp
new file mode 100644
index 00000000000..aaf079a22b1
--- /dev/null
+++ b/src/liblua/lua.hpp
@@ -0,0 +1,21 @@
+#ifndef LIB_LUA_LUA_HPP
+#define LIB_LUA_LUA_HPP
+
+#include "include/types.h"
+
+extern "C" {
+#include "liblua/src/lua.h"
+#include "liblua/src/lualib.h"
+#include "liblua/src/lauxlib.h"
+}
+
+extern "C" {
+  LUALIB_API int luaopen_cmsgpack(lua_State *L);
+}
+
+LUALIB_API int luaopen_bufferlist(lua_State *L);
+
+extern bufferlist *clslua_checkbufferlist(lua_State *L, int pos = 1);
+extern bufferlist *clslua_pushbufferlist(lua_State *L, bufferlist *set);
+
+#endif
diff --git a/src/liblua/src/lua_bufferlist.cc b/src/liblua/src/lua_bufferlist.cc
new file mode 100644
index 00000000000..bb2b6084633
--- /dev/null
+++ b/src/liblua/src/lua_bufferlist.cc
@@ -0,0 +1,129 @@
+/*
+ * Lua module wrapping librados::bufferlist
+ */
+#include <errno.h>
+#include <string>
+#include <sstream>
+#include <math.h>
+#include "liblua/lua.hpp"
+#include "include/types.h"
+#include "include/buffer.h"
+#include "objclass/objclass.h"
+#include "cls/lua/cls_lua.h"
+
+#define LUA_BUFFERLIST "ClsLua.Bufferlist"
+
+struct bufferlist_wrap {
+  bufferlist *bl;
+  int gc; /* do garbage collect? */
+};
+
+static inline struct bufferlist_wrap *to_blwrap(lua_State *L, int pos = 1)
+{
+  return (bufferlist_wrap *)luaL_checkudata(L, pos, LUA_BUFFERLIST);
+}
+
+bufferlist *clslua_checkbufferlist(lua_State *L, int pos)
+{
+  struct bufferlist_wrap *blw = to_blwrap(L, pos);
+  return blw->bl;
+}
+
+/*
+ * Pushes a new bufferlist userdata object onto the stack. If @set is non-null
+ * it is assumed to be a bufferlist that should not be garbage collected.
+ */
+bufferlist *clslua_pushbufferlist(lua_State *L, bufferlist *set)
+{
+  bufferlist_wrap *blw = (bufferlist_wrap *)lua_newuserdata(L, sizeof(*blw));
+  blw->bl = set ? set : new bufferlist();
+  blw->gc = set ? 0 : 1;
+  luaL_getmetatable(L, LUA_BUFFERLIST);
+  lua_setmetatable(L, -2);
+  return blw->bl;
+}
+
+/*
+ * Create a new bufferlist
+ */
+static int bl_new(lua_State *L)
+{
+  clslua_pushbufferlist(L, NULL);
+  return 1;
+}
+
+/*
+ * Convert bufferlist to Lua string
+ */
+static int bl_str(lua_State *L)
+{
+  bufferlist *bl = clslua_checkbufferlist(L);
+  lua_pushlstring(L, bl->c_str(), bl->length());
+  return 1;
+}
+
+/*
+ * Append a Lua string to bufferlist
+ */
+static int bl_append(lua_State *L)
+{
+  bufferlist *bl = clslua_checkbufferlist(L);
+  luaL_checktype(L, 2, LUA_TSTRING);
+
+  size_t len;
+  const char *data = lua_tolstring(L, 2, &len);
+  bl->append(data, len);
+
+  return 0;
+}
+
+/*
+ * Perform byte-for-byte bufferlist equality test
+ */
+static int bl_eq(lua_State *L)
+{
+  bufferlist *bl1 = clslua_checkbufferlist(L, 1);
+  bufferlist *bl2 = clslua_checkbufferlist(L, 2);
+  lua_pushboolean(L, *bl1 == *bl2 ? 1 : 0);
+  return 1;
+}
+
+/*
+ * Garbage collect bufferlist
+ */
+static int bl_gc(lua_State *L)
+{
+  struct bufferlist_wrap *blw = to_blwrap(L);
+  assert(blw);
+  assert(blw->bl);
+  if (blw->gc)
+    delete blw->bl;
+  return 0;
+}
+
