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// compatibility with perl <5.18
23#ifndef HvNAMELEN_get
24# define HvNAMELEN_get(hv) strlen (HvNAME (hv))
25#endif
26#ifndef HvNAMELEN
27# define HvNAMELEN(hv) HvNAMELEN_get (hv)
28#endif
29#ifndef HvNAMEUTF8
30# define HvNAMEUTF8(hv) 0
31#endif
32
33// three extra for rounding, sign, and end of string
34#define IVUV_MAXCHARS (sizeof (UV) * CHAR_BIT * 28 / 93 + 3)
35
36#define F_ASCII          0x00000001UL
37#define F_LATIN1         0x00000002UL
38#define F_UTF8           0x00000004UL
39#define F_INDENT         0x00000008UL
40#define F_CANONICAL      0x00000010UL
41#define F_SPACE_BEFORE   0x00000020UL
42#define F_SPACE_AFTER    0x00000040UL
43#define F_ALLOW_NONREF   0x00000100UL
44#define F_SHRINK         0x00000200UL
45#define F_ALLOW_BLESSED  0x00000400UL
46#define F_CONV_BLESSED   0x00000800UL
47#define F_RELAXED        0x00001000UL
48#define F_ALLOW_UNKNOWN  0x00002000UL
49#define F_ALLOW_TAGS     0x00004000UL
50#define F_HOOK           0x00080000UL // some hooks exist, so slow-path processing
51
52#define F_PRETTY    F_INDENT | F_SPACE_BEFORE | F_SPACE_AFTER
53
54#define INIT_SIZE   32 // initial scalar size to be allocated
55#define INDENT_STEP 3  // spaces per indentation level
56
57#define SHORT_STRING_LEN 16384 // special-case strings of up to this size
58
59#define DECODE_WANTS_OCTETS(json) ((json)->flags & F_UTF8)
60
61#define SB do {
62#define SE } while (0)
63
64#if __GNUC__ >= 3
65# define expect(expr,value)         __builtin_expect ((expr), (value))
66# define INLINE                     static inline
67#else
68# define expect(expr,value)         (expr)
69# define INLINE                     static
70#endif
71
72#define expect_false(expr) expect ((expr) != 0, 0)
73#define expect_true(expr)  expect ((expr) != 0, 1)
74
75#define IN_RANGE_INC(type,val,beg,end) \
76  ((unsigned type)((unsigned type)(val) - (unsigned type)(beg)) \
77  <= (unsigned type)((unsigned type)(end) - (unsigned type)(beg)))
78
79#define ERR_NESTING_EXCEEDED "json text or perl structure exceeds maximum nesting level (max_depth set too low?)"
80
81#ifdef USE_ITHREADS
82# define JSON_SLOW 1
83# define JSON_STASH (json_stash ? json_stash : gv_stashpv ("JSON::XS", 1))
84#else
85# define JSON_SLOW 0
86# define JSON_STASH json_stash
87#endif
88
89// the amount of HEs to allocate on the stack, when sorting keys
90#define STACK_HES 64
91
92static HV *json_stash, *types_boolean_stash; // JSON::XS::
93static SV *types_true, *types_false, *sv_json;
94
95enum {
96  INCR_M_WS = 0, // initial whitespace skipping, must be 0
97  INCR_M_STR,    // inside string
98  INCR_M_BS,     // inside backslash
99  INCR_M_C0,     // inside comment in initial whitespace sequence
100  INCR_M_C1,     // inside comment in other places
101  INCR_M_JSON    // outside anything, count nesting
102};
103
104#define INCR_DONE(json) ((json)->incr_nest <= 0 && (json)->incr_mode == INCR_M_JSON)
105
106typedef struct {
107  U32 flags;
108  U32 max_depth;
109  STRLEN max_size;
110
111  SV *cb_object;
112  HV *cb_sk_object;
113
114  // for the incremental parser
115  SV *incr_text;   // the source text so far
116  STRLEN incr_pos; // the current offset into the text
117  int incr_nest;   // {[]}-nesting level
118  unsigned char incr_mode;
119} JSON;
120
121INLINE void
122json_init (JSON *json)
123{
124  Zero (json, 1, JSON);
125  json->max_depth = 512;
126}
127
128/////////////////////////////////////////////////////////////////////////////
129// utility functions
130
131INLINE SV *
132get_bool (const char *name)
133{
134  SV *sv = get_sv (name, 1);
135
136  SvREADONLY_on (sv);
137  SvREADONLY_on (SvRV (sv));
138
139  return sv;
140}
141
142INLINE void
143shrink (SV *sv)
144{
145  sv_utf8_downgrade (sv, 1);
146
147  if (SvLEN (sv) > SvCUR (sv) + 1)
148    {
149#ifdef SvPV_shrink_to_cur
150      SvPV_shrink_to_cur (sv);
151#elif defined (SvPV_renew)
152      SvPV_renew (sv, SvCUR (sv) + 1);
153#endif
154    }
155}
156
157// decode an utf-8 character and return it, or (UV)-1 in
158// case of an error.
159// we special-case "safe" characters from U+80 .. U+7FF,
160// but use the very good perl function to parse anything else.
