aboutsummaryrefslogtreecommitdiff
path: root/src/sysbin/lx/lua_cmsgpack.c
blob: 8eb15fc72afc3b51c0f946dcade690dcb43cd217 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
#include <math.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <assert.h>

#include <lua/lua.h>
#include <lua/lauxlib.h>

#define LUACMSGPACK_NAME        "lx.msg"
#define LUACMSGPACK_SAFE_NAME   "cmsgpack_safe"
#define LUACMSGPACK_VERSION     "lua-cmsgpack 0.4.0alex1"
#define LUACMSGPACK_COPYRIGHT   "Copyright (C) 2012, Salvatore Sanfilippo, 2017, Alex Auvolat"
#define LUACMSGPACK_DESCRIPTION "MessagePack C implementation for Lua"

/* Allows a preprocessor directive to override MAX_NESTING */
#ifndef LUACMSGPACK_MAX_NESTING
    #define LUACMSGPACK_MAX_NESTING  16 /* Max tables nesting. */
#endif

/* Check if float or double can be an integer without loss of precision */
#define isinf(x) (false)
#define IS_INT_TYPE_EQUIVALENT(x, T) (!isinf(x) && (T)(x) == (x))

#define IS_INT64_EQUIVALENT(x) IS_INT_TYPE_EQUIVALENT(x, int64_t)
#define IS_INT_EQUIVALENT(x) IS_INT_TYPE_EQUIVALENT(x, int)

/* If size of pointer is equal to a 4 byte integer, we're on 32 bits. */
#if UINTPTR_MAX == UINT_MAX
    #define BITS_32 1
#else
    #define BITS_32 0
#endif

#if LUA_INT_TYPE == LUA_INT_LONGLONG
    #define lua_pushunsigned(L, n) lua_pushinteger(L, n)
#else
    #define lua_pushunsigned(L, n) { if ((uint64_t)(n) <= (uint64_t)LUA_MAXINTEGER) lua_pushinteger(L, n); else lua_pushnumber(L, n); }
#endif

/* =============================================================================
 * MessagePack implementation and bindings for Lua 5.1/5.2.
 * 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).
 * 04-Apr-2014 (ver 0.3.1): Lua 5.2 support and minor bug fix.
 * 07-Apr-2014 (ver 0.4.0): Multiple pack/unpack, lua allocator, efficiency.
 * ========================================================================== */

/* -------------------------- Endian conversion --------------------------------
 * We use it only for floats and doubles, all the other conversions performed
 * in an endian independent fashion. So the only thing we need is a function
 * that swaps a binary string if 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 check for endianess at runtime.
 * The performance difference should be acceptable. */
void memrevifle(void *ptr, size_t len) {
    unsigned char   *p = (unsigned char *)ptr,
                    *e = (unsigned char *)p+len-1,
                    aux;
    int test = 1;
    unsigned char *testp = (unsigned char*) &test;

    if (testp[0] == 0) return; /* Big endian, nothing 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 operation
 * 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;

void *mp_realloc(lua_State *L, void *target, size_t osize,size_t nsize) {
    void *(*local_realloc) (void *, void *, size_t osize, size_t nsize) = NULL;
    void *ud;

    local_realloc = lua_getallocf(L, &ud);

    return local_realloc(ud, target, osize, nsize);
}

mp_buf *mp_buf_new(lua_State *L) {
    mp_buf *buf = NULL;

    /* Old size = 0; new size = sizeof(*buf) */
    buf = (mp_buf*)mp_realloc(L, NULL, 0, sizeof(*buf));

    buf->b = NULL;
    buf->len = buf->free = 0;
    return buf;
}

void mp_buf_append(lua_State *L, mp_buf *buf, const unsigned char *s, size_t len) {
    if (buf->free < len) {
        size_t newsize = (buf->len+len)*2;

        buf->b = (unsigned char*)mp_realloc(L, buf->b, buf->len + buf->free, newsize);
        buf->free = newsize - buf->len;
    }
    memcpy(buf->b+buf->len,s,len);
    buf->len += len;
    buf->free -= len;
}

void mp_buf_free(lua_State *L, mp_buf *buf) {
    mp_realloc(L, buf->b, buf->len + buf->free, 0); /* realloc to 0 = free */
    mp_realloc(L, buf, sizeof(*buf), 0);
}