+static const struct luaL_Reg bufferlist_methods[] = {
+  {"str", bl_str},
+  {"append", bl_append},
+  {"__gc", bl_gc},
+  {"__eq", bl_eq},
+  {NULL, NULL}
+};
+
+static const struct luaL_Reg bllib_f[] = {
+  {"new", bl_new},
+  {NULL, NULL}
+};
+
+LUALIB_API int luaopen_bufferlist(lua_State *L)
+{
+  /* Setup bufferlist user-data type */
+  luaL_newmetatable(L, LUA_BUFFERLIST);
+  lua_pushvalue(L, -1);
+  lua_setfield(L, -2, "__index");
+  luaL_register(L, NULL, bufferlist_methods);
+  lua_pop(L, 1);
+
+  luaL_register(L, "bufferlist", bllib_f);
+
+  return 1;
+}
diff --git a/src/liblua/src/lua_cmsgpack.c b/src/liblua/src/lua_cmsgpack.c
new file mode 100644
index 00000000000..1994862e90a
--- /dev/null
+++ b/src/liblua/src/lua_cmsgpack.c
@@ -0,0 +1,730 @@
+#include <math.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <assert.h>
+
+#include "liblua/src/lua.h"
+#include "liblua/src/lauxlib.h"
+
+#define LUACMSGPACK_VERSION     "lua-cmsgpack 0.3.0"
+#define LUACMSGPACK_COPYRIGHT   "Copyright (C) 2012, Salvatore Sanfilippo"
+#define LUACMSGPACK_DESCRIPTION "MessagePack C implementation for Lua"
+
+#define LUACMSGPACK_MAX_NESTING  16 /* Max tables nesting. */
+
+/* ==============================================================================
+ * MessagePack implementation and bindings for Lua 5.1.
+ * Copyright(C) 2012 Salvatore Sanfilippo <antirez@gmail.com>
+ *
+ * http://github.com/antirez/lua-cmsgpack
+ *
+ * For MessagePack specification check the following web site:
+ * http://wiki.msgpack.org/display/MSGPACK/Format+specification
+ *
+ * See Copyright Notice at the end of this file.
+ *
+ * CHANGELOG:
+ * 19-Feb-2012 (ver 0.1.0): Initial release.
+ * 20-Feb-2012 (ver 0.2.0): Tables encoding improved.
+ * 20-Feb-2012 (ver 0.2.1): Minor bug fixing.
+ * 20-Feb-2012 (ver 0.3.0): Module renamed lua-cmsgpack (was lua-msgpack).
+ * ============================================================================ */
+
+/* --------------------------- Endian conversion --------------------------------
+ * We use it only for floats and doubles, all the other conversions are performed
+ * in an endian independent fashion. So the only thing we need is a function
+ * that swaps a binary string if the arch is little endian (and left it untouched
+ * otherwise). */
+
+/* Reverse memory bytes if arch is little endian. Given the conceptual
+ * simplicity of the Lua build system we prefer to check for endianess at runtime.
+ * The performance difference should be acceptable. */
+static void memrevifle(void *ptr, size_t len) {
+    unsigned char *p = ptr, *e = p+len-1, aux;
+    int test = 1;
+    unsigned char *testp = (unsigned char*) &test;
+
+    if (testp[0] == 0) return; /* Big endian, nothign to do. */
+    len /= 2;
+    while(len--) {
+        aux = *p;
+        *p = *e;
+        *e = aux;
+        p++;
+        e--;
+    }
+}
+
+/* ----------------------------- String buffer ----------------------------------
+ * This is a simple implementation of string buffers. The only opereation
+ * supported is creating empty buffers and appending bytes to it.
