1#include "EXTERN.h"
2#include "perl.h"
3#include "XSUB.h"
4
5#include <assert.h>
6#include <string.h>
7#include <stdlib.h>
8#include <stdio.h>
9#include <limits.h>
10#include <float.h>
11
12#if defined(__BORLANDC__) || defined(_MSC_VER)
13# define snprintf _snprintf // C compilers have this in stdio.h
14#endif
15
16// some old perls do not have this, try to make it work, no
17// guarantees, though. if it breaks, you get to keep the pieces.
18#ifndef UTF8_MAXBYTES
19# define UTF8_MAXBYTES 13
20#endif
21
22// three extra for rounding, sign, and end of string
23#define IVUV_MAXCHARS (sizeof (UV) * CHAR_BIT * 28 / 93 + 3)
24
25#define F_ASCII          0x00000001UL
26#define F_LATIN1         0x00000002UL
27#define F_UTF8           0x00000004UL
28#define F_INDENT         0x00000008UL
29#define F_CANONICAL      0x00000010UL
30#define F_SPACE_BEFORE   0x00000020UL
31#define F_SPACE_AFTER    0x00000040UL
32#define F_ALLOW_NONREF   0x00000100UL
33#define F_SHRINK         0x00000200UL
34#define F_ALLOW_BLESSED  0x00000400UL
35#define F_CONV_BLESSED   0x00000800UL
36#define F_RELAXED        0x00001000UL
37#define F_ALLOW_UNKNOWN  0x00002000UL
38#define F_HOOK           0x00080000UL // some hooks exist, so slow-path processing
39
40#define F_PRETTY    F_INDENT | F_SPACE_BEFORE | F_SPACE_AFTER
41
42#define INIT_SIZE   32 // initial scalar size to be allocated
43#define INDENT_STEP 3  // spaces per indentation level
44
45#define SHORT_STRING_LEN 16384 // special-case strings of up to this size
46
47#define DECODE_WANTS_OCTETS(json) ((json)->flags & F_UTF8)
48
49#define SB do {
50#define SE } while (0)
51
52#if __GNUC__ >= 3
53# define expect(expr,value)         __builtin_expect ((expr), (value))
54# define INLINE                     static inline
55#else
56# define expect(expr,value)         (expr)
57# define INLINE                     static
58#endif
59
60#define expect_false(expr) expect ((expr) != 0, 0)
61#define expect_true(expr)  expect ((expr) != 0, 1)
62
63#define IN_RANGE_INC(type,val,beg,end) \
64  ((unsigned type)((unsigned type)(val) - (unsigned type)(beg)) \
65  <= (unsigned type)((unsigned type)(end) - (unsigned type)(beg)))
66
67#define ERR_NESTING_EXCEEDED "json text or perl structure exceeds maximum nesting level (max_depth set too low?)"
68
69#ifdef USE_ITHREADS
70# define JSON_SLOW 1
71# define JSON_STASH (json_stash ? json_stash : gv_stashpv ("JSON::XS", 1))
72#else
73# define JSON_SLOW 0
74# define JSON_STASH json_stash
75#endif
76
77static HV *json_stash, *json_boolean_stash; // JSON::XS::
78static SV *json_true, *json_false;
79
80enum {
81  INCR_M_WS = 0, // initial whitespace skipping, must be 0
82  INCR_M_STR,    // inside string
83  INCR_M_BS,     // inside backslash
84  INCR_M_C0,     // inside comment in initial whitespace sequence
85  INCR_M_C1,     // inside comment in other places
86  INCR_M_JSON    // outside anything, count nesting
87};
88
89#define INCR_DONE(json) ((json)->incr_nest <= 0 && (json)->incr_mode == INCR_M_JSON)
90
91typedef struct {
92  U32 flags;
93  U32 max_depth;
94  STRLEN max_size;
95
96  SV *cb_object;
97  HV *cb_sk_object;
98
99  // for the incremental parser
100  SV *incr_text;   // the source text so far
101  STRLEN incr_pos; // the current offset into the text
102  int incr_nest;   // {[]}-nesting level
103  unsigned char incr_mode;
104} JSON;
105
106INLINE void
107json_init (JSON *json)
108{
109  Zero (json, 1, JSON);
110  json->max_depth = 512;
111}
112
113/////////////////////////////////////////////////////////////////////////////
114// utility functions
115
116INLINE SV *
117get_bool (const char *name)
118{
119  SV *sv = get_sv (name, 1);
120
121  SvREADONLY_on (sv);
122  SvREADONLY_on (SvRV (sv));
123
124  return sv;
125}
126
127INLINE void
128shrink (SV *sv)
129{
130  sv_utf8_downgrade (sv, 1);
131
132  if (SvLEN (sv) > SvCUR (sv) + 1)
133    {
134#ifdef SvPV_shrink_to_cur
135      SvPV_shrink_to_cur (sv);
136#elif defined (SvPV_renew)
137      SvPV_renew (sv, SvCUR (sv) + 1);
138#endif
139    }
140}
141
142// decode an utf-8 character and return it, or (UV)-1 in
143// case of an error.
144// we special-case "safe" characters from U+80 .. U+7FF,
145// but use the very good perl function to parse anything else.
146// note that we never call this function for a ascii codepoints
147INLINE UV
148decode_utf8 (unsigned char *s, STRLEN len, STRLEN *clen)
149{
150  if (expect_true (len >= 2
151                   && IN_RANGE_INC (char, s[0], 0xc2, 0xdf)
152                   && IN_RANGE_INC (char, s[1], 0x80, 0xbf)))
153    {
154      *clen = 2;
155      return ((s[0] & 0x1f) << 6) | (s[1] & 0x3f);
156    }
157  else
158    return utf8n_to_uvuni (s, len, clen, UTF8_CHECK_ONLY);
159}
160
161// likewise for encoding, also never called for ascii codepoints
162// this function takes advantage of this fact, although current gccs
163// seem to optimise the check for >= 0x80 away anyways
164INLINE unsigned char *
165encode_utf8 (unsigned char *s, UV ch)
166{
167  if      (expect_false (ch < 0x000080))
168    *s++ = ch;
169  else if (expect_true  (ch < 0x000800))
170    *s++ = 0xc0 | ( ch >>  6),
171    *s++ = 0x80 | ( ch        & 0x3f);
172  else if (              ch < 0x010000)
173    *s++ = 0xe0 | ( ch >> 12),
174    *s++ = 0x80 | ((ch >>  6) & 0x3f),
175    *s++ = 0x80 | ( ch        & 0x3f);
176  else if (              ch < 0x110000)
177    *s++ = 0xf0 | ( ch >> 18),
178    *s++ = 0x80 | ((ch >> 12) & 0x3f),
179    *s++ = 0x80 | ((ch >>  6) & 0x3f),
180    *s++ = 0x80 | ( ch        & 0x3f);
181
182  return s;
183}
184
185// convert offset pointer to character index, sv must be string
186static STRLEN
187ptr_to_index (SV *sv, char *offset)
188{
189  return SvUTF8 (sv)
190         ? utf8_distance (offset, SvPVX (sv))
191         : offset - SvPVX (sv);
192}
193
194/////////////////////////////////////////////////////////////////////////////
195// fp hell
196
197// scan a group of digits, and a trailing exponent
198static void
199json_atof_scan1 (const char *s, NV *accum, int *expo, int postdp, int maxdepth)
200{
201  UV  uaccum = 0;
202  int eaccum = 0;
203
204  // if we recurse too deep, skip all remaining digits
205  // to avoid a stack overflow attack
206  if (expect_false (--maxdepth <= 0))
207    while (((U8)*s - '0') < 10)
208      ++s;
209
210  for (;;)
211    {
212      U8 dig = (U8)*s - '0';
213
214      if (expect_false (dig >= 10))
215        {
216          if (dig == (U8)((U8)'.' - (U8)'0'))
217            {
218              ++s;
219              json_atof_scan1 (s, accum, expo, 1, maxdepth);
220            }
221          else if ((dig | ' ') == 'e' - '0')
222            {
223              int exp2 = 0;
224              int neg  = 0;
225
226              ++s;
227
228              if (*s == '-')
229                {
230                  ++s;
231                  neg = 1;
232                }
233              else if (*s == '+')
234                ++s;
235
236              while ((dig = (U8)*s - '0') < 10)
237                exp2 = exp2 * 10 + *s++ - '0';
238
239              *expo += neg ? -exp2 : exp2;
240            }
241
242          break;
243        }
244
245      ++s;
246
247      uaccum = uaccum * 10 + dig;
248      ++eaccum;
249
250      // if we have too many digits, then recurse for more
251      // we actually do this for rather few digits
252      if (uaccum >= (UV_MAX - 9) / 10)
253        {
254          if (postdp) *expo -= eaccum;
255          json_atof_scan1 (s, accum, expo, postdp, maxdepth);
256          if (postdp) *expo += eaccum;
257
258          break;
259        }
260    }
261
262  // this relies greatly on the quality of the pow ()
263  // implementation of the platform, but a good
264  // implementation is hard to beat.