/* ---------------------------- 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 operation. */
#define MP_CUR_ERROR_BADFMT 2   /* Bad data format */

typedef struct mp_cur {
    const unsigned char *p;
    size_t left;
    int err;
} mp_cur;

void mp_cur_init(mp_cur *cursor, const unsigned char *s, size_t len) {
    cursor->p = s;
    cursor->left = len;
    cursor->err = MP_CUR_ERROR_NONE;
}

#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 -------------------------- */

void mp_encode_bytes(lua_State *L, 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 <= 0xff) {
        hdr[0] = 0xd9;
        hdr[1] = len;
        hdrlen = 2;
    } 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(L,buf,hdr,hdrlen);
    mp_buf_append(L,buf,s,len);
}

/* we assume IEEE 754 internal format for single and double precision floats. */
void mp_encode_double(lua_State *L, 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(L,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(L,buf,b,9);
    }
}

void mp_encode_int(lua_State *L, 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] = ((signed 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(L,buf,b,enclen);
}

void mp_encode_array(lua_State *L, 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(L,buf,b,enclen);
}

void mp_encode_map(lua_State *L, 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(L,buf,b,enclen);
}

/* --------------------------- Lua types encoding --------------------------- */

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(L,buf,(const unsigned char*)s,len);
}

void mp_encode_lua_bool(lua_State *L, mp_buf *buf) {
    unsigned char b = lua_toboolean(L,-1) ? 0xc3 : 0xc2;
    mp_buf_append(L,buf,&b,1);
}

/* Lua 5.3 has a built in 64-bit integer type */
void mp_encode_lua_integer(lua_State *L, mp_buf *buf) {
#if (LUA_VERSION_NUM < 503) && BITS_32
    lua_Number i = lua_tonumber(L,-1);
#else
    lua_Integer i = lua_tointeger(L,-1);
#endif
    mp_encode_int(L, buf, (int64_t)i);
}

/* Lua 5.2 and lower only has 64-bit doubles, so we need to
 * detect if the double may be representable as an int
 * for Lua < 5.3 */
void mp_encode_lua_number(lua_State *L, mp_buf *buf) {
    lua_Number n = lua_tonumber(L,-1);

    if (IS_INT64_EQUIVALENT(n)) {
        mp_encode_lua_integer(L, buf);
    } else {
        mp_encode_double(L,buf,(double)n);
    }
}

void mp_encode_lua_type(lua_State *L, mp_buf *buf, int level);

/* Convert a lua table into a message pack list. */
void mp_encode_lua_table_as_array(lua_State *L, mp_buf *buf, int level) {
#if LUA_VERSION_NUM < 502
    size_t len = lua_objlen(L,-1), j;
#else
    size_t len = lua_rawlen(L,-1), j;
#endif

    mp_encode_array(L,buf,len);
    for (j = 1; j <= len; j++) {
        lua_pushinteger(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. */
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 hackish 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(L,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. */
int table_is_an_array(lua_State *L) {
    int count = 0, max = 0;
#if LUA_VERSION_NUM < 503
    lua_Number n;
#else
    lua_Integer n;
#endif

    /* Stack top on function entry */
    int stacktop;

    stacktop = lua_gettop(L);

    lua_pushnil(L);
    while(lua_next(L,-2)) {
        /* Stack: ... key value */
        lua_pop(L,1); /* Stack: ... key */
        /* The <= 0 check is valid here because we're comparing indexes. */
#if LUA_VERSION_NUM < 503
        if ((LUA_TNUMBER != lua_type(L,-1)) || (n = lua_tonumber(L, -1)) <= 0 ||
            !IS_INT_EQUIVALENT(n))
#else
        if (!lua_isinteger(L,-1) || (n = lua_tointeger(L, -1)) <= 0)
#endif
        {
            lua_settop(L, stacktop);
            return 0;
        }
        max = (n > max ? n : max);
        count++;
    }
    /* We have the total number of elements in "count". Also we have
     * the max index encountered in "max". 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 max==count you are sure
     * that there are all the keys form 1 to count (both included). */
    lua_settop(L, stacktop);
    return max == count;
}

/* 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. */
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);
}

void mp_encode_lua_null(lua_State *L, mp_buf *buf) {
    unsigned char b[1];

    b[0] = 0xc0;
    mp_buf_append(L,buf,b,1);
}

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 specified 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:
    #if LUA_VERSION_NUM < 503
        mp_encode_lua_number(L,buf); break;
    #else
        if (lua_isinteger(L, -1)) {
            mp_encode_lua_integer(L, buf);
        } else {
            mp_encode_lua_number(L, buf);
        }
        break;
    #endif
    case LUA_TTABLE: mp_encode_lua_table(L,buf,level); break;
    default: mp_encode_lua_null(L,buf); break;
    }
    lua_pop(L,1);
}