+ * The string buffer uses 2x preallocation on every realloc for O(N) append
+ * behavior.  */
+
+typedef struct mp_buf {
+    unsigned char *b;
+    size_t len, free;
+} mp_buf;
+
+static mp_buf *mp_buf_new(void) {
+    mp_buf *buf = malloc(sizeof(*buf));
+    
+    buf->b = NULL;
+    buf->len = buf->free = 0;
+    return buf;
+}
+
+void mp_buf_append(mp_buf *buf, const unsigned char *s, size_t len) {
+    if (buf->free < len) {
+        size_t newlen = buf->len+len;
+
+        buf->b = realloc(buf->b,newlen*2);
+        buf->free = newlen;
+    }
+    memcpy(buf->b+buf->len,s,len);
+    buf->len += len;
+    buf->free -= len;
+}
+
+void mp_buf_free(mp_buf *buf) {
+    free(buf->b);
+    free(buf);
+}
+
+/* ------------------------------ String cursor ----------------------------------
+ * This simple data structure is used for parsing. Basically you create a cursor
+ * using a string pointer and a length, then it is possible to access the
+ * current string position with cursor->p, check the remaining length
+ * in cursor->left, and finally consume more string using
+ * mp_cur_consume(cursor,len), to advance 'p' and subtract 'left'.
+ * An additional field cursor->error is set to zero on initialization and can
+ * be used to report errors. */
+
+#define MP_CUR_ERROR_NONE   0
+#define MP_CUR_ERROR_EOF    1   /* Not enough data to complete the opereation. */
+#define MP_CUR_ERROR_BADFMT 2   /* Bad data format */
+
+typedef struct mp_cur {
+    const unsigned char *p;
+    size_t left;
+    int err;
+} mp_cur;
+
+static mp_cur *mp_cur_new(const unsigned char *s, size_t len) {
+    mp_cur *cursor = malloc(sizeof(*cursor));
+
+    cursor->p = s;
+    cursor->left = len;
+    cursor->err = MP_CUR_ERROR_NONE;
+    return cursor;
+}
+
+static void mp_cur_free(mp_cur *cursor) {
+    free(cursor);
+}
+
+#define mp_cur_consume(_c,_len) do { _c->p += _len; _c->left -= _len; } while(0)
+
+/* When there is not enough room we set an error in the cursor and return, this
+ * is very common across the code so we have a macro to make the code look
+ * a bit simpler. */
+#define mp_cur_need(_c,_len) do { \
+    if (_c->left < _len) { \
+        _c->err = MP_CUR_ERROR_EOF; \
+        return; \
+    } \
+} while(0)
+
+/* --------------------------- Low level MP encoding -------------------------- */
+
+static void mp_encode_bytes(mp_buf *buf, const unsigned char *s, size_t len) {
+    unsigned char hdr[5];
+    int hdrlen;
+
+    if (len < 32) {
+        hdr[0] = 0xa0 | (len&0xff); /* fix raw */
+        hdrlen = 1;
+    } else if (len <= 0xffff) {
+        hdr[0] = 0xda;
+        hdr[1] = (len&0xff00)>>8;
+        hdr[2] = len&0xff;
+        hdrlen = 3;
+    } else {
+        hdr[0] = 0xdb;
+        hdr[1] = (len&0xff000000)>>24;
+        hdr[2] = (len&0xff0000)>>16;
+        hdr[3] = (len&0xff00)>>8;
+        hdr[4] = len&0xff;
+        hdrlen = 5;
+    }
+    mp_buf_append(buf,hdr,hdrlen);
+    mp_buf_append(buf,s,len);
+}
+
+/* we assume IEEE 754 internal format for single and double precision floats. */
+static void mp_encode_double(mp_buf *buf, double d) {
+    unsigned char b[9];
+    float f = d;
+
+    assert(sizeof(f) == 4 && sizeof(d) == 8);
+    if (d == (double)f) {
+        b[0] = 0xca;    /* float IEEE 754 */
+        memcpy(b+1,&f,4);
+        memrevifle(b+1,4);
+        mp_buf_append(buf,b,5);
+    } else if (sizeof(d) == 8) {
+        b[0] = 0xcb;    /* double IEEE 754 */
+        memcpy(b+1,&d,8);