265  // (IEEE 754 conformant ones are required to be exact)
266  if (postdp) *expo -= eaccum;
267  *accum += uaccum * Perl_pow (10., *expo);
268  *expo += eaccum;
269}
270
271static NV
272json_atof (const char *s)
273{
274  NV accum = 0.;
275  int expo = 0;
276  int neg  = 0;
277
278  if (*s == '-')
279    {
280      ++s;
281      neg = 1;
282    }
283
284  // a recursion depth of ten gives us >>500 bits
285  json_atof_scan1 (s, &accum, &expo, 0, 10);
286
287  return neg ? -accum : accum;
288}
289/////////////////////////////////////////////////////////////////////////////
290// encoder
291
292// structure used for encoding JSON
293typedef struct
294{
295  char *cur;  // SvPVX (sv) + current output position
296  char *end;  // SvEND (sv)
297  SV *sv;     // result scalar
298  JSON json;
299  U32 indent; // indentation level
300  UV limit;   // escape character values >= this value when encoding
301} enc_t;
302
303INLINE void
304need (enc_t *enc, STRLEN len)
305{
306  if (expect_false (enc->cur + len >= enc->end))
307    {
308      STRLEN cur = enc->cur - (char *)SvPVX (enc->sv);
309      SvGROW (enc->sv, cur + (len < (cur >> 2) ? cur >> 2 : len) + 1);
310      enc->cur = SvPVX (enc->sv) + cur;
311      enc->end = SvPVX (enc->sv) + SvLEN (enc->sv) - 1;
312    }
313}
314
315INLINE void
316encode_ch (enc_t *enc, char ch)
317{
318  need (enc, 1);
319  *enc->cur++ = ch;
320}
321
322static void
323encode_str (enc_t *enc, char *str, STRLEN len, int is_utf8)
324{
325  char *end = str + len;
326
327  need (enc, len);
328
329  while (str < end)
330    {
331      unsigned char ch = *(unsigned char *)str;
332
333      if (expect_true (ch >= 0x20 && ch < 0x80)) // most common case
334        {
335          if (expect_false (ch == '"')) // but with slow exceptions
336            {
337              need (enc, len += 1);
338              *enc->cur++ = '\\';
339              *enc->cur++ = '"';
340            }
341          else if (expect_false (ch == '\\'))
342            {
343              need (enc, len += 1);
344              *enc->cur++ = '\\';
345              *enc->cur++ = '\\';
346            }
347          else
348            *enc->cur++ = ch;
349
350          ++str;
351        }
352      else
353        {
354          switch (ch)
355            {
356              case '\010': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 'b'; ++str; break;
357              case '\011': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 't'; ++str; break;
358              case '\012': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 'n'; ++str; break;
359              case '\014': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 'f'; ++str; break;
360              case '\015': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 'r'; ++str; break;
361
362              default:
363                {
364                  STRLEN clen;
365                  UV uch;
366
367                  if (is_utf8)
368                    {
369                      uch = decode_utf8 (str, end - str, &clen);
370                      if (clen == (STRLEN)-1)
371                        croak ("malformed or illegal unicode character in string [%.11s], cannot convert to JSON", str);
372                    }
373                  else
374                    {
375                      uch = ch;
376                      clen = 1;
377                    }
378
379                  if (uch < 0x80/*0x20*/ || uch >= enc->limit)
380                    {
381                      if (uch >= 0x10000UL)
382                        {
383                          if (uch >= 0x110000UL)
384                            croak ("out of range codepoint (0x%lx) encountered, unrepresentable in JSON", (unsigned long)uch);
385
386                          need (enc, len += 11);
387                          sprintf (enc->cur, "\\u%04x\\u%04x",
388                                   (int)((uch - 0x10000) / 0x400 + 0xD800),
389                                   (int)((uch - 0x10000) % 0x400 + 0xDC00));
390                          enc->cur += 12;
391                        }
392                      else
393                        {
394                          need (enc, len += 5);
395                          *enc->cur++ = '\\';
396                          *enc->cur++ = 'u';
397                          *enc->cur++ = PL_hexdigit [ uch >> 12      ];
398                          *enc->cur++ = PL_hexdigit [(uch >>  8) & 15];
399                          *enc->cur++ = PL_hexdigit [(uch >>  4) & 15];
400                          *enc->cur++ = PL_hexdigit [(uch >>  0) & 15];
401                        }
402
403                      str += clen;
404                    }
405                  else if (enc->json.flags & F_LATIN1)
406                    {
407                      *enc->cur++ = uch;
408                      str += clen;
409                    }
410                  else if (is_utf8)
411                    {
412                      need (enc, len += clen);
413                      do
414                        {
415                          *enc->cur++ = *str++;
416                        }
417                      while (--clen);
418                    }
419                  else
420                    {
421                      need (enc, len += UTF8_MAXBYTES - 1); // never more than 11 bytes needed
422                      enc->cur = encode_utf8 (enc->cur, uch);
423                      ++str;
424                    }
425                }
426            }
427        }
428
429      --len;
430    }
431}
432
433INLINE void
434encode_indent (enc_t *enc)
435{
436  if (enc->json.flags & F_INDENT)
437    {
438      int spaces = enc->indent * INDENT_STEP;
439
440      need (enc, spaces);
441      memset (enc->cur, ' ', spaces);
442      enc->cur += spaces;
443    }
444}
445
446INLINE void
447encode_space (enc_t *enc)
448{
449  need (enc, 1);
450  encode_ch (enc, ' ');
451}
452
453INLINE void
454encode_nl (enc_t *enc)
455{
456  if (enc->json.flags & F_INDENT)
457    {
458      need (enc, 1);
459      encode_ch (enc, '\n');
460    }
461}
462
463INLINE void
464encode_comma (enc_t *enc)
465{
466  encode_ch (enc, ',');
467
468  if (enc->json.flags & F_INDENT)
469    encode_nl (enc);
470  else if (enc->json.flags & F_SPACE_AFTER)
471    encode_space (enc);
472}
473
474static void encode_sv (enc_t *enc, SV *sv);
475
476static void
477encode_av (enc_t *enc, AV *av)
478{
479  int i, len = av_len (av);
480
481  if (enc->indent >= enc->json.max_depth)
482    croak (ERR_NESTING_EXCEEDED);
483
484  encode_ch (enc, '[');
485
486  if (len >= 0)
487    {
488      encode_nl (enc); ++enc->indent;
489
490      for (i = 0; i <= len; ++i)
491        {
492          SV **svp = av_fetch (av, i, 0);
493
494          encode_indent (enc);
495
496          if (svp)
497            encode_sv (enc, *svp);
498          else
499            encode_str (enc, "null", 4, 0);
500
501          if (i < len)
502            encode_comma (enc);
503        }
504
505      encode_nl (enc); --enc->indent; encode_indent (enc);
506    }
507
508  encode_ch (enc, ']');
509}
510
511static void
512encode_hk (enc_t *enc, HE *he)
513{
514  encode_ch (enc, '"');
515
516  if (HeKLEN (he) == HEf_SVKEY)
517    {
518      SV *sv = HeSVKEY (he);
519      STRLEN len;
520      char *str;
521
522      SvGETMAGIC (sv);
523      str = SvPV (sv, len);
524
525      encode_str (enc, str, len, SvUTF8 (sv));
526    }
527  else
528    encode_str (enc, HeKEY (he), HeKLEN (he), HeKUTF8 (he));
529
530  encode_ch (enc, '"');
531
532  if (enc->json.flags & F_SPACE_BEFORE) encode_space (enc);
533  encode_ch (enc, ':');
534  if (enc->json.flags & F_SPACE_AFTER ) encode_space (enc);
535}
536
537// compare hash entries, used when all keys are bytestrings
538static int
539he_cmp_fast (const void *a_, const void *b_)
540{
541  int cmp;
542
543  HE *a = *(HE **)a_;
544  HE *b = *(HE **)b_;
545
546  STRLEN la = HeKLEN (a);
547  STRLEN lb = HeKLEN (b);
548
549  if (!(cmp = memcmp (HeKEY (b), HeKEY (a), lb < la ? lb : la)))
550    cmp = lb - la;
551
552  return cmp;
553}
554
555// compare hash entries, used when some keys are sv's or utf-x
556static int
557he_cmp_slow (const void *a, const void *b)
558{
559  return sv_cmp (HeSVKEY_force (*(HE **)b), HeSVKEY_force (*(HE **)a));
560}
561
562static void
563encode_hv (enc_t *enc, HV *hv)
564{
565  HE *he;
566
567  if (enc->indent >= enc->json.max_depth)
568    croak (ERR_NESTING_EXCEEDED);
569
570  encode_ch (enc, '{');
571
572  // for canonical output we have to sort by keys first
573  // actually, this is mostly due to the stupid so-called
574  // security workaround added somewhere in 5.8.x
575  // that randomises hash orderings
576  if (enc->json.flags & F_CANONICAL && !SvRMAGICAL (hv))
577    {
578      int count = hv_iterinit (hv);
579
580      if (SvMAGICAL (hv))
581        {
582          // need to count by iterating. could improve by dynamically building the vector below
583          // but I don't care for the speed of this special case.