161// note that we never call this function for a ascii codepoints
162INLINE UV
163decode_utf8 (unsigned char *s, STRLEN len, STRLEN *clen)
164{
165  if (expect_true (len >= 2
166                   && IN_RANGE_INC (char, s[0], 0xc2, 0xdf)
167                   && IN_RANGE_INC (char, s[1], 0x80, 0xbf)))
168    {
169      *clen = 2;
170      return ((s[0] & 0x1f) << 6) | (s[1] & 0x3f);
171    }
172  else
173    return utf8n_to_uvuni (s, len, clen, UTF8_CHECK_ONLY);
174}
175
176// likewise for encoding, also never called for ascii codepoints
177// this function takes advantage of this fact, although current gccs
178// seem to optimise the check for >= 0x80 away anyways
179INLINE unsigned char *
180encode_utf8 (unsigned char *s, UV ch)
181{
182  if      (expect_false (ch < 0x000080))
183    *s++ = ch;
184  else if (expect_true  (ch < 0x000800))
185    *s++ = 0xc0 | ( ch >>  6),
186    *s++ = 0x80 | ( ch        & 0x3f);
187  else if (              ch < 0x010000)
188    *s++ = 0xe0 | ( ch >> 12),
189    *s++ = 0x80 | ((ch >>  6) & 0x3f),
190    *s++ = 0x80 | ( ch        & 0x3f);
191  else if (              ch < 0x110000)
192    *s++ = 0xf0 | ( ch >> 18),
193    *s++ = 0x80 | ((ch >> 12) & 0x3f),
194    *s++ = 0x80 | ((ch >>  6) & 0x3f),
195    *s++ = 0x80 | ( ch        & 0x3f);
196
197  return s;
198}
199
200// convert offset pointer to character index, sv must be string
201static STRLEN
202ptr_to_index (SV *sv, char *offset)
203{
204  return SvUTF8 (sv)
205         ? utf8_distance (offset, SvPVX (sv))
206         : offset - SvPVX (sv);
207}
208
209/////////////////////////////////////////////////////////////////////////////
210// fp hell
211
212// scan a group of digits, and a trailing exponent
213static void
214json_atof_scan1 (const char *s, NV *accum, int *expo, int postdp, int maxdepth)
215{
216  UV  uaccum = 0;
217  int eaccum = 0;
218
219  // if we recurse too deep, skip all remaining digits
220  // to avoid a stack overflow attack
221  if (expect_false (--maxdepth <= 0))
222    while (((U8)*s - '0') < 10)
223      ++s;
224
225  for (;;)
226    {
227      U8 dig = (U8)*s - '0';
228
229      if (expect_false (dig >= 10))
230        {
231          if (dig == (U8)((U8)'.' - (U8)'0'))
232            {
233              ++s;
234              json_atof_scan1 (s, accum, expo, 1, maxdepth);
235            }
236          else if ((dig | ' ') == 'e' - '0')
237            {
238              int exp2 = 0;
239              int neg  = 0;
240
241              ++s;
242
243              if (*s == '-')
244                {
245                  ++s;
246                  neg = 1;
247                }
248              else if (*s == '+')
249                ++s;
250
251              while ((dig = (U8)*s - '0') < 10)
252                exp2 = exp2 * 10 + *s++ - '0';
253
254              *expo += neg ? -exp2 : exp2;
255            }
256
257          break;
258        }
259
260      ++s;
261
262      uaccum = uaccum * 10 + dig;
263      ++eaccum;
264
265      // if we have too many digits, then recurse for more
266      // we actually do this for rather few digits
267      if (uaccum >= (UV_MAX - 9) / 10)
268        {
269          if (postdp) *expo -= eaccum;
270          json_atof_scan1 (s, accum, expo, postdp, maxdepth);
271          if (postdp) *expo += eaccum;
272
273          break;
274        }
275    }
276
277  // this relies greatly on the quality of the pow ()
278  // implementation of the platform, but a good
279  // implementation is hard to beat.
280  // (IEEE 754 conformant ones are required to be exact)
281  if (postdp) *expo -= eaccum;
282  *accum += uaccum * Perl_pow (10., *expo);
283  *expo += eaccum;
284}
285
286static NV
287json_atof (const char *s)
288{
289  NV accum = 0.;
290  int expo = 0;
291  int neg  = 0;
292
293  if (*s == '-')
294    {
295      ++s;
296      neg = 1;
297    }
298
299  // a recursion depth of ten gives us >>500 bits
300  json_atof_scan1 (s, &accum, &expo, 0, 10);
301
302  return neg ? -accum : accum;
303}
304/////////////////////////////////////////////////////////////////////////////
305// encoder
306
307// structure used for encoding JSON
308typedef struct
309{
310  char *cur;  // SvPVX (sv) + current output position
311  char *end;  // SvEND (sv)
312  SV *sv;     // result scalar
313  JSON json;
314  U32 indent; // indentation level
315  UV limit;   // escape character values >= this value when encoding
316} enc_t;
317
318INLINE void
319need (enc_t *enc, STRLEN len)
320{
321  if (expect_false (enc->cur + len >= enc->end))
322    {
323      STRLEN cur = enc->cur - (char *)SvPVX (enc->sv);
324      SvGROW (enc->sv, cur + (len < (cur >> 2) ? cur >> 2 : len) + 1);
325      enc->cur = SvPVX (enc->sv) + cur;
326      enc->end = SvPVX (enc->sv) + SvLEN (enc->sv) - 1;
327    }
328}
329
330INLINE void
331encode_ch (enc_t *enc, char ch)
332{
333  need (enc, 1);
334  *enc->cur++ = ch;
335}
336
337static void
338encode_str (enc_t *enc, char *str, STRLEN len, int is_utf8)
339{
340  char *end = str + len;
341
342  need (enc, len);
343
344  while (str < end)
345    {