+        memrevifle(b+1,8);
+        mp_buf_append(buf,b,9);
+    }
+}
+
+static void mp_encode_int(mp_buf *buf, int64_t n) {
+    unsigned char b[9];
+    int enclen;
+
+    if (n >= 0) {
+        if (n <= 127) {
+            b[0] = n & 0x7f;    /* positive fixnum */
+            enclen = 1;
+        } else if (n <= 0xff) {
+            b[0] = 0xcc;        /* uint 8 */
+            b[1] = n & 0xff;
+            enclen = 2;
+        } else if (n <= 0xffff) {
+            b[0] = 0xcd;        /* uint 16 */
+            b[1] = (n & 0xff00) >> 8;
+            b[2] = n & 0xff;
+            enclen = 3;
+        } else if (n <= 0xffffffffLL) {
+            b[0] = 0xce;        /* uint 32 */
+            b[1] = (n & 0xff000000) >> 24;
+            b[2] = (n & 0xff0000) >> 16;
+            b[3] = (n & 0xff00) >> 8;
+            b[4] = n & 0xff;
+            enclen = 5;
+        } else {
+            b[0] = 0xcf;        /* uint 64 */
+            b[1] = (n & 0xff00000000000000LL) >> 56;
+            b[2] = (n & 0xff000000000000LL) >> 48;
+            b[3] = (n & 0xff0000000000LL) >> 40;
+            b[4] = (n & 0xff00000000LL) >> 32;
+            b[5] = (n & 0xff000000) >> 24;
+            b[6] = (n & 0xff0000) >> 16;
+            b[7] = (n & 0xff00) >> 8;
+            b[8] = n & 0xff;
+            enclen = 9;
+        }
+    } else {
+        if (n >= -32) {
+            b[0] = ((char)n);   /* negative fixnum */
+            enclen = 1;
+        } else if (n >= -128) {
+            b[0] = 0xd0;        /* int 8 */
+            b[1] = n & 0xff;
+            enclen = 2;
+        } else if (n >= -32768) {
+            b[0] = 0xd1;        /* int 16 */
+            b[1] = (n & 0xff00) >> 8;
+            b[2] = n & 0xff;
+            enclen = 3;
+        } else if (n >= -2147483648LL) {
+            b[0] = 0xd2;        /* int 32 */
+            b[1] = (n & 0xff000000) >> 24;
+            b[2] = (n & 0xff0000) >> 16;
+            b[3] = (n & 0xff00) >> 8;
+            b[4] = n & 0xff;
+            enclen = 5;
+        } else {
+            b[0] = 0xd3;        /* int 64 */
+            b[1] = (n & 0xff00000000000000LL) >> 56;
+            b[2] = (n & 0xff000000000000LL) >> 48;
+            b[3] = (n & 0xff0000000000LL) >> 40;
+            b[4] = (n & 0xff00000000LL) >> 32;
+            b[5] = (n & 0xff000000) >> 24;
+            b[6] = (n & 0xff0000) >> 16;
+            b[7] = (n & 0xff00) >> 8;
+            b[8] = n & 0xff;
+            enclen = 9;
+        }
+    }
+    mp_buf_append(buf,b,enclen);
+}
+
+static void mp_encode_array(mp_buf *buf, int64_t n) {
+    unsigned char b[5];
+    int enclen;
+
+    if (n <= 15) {
+        b[0] = 0x90 | (n & 0xf);    /* fix array */
+        enclen = 1;
+    } else if (n <= 65535) {
+        b[0] = 0xdc;                /* array 16 */
+        b[1] = (n & 0xff00) >> 8;
+        b[2] = n & 0xff;
+        enclen = 3;
+    } else {
+        b[0] = 0xdd;                /* array 32 */
+        b[1] = (n & 0xff000000) >> 24;
+        b[2] = (n & 0xff0000) >> 16;
+        b[3] = (n & 0xff00) >> 8;
+        b[4] = n & 0xff;
+        enclen = 5;
+    }
+    mp_buf_append(buf,b,enclen);
+}
+
+static void mp_encode_map(mp_buf *buf, int64_t n) {
+    unsigned char b[5];
+    int enclen;
+
+    if (n <= 15) {
+        b[0] = 0x80 | (n & 0xf);    /* fix map */
+        enclen = 1;
+    } else if (n <= 65535) {
+        b[0] = 0xde;                /* map 16 */
+        b[1] = (n & 0xff00) >> 8;