584          // note also that we will run into undefined behaviour when the two iterations
585          // do not result in the same count, something I might care for in some later release.
586
587          count = 0;
588          while (hv_iternext (hv))
589            ++count;
590
591          hv_iterinit (hv);
592        }
593
594      if (count)
595        {
596          int i, fast = 1;
597#if defined(__BORLANDC__) || defined(_MSC_VER)
598          HE **hes = _alloca (count * sizeof (HE));
599#else
600          HE *hes [count]; // if your compiler dies here, you need to enable C99 mode
601#endif
602
603          i = 0;
604          while ((he = hv_iternext (hv)))
605            {
606              hes [i++] = he;
607              if (HeKLEN (he) < 0 || HeKUTF8 (he))
608                fast = 0;
609            }
610
611          assert (i == count);
612
613          if (fast)
614            qsort (hes, count, sizeof (HE *), he_cmp_fast);
615          else
616            {
617              // hack to forcefully disable "use bytes"
618              COP cop = *PL_curcop;
619              cop.op_private = 0;
620
621              ENTER;
622              SAVETMPS;
623
624              SAVEVPTR (PL_curcop);
625              PL_curcop = &cop;
626
627              qsort (hes, count, sizeof (HE *), he_cmp_slow);
628
629              FREETMPS;
630              LEAVE;
631            }
632
633          encode_nl (enc); ++enc->indent;
634
635          while (count--)
636            {
637              encode_indent (enc);
638              he = hes [count];
639              encode_hk (enc, he);
640              encode_sv (enc, expect_false (SvMAGICAL (hv)) ? hv_iterval (hv, he) : HeVAL (he));
641
642              if (count)
643                encode_comma (enc);
644            }
645
646          encode_nl (enc); --enc->indent; encode_indent (enc);
647        }
648    }
649  else
650    {
651      if (hv_iterinit (hv) || SvMAGICAL (hv))
652        if ((he = hv_iternext (hv)))
653          {
654            encode_nl (enc); ++enc->indent;
655
656            for (;;)
657              {
658                encode_indent (enc);
659                encode_hk (enc, he);
660                encode_sv (enc, expect_false (SvMAGICAL (hv)) ? hv_iterval (hv, he) : HeVAL (he));
661
662                if (!(he = hv_iternext (hv)))
663                  break;
664
665                encode_comma (enc);
666              }
667
668            encode_nl (enc); --enc->indent; encode_indent (enc);
669          }
670    }
671
672  encode_ch (enc, '}');
673}
674
675// encode objects, arrays and special \0=false and \1=true values.
676static void
677encode_rv (enc_t *enc, SV *sv)
678{
679  svtype svt;
680
681  SvGETMAGIC (sv);
682  svt = SvTYPE (sv);
683
684  if (expect_false (SvOBJECT (sv)))
685    {
686      HV *stash = !JSON_SLOW || json_boolean_stash
687                  ? json_boolean_stash
688                  : gv_stashpv ("JSON::XS::Boolean", 1);
689
690      if (SvSTASH (sv) == stash)
691        {
692          if (SvIV (sv))
693            encode_str (enc, "true", 4, 0);
694          else
695            encode_str (enc, "false", 5, 0);
696        }
697      else
698        {
699#if 0
700          if (0 && sv_derived_from (rv, "JSON::Literal"))
701            {
702              // not yet
703            }
704#endif
705          if (enc->json.flags & F_CONV_BLESSED)
706            {
707              // we re-bless the reference to get overload and other niceties right
708              GV *to_json = gv_fetchmethod_autoload (SvSTASH (sv), "TO_JSON", 0);
709
710              if (to_json)
711                {
712                  dSP;
713
714                  ENTER; SAVETMPS; PUSHMARK (SP);
715                  XPUSHs (sv_bless (sv_2mortal (newRV_inc (sv)), SvSTASH (sv)));
716
717                  // calling with G_SCALAR ensures that we always get a 1 return value
718                  PUTBACK;
719                  call_sv ((SV *)GvCV (to_json), G_SCALAR);
720                  SPAGAIN;
721
722                  // catch this surprisingly common error
723                  if (SvROK (TOPs) && SvRV (TOPs) == sv)
724                    croak ("%s::TO_JSON method returned same object as was passed instead of a new one", HvNAME (SvSTASH (sv)));
725
726                  sv = POPs;
727                  PUTBACK;
728
729                  encode_sv (enc, sv);
730
731                  FREETMPS; LEAVE;
732                }
733              else if (enc->json.flags & F_ALLOW_BLESSED)
734                encode_str (enc, "null", 4, 0);
735              else
736                croak ("encountered object '%s', but neither allow_blessed enabled nor TO_JSON method available on it",
737                       SvPV_nolen (sv_2mortal (newRV_inc (sv))));
738            }
739          else if (enc->json.flags & F_ALLOW_BLESSED)
740            encode_str (enc, "null", 4, 0);
741          else
742            croak ("encountered object '%s', but neither allow_blessed nor convert_blessed settings are enabled",
743                   SvPV_nolen (sv_2mortal (newRV_inc (sv))));
744        }
745    }
746  else if (svt == SVt_PVHV)
747    encode_hv (enc, (HV *)sv);
748  else if (svt == SVt_PVAV)
749    encode_av (enc, (AV *)sv);
750  else if (svt < SVt_PVAV)
751    {
752      STRLEN len = 0;
753      char *pv = svt ? SvPV (sv, len) : 0;
754
755      if (len == 1 && *pv == '1')
756        encode_str (enc, "true", 4, 0);
757      else if (len == 1 && *pv == '0')
758        encode_str (enc, "false", 5, 0);
759      else if (enc->json.flags & F_ALLOW_UNKNOWN)
760        encode_str (enc, "null", 4, 0);
761      else
762        croak ("cannot encode reference to scalar '%s' unless the scalar is 0 or 1",
763               SvPV_nolen (sv_2mortal (newRV_inc (sv))));
764    }
765  else if (enc->json.flags & F_ALLOW_UNKNOWN)
766    encode_str (enc, "null", 4, 0);
767  else
768    croak ("encountered %s, but JSON can only represent references to arrays or hashes",
769           SvPV_nolen (sv_2mortal (newRV_inc (sv))));
770}
771
772static void
773encode_sv (enc_t *enc, SV *sv)
774{
775  SvGETMAGIC (sv);
776
777  if (SvPOKp (sv))
778    {
779      STRLEN len;
780      char *str = SvPV (sv, len);
781      encode_ch (enc, '"');
782      encode_str (enc, str, len, SvUTF8 (sv));
783      encode_ch (enc, '"');
784    }
785  else if (SvNOKp (sv))
786    {
787      // trust that perl will do the right thing w.r.t. JSON syntax.
788      need (enc, NV_DIG + 32);
789      Gconvert (SvNVX (sv), NV_DIG, 0, enc->cur);
790      enc->cur += strlen (enc->cur);
791    }
792  else if (SvIOKp (sv))
793    {
794      // we assume we can always read an IV as a UV and vice versa
795      // we assume two's complement
796      // we assume no aliasing issues in the union
797      if (SvIsUV (sv) ? SvUVX (sv) <= 59000
798                      : SvIVX (sv) <= 59000 && SvIVX (sv) >= -59000)
799        {
800          // optimise the "small number case"
801          // code will likely be branchless and use only a single multiplication
802          // works for numbers up to 59074
803          I32 i = SvIVX (sv);
804          U32 u;
805          char digit, nz = 0;
806
807          need (enc, 6);
808
809          *enc->cur = '-'; enc->cur += i < 0 ? 1 : 0;
810          u = i < 0 ? -i : i;
811
812          // convert to 4.28 fixed-point representation
813          u = u * ((0xfffffff + 10000) / 10000); // 10**5, 5 fractional digits
814
815          // now output digit by digit, each time masking out the integer part
816          // and multiplying by 5 while moving the decimal point one to the right,
817          // resulting in a net multiplication by 10.