346      unsigned char ch = *(unsigned char *)str;
347
348      if (expect_true (ch >= 0x20 && ch < 0x80)) // most common case
349        {
350          if (expect_false (ch == '"')) // but with slow exceptions
351            {
352              need (enc, len += 1);
353              *enc->cur++ = '\\';
354              *enc->cur++ = '"';
355            }
356          else if (expect_false (ch == '\\'))
357            {
358              need (enc, len += 1);
359              *enc->cur++ = '\\';
360              *enc->cur++ = '\\';
361            }
362          else
363            *enc->cur++ = ch;
364
365          ++str;
366        }
367      else
368        {
369          switch (ch)
370            {
371              case '\010': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 'b'; ++str; break;
372              case '\011': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 't'; ++str; break;
373              case '\012': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 'n'; ++str; break;
374              case '\014': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 'f'; ++str; break;
375              case '\015': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 'r'; ++str; break;
376
377              default:
378                {
379                  STRLEN clen;
380                  UV uch;
381
382                  if (is_utf8)
383                    {
384                      uch = decode_utf8 (str, end - str, &clen);
385                      if (clen == (STRLEN)-1)
386                        croak ("malformed or illegal unicode character in string [%.11s], cannot convert to JSON", str);
387                    }
388                  else
389                    {
390                      uch = ch;
391                      clen = 1;
392                    }
393
394                  if (uch < 0x80/*0x20*/ || uch >= enc->limit)
395                    {
396                      if (uch >= 0x10000UL)
397                        {
398                          if (uch >= 0x110000UL)
399                            croak ("out of range codepoint (0x%lx) encountered, unrepresentable in JSON", (unsigned long)uch);
400
401                          need (enc, len += 11);
402                          sprintf (enc->cur, "\\u%04x\\u%04x",
403                                   (int)((uch - 0x10000) / 0x400 + 0xD800),
404                                   (int)((uch - 0x10000) % 0x400 + 0xDC00));
405                          enc->cur += 12;
406                        }
407                      else
408                        {
409                          need (enc, len += 5);
410                          *enc->cur++ = '\\';
411                          *enc->cur++ = 'u';
412                          *enc->cur++ = PL_hexdigit [ uch >> 12      ];
413                          *enc->cur++ = PL_hexdigit [(uch >>  8) & 15];
414                          *enc->cur++ = PL_hexdigit [(uch >>  4) & 15];
415                          *enc->cur++ = PL_hexdigit [(uch >>  0) & 15];
416                        }
417
418                      str += clen;
419                    }
420                  else if (enc->json.flags & F_LATIN1)
421                    {
422                      *enc->cur++ = uch;
423                      str += clen;
424                    }
425                  else if (is_utf8)
426                    {
427                      need (enc, len += clen);
428                      do
429                        {
430                          *enc->cur++ = *str++;
431                        }
432                      while (--clen);
433                    }
434                  else
435                    {
436                      need (enc, len += UTF8_MAXBYTES - 1); // never more than 11 bytes needed
437                      enc->cur = encode_utf8 (enc->cur, uch);
438                      ++str;
439                    }
440                }
441            }
442        }
443
444      --len;
445    }
446}
447
448INLINE void
449encode_indent (enc_t *enc)
450{
451  if (enc->json.flags & F_INDENT)
452    {
453      int spaces = enc->indent * INDENT_STEP;
454
455      need (enc, spaces);
456      memset (enc->cur, ' ', spaces);
457      enc->cur += spaces;
458    }
459}
460
461INLINE void
462encode_space (enc_t *enc)
463{
464  need (enc, 1);
465  encode_ch (enc, ' ');
466}
467
468INLINE void
469encode_nl (enc_t *enc)
470{
471  if (enc->json.flags & F_INDENT)
472    {
473      need (enc, 1);
474      encode_ch (enc, '\n');
475    }
476}
477
478INLINE void
479encode_comma (enc_t *enc)
480{
481  encode_ch (enc, ',');
482
483  if (enc->json.flags & F_INDENT)
484    encode_nl (enc);
485  else if (enc->json.flags & F_SPACE_AFTER)
486    encode_space (enc);
487}
488
489static void encode_sv (enc_t *enc, SV *sv);
490
491static void
492encode_av (enc_t *enc, AV *av)
493{
494  int i, len = av_len (av);
495
496  if (enc->indent >= enc->json.max_depth)
497    croak (ERR_NESTING_EXCEEDED);
498
499  encode_ch (enc, '[');
500
501  if (len >= 0)
502    {
503      encode_nl (enc); ++enc->indent;
504
505      for (i = 0; i <= len; ++i)