+        b[2] = n & 0xff;
+        enclen = 3;
+    } else {
+        b[0] = 0xdf;                /* map 32 */
+        b[1] = (n & 0xff000000) >> 24;
+        b[2] = (n & 0xff0000) >> 16;
+        b[3] = (n & 0xff00) >> 8;
+        b[4] = n & 0xff;
+        enclen = 5;
+    }
+    mp_buf_append(buf,b,enclen);
+}
+
+/* ----------------------------- Lua types encoding --------------------------- */
+
+static void mp_encode_lua_string(lua_State *L, mp_buf *buf) {
+    size_t len;
+    const char *s;
+
+    s = lua_tolstring(L,-1,&len);
+    mp_encode_bytes(buf,(const unsigned char*)s,len);
+}
+
+static void mp_encode_lua_bool(lua_State *L, mp_buf *buf) {
+    unsigned char b = lua_toboolean(L,-1) ? 0xc3 : 0xc2;
+    mp_buf_append(buf,&b,1);
+}
+
+static void mp_encode_lua_number(lua_State *L, mp_buf *buf) {
+    lua_Number n = lua_tonumber(L,-1);
+
+    if (floor(n) != n) {
+        mp_encode_double(buf,(double)n);
+    } else {
+        mp_encode_int(buf,(int64_t)n);
+    }
+}
+
+static void mp_encode_lua_type(lua_State *L, mp_buf *buf, int level);
+
+/* Convert a lua table into a message pack list. */
+static void mp_encode_lua_table_as_array(lua_State *L, mp_buf *buf, int level) {
+    size_t len = lua_objlen(L,-1), j;
+
+    mp_encode_array(buf,len);
+    for (j = 1; j <= len; j++) {
+        lua_pushnumber(L,j);
+        lua_gettable(L,-2);
+        mp_encode_lua_type(L,buf,level+1);
+    }
+}
+
+/* Convert a lua table into a message pack key-value map. */
+static void mp_encode_lua_table_as_map(lua_State *L, mp_buf *buf, int level) {
+    size_t len = 0;
+
+    /* First step: count keys into table. No other way to do it with the
+     * Lua API, we need to iterate a first time. Note that an alternative
+     * would be to do a single run, and then hack the buffer to insert the
+     * map opcodes for message pack. Too hachish for this lib. */
+    lua_pushnil(L);
+    while(lua_next(L,-2)) {
+        lua_pop(L,1); /* remove value, keep key for next iteration. */
+        len++;
+    }
+
+    /* Step two: actually encoding of the map. */
+    mp_encode_map(buf,len);
+    lua_pushnil(L);
+    while(lua_next(L,-2)) {
+        /* Stack: ... key value */
+        lua_pushvalue(L,-2); /* Stack: ... key value key */
+        mp_encode_lua_type(L,buf,level+1); /* encode key */
+        mp_encode_lua_type(L,buf,level+1); /* encode val */
+    }
+}
+
+/* Returns true if the Lua table on top of the stack is exclusively composed
+ * of keys from numerical keys from 1 up to N, with N being the total number
+ * of elements, without any hole in the middle. */
+static int table_is_an_array(lua_State *L) {
+    //long count = 0, max = 0, idx = 0;
+    long count = 0, idx = 0;
+    lua_Number n;
+
+    lua_pushnil(L);
+    while(lua_next(L,-2)) {
+        /* Stack: ... key value */
+        lua_pop(L,1); /* Stack: ... key */
+        if (!lua_isnumber(L,-1)) goto not_array;
+        n = lua_tonumber(L,-1);
+        idx = n;
+        if (idx != n || idx < 1) goto not_array;
+        count++;
+        //max = idx;
+    }
+    /* We have the total number of elements in "count". Also we have
+     * the max index encountered in "idx". We can't reach this code
+     * if there are indexes <= 0. If you also note that there can not be
+     * repeated keys into a table, you have that if idx==count you are sure
+     * that there are all the keys form 1 to count (both included). */
+    return idx == count;
+
+not_array:
+    lua_pop(L,1);