818          // we always write the digit to memory but conditionally increment
819          // the pointer, to enable the use of conditional move instructions.
820          digit = u >> 28; *enc->cur = digit + '0'; enc->cur += (nz = nz || digit); u = (u & 0xfffffffUL) * 5;
821          digit = u >> 27; *enc->cur = digit + '0'; enc->cur += (nz = nz || digit); u = (u & 0x7ffffffUL) * 5;
822          digit = u >> 26; *enc->cur = digit + '0'; enc->cur += (nz = nz || digit); u = (u & 0x3ffffffUL) * 5;
823          digit = u >> 25; *enc->cur = digit + '0'; enc->cur += (nz = nz || digit); u = (u & 0x1ffffffUL) * 5;
824          digit = u >> 24; *enc->cur = digit + '0'; enc->cur += 1; // correctly generate '0'
825        }
826      else
827        {
828          // large integer, use the (rather slow) snprintf way.
829          need (enc, IVUV_MAXCHARS);
830          enc->cur +=
831             SvIsUV(sv)
832                ? snprintf (enc->cur, IVUV_MAXCHARS, "%"UVuf, (UV)SvUVX (sv))
833                : snprintf (enc->cur, IVUV_MAXCHARS, "%"IVdf, (IV)SvIVX (sv));
834        }
835    }
836  else if (SvROK (sv))
837    encode_rv (enc, SvRV (sv));
838  else if (!SvOK (sv) || enc->json.flags & F_ALLOW_UNKNOWN)
839    encode_str (enc, "null", 4, 0);
840  else
841    croak ("encountered perl type (%s,0x%x) that JSON cannot handle, you might want to report this",
842           SvPV_nolen (sv), (unsigned int)SvFLAGS (sv));
843}
844
845static SV *
846encode_json (SV *scalar, JSON *json)
847{
848  enc_t enc;
849
850  if (!(json->flags & F_ALLOW_NONREF) && !SvROK (scalar))
851    croak ("hash- or arrayref expected (not a simple scalar, use allow_nonref to allow this)");
852
853  enc.json      = *json;
854  enc.sv        = sv_2mortal (NEWSV (0, INIT_SIZE));
855  enc.cur       = SvPVX (enc.sv);
856  enc.end       = SvEND (enc.sv);
857  enc.indent    = 0;
858  enc.limit     = enc.json.flags & F_ASCII  ? 0x000080UL
859                : enc.json.flags & F_LATIN1 ? 0x000100UL
860                                            : 0x110000UL;
861
862  SvPOK_only (enc.sv);
863  encode_sv (&enc, scalar);
864  encode_nl (&enc);
865
866  SvCUR_set (enc.sv, enc.cur - SvPVX (enc.sv));
867  *SvEND (enc.sv) = 0; // many xs functions expect a trailing 0 for text strings
868
869  if (!(enc.json.flags & (F_ASCII | F_LATIN1 | F_UTF8)))
870    SvUTF8_on (enc.sv);
871
872  if (enc.json.flags & F_SHRINK)
873    shrink (enc.sv);
874
875  return enc.sv;
876}
877
878/////////////////////////////////////////////////////////////////////////////
879// decoder
880
881// structure used for decoding JSON
882typedef struct
883{
884  char *cur; // current parser pointer
885  char *end; // end of input string
886  const char *err; // parse error, if != 0
887  JSON json;
888  U32 depth; // recursion depth
889  U32 maxdepth; // recursion depth limit
890} dec_t;
891
892INLINE void
893decode_comment (dec_t *dec)
894{
895  // only '#'-style comments allowed a.t.m.
896
897  while (*dec->cur && *dec->cur != 0x0a && *dec->cur != 0x0d)
898    ++dec->cur;
899}
900
901INLINE void
902decode_ws (dec_t *dec)
903{
904  for (;;)
905    {
906      char ch = *dec->cur;
907
908      if (ch > 0x20)
909        {
910          if (expect_false (ch == '#'))
911            {
912              if (dec->json.flags & F_RELAXED)
913                decode_comment (dec);
914              else
915                break;
916            }
917          else
918            break;
919        }
920      else if (ch != 0x20 && ch != 0x0a && ch != 0x0d && ch != 0x09)
921        break; // parse error, but let higher level handle it, gives better error messages
922
923      ++dec->cur;
924    }
925}
926
927#define ERR(reason) SB dec->err = reason; goto fail; SE
928
929#define EXPECT_CH(ch) SB \
930  if (*dec->cur != ch)		\
931    ERR (# ch " expected");	\
932  ++dec->cur;			\
933  SE
934
935#define DEC_INC_DEPTH if (++dec->depth > dec->json.max_depth) ERR (ERR_NESTING_EXCEEDED)
936#define DEC_DEC_DEPTH --dec->depth
937
938static SV *decode_sv (dec_t *dec);
939
940static signed char decode_hexdigit[256];
941
942static UV
943decode_4hex (dec_t *dec)
944{
945  signed char d1, d2, d3, d4;
946  unsigned char *cur = (unsigned char *)dec->cur;
947
948  d1 = decode_hexdigit [cur [0]]; if (expect_false (d1 < 0)) ERR ("exactly four hexadecimal digits expected");
949  d2 = decode_hexdigit [cur [1]]; if (expect_false (d2 < 0)) ERR ("exactly four hexadecimal digits expected");
950  d3 = decode_hexdigit [cur [2]]; if (expect_false (d3 < 0)) ERR ("exactly four hexadecimal digits expected");
951  d4 = decode_hexdigit [cur [3]]; if (expect_false (d4 < 0)) ERR ("exactly four hexadecimal digits expected");
952
953  dec->cur += 4;
954
955  return ((UV)d1) << 12
956       | ((UV)d2) <<  8
957       | ((UV)d3) <<  4
958       | ((UV)d4);
959
960fail:
961  return (UV)-1;
962}
963
964static SV *
965decode_str (dec_t *dec)
966{
967  SV *sv = 0;
968  int utf8 = 0;
969  char *dec_cur = dec->cur;
970
971  do
972    {
973      char buf [SHORT_STRING_LEN + UTF8_MAXBYTES];
974      char *cur = buf;
975
976      do
977        {
978          unsigned char ch = *(unsigned char *)dec_cur++;
979
980          if (expect_false (ch == '"'))
981            {
982              --dec_cur;
983              break;
984            }
985          else if (expect_false (ch == '\\'))
986            {
987              switch (*dec_cur)
988                {
989                  case '\\':
990                  case '/':
991                  case '"': *cur++ = *dec_cur++; break;
992
993                  case 'b': ++dec_cur; *cur++ = '\010'; break;
994                  case 't': ++dec_cur; *cur++ = '\011'; break;
995                  case 'n': ++dec_cur; *cur++ = '\012'; break;
996                  case 'f': ++dec_cur; *cur++ = '\014'; break;
997                  case 'r': ++dec_cur; *cur++ = '\015'; break;
998
999                  case 'u':
1000                    {
1001                      UV lo, hi;
1002                      ++dec_cur;
1003
1004                      dec->cur = dec_cur;
1005                      hi = decode_4hex (dec);
1006                      dec_cur = dec->cur;
1007                      if (hi == (UV)-1)
1008                        goto fail;
1009
1010                      // possibly a surrogate pair
1011                      if (hi >= 0xd800)
1012                        if (hi < 0xdc00)
1013                          {
1014                            if (dec_cur [0] != '\\' || dec_cur [1] != 'u')
1015                              ERR ("missing low surrogate character in surrogate pair");
1016
1017                            dec_cur += 2;
1018
1019                            dec->cur = dec_cur;
1020                            lo = decode_4hex (dec);
1021                            dec_cur = dec->cur;
1022                            if (lo == (UV)-1)
1023                              goto fail;
1024
1025                            if (lo < 0xdc00 || lo >= 0xe000)
1026                              ERR ("surrogate pair expected");
1027
1028                            hi = (hi - 0xD800) * 0x400 + (lo - 0xDC00) + 0x10000;
1029                          }
1030                        else if (hi < 0xe000)
1031                          ERR ("missing high surrogate character in surrogate pair");
1032
1033                      if (hi >= 0x80)
1034                        {
1035                          utf8 = 1;
1036
1037                          cur = encode_utf8 (cur, hi);
1038                        }
1039                      else
1040                        *cur++ = hi;
1041                    }