/*
 * Packs all arguments as a stream for multiple upacking later.
 * Returns error if no arguments provided.
 */
int mp_pack(lua_State *L) {
    int nargs = lua_gettop(L);
    int i;
    mp_buf *buf;

    if (nargs == 0)
        return luaL_argerror(L, 0, "MessagePack pack needs input.");

    buf = mp_buf_new(L);
    for(i = 1; i <= nargs; i++) {
        /* Copy argument i to top of stack for _encode processing;
         * the encode function pops it from the stack when complete. */
        lua_pushvalue(L, i);

        mp_encode_lua_type(L,buf,0);

        lua_pushlstring(L,(char*)buf->b,buf->len);

        /* Reuse the buffer for the next operation by
         * setting its free count to the total buffer size
         * and the current position to zero. */
        buf->free += buf->len;
        buf->len = 0;
    }
    mp_buf_free(L, buf);

    /* Concatenate all nargs buffers together */
    lua_concat(L, nargs);
    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) {
    assert(len <= UINT_MAX);
    int index = 1;

    lua_newtable(L);
    while(len--) {
        lua_pushunsigned(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) {
    assert(len <= UINT_MAX);
    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);

    /* If we return more than 18 elements, we must resize the stack to
     * fit all our return values.  But, there is no way to
     * determine how many objects a msgpack will unpack to up front, so
     * we request a +1 larger stack on each iteration (noop if stack is
     * big enough, and when stack does require resize it doubles in size) */
    luaL_checkstack(L, 1,
        "too many return values at once; "
        "use unpack_one or unpack_limit instead.");

    switch(c->p[0]) {
    case 0xcc:  /* uint 8 */
        mp_cur_need(c,2);
        lua_pushunsigned(L,c->p[1]);
        mp_cur_consume(c,2);
        break;
    case 0xd0:  /* int 8 */
        mp_cur_need(c,2);
        lua_pushinteger(L,(signed char)c->p[1]);
        mp_cur_consume(c,2);
        break;
    case 0xcd:  /* uint 16 */
        mp_cur_need(c,3);
        lua_pushunsigned(L,
            (c->p[1] << 8) |
             c->p[2]);
        mp_cur_consume(c,3);
        break;
    case 0xd1:  /* int 16 */
        mp_cur_need(c,3);
        lua_pushinteger(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_pushunsigned(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_pushinteger(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_pushunsigned(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);
#if LUA_VERSION_NUM < 503
        lua_pushnumber(L,
#else
        lua_pushinteger(L,
#endif
            ((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 0xd9:  /* raw 8 */
        mp_cur_need(c,2);
        {
            size_t l = c->p[1];
            mp_cur_need(c,2+l);
            lua_pushlstring(L,(char*)c->p+2,l);
            mp_cur_consume(c,2+l);
        }
        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 = ((size_t)c->p[1] << 24) |
                       ((size_t)c->p[2] << 16) |
                       ((size_t)c->p[3] << 8) |
                       (size_t)c->p[4];
            mp_cur_consume(c,5);
            mp_cur_need(c,l);
            lua_pushlstring(L,(char*)c->p,l);
            mp_cur_consume(c,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 = ((size_t)c->p[1] << 24) |
                       ((size_t)c->p[2] << 16) |
                       ((size_t)c->p[3] << 8) |
                       (size_t)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 = ((size_t)c->p[1] << 24) |
                       ((size_t)c->p[2] << 16) |
                       ((size_t)c->p[3] << 8) |
                       (size_t)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_pushunsigned(L,c->p[0]);
            mp_cur_consume(c,1);
        } else if ((c->p[0] & 0xe0) == 0xe0) {  /* negative fixnum */
            lua_pushinteger(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;
        }
    }
}

int mp_unpack_full(lua_State *L, int limit, int offset) {
    size_t len;
    const char *s;
    mp_cur c;
    int cnt; /* Number of objects unpacked */
    int decode_all = (!limit && !offset);

    s = luaL_checklstring(L,1,&len); /* if no match, exits */

    if (offset < 0 || limit < 0) /* requesting negative off or lim is invalid */
        return luaL_error(L,
            "Invalid request to unpack with offset of %d and limit of %d.",
            offset, len);
    else if ((size_t)offset > len)
        return luaL_error(L,
            "Start offset %d greater than input length %d.", offset, len);

    if (decode_all) limit = INT_MAX;

    mp_cur_init(&c,(const unsigned char *)s+offset,len-offset);