506        {
507          SV **svp = av_fetch (av, i, 0);
508
509          encode_indent (enc);
510
511          if (svp)
512            encode_sv (enc, *svp);
513          else
514            encode_str (enc, "null", 4, 0);
515
516          if (i < len)
517            encode_comma (enc);
518        }
519
520      encode_nl (enc); --enc->indent; encode_indent (enc);
521    }
522
523  encode_ch (enc, ']');
524}
525
526static void
527encode_hk (enc_t *enc, HE *he)
528{
529  encode_ch (enc, '"');
530
531  if (HeKLEN (he) == HEf_SVKEY)
532    {
533      SV *sv = HeSVKEY (he);
534      STRLEN len;
535      char *str;
536
537      SvGETMAGIC (sv);
538      str = SvPV (sv, len);
539
540      encode_str (enc, str, len, SvUTF8 (sv));
541    }
542  else
543    encode_str (enc, HeKEY (he), HeKLEN (he), HeKUTF8 (he));
544
545  encode_ch (enc, '"');
546
547  if (enc->json.flags & F_SPACE_BEFORE) encode_space (enc);
548  encode_ch (enc, ':');
549  if (enc->json.flags & F_SPACE_AFTER ) encode_space (enc);
550}
551
552// compare hash entries, used when all keys are bytestrings
553static int
554he_cmp_fast (const void *a_, const void *b_)
555{
556  int cmp;
557
558  HE *a = *(HE **)a_;
559  HE *b = *(HE **)b_;
560
561  STRLEN la = HeKLEN (a);
562  STRLEN lb = HeKLEN (b);
563
564  if (!(cmp = memcmp (HeKEY (b), HeKEY (a), lb < la ? lb : la)))
565    cmp = lb - la;
566
567  return cmp;
568}
569
570// compare hash entries, used when some keys are sv's or utf-x
571static int
572he_cmp_slow (const void *a, const void *b)
573{
574  return sv_cmp (HeSVKEY_force (*(HE **)b), HeSVKEY_force (*(HE **)a));
575}
576
577static void
578encode_hv (enc_t *enc, HV *hv)
579{
580  HE *he;
581
582  if (enc->indent >= enc->json.max_depth)
583    croak (ERR_NESTING_EXCEEDED);
584
585  encode_ch (enc, '{');
586
587  // for canonical output we have to sort by keys first
588  // actually, this is mostly due to the stupid so-called
589  // security workaround added somewhere in 5.8.x
590  // that randomises hash orderings
591  if (enc->json.flags & F_CANONICAL && !SvRMAGICAL (hv))
592    {
593      int count = hv_iterinit (hv);
594
595      if (SvMAGICAL (hv))
596        {
597          // need to count by iterating. could improve by dynamically building the vector below
598          // but I don't care for the speed of this special case.
599          // note also that we will run into undefined behaviour when the two iterations
600          // do not result in the same count, something I might care for in some later release.
601
602          count = 0;
603          while (hv_iternext (hv))
604            ++count;
605
606          hv_iterinit (hv);
607        }
608
609      if (count)
610        {
611          int i, fast = 1;
612          HE *hes_stack [STACK_HES];
613          HE **hes = hes_stack;
614
615          // allocate larger arrays on the heap
616          if (count > STACK_HES)
617            {
618              SV *sv = sv_2mortal (NEWSV (0, count * sizeof (*hes)));
619              hes = (HE **)SvPVX (sv);
620            }
621
622          i = 0;
623          while ((he = hv_iternext (hv)))
624            {
625              hes [i++] = he;
626              if (HeKLEN (he) < 0 || HeKUTF8 (he))
627                fast = 0;
628            }
629
630          assert (i == count);
631
632          if (fast)
633            qsort (hes, count, sizeof (HE *), he_cmp_fast);
634          else
635            {
636              // hack to forcefully disable "use bytes"
637              COP cop = *PL_curcop;
638              cop.op_private = 0;
639
640              ENTER;
641              SAVETMPS;
642
643              SAVEVPTR (PL_curcop);
644              PL_curcop = &cop;
645
646              qsort (hes, count, sizeof (HE *), he_cmp_slow);
647
648              FREETMPS;
649              LEAVE;
650            }
651
652          encode_nl (enc); ++enc->indent;
653
654          while (count--)
655            {
656              encode_indent (enc);
657              he = hes [count];
658              encode_hk (enc, he);
659              encode_sv (enc, expect_false (SvMAGICAL (hv)) ? hv_iterval (hv, he) : HeVAL (he));
660
661              if (count)
662                encode_comma (enc);
663            }
664
665          encode_nl (enc); --enc->indent; encode_indent (enc);
666        }
667    }
668  else
669    {
670      if (hv_iterinit (hv) || SvMAGICAL (hv))
671        if ((he = hv_iternext (hv)))
672          {
673            encode_nl (enc); ++enc->indent;
674
675            for (;;)
676              {
677                encode_indent (enc);
678                encode_hk (enc, he);
679                encode_sv (enc, expect_false (SvMAGICAL (hv)) ? hv_iterval (hv, he) : HeVAL (he));
680
681                if (!(he = hv_iternext (hv)))
682                  break;
683
684                encode_comma (enc);
685              }
686
687            encode_nl (enc); --enc->indent; encode_indent (enc);
688          }
689    }
690
691  encode_ch (enc, '}');
692}
693
694// encode objects, arrays and special \0=false and \1=true values.