1042                    break;
1043
1044                  default:
1045                    --dec_cur;
1046                    ERR ("illegal backslash escape sequence in string");
1047                }
1048            }
1049          else if (expect_true (ch >= 0x20 && ch < 0x80))
1050            *cur++ = ch;
1051          else if (ch >= 0x80)
1052            {
1053              STRLEN clen;
1054
1055              --dec_cur;
1056
1057              decode_utf8 (dec_cur, dec->end - dec_cur, &clen);
1058              if (clen == (STRLEN)-1)
1059                ERR ("malformed UTF-8 character in JSON string");
1060
1061              do
1062                *cur++ = *dec_cur++;
1063              while (--clen);
1064
1065              utf8 = 1;
1066            }
1067          else
1068            {
1069              --dec_cur;
1070
1071              if (!ch)
1072                ERR ("unexpected end of string while parsing JSON string");
1073              else
1074                ERR ("invalid character encountered while parsing JSON string");
1075            }
1076        }
1077      while (cur < buf + SHORT_STRING_LEN);
1078
1079      {
1080        STRLEN len = cur - buf;
1081
1082        if (sv)
1083          {
1084            STRLEN cur = SvCUR (sv);
1085
1086            if (SvLEN (sv) <= cur + len)
1087              SvGROW (sv, cur + (len < (cur >> 2) ? cur >> 2 : len) + 1);
1088
1089            memcpy (SvPVX (sv) + SvCUR (sv), buf, len);
1090            SvCUR_set (sv, SvCUR (sv) + len);
1091          }
1092        else
1093          sv = newSVpvn (buf, len);
1094      }
1095    }
1096  while (*dec_cur != '"');
1097
1098  ++dec_cur;
1099
1100  if (sv)
1101    {
1102      SvPOK_only (sv);
1103      *SvEND (sv) = 0;
1104
1105      if (utf8)
1106        SvUTF8_on (sv);
1107    }
1108  else
1109    sv = newSVpvn ("", 0);
1110
1111  dec->cur = dec_cur;
1112  return sv;
1113
1114fail:
1115  dec->cur = dec_cur;
1116  return 0;
1117}
1118
1119static SV *
1120decode_num (dec_t *dec)
1121{
1122  int is_nv = 0;
1123  char *start = dec->cur;
1124
1125  // [minus]
1126  if (*dec->cur == '-')
1127    ++dec->cur;
1128
1129  if (*dec->cur == '0')
1130    {
1131      ++dec->cur;
1132      if (*dec->cur >= '0' && *dec->cur <= '9')
1133         ERR ("malformed number (leading zero must not be followed by another digit)");
1134    }
1135  else if (*dec->cur < '0' || *dec->cur > '9')
1136    ERR ("malformed number (no digits after initial minus)");
1137  else
1138    do
1139      {
1140        ++dec->cur;
1141      }
1142    while (*dec->cur >= '0' && *dec->cur <= '9');
1143
1144  // [frac]
1145  if (*dec->cur == '.')
1146    {
1147      ++dec->cur;
1148
1149      if (*dec->cur < '0' || *dec->cur > '9')
1150        ERR ("malformed number (no digits after decimal point)");
1151
1152      do
1153        {
1154          ++dec->cur;
1155        }
1156      while (*dec->cur >= '0' && *dec->cur <= '9');
1157
1158      is_nv = 1;
1159    }
1160
1161  // [exp]
1162  if (*dec->cur == 'e' || *dec->cur == 'E')
1163    {
1164      ++dec->cur;
1165
1166      if (*dec->cur == '-' || *dec->cur == '+')
1167        ++dec->cur;
1168
1169      if (*dec->cur < '0' || *dec->cur > '9')
1170        ERR ("malformed number (no digits after exp sign)");
1171
1172      do
1173        {
1174          ++dec->cur;
1175        }
1176      while (*dec->cur >= '0' && *dec->cur <= '9');
1177
1178      is_nv = 1;
1179    }
1180
1181  if (!is_nv)
1182    {
1183      int len = dec->cur - start;
1184
1185      // special case the rather common 1..5-digit-int case
1186      if (*start == '-')
1187        switch (len)
1188          {
1189            case 2: return newSViv (-(IV)(                                                                          start [1] - '0' *     1));
1190            case 3: return newSViv (-(IV)(                                                         start [1] * 10 + start [2] - '0' *    11));
1191            case 4: return newSViv (-(IV)(                                       start [1] * 100 + start [2] * 10 + start [3] - '0' *   111));
1192            case 5: return newSViv (-(IV)(                    start [1] * 1000 + start [2] * 100 + start [3] * 10 + start [4] - '0' *  1111));
1193            case 6: return newSViv (-(IV)(start [1] * 10000 + start [2] * 1000 + start [3] * 100 + start [4] * 10 + start [5] - '0' * 11111));
1194          }
1195      else
1196        switch (len)
1197          {
1198            case 1: return newSViv (                                                                                start [0] - '0' *     1);
1199            case 2: return newSViv (                                                               start [0] * 10 + start [1] - '0' *    11);
1200            case 3: return newSViv (                                             start [0] * 100 + start [1] * 10 + start [2] - '0' *   111);
1201            case 4: return newSViv (                          start [0] * 1000 + start [1] * 100 + start [2] * 10 + start [3] - '0' *  1111);
1202            case 5: return newSViv (      start [0] * 10000 + start [1] * 1000 + start [2] * 100 + start [3] * 10 + start [4] - '0' * 11111);
1203          }
1204
1205      {
1206        UV uv;
1207        int numtype = grok_number (start, len, &uv);
1208        if (numtype & IS_NUMBER_IN_UV)
1209          if (numtype & IS_NUMBER_NEG)
1210            {
1211              if (uv < (UV)IV_MIN)
1212                return newSViv (-(IV)uv);
1213            }
1214          else
1215            return newSVuv (uv);
1216      }
1217
1218      len -= *start == '-' ? 1 : 0;
1219
1220      // does not fit into IV or UV, try NV
1221      if (len <= NV_DIG)
1222        // fits into NV without loss of precision
1223        return newSVnv (json_atof (start));
1224
1225      // everything else fails, convert it to a string
1226      return newSVpvn (start, dec->cur - start);
1227    }
1228
1229  // loss of precision here
1230  return newSVnv (json_atof (start));
1231
1232fail:
1233  return 0;
1234}
1235
1236static SV *
1237decode_av (dec_t *dec)
1238{
1239  AV *av = newAV ();
1240
1241  DEC_INC_DEPTH;
1242  decode_ws (dec);
1243
1244  if (*dec->cur == ']')
1245    ++dec->cur;
1246  else
1247    for (;;)
1248      {
1249        SV *value;
1250
1251        value = decode_sv (dec);
1252        if (!value)
1253          goto fail;
1254
1255        av_push (av, value);
1256
1257        decode_ws (dec);
1258
1259        if (*dec->cur == ']')
1260          {
1261            ++dec->cur;
1262            break;
1263          }
1264
1265        if (*dec->cur != ',')
1266          ERR (", or ] expected while parsing array");
1267
1268        ++dec->cur;
1269
1270        decode_ws (dec);
1271
1272        if (*dec->cur == ']' && dec->json.flags & F_RELAXED)
1273          {
1274            ++dec->cur;
1275            break;
1276          }
1277      }
1278
1279  DEC_DEC_DEPTH;
1280  return newRV_noinc ((SV *)av);
1281
1282fail:
1283  SvREFCNT_dec (av);
1284  DEC_DEC_DEPTH;
1285  return 0;
1286}
1287
1288static SV *
1289decode_hv (dec_t *dec)
1290{
1291  SV *sv;
1292  HV *hv = newHV ();
1293
1294  DEC_INC_DEPTH;
1295  decode_ws (dec);
1296
1297  if (*dec->cur == '}')
1298    ++dec->cur;
1299  else
1300    for (;;)
1301      {
1302        EXPECT_CH ('"');
1303
1304        // heuristic: assume that
1305        // a) decode_str + hv_store_ent are abysmally slow.
1306        // b) most hash keys are short, simple ascii text.
1307        // => try to "fast-match" such strings to avoid
1308        // the overhead of decode_str + hv_store_ent.