+    return 0;
+}
+
+/* If the length operator returns non-zero, that is, there is at least
+ * an object at key '1', we serialize to message pack list. Otherwise
+ * we use a map. */
+static void mp_encode_lua_table(lua_State *L, mp_buf *buf, int level) {
+    if (table_is_an_array(L))
+        mp_encode_lua_table_as_array(L,buf,level);
+    else
+        mp_encode_lua_table_as_map(L,buf,level);
+}
+
+static void mp_encode_lua_null(lua_State *L, mp_buf *buf) {
+    unsigned char b[1];
+
+    b[0] = 0xc0;
+    mp_buf_append(buf,b,1);
+}
+
+static void mp_encode_lua_type(lua_State *L, mp_buf *buf, int level) {
+    int t = lua_type(L,-1);
+
+    /* Limit the encoding of nested tables to a specfiied maximum depth, so that
+     * we survive when called against circular references in tables. */
+    if (t == LUA_TTABLE && level == LUACMSGPACK_MAX_NESTING) t = LUA_TNIL;
+    switch(t) {
+    case LUA_TSTRING: mp_encode_lua_string(L,buf); break;
+    case LUA_TBOOLEAN: mp_encode_lua_bool(L,buf); break;
+    case LUA_TNUMBER: mp_encode_lua_number(L,buf); break;
+    case LUA_TTABLE: mp_encode_lua_table(L,buf,level); break;
+    default: mp_encode_lua_null(L,buf); break;
+    }
+    lua_pop(L,1);
+}
+
+static int mp_pack(lua_State *L) {
+    mp_buf *buf = mp_buf_new();
+
+    mp_encode_lua_type(L,buf,0);
+    lua_pushlstring(L,(char*)buf->b,buf->len);
+    mp_buf_free(buf);
+    return 1;
+}
+
+/* --------------------------------- Decoding --------------------------------- */
+
+void mp_decode_to_lua_type(lua_State *L, mp_cur *c);
+
+void mp_decode_to_lua_array(lua_State *L, mp_cur *c, size_t len) {
+    int index = 1;
+
+    lua_newtable(L);
+    while(len--) {
+        lua_pushnumber(L,index++);
+        mp_decode_to_lua_type(L,c);
+        if (c->err) return;
+        lua_settable(L,-3);
+    }
+}
+
+void mp_decode_to_lua_hash(lua_State *L, mp_cur *c, size_t len) {
+    lua_newtable(L);
+    while(len--) {
+        mp_decode_to_lua_type(L,c); /* key */
+        if (c->err) return;
+        mp_decode_to_lua_type(L,c); /* value */
+        if (c->err) return;
+        lua_settable(L,-3);
+    }
+}
+
+/* Decode a Message Pack raw object pointed by the string cursor 'c' to
+ * a Lua type, that is left as the only result on the stack. */
+void mp_decode_to_lua_type(lua_State *L, mp_cur *c) {
+    mp_cur_need(c,1);
+    switch(c->p[0]) {
+    case 0xcc:  /* uint 8 */
+        mp_cur_need(c,2);
+        lua_pushnumber(L,c->p[1]);
+        mp_cur_consume(c,2);
+        break;
+    case 0xd0:  /* int 8 */
+        mp_cur_need(c,2);
+        lua_pushnumber(L,(char)c->p[1]);
+        mp_cur_consume(c,2);
+        break;
+    case 0xcd:  /* uint 16 */
+        mp_cur_need(c,3);
+        lua_pushnumber(L,
+            (c->p[1] << 8) |
+             c->p[2]);
+        mp_cur_consume(c,3);
+        break;
+    case 0xd1:  /* int 16 */
+        mp_cur_need(c,3);
+        lua_pushnumber(L,(int16_t)
+            (c->p[1] << 8) |
+             c->p[2]);
+        mp_cur_consume(c,3);
+        break;
+    case 0xce:  /* uint 32 */
+        mp_cur_need(c,5);
+        lua_pushnumber(L,
+            ((uint32_t)c->p[1] << 24) |
+            ((uint32_t)c->p[2] << 16) |
+            ((uint32_t)c->p[3] << 8) |
+             (uint32_t)c->p[4]);
+        mp_cur_consume(c,5);
+        break;
+    case 0xd2:  /* int 32 */
+        mp_cur_need(c,5);
+        lua_pushnumber(L,
+            ((int32_t)c->p[1] << 24) |
+            ((int32_t)c->p[2] << 16) |