695static void
696encode_rv (enc_t *enc, SV *sv)
697{
698  svtype svt;
699  GV *method;
700
701  SvGETMAGIC (sv);
702  svt = SvTYPE (sv);
703
704  if (expect_false (SvOBJECT (sv)))
705    {
706      HV *boolean_stash = !JSON_SLOW || types_boolean_stash
707                          ? types_boolean_stash
708                          : gv_stashpv ("Types::Serialiser::Boolean", 1);
709      HV *stash = SvSTASH (sv);
710
711      if (stash == boolean_stash)
712        {
713          if (SvIV (sv))
714            encode_str (enc, "true", 4, 0);
715          else
716            encode_str (enc, "false", 5, 0);
717        }
718      else if ((enc->json.flags & F_ALLOW_TAGS) && (method = gv_fetchmethod_autoload (stash, "FREEZE", 0)))
719        {
720          int count;
721          dSP;
722
723          ENTER; SAVETMPS; PUSHMARK (SP);
724          EXTEND (SP, 2);
725          // we re-bless the reference to get overload and other niceties right
726          PUSHs (sv_bless (sv_2mortal (newRV_inc (sv)), stash));
727          PUSHs (sv_json);
728
729          PUTBACK;
730          count = call_sv ((SV *)GvCV (method), G_ARRAY);
731          SPAGAIN;
732
733          // catch this surprisingly common error
734          if (SvROK (TOPs) && SvRV (TOPs) == sv)
735            croak ("%s::TO_JSON method returned same object as was passed instead of a new one", HvNAME (SvSTASH (sv)));
736
737          encode_ch (enc, '(');
738          encode_ch (enc, '"');
739          encode_str (enc, HvNAME (stash), HvNAMELEN (stash), HvNAMEUTF8 (stash));
740          encode_ch (enc, '"');
741          encode_ch (enc, ')');
742          encode_ch (enc, '[');
743
744          while (count)
745            {
746              encode_sv (enc, SP[1 - count--]);
747
748              if (count)
749                encode_ch (enc, ',');
750            }
751
752          encode_ch (enc, ']');
753
754          PUTBACK;
755
756          FREETMPS; LEAVE;
757        }
758      else if ((enc->json.flags & F_CONV_BLESSED) && (method = gv_fetchmethod_autoload (stash, "TO_JSON", 0)))
759        {
760          dSP;
761
762          ENTER; SAVETMPS; PUSHMARK (SP);
763          // we re-bless the reference to get overload and other niceties right
764          XPUSHs (sv_bless (sv_2mortal (newRV_inc (sv)), stash));
765
766          // calling with G_SCALAR ensures that we always get a 1 return value
767          PUTBACK;
768          call_sv ((SV *)GvCV (method), G_SCALAR);
769          SPAGAIN;
770
771          // catch this surprisingly common error
772          if (SvROK (TOPs) && SvRV (TOPs) == sv)
773            croak ("%s::TO_JSON method returned same object as was passed instead of a new one", HvNAME (SvSTASH (sv)));
774
775          sv = POPs;
776          PUTBACK;
777
778          encode_sv (enc, sv);
779
780          FREETMPS; LEAVE;
781        }
782      else if (enc->json.flags & F_ALLOW_BLESSED)
783        encode_str (enc, "null", 4, 0);
784      else
785        croak ("encountered object '%s', but neither allow_blessed, convert_blessed nor allow_tags settings are enabled (or TO_JSON/FREEZE method missing)",
786               SvPV_nolen (sv_2mortal (newRV_inc (sv))));
787    }
788  else if (svt == SVt_PVHV)
789    encode_hv (enc, (HV *)sv);
790  else if (svt == SVt_PVAV)
791    encode_av (enc, (AV *)sv);
792  else if (svt < SVt_PVAV)
793    {
794      STRLEN len = 0;
795      char *pv = svt ? SvPV (sv, len) : 0;
796
797      if (len == 1 && *pv == '1')
798        encode_str (enc, "true", 4, 0);
799      else if (len == 1 && *pv == '0')
800        encode_str (enc, "false", 5, 0);
801      else if (enc->json.flags & F_ALLOW_UNKNOWN)
802        encode_str (enc, "null", 4, 0);
803      else
804        croak ("cannot encode reference to scalar '%s' unless the scalar is 0 or 1",
805               SvPV_nolen (sv_2mortal (newRV_inc (sv))));
806    }
807  else if (enc->json.flags & F_ALLOW_UNKNOWN)
808    encode_str (enc, "null", 4, 0);
809  else
810    croak ("encountered %s, but JSON can only represent references to arrays or hashes",
811           SvPV_nolen (sv_2mortal (newRV_inc (sv))));
812}
813
814static void
815encode_sv (enc_t *enc, SV *sv)
816{
817  SvGETMAGIC (sv);
818
819  if (SvPOKp (sv))
820    {
821      STRLEN len;
822      char *str = SvPV (sv, len);
823      encode_ch (enc, '"');
824      encode_str (enc, str, len, SvUTF8 (sv));
825      encode_ch (enc, '"');
826    }
827  else if (SvNOKp (sv))
828    {
829      // trust that perl will do the right thing w.r.t. JSON syntax.
830      need (enc, NV_DIG + 32);
831      Gconvert (SvNVX (sv), NV_DIG, 0, enc->cur);
832      enc->cur += strlen (enc->cur);
833    }
834  else if (SvIOKp (sv))
835    {
836      // we assume we can always read an IV as a UV and vice versa
837      // we assume two's complement
838      // we assume no aliasing issues in the union
839      if (SvIsUV (sv) ? SvUVX (sv) <= 59000
840                      : SvIVX (sv) <= 59000 && SvIVX (sv) >= -59000)
841        {
842          // optimise the "small number case"
843          // code will likely be branchless and use only a single multiplication
844          // works for numbers up to 59074
845          I32 i = SvIVX (sv);
846          U32 u;
847          char digit, nz = 0;
848
849          need (enc, 6);
850
851          *enc->cur = '-'; enc->cur += i < 0 ? 1 : 0;
852          u = i < 0 ? -i : i;
853
854          // convert to 4.28 fixed-point representation
855          u = u * ((0xfffffff + 10000) / 10000); // 10**5, 5 fractional digits
856
857          // now output digit by digit, each time masking out the integer part
858          // and multiplying by 5 while moving the decimal point one to the right,
859          // resulting in a net multiplication by 10.
860          // we always write the digit to memory but conditionally increment
861          // the pointer, to enable the use of conditional move instructions.