1309        {
1310          SV *value;
1311          char *p = dec->cur;
1312          char *e = p + 24; // only try up to 24 bytes
1313
1314          for (;;)
1315            {
1316              // the >= 0x80 is false on most architectures
1317              if (p == e || *p < 0x20 || *p >= 0x80 || *p == '\\')
1318                {
1319                  // slow path, back up and use decode_str
1320                  SV *key = decode_str (dec);
1321                  if (!key)
1322                    goto fail;
1323
1324                  decode_ws (dec); EXPECT_CH (':');
1325
1326                  decode_ws (dec);
1327                  value = decode_sv (dec);
1328                  if (!value)
1329                    {
1330                      SvREFCNT_dec (key);
1331                      goto fail;
1332                    }
1333
1334                  hv_store_ent (hv, key, value, 0);
1335                  SvREFCNT_dec (key);
1336
1337                  break;
1338                }
1339              else if (*p == '"')
1340                {
1341                  // fast path, got a simple key
1342                  char *key = dec->cur;
1343                  int len = p - key;
1344                  dec->cur = p + 1;
1345
1346                  decode_ws (dec); EXPECT_CH (':');
1347
1348                  decode_ws (dec);
1349                  value = decode_sv (dec);
1350                  if (!value)
1351                    goto fail;
1352
1353                  hv_store (hv, key, len, value, 0);
1354
1355                  break;
1356                }
1357
1358              ++p;
1359            }
1360        }
1361
1362        decode_ws (dec);
1363
1364        if (*dec->cur == '}')
1365          {
1366            ++dec->cur;
1367            break;
1368          }
1369
1370        if (*dec->cur != ',')
1371          ERR (", or } expected while parsing object/hash");
1372
1373        ++dec->cur;
1374
1375        decode_ws (dec);
1376
1377        if (*dec->cur == '}' && dec->json.flags & F_RELAXED)
1378          {
1379            ++dec->cur;
1380            break;
1381          }
1382      }
1383
1384  DEC_DEC_DEPTH;
1385  sv = newRV_noinc ((SV *)hv);
1386
1387  // check filter callbacks
1388  if (dec->json.flags & F_HOOK)
1389    {
1390      if (dec->json.cb_sk_object && HvKEYS (hv) == 1)
1391        {
1392          HE *cb, *he;
1393
1394          hv_iterinit (hv);
1395          he = hv_iternext (hv);
1396          hv_iterinit (hv);
1397
1398          // the next line creates a mortal sv each time its called.
1399          // might want to optimise this for common cases.
1400          cb = hv_fetch_ent (dec->json.cb_sk_object, hv_iterkeysv (he), 0, 0);
1401
1402          if (cb)
1403            {
1404              dSP;
1405              int count;
1406
1407              ENTER; SAVETMPS; PUSHMARK (SP);
1408              XPUSHs (HeVAL (he));
1409              sv_2mortal (sv);
1410
1411              PUTBACK; count = call_sv (HeVAL (cb), G_ARRAY); SPAGAIN;
1412
1413              if (count == 1)
1414                {
1415                  sv = newSVsv (POPs);
1416                  FREETMPS; LEAVE;
1417                  return sv;
1418                }
1419
1420              SvREFCNT_inc (sv);
1421              FREETMPS; LEAVE;
1422            }
1423        }
1424
1425      if (dec->json.cb_object)
1426        {
1427          dSP;
1428          int count;
1429
1430          ENTER; SAVETMPS; PUSHMARK (SP);
1431          XPUSHs (sv_2mortal (sv));
1432
1433          PUTBACK; count = call_sv (dec->json.cb_object, G_ARRAY); SPAGAIN;
1434
1435          if (count == 1)
1436            {
1437              sv = newSVsv (POPs);
1438              FREETMPS; LEAVE;
1439              return sv;
1440            }
1441
1442          SvREFCNT_inc (sv);
1443          FREETMPS; LEAVE;
1444        }
1445    }
1446
1447  return sv;
1448
1449fail:
1450  SvREFCNT_dec (hv);
1451  DEC_DEC_DEPTH;
1452  return 0;
1453}
1454
1455static SV *
1456decode_sv (dec_t *dec)
1457{
1458  // the beauty of JSON: you need exactly one character lookahead
1459  // to parse everything.
1460  switch (*dec->cur)
1461    {
1462      case '"': ++dec->cur; return decode_str (dec);
1463      case '[': ++dec->cur; return decode_av  (dec);
1464      case '{': ++dec->cur; return decode_hv  (dec);
1465
1466      case '-':
1467      case '0': case '1': case '2': case '3': case '4':
1468      case '5': case '6': case '7': case '8': case '9':
1469        return decode_num (dec);
1470
1471      case 't':
1472        if (dec->end - dec->cur >= 4 && !memcmp (dec->cur, "true", 4))
1473          {
1474            dec->cur += 4;
1475#if JSON_SLOW
1476            json_true = get_bool ("JSON::XS::true");
1477#endif
1478            return newSVsv (json_true);
1479          }
1480        else
1481          ERR ("'true' expected");
1482
1483        break;
1484
1485      case 'f':
1486        if (dec->end - dec->cur >= 5 && !memcmp (dec->cur, "false", 5))
1487          {
1488            dec->cur += 5;
1489#if JSON_SLOW
1490            json_false = get_bool ("JSON::XS::false");
1491#endif
1492            return newSVsv (json_false);
1493          }
1494        else
1495          ERR ("'false' expected");
1496
1497        break;
1498
1499      case 'n':
1500        if (dec->end - dec->cur >= 4 && !memcmp (dec->cur, "null", 4))
1501          {
1502            dec->cur += 4;
1503            return newSVsv (&PL_sv_undef);
1504          }
1505        else
1506          ERR ("'null' expected");
1507
1508        break;
1509
1510      default:
1511        ERR ("malformed JSON string, neither array, object, number, string or atom");
1512        break;
1513    }
1514
1515fail:
1516  return 0;
1517}
1518
1519static SV *
1520decode_json (SV *string, JSON *json, char **offset_return)
1521{
1522  dec_t dec;
1523  SV *sv;
1524
1525  /* work around bugs in 5.10 where manipulating magic values
1526   * will perl ignore the magic in subsequent accesses.
1527   * also make a copy of non-PV values, to get them into a clean
1528   * state (SvPV should do that, but it's buggy, see below).
1529   */
1530  /*SvGETMAGIC (string);*/
1531  if (SvMAGICAL (string) || !SvPOK (string))
1532    string = sv_2mortal (newSVsv (string));
1533
1534  SvUPGRADE (string, SVt_PV);
1535
1536  /* work around a bug in perl 5.10, which causes SvCUR to fail an
1537   * assertion with -DDEBUGGING, although SvCUR is documented to
1538   * return the xpv_cur field which certainly exists after upgrading.
1539   * according to nicholas clark, calling SvPOK fixes this.
1540   * But it doesn't fix it, so try another workaround, call SvPV_nolen
1541   * and hope for the best.
1542   * Damnit, SvPV_nolen still trips over yet another assertion. This
1543   * assertion business is seriously broken, try yet another workaround
1544   * for the broken -DDEBUGGING.