+            ((int32_t)c->p[3] << 8) |
+             (int32_t)c->p[4]);
+        mp_cur_consume(c,5);
+        break;
+    case 0xcf:  /* uint 64 */
+        mp_cur_need(c,9);
+        lua_pushnumber(L,
+            ((uint64_t)c->p[1] << 56) |
+            ((uint64_t)c->p[2] << 48) |
+            ((uint64_t)c->p[3] << 40) |
+            ((uint64_t)c->p[4] << 32) |
+            ((uint64_t)c->p[5] << 24) |
+            ((uint64_t)c->p[6] << 16) |
+            ((uint64_t)c->p[7] << 8) |
+             (uint64_t)c->p[8]);
+        mp_cur_consume(c,9);
+        break;
+    case 0xd3:  /* int 64 */
+        mp_cur_need(c,9);
+        lua_pushnumber(L,
+            ((int64_t)c->p[1] << 56) |
+            ((int64_t)c->p[2] << 48) |
+            ((int64_t)c->p[3] << 40) |
+            ((int64_t)c->p[4] << 32) |
+            ((int64_t)c->p[5] << 24) |
+            ((int64_t)c->p[6] << 16) |
+            ((int64_t)c->p[7] << 8) |
+             (int64_t)c->p[8]);
+        mp_cur_consume(c,9);
+        break;
+    case 0xc0:  /* nil */
+        lua_pushnil(L);
+        mp_cur_consume(c,1);
+        break;
+    case 0xc3:  /* true */
+        lua_pushboolean(L,1);
+        mp_cur_consume(c,1);
+        break;
+    case 0xc2:  /* false */
+        lua_pushboolean(L,0);
+        mp_cur_consume(c,1);
+        break;
+    case 0xca:  /* float */
+        mp_cur_need(c,5);
+        assert(sizeof(float) == 4);
+        {
+            float f;
+            memcpy(&f,c->p+1,4);
+            memrevifle(&f,4);
+            lua_pushnumber(L,f);
+            mp_cur_consume(c,5);
+        }
+        break;
+    case 0xcb:  /* double */
+        mp_cur_need(c,9);
+        assert(sizeof(double) == 8);
+        {
+            double d;
+            memcpy(&d,c->p+1,8);
+            memrevifle(&d,8);
+            lua_pushnumber(L,d);
+            mp_cur_consume(c,9);
+        }
+        break;
+    case 0xda:  /* raw 16 */
+        mp_cur_need(c,3);
+        {
+            size_t l = (c->p[1] << 8) | c->p[2];
+            mp_cur_need(c,3+l);
+            lua_pushlstring(L,(char*)c->p+3,l);
+            mp_cur_consume(c,3+l);
+        }
+        break;
+    case 0xdb:  /* raw 32 */
+        mp_cur_need(c,5);
+        {
+            size_t l = (c->p[1] << 24) |
+                       (c->p[2] << 16) |
+                       (c->p[3] << 8) |
+                       c->p[4];
+            mp_cur_need(c,5+l);
+            lua_pushlstring(L,(char*)c->p+5,l);
+            mp_cur_consume(c,5+l);
+        }
+        break;
+    case 0xdc:  /* array 16 */
+        mp_cur_need(c,3);
+        {
+            size_t l = (c->p[1] << 8) | c->p[2];
+            mp_cur_consume(c,3);
+            mp_decode_to_lua_array(L,c,l);
+        }
+        break;
+    case 0xdd:  /* array 32 */
+        mp_cur_need(c,5);
+        {
+            size_t l = (c->p[1] << 24) |
+                       (c->p[2] << 16) |
+                       (c->p[3] << 8) |
+                       c->p[4];
+            mp_cur_consume(c,5);
+            mp_decode_to_lua_array(L,c,l);
+        }
+        break;
+    case 0xde:  /* map 16 */
+        mp_cur_need(c,3);
+        {
+            size_t l = (c->p[1] << 8) | c->p[2];
+            mp_cur_consume(c,3);
+            mp_decode_to_lua_hash(L,c,l);
+        }
+        break;
+    case 0xdf:  /* map 32 */
+        mp_cur_need(c,5);
+        {
+            size_t l = (c->p[1] << 24) |
+                       (c->p[2] << 16) |