    /* We loop over the decode because this could be a stream
     * of multiple top-level values serialized together */
    for(cnt = 0; c.left > 0 && cnt < limit; cnt++) {
        mp_decode_to_lua_type(L,&c);

        if (c.err == MP_CUR_ERROR_EOF) {
            return luaL_error(L,"Missing bytes in input.");
        } else if (c.err == MP_CUR_ERROR_BADFMT) {
            return luaL_error(L,"Bad data format in input.");
        }
    }

    if (!decode_all) {
        /* c->left is the remaining size of the input buffer.
         * subtract the entire buffer size from the unprocessed size
         * to get our next start offset */
        int offset = len - c.left;
        /* Return offset -1 when we have have processed the entire buffer. */
        lua_pushinteger(L, c.left == 0 ? -1 : offset);
        /* Results are returned with the arg elements still
         * in place. Lua takes care of only returning
         * elements above the args for us.
         * In this case, we have one arg on the stack
         * for this function, so we insert our first return
         * value at position 2. */
        lua_insert(L, 2);
        cnt += 1; /* increase return count by one to make room for offset */
    }

    return cnt;
}

int mp_unpack(lua_State *L) {
    return mp_unpack_full(L, 0, 0);
}

int mp_unpack_one(lua_State *L) {
    int offset = luaL_optinteger(L, 2, 0);
    /* Variable pop because offset may not exist */
    lua_pop(L, lua_gettop(L)-1);
    return mp_unpack_full(L, 1, offset);
}

int mp_unpack_limit(lua_State *L) {
    int limit = luaL_checkinteger(L, 2);
    int offset = luaL_optinteger(L, 3, 0);
    /* Variable pop because offset may not exist */
    lua_pop(L, lua_gettop(L)-1);

    return mp_unpack_full(L, limit, offset);
}

int mp_safe(lua_State *L) {
    int argc, err, total_results;

    argc = lua_gettop(L);

    /* This adds our function to the bottom of the stack
     * (the "call this function" position) */
    lua_pushvalue(L, lua_upvalueindex(1));
    lua_insert(L, 1);

    err = lua_pcall(L, argc, LUA_MULTRET, 0);
    total_results = lua_gettop(L);

    if (!err) {
        return total_results;
    } else {
        lua_pushnil(L);
        lua_insert(L,-2);
        return 2;
    }
}

/* -------------------------------------------------------------------------- */
const struct luaL_Reg cmds[] = {
    {"pack", mp_pack},
    {"unpack", mp_unpack},
    {"unpack_one", mp_unpack_one},
    {"unpack_limit", mp_unpack_limit},
    {0}
};

int luaopen_create(lua_State *L) {
    size_t i;
    /* Manually construct our module table instead of
     * relying on _register or _newlib */
    lua_newtable(L);

    for (i = 0; i < (sizeof(cmds)/sizeof(*cmds) - 1); i++) {
        lua_pushcfunction(L, cmds[i].func);
        lua_setfield(L, -2, cmds[i].name);
    }

    /* Add metadata */
    lua_pushliteral(L, LUACMSGPACK_NAME);
    lua_setfield(L, -2, "_NAME");
    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;
}

LUALIB_API int luaopen_cmsgpack(lua_State *L) {
    luaopen_create(L);

#if LUA_VERSION_NUM < 502
    /* Register name globally for 5.1 */
    lua_pushvalue(L, -1);
    lua_setglobal(L, LUACMSGPACK_NAME);
#endif

    return 1;
}

LUALIB_API int luaopen_cmsgpack_safe(lua_State *L) {
    size_t i;

    luaopen_cmsgpack(L);

    /* Wrap all functions in the safe handler */
    for (i = 0; i < (sizeof(cmds)/sizeof(*cmds) - 1); i++) {
        lua_getfield(L, -1, cmds[i].name);
        lua_pushcclosure(L, mp_safe, 1);
        lua_setfield(L, -2, cmds[i].name);
    }

#if LUA_VERSION_NUM < 502
    /* Register name globally for 5.1 */
    lua_pushvalue(L, -1);
    lua_setglobal(L, LUACMSGPACK_SAFE_NAME);
#endif

    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.
******************************************************************************/