1545   */
1546  {
1547#ifdef DEBUGGING
1548    STRLEN offset = SvOK (string) ? sv_len (string) : 0;
1549#else
1550    STRLEN offset = SvCUR (string);
1551#endif
1552
1553    if (offset > json->max_size && json->max_size)
1554      croak ("attempted decode of JSON text of %lu bytes size, but max_size is set to %lu",
1555             (unsigned long)SvCUR (string), (unsigned long)json->max_size);
1556  }
1557
1558  if (DECODE_WANTS_OCTETS (json))
1559    sv_utf8_downgrade (string, 0);
1560  else
1561    sv_utf8_upgrade (string);
1562
1563  SvGROW (string, SvCUR (string) + 1); // should basically be a NOP
1564
1565  dec.json  = *json;
1566  dec.cur   = SvPVX (string);
1567  dec.end   = SvEND (string);
1568  dec.err   = 0;
1569  dec.depth = 0;
1570
1571  if (dec.json.cb_object || dec.json.cb_sk_object)
1572    dec.json.flags |= F_HOOK;
1573
1574  *dec.end = 0; // this should basically be a nop, too, but make sure it's there
1575
1576  decode_ws (&dec);
1577  sv = decode_sv (&dec);
1578
1579  if (offset_return)
1580    *offset_return = dec.cur;
1581
1582  if (!(offset_return || !sv))
1583    {
1584      // check for trailing garbage
1585      decode_ws (&dec);
1586
1587      if (*dec.cur)
1588        {
1589          dec.err = "garbage after JSON object";
1590          SvREFCNT_dec (sv);
1591          sv = 0;
1592        }
1593    }
1594
1595  if (!sv)
1596    {
1597      SV *uni = sv_newmortal ();
1598
1599      // horrible hack to silence warning inside pv_uni_display
1600      COP cop = *PL_curcop;
1601      cop.cop_warnings = pWARN_NONE;
1602      ENTER;
1603      SAVEVPTR (PL_curcop);
1604      PL_curcop = &cop;
1605      pv_uni_display (uni, dec.cur, dec.end - dec.cur, 20, UNI_DISPLAY_QQ);
1606      LEAVE;
1607
1608      croak ("%s, at character offset %d (before \"%s\")",
1609             dec.err,
1610             (int)ptr_to_index (string, dec.cur),
1611             dec.cur != dec.end ? SvPV_nolen (uni) : "(end of string)");
1612    }
1613
1614  sv = sv_2mortal (sv);
1615
1616  if (!(dec.json.flags & F_ALLOW_NONREF) && !SvROK (sv))
1617    croak ("JSON text must be an object or array (but found number, string, true, false or null, use allow_nonref to allow this)");
1618
1619  return sv;
1620}
1621
1622/////////////////////////////////////////////////////////////////////////////
1623// incremental parser
1624
1625static void
1626incr_parse (JSON *self)
1627{
1628  const char *p = SvPVX (self->incr_text) + self->incr_pos;
1629
1630  // the state machine here is a bit convoluted and could be simplified a lot
1631  // but this would make it slower, so...
1632
1633  for (;;)
1634    {
1635      //printf ("loop pod %d *p<%c><%s>, mode %d nest %d\n", p - SvPVX (self->incr_text), *p, p, self->incr_mode, self->incr_nest);//D
1636      switch (self->incr_mode)
1637        {
1638          // only used for initial whitespace skipping
1639          case INCR_M_WS:
1640            for (;;)
1641              {
1642                if (*p > 0x20)
1643                  {
1644                    if (*p == '#')
1645                      {
1646                        self->incr_mode = INCR_M_C0;
1647                        goto incr_m_c;
1648                      }
1649                    else
1650                      {
1651                        self->incr_mode = INCR_M_JSON;
1652                        goto incr_m_json;
1653                      }
1654                  }
1655                else if (!*p)
1656                  goto interrupt;
1657
1658                ++p;
1659              }
1660
1661          // skip a single char inside a string (for \\-processing)
1662          case INCR_M_BS:
1663            if (!*p)
1664              goto interrupt;
1665
1666            ++p;
1667            self->incr_mode = INCR_M_STR;
1668            goto incr_m_str;
1669
1670          // inside #-style comments
1671          case INCR_M_C0:
1672          case INCR_M_C1:
1673          incr_m_c:
1674            for (;;)
1675              {
1676                if (*p == '\n')
1677                  {
1678                    self->incr_mode = self->incr_mode == INCR_M_C0 ? INCR_M_WS : INCR_M_JSON;
1679                    break;
1680                  }
1681                else if (!*p)
1682                  goto interrupt;
1683
1684                ++p;
1685              }
1686
1687            break;
1688
1689          // inside a string
1690          case INCR_M_STR:
1691          incr_m_str:
1692            for (;;)
1693              {
1694                if (*p == '"')
1695                  {
1696                    ++p;
1697                    self->incr_mode = INCR_M_JSON;
1698
1699                    if (!self->incr_nest)
1700                      goto interrupt;
1701
1702                    goto incr_m_json;
1703                  }
1704                else if (*p == '\\')
1705                  {
1706                    ++p; // "virtually" consumes character after \
1707
1708                    if (!*p) // if at end of string we have to switch modes
1709                      {
1710                        self->incr_mode = INCR_M_BS;
1711                        goto interrupt;
1712                      }
1713                  }
1714                else if (!*p)
1715                  goto interrupt;
1716
1717                ++p;
1718              }
1719
1720          // after initial ws, outside string
1721          case INCR_M_JSON:
1722          incr_m_json:
1723            for (;;)
1724              {
1725                switch (*p++)
1726                  {
1727                    case 0:
1728                      --p;
1729                      goto interrupt;
1730
1731                    case 0x09:
1732                    case 0x0a:
1733                    case 0x0d:
1734                    case 0x20:
1735                      if (!self->incr_nest)
1736                        {
1737                          --p; // do not eat the whitespace, let the next round do it
1738                          goto interrupt;
1739                        }
1740                      break;
1741
1742                    case '"':
1743                      self->incr_mode = INCR_M_STR;
1744                      goto incr_m_str;
1745
1746                    case '[':
1747                    case '{':
1748                      if (++self->incr_nest > self->max_depth)
1749                        croak (ERR_NESTING_EXCEEDED);
1750                      break;
1751
1752                    case ']':
1753                    case '}':
1754                      if (--self->incr_nest <= 0)
1755                        goto interrupt;
1756                      break;
1757
1758                    case '#':
1759                      self->incr_mode = INCR_M_C1;
1760                      goto incr_m_c;
1761                  }
1762              }
1763        }
1764
1765      modechange:
1766        ;
1767    }
1768
1769interrupt:
1770  self->incr_pos = p - SvPVX (self->incr_text);
1771  //printf ("interrupt<%.*s>\n", self->incr_pos, SvPVX(self->incr_text));//D
1772  //printf ("return pos %d mode %d nest %d\n", self->incr_pos, self->incr_mode, self->incr_nest);//D
1773}
1774
1775/////////////////////////////////////////////////////////////////////////////
1776// XS interface functions
1777
1778MODULE = JSON::XS		PACKAGE = JSON::XS
1779
1780BOOT:
1781{
1782	int i;
1783
1784        for (i = 0; i < 256; ++i)
1785          decode_hexdigit [i] =
1786            i >= '0' && i <= '9' ? i - '0'
1787            : i >= 'a' && i <= 'f' ? i - 'a' + 10
1788            : i >= 'A' && i <= 'F' ? i - 'A' + 10
1789            : -1;
1790
1791	json_stash         = gv_stashpv ("JSON::XS"         , 1);
1792	json_boolean_stash = gv_stashpv ("JSON::XS::Boolean", 1);
1793
1794        json_true  = get_bool ("JSON::XS::true");
1795        json_false = get_bool ("JSON::XS::false");
1796
1797        CvNODEBUG_on (get_cv ("JSON::XS::incr_text", 0)); /* the debugger completely breaks lvalue subs */
1798}
1799
1800PROTOTYPES: DISABLE
1801
1802void CLONE (...)