862          digit = u >> 28; *enc->cur = digit + '0'; enc->cur += (nz = nz || digit); u = (u & 0xfffffffUL) * 5;
863          digit = u >> 27; *enc->cur = digit + '0'; enc->cur += (nz = nz || digit); u = (u & 0x7ffffffUL) * 5;
864          digit = u >> 26; *enc->cur = digit + '0'; enc->cur += (nz = nz || digit); u = (u & 0x3ffffffUL) * 5;
865          digit = u >> 25; *enc->cur = digit + '0'; enc->cur += (nz = nz || digit); u = (u & 0x1ffffffUL) * 5;
866          digit = u >> 24; *enc->cur = digit + '0'; enc->cur += 1; // correctly generate '0'
867        }
868      else
869        {
870          // large integer, use the (rather slow) snprintf way.
871          need (enc, IVUV_MAXCHARS);
872          enc->cur +=
873             SvIsUV(sv)
874                ? snprintf (enc->cur, IVUV_MAXCHARS, "%"UVuf, (UV)SvUVX (sv))
875                : snprintf (enc->cur, IVUV_MAXCHARS, "%"IVdf, (IV)SvIVX (sv));
876        }
877    }
878  else if (SvROK (sv))
879    encode_rv (enc, SvRV (sv));
880  else if (!SvOK (sv) || enc->json.flags & F_ALLOW_UNKNOWN)
881    encode_str (enc, "null", 4, 0);
882  else
883    croak ("encountered perl type (%s,0x%x) that JSON cannot handle, check your input data",
884           SvPV_nolen (sv), (unsigned int)SvFLAGS (sv));
885}
886
887static SV *
888encode_json (SV *scalar, JSON *json)
889{
890  enc_t enc;
891
892  if (!(json->flags & F_ALLOW_NONREF) && !SvROK (scalar))
893    croak ("hash- or arrayref expected (not a simple scalar, use allow_nonref to allow this)");
894
895  enc.json      = *json;
896  enc.sv        = sv_2mortal (NEWSV (0, INIT_SIZE));
897  enc.cur       = SvPVX (enc.sv);
898  enc.end       = SvEND (enc.sv);
899  enc.indent    = 0;
900  enc.limit     = enc.json.flags & F_ASCII  ? 0x000080UL
901                : enc.json.flags & F_LATIN1 ? 0x000100UL
902                                            : 0x110000UL;
903
904  SvPOK_only (enc.sv);
905  encode_sv (&enc, scalar);
906  encode_nl (&enc);
907
908  SvCUR_set (enc.sv, enc.cur - SvPVX (enc.sv));
909  *SvEND (enc.sv) = 0; // many xs functions expect a trailing 0 for text strings
910
911  if (!(enc.json.flags & (F_ASCII | F_LATIN1 | F_UTF8)))
912    SvUTF8_on (enc.sv);
913
914  if (enc.json.flags & F_SHRINK)
915    shrink (enc.sv);
916
917  return enc.sv;
918}
919
920/////////////////////////////////////////////////////////////////////////////
921// decoder
922
923// structure used for decoding JSON
924typedef struct
925{
926  char *cur; // current parser pointer
927  char *end; // end of input string
928  const char *err; // parse error, if != 0
929  JSON json;
930  U32 depth; // recursion depth
931  U32 maxdepth; // recursion depth limit
932} dec_t;
933
934INLINE void
935decode_comment (dec_t *dec)
936{
937  // only '#'-style comments allowed a.t.m.
938
939  while (*dec->cur && *dec->cur != 0x0a && *dec->cur != 0x0d)
940    ++dec->cur;
941}
942
943INLINE void
944decode_ws (dec_t *dec)
945{
946  for (;;)
947    {
948      char ch = *dec->cur;
949
950      if (ch > 0x20)
951        {
952          if (expect_false (ch == '#'))
953            {
954              if (dec->json.flags & F_RELAXED)
955                decode_comment (dec);
956              else
957                break;
958            }
959          else
960            break;
961        }
962      else if (ch != 0x20 && ch != 0x0a && ch != 0x0d && ch != 0x09)
963        break; // parse error, but let higher level handle it, gives better error messages
964
965      ++dec->cur;
966    }
967}
968
969#define ERR(reason) SB dec->err = reason; goto fail; SE
970
971#define EXPECT_CH(ch) SB \
972  if (*dec->cur != ch)		\
973    ERR (# ch " expected");	\
974  ++dec->cur;			\
975  SE
976
977#define DEC_INC_DEPTH if (++dec->depth > dec->json.max_depth) ERR (ERR_NESTING_EXCEEDED)
978#define DEC_DEC_DEPTH --dec->depth
979
980static SV *decode_sv (dec_t *dec);
981
982static signed char decode_hexdigit[256];
983
984static UV
985decode_4hex (dec_t *dec)
986{
987  signed char d1, d2, d3, d4;
988  unsigned char *cur = (unsigned char *)dec->cur;
989
990  d1 = decode_hexdigit [cur [0]]; if (expect_false (d1 < 0)) ERR ("exactly four hexadecimal digits expected");
991  d2 = decode_hexdigit [cur [1]]; if (expect_false (d2 < 0)) ERR ("exactly four hexadecimal digits expected");
992  d3 = decode_hexdigit [cur [2]]; if (expect_false (d3 < 0)) ERR ("exactly four hexadecimal digits expected");
993  d4 = decode_hexdigit [cur [3]]; if (expect_false (d4 < 0)) ERR ("exactly four hexadecimal digits expected");
994
995  dec->cur += 4;
996
997  return ((UV)d1) << 12
998       | ((UV)d2) <<  8
999       | ((UV)d3) <<  4
1000       | ((UV)d4);
1001
1002fail:
1003  return (UV)-1;
1004}
1005
1006static SV *
1007decode_str (dec_t *dec)
1008{
1009  SV *sv = 0;
1010  int utf8 = 0;
1011  char *dec_cur = dec->cur;
1012
1013  do
1014    {
1015      char buf [SHORT_STRING_LEN + UTF8_MAXBYTES];
1016      char *cur = buf;
1017
1018      do
1019        {
1020          unsigned char ch = *(unsigned char *)dec_cur++;
1021
1022          if (expect_false (ch == '"'))
1023            {
1024              --dec_cur;
1025              break;
1026            }
1027          else if (expect_false (ch == '\\'))
1028            {
1029              switch (*dec_cur)
1030                {
1031                  case '\\':
1032                  case '/':
1033                  case '"': *cur++ = *dec_cur++; break;
1034
1035                  case 'b': ++dec_cur; *cur++ = '\010'; break;
1036                  case 't': ++dec_cur; *cur++ = '\011'; break;
1037                  case 'n': ++dec_cur; *cur++ = '\012'; break;
1038                  case 'f': ++dec_cur; *cur++ = '\014'; break;
1039                  case 'r': ++dec_cur; *cur++ = '\015'; break;
1040
1041                  case 'u':
1042                    {
1043                      UV lo, hi;
1044                      ++dec_cur;
1045
1046                      dec->cur = dec_cur;
1047                      hi = decode_4hex (dec);
1048                      dec_cur = dec->cur;
1049                      if (hi == (UV)-1)
1050                        goto fail;
1051
1052                      // possibly a surrogate pair
1053                      if (hi >= 0xd800)
1054                        if (hi < 0xdc00)
1055                          {
1056                            if (dec_cur [0] != '\\' || dec_cur [1] != 'u')
1057                              ERR ("missing low surrogate character in surrogate pair");
1058
1059                            dec_cur += 2;
1060
1061                            dec->cur = dec_cur;
1062                            lo = decode_4hex (dec);
1063                            dec_cur = dec->cur;
1064                            if (lo == (UV)-1)
1065                              goto fail;
1066
1067                            if (lo < 0xdc00 || lo >= 0xe000)
1068                              ERR ("surrogate pair expected");
1069
1070                            hi = (hi - 0xD800) * 0x400 + (lo - 0xDC00) + 0x10000;
1071                          }
1072                        else if (hi < 0xe000)
1073                          ERR ("missing high surrogate character in surrogate pair");
1074
1075                      if (hi >= 0x80)
1076                        {
1077                          utf8 = 1;
1078
1079                          cur = encode_utf8 (cur, hi);
1080                        }
1081                      else
1082                        *cur++ = hi;
1083                    }
1084                    break;
1085
1086                  default:
1087                    --dec_cur;
1088                    ERR ("illegal backslash escape sequence in string");
1089                }
1090            }
1091          else if (expect_true (ch >= 0x20 && ch < 0x80))
1092            *cur++ = ch;
1093          else if (ch >= 0x80)
1094            {
1095              STRLEN clen;
1096
1097              --dec_cur;
1098
1099              decode_utf8 (dec_cur, dec->end - dec_cur, &clen);
1100              if (clen == (STRLEN)-1)
1101                ERR ("malformed UTF-8 character in JSON string");
1102
1103              do
1104                *cur++ = *dec_cur++;
1105              while (--clen);
1106
1107              utf8 = 1;
1108            }
1109          else
1110            {
1111              --dec_cur;
1112
1113              if (!ch)
1114                ERR ("unexpected end of string while parsing JSON string");
1115              else
1116                ERR ("invalid character encountered while parsing JSON string");
1117            }
1118        }
1119      while (cur < buf + SHORT_STRING_LEN);
1120
1121      {
1122        STRLEN len = cur - buf;
1123
1124        if (sv)
1125          {
1126            STRLEN cur = SvCUR (sv);
1127
1128            if (SvLEN (sv) <= cur + len)
1129              SvGROW (sv, cur + (len < (cur >> 2) ? cur >> 2 : len) + 1);
1130
1131            memcpy (SvPVX (sv) + SvCUR (sv), buf, len);
1132            SvCUR_set (sv, SvCUR (sv) + len);
1133          }
1134        else
1135          sv = newSVpvn (buf, len);
1136      }
1137    }
1138  while (*dec_cur != '"');
1139
1140  ++dec_cur;
1141
1142  if (sv)
1143    {
1144      SvPOK_only (sv);
1145      *SvEND (sv) = 0;
1146
1147      if (utf8)
1148        SvUTF8_on (sv);
1149    }
1150  else
1151    sv = newSVpvn ("", 0);
1152
1153  dec->cur = dec_cur;
1154  return sv;
1155
1156fail:
1157  dec->cur = dec_cur;
1158  return 0;
1159}
1160
1161static SV *
1162decode_num (dec_t *dec)
1163{
1164  int is_nv = 0;
1165  char *start = dec->cur;
1166
1167  // [minus]
1168  if (*dec->cur == '-')
1169    ++dec->cur;
1170
1171  if (*dec->cur == '0')
1172    {
1173      ++dec->cur;
1174      if (*dec->cur >= '0' && *dec->cur <= '9')
1175         ERR ("malformed number (leading zero must not be followed by another digit)");
1176    }
1177  else if (*dec->cur < '0' || *dec->cur > '9')
1178    ERR ("malformed number (no digits after initial minus)");
1179  else
1180    do
1181      {
1182        ++dec->cur;
1183      }
1184    while (*dec->cur >= '0' && *dec->cur <= '9');
1185
1186  // [frac]
1187  if (*dec->cur == '.')
1188    {
1189      ++dec->cur;
1190
1191      if (*dec->cur < '0' || *dec->cur > '9')
1192        ERR ("malformed number (no digits after decimal point)");
1193
1194      do
1195        {
1196          ++dec->cur;
1197        }
1198      while (*dec->cur >= '0' && *dec->cur <= '9');
1199
1200      is_nv = 1;
1201    }
1202
1203  // [exp]
1204  if (*dec->cur == 'e' || *dec->cur == 'E')
1205    {
1206      ++dec->cur;
1207
1208      if (*dec->cur == '-' || *dec->cur == '+')
1209        ++dec->cur;
1210
1211      if (*dec->cur < '0' || *dec->cur > '9')
1212        ERR ("malformed number (no digits after exp sign)");
1213
1214      do
1215        {
1216          ++dec->cur;
1217        }
1218      while (*dec->cur >= '0' && *dec->cur <= '9');
1219
1220      is_nv = 1;
1221    }
1222
1223  if (!is_nv)
1224    {
1225      int len = dec->cur - start;
1226
1227      // special case the rather common 1..5-digit-int case
1228      if (*start == '-')
1229        switch (len)
1230          {
1231            case 2: return newSViv (-(IV)(                                                                          start [1] - '0' *     1));
1232            case 3: return newSViv (-(IV)(                                                         start [1] * 10 + start [2] - '0' *    11));
1233            case 4: return newSViv (-(IV)(                                       start [1] * 100 + start [2] * 10 + start [3] - '0' *   111));
1234            case 5: return newSViv (-(IV)(                    start [1] * 1000 + start [2] * 100 + start [3] * 10 + start [4] - '0' *  1111));
1235            case 6: return newSViv (-(IV)(start [1] * 10000 + start [2] * 1000 + start [3] * 100 + start [4] * 10 + start [5] - '0' * 11111));
1236          }
1237      else
1238        switch (len)
1239          {
1240            case 1: return newSViv (                                                                                start [0] - '0' *     1);
1241            case 2: return newSViv (                                                               start [0] * 10 + start [1] - '0' *    11);
1242            case 3: return newSViv (                                             start [0] * 100 + start [1] * 10 + start [2] - '0' *   111);
1243            case 4: return newSViv (                          start [0] * 1000 + start [1] * 100 + start [2] * 10 + start [3] - '0' *  1111);
1244            case 5: return newSViv (      start [0] * 10000 + start [1] * 1000 + start [2] * 100 + start [3] * 10 + start [4] - '0' * 11111);
1245          }
1246
1247      {
1248        UV uv;
1249        int numtype = grok_number (start, len, &uv);
1250        if (numtype & IS_NUMBER_IN_UV)
1251          if (numtype & IS_NUMBER_NEG)
1252            {
1253              if (uv < (UV)IV_MIN)
1254                return newSViv (-(IV)uv);
1255            }
1256          else
1257            return newSVuv (uv);
1258      }
1259
1260      len -= *start == '-' ? 1 : 0;
1261
1262      // does not fit into IV or UV, try NV
1263      if (len <= NV_DIG)
1264        // fits into NV without loss of precision
1265        return newSVnv (json_atof (start));
1266
1267      // everything else fails, convert it to a string
1268      return newSVpvn (start, dec->cur - start);
1269    }
1270
1271  // loss of precision here
1272  return newSVnv (json_atof (start));
1273
1274fail:
1275  return 0;
1276}
1277
1278static SV *
1279decode_av (dec_t *dec)
1280{
1281  AV *av = newAV ();
1282
1283  DEC_INC_DEPTH;
1284  decode_ws (dec);
1285
1286  if (*dec->cur == ']')
1287    ++dec->cur;
1288  else
1289    for (;;)
1290      {
1291        SV *value;
1292
1293        value = decode_sv (dec);
1294        if (!value)
1295          goto fail;
1296
1297        av_push (av, value);
1298
1299        decode_ws (dec);
1300
1301        if (*dec->cur == ']')
1302          {
1303            ++dec->cur;
1304            break;
1305          }
1306
1307        if (*dec->cur != ',')
1308          ERR (", or ] expected while parsing array");
1309
1310        ++dec->cur;
1311
1312        decode_ws (dec);
1313
1314        if (*dec->cur == ']' && dec->json.flags & F_RELAXED)
1315          {
1316            ++dec->cur;
1317            break;
1318          }
1319      }
1320
1321  DEC_DEC_DEPTH;
1322  return newRV_noinc ((SV *)av);
1323
1324fail:
1325  SvREFCNT_dec (av);
1326  DEC_DEC_DEPTH;
1327  return 0;
1328}
1329
1330static SV *
1331decode_hv (dec_t *dec)
1332{
1333  SV *sv;
1334  HV *hv = newHV ();
1335
1336  DEC_INC_DEPTH;
1337  decode_ws (dec);
1338
1339  if (*dec->cur == '}')
1340    ++dec->cur;
1341  else
1342    for (;;)
1343      {
1344        EXPECT_CH ('"');
1345
1346        // heuristic: assume that
1347        // a) decode_str + hv_store_ent are abysmally slow.
1348        // b) most hash keys are short, simple ascii text.
1349        // => try to "fast-match" such strings to avoid
1350        // the overhead of decode_str + hv_store_ent.