+                       (c->p[3] << 8) |
+                       c->p[4];
+            mp_cur_consume(c,5);
+            mp_decode_to_lua_hash(L,c,l);
+        }
+        break;
+    default:    /* types that can't be idenitified by first byte value. */
+        if ((c->p[0] & 0x80) == 0) {   /* positive fixnum */
+            lua_pushnumber(L,c->p[0]);
+            mp_cur_consume(c,1);
+        } else if ((c->p[0] & 0xe0) == 0xe0) {  /* negative fixnum */
+            lua_pushnumber(L,(signed char)c->p[0]);
+            mp_cur_consume(c,1);
+        } else if ((c->p[0] & 0xe0) == 0xa0) {  /* fix raw */
+            size_t l = c->p[0] & 0x1f;
+            mp_cur_need(c,1+l);
+            lua_pushlstring(L,(char*)c->p+1,l);
+            mp_cur_consume(c,1+l);
+        } else if ((c->p[0] & 0xf0) == 0x90) {  /* fix map */
+            size_t l = c->p[0] & 0xf;
+            mp_cur_consume(c,1);
+            mp_decode_to_lua_array(L,c,l);
+        } else if ((c->p[0] & 0xf0) == 0x80) {  /* fix map */
+            size_t l = c->p[0] & 0xf;
+            mp_cur_consume(c,1);
+            mp_decode_to_lua_hash(L,c,l);
+        } else {
+            c->err = MP_CUR_ERROR_BADFMT;
+        }
+    }
+}
+
+static int mp_unpack(lua_State *L) {
+    size_t len;
+    const unsigned char *s;
+    mp_cur *c;
+
+    if (!lua_isstring(L,-1)) {
+        lua_pushstring(L,"MessagePack decoding needs a string as input.");
+        lua_error(L);
+    }
+
+    s = (const unsigned char*) lua_tolstring(L,-1,&len);
+    c = mp_cur_new(s,len);
+    mp_decode_to_lua_type(L,c);
+    
+    if (c->err == MP_CUR_ERROR_EOF) {
+        mp_cur_free(c);
+        lua_pushstring(L,"Missing bytes in input.");
+        lua_error(L);
+    } else if (c->err == MP_CUR_ERROR_BADFMT) {
+        mp_cur_free(c);
+        lua_pushstring(L,"Bad data format in input.");
+        lua_error(L);
+    } else if (c->left != 0) {
+        mp_cur_free(c);
+        lua_pushstring(L,"Extra bytes in input.");
+        lua_error(L);
+    }
+    mp_cur_free(c);
+    return 1;
+}
+
+/* ---------------------------------------------------------------------------- */
+
+static const struct luaL_reg thislib[] = {
+    {"pack", mp_pack},
+    {"unpack", mp_unpack},
+    {NULL, NULL}
+};
+
+LUALIB_API int luaopen_cmsgpack (lua_State *L) {
+    luaL_register(L, "cmsgpack", thislib);
+
+    lua_pushliteral(L, LUACMSGPACK_VERSION);
+    lua_setfield(L, -2, "_VERSION");
+    lua_pushliteral(L, LUACMSGPACK_COPYRIGHT);
+    lua_setfield(L, -2, "_COPYRIGHT");
+    lua_pushliteral(L, LUACMSGPACK_DESCRIPTION);
+    lua_setfield(L, -2, "_DESCRIPTION"); 
+    return 1;
+}
+
+/******************************************************************************
+* Copyright (C) 2012 Salvatore Sanfilippo.  All rights reserved.
+*
+* Permission is hereby granted, free of charge, to any person obtaining
+* a copy of this software and associated documentation files (the
+* "Software"), to deal in the Software without restriction, including
+* without limitation the rights to use, copy, modify, merge, publish,
+* distribute, sublicense, and/or sell copies of the Software, and to
+* permit persons to whom the Software is furnished to do so, subject to
+* the following conditions:
+*
+* The above copyright notice and this permission notice shall be
+* included in all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+******************************************************************************/