1803	CODE:
1804        json_stash         = 0;
1805        json_boolean_stash = 0;
1806
1807void new (char *klass)
1808	PPCODE:
1809{
1810  	SV *pv = NEWSV (0, sizeof (JSON));
1811        SvPOK_only (pv);
1812        json_init ((JSON *)SvPVX (pv));
1813        XPUSHs (sv_2mortal (sv_bless (
1814           newRV_noinc (pv),
1815           strEQ (klass, "JSON::XS") ? JSON_STASH : gv_stashpv (klass, 1)
1816        )));
1817}
1818
1819void ascii (JSON *self, int enable = 1)
1820	ALIAS:
1821        ascii           = F_ASCII
1822        latin1          = F_LATIN1
1823        utf8            = F_UTF8
1824        indent          = F_INDENT
1825        canonical       = F_CANONICAL
1826        space_before    = F_SPACE_BEFORE
1827        space_after     = F_SPACE_AFTER
1828        pretty          = F_PRETTY
1829        allow_nonref    = F_ALLOW_NONREF
1830        shrink          = F_SHRINK
1831        allow_blessed   = F_ALLOW_BLESSED
1832        convert_blessed = F_CONV_BLESSED
1833        relaxed         = F_RELAXED
1834        allow_unknown   = F_ALLOW_UNKNOWN
1835	PPCODE:
1836{
1837        if (enable)
1838          self->flags |=  ix;
1839        else
1840          self->flags &= ~ix;
1841
1842        XPUSHs (ST (0));
1843}
1844
1845void get_ascii (JSON *self)
1846	ALIAS:
1847        get_ascii           = F_ASCII
1848        get_latin1          = F_LATIN1
1849        get_utf8            = F_UTF8
1850        get_indent          = F_INDENT
1851        get_canonical       = F_CANONICAL
1852        get_space_before    = F_SPACE_BEFORE
1853        get_space_after     = F_SPACE_AFTER
1854        get_allow_nonref    = F_ALLOW_NONREF
1855        get_shrink          = F_SHRINK
1856        get_allow_blessed   = F_ALLOW_BLESSED
1857        get_convert_blessed = F_CONV_BLESSED
1858        get_relaxed         = F_RELAXED
1859        get_allow_unknown   = F_ALLOW_UNKNOWN
1860	PPCODE:
1861        XPUSHs (boolSV (self->flags & ix));
1862
1863void max_depth (JSON *self, U32 max_depth = 0x80000000UL)
1864	PPCODE:
1865        self->max_depth = max_depth;
1866        XPUSHs (ST (0));
1867
1868U32 get_max_depth (JSON *self)
1869	CODE:
1870        RETVAL = self->max_depth;
1871	OUTPUT:
1872        RETVAL
1873
1874void max_size (JSON *self, U32 max_size = 0)
1875	PPCODE:
1876        self->max_size = max_size;
1877        XPUSHs (ST (0));
1878
1879int get_max_size (JSON *self)
1880	CODE:
1881        RETVAL = self->max_size;
1882	OUTPUT:
1883        RETVAL
1884
1885void filter_json_object (JSON *self, SV *cb = &PL_sv_undef)
1886	PPCODE:
1887{
1888        SvREFCNT_dec (self->cb_object);
1889        self->cb_object = SvOK (cb) ? newSVsv (cb) : 0;
1890
1891        XPUSHs (ST (0));
1892}
1893
1894void filter_json_single_key_object (JSON *self, SV *key, SV *cb = &PL_sv_undef)
1895	PPCODE:
1896{
1897	if (!self->cb_sk_object)
1898          self->cb_sk_object = newHV ();
1899
1900        if (SvOK (cb))
1901          hv_store_ent (self->cb_sk_object, key, newSVsv (cb), 0);
1902        else
1903          {
1904            hv_delete_ent (self->cb_sk_object, key, G_DISCARD, 0);
1905
1906            if (!HvKEYS (self->cb_sk_object))
1907              {
1908                SvREFCNT_dec (self->cb_sk_object);
1909                self->cb_sk_object = 0;
1910              }
1911          }
1912
1913        XPUSHs (ST (0));
1914}
1915
1916void encode (JSON *self, SV *scalar)
1917	PPCODE:
1918        PUTBACK; scalar = encode_json (scalar, self); SPAGAIN;
1919        XPUSHs (scalar);
1920
1921void decode (JSON *self, SV *jsonstr)
1922	PPCODE:
1923        PUTBACK; jsonstr = decode_json (jsonstr, self, 0); SPAGAIN;
1924        XPUSHs (jsonstr);
1925
1926void decode_prefix (JSON *self, SV *jsonstr)
1927	PPCODE:
1928{
1929	SV *sv;
1930        char *offset;
1931        PUTBACK; sv = decode_json (jsonstr, self, &offset); SPAGAIN;
1932        EXTEND (SP, 2);
1933        PUSHs (sv);
1934        PUSHs (sv_2mortal (newSVuv (ptr_to_index (jsonstr, offset))));
1935}
1936
1937void incr_parse (JSON *self, SV *jsonstr = 0)
1938	PPCODE:
1939{
1940	if (!self->incr_text)
1941          self->incr_text = newSVpvn ("", 0);
1942
1943        /* if utf8-ness doesn't match the decoder, need to upgrade/downgrade */
1944        if (!DECODE_WANTS_OCTETS (self) == !SvUTF8 (self->incr_text))
1945          if (DECODE_WANTS_OCTETS (self))
1946            {
1947              if (self->incr_pos)
1948                self->incr_pos = utf8_length ((U8 *)SvPVX (self->incr_text),
1949                                              (U8 *)SvPVX (self->incr_text) + self->incr_pos);
1950
1951              sv_utf8_downgrade (self->incr_text, 0);
1952            }
1953          else
1954            {
1955              sv_utf8_upgrade (self->incr_text);
1956
1957              if (self->incr_pos)
1958                self->incr_pos = utf8_hop ((U8 *)SvPVX (self->incr_text), self->incr_pos)
1959                                 - (U8 *)SvPVX (self->incr_text);
1960            }
1961
1962        // append data, if any
1963        if (jsonstr)
1964          {
1965            /* make sure both strings have same encoding */
1966            if (SvUTF8 (jsonstr) != SvUTF8 (self->incr_text))
1967              if (SvUTF8 (jsonstr))
1968                sv_utf8_downgrade (jsonstr, 0);
1969              else
1970                sv_utf8_upgrade (jsonstr);
1971
1972            /* and then just blindly append */
1973            {
1974              STRLEN len;
1975              const char *str = SvPV (jsonstr, len);
1976              STRLEN cur = SvCUR (self->incr_text);
1977
1978              if (SvLEN (self->incr_text) <= cur + len)
1979                SvGROW (self->incr_text, cur + (len < (cur >> 2) ? cur >> 2 : len) + 1);
1980
1981              Move (str, SvEND (self->incr_text), len, char);
1982              SvCUR_set (self->incr_text, SvCUR (self->incr_text) + len);
1983              *SvEND (self->incr_text) = 0; // this should basically be a nop, too, but make sure it's there
1984            }
1985          }
1986
1987        if (GIMME_V != G_VOID)
1988          do
1989            {
1990              SV *sv;
1991              char *offset;
1992
1993              if (!INCR_DONE (self))
1994                {
1995                  incr_parse (self);
1996
1997                  if (self->incr_pos > self->max_size && self->max_size)
1998                    croak ("attempted decode of JSON text of %lu bytes size, but max_size is set to %lu",
1999                           (unsigned long)self->incr_pos, (unsigned long)self->max_size);
2000
2001                  if (!INCR_DONE (self))
2002                    {
2003                      // as an optimisation, do not accumulate white space in the incr buffer
2004                      if (self->incr_mode == INCR_M_WS && self->incr_pos)
2005                        {
2006                          self->incr_pos = 0;
2007                          SvCUR_set (self->incr_text, 0);
2008                        }
2009
2010                      break;
2011                    }
2012                }
2013
2014              PUTBACK; sv = decode_json (self->incr_text, self, &offset); SPAGAIN;
2015              XPUSHs (sv);
2016
2017              self->incr_pos -= offset - SvPVX (self->incr_text);
2018              self->incr_nest = 0;
2019              self->incr_mode = 0;
2020
2021              sv_chop (self->incr_text, offset);
2022            }
2023          while (GIMME_V == G_ARRAY);
2024}
2025
2026SV *incr_text (JSON *self)
2027	ATTRS: lvalue
2028	CODE:
2029{
2030        if (self->incr_pos)
2031          croak ("incr_text can not be called when the incremental parser already started parsing");
2032
2033        RETVAL = self->incr_text ? SvREFCNT_inc (self->incr_text) : &PL_sv_undef;
2034}
2035	OUTPUT:
2036        RETVAL
2037
2038void incr_skip (JSON *self)
2039	CODE:
2040{
2041        if (self->incr_pos)
2042          {
2043            sv_chop (self->incr_text, SvPV_nolen (self->incr_text) + self->incr_pos);
2044            self->incr_pos  = 0;
2045            self->incr_nest = 0;
2046            self->incr_mode = 0;
2047          }
2048}
2049
2050void incr_reset (JSON *self)
2051	CODE:
2052{
2053	SvREFCNT_dec (self->incr_text);
2054        self->incr_text = 0;
2055        self->incr_pos  = 0;
2056        self->incr_nest = 0;
2057        self->incr_mode = 0;
2058}
2059
2060void DESTROY (JSON *self)
2061	CODE:
2062        SvREFCNT_dec (self->cb_sk_object);
2063        SvREFCNT_dec (self->cb_object);
2064        SvREFCNT_dec (self->incr_text);
2065
2066PROTOTYPES: ENABLE
2067
2068void encode_json (SV *scalar)
2069	ALIAS:
2070        to_json_    = 0
2071        encode_json = F_UTF8
2072	PPCODE:
2073{
2074        JSON json;
2075        json_init (&json);
2076        json.flags |= ix;
2077        PUTBACK; scalar = encode_json (scalar, &json); SPAGAIN;
2078        XPUSHs (scalar);
2079}
2080
2081void decode_json (SV *jsonstr)
2082	ALIAS:
2083        from_json_  = 0
2084        decode_json = F_UTF8
2085	PPCODE:
2086{
2087        JSON json;
2088        json_init (&json);
2089        json.flags |= ix;
2090        PUTBACK; jsonstr = decode_json (jsonstr, &json, 0); SPAGAIN;
2091        XPUSHs (jsonstr);
2092}
2093
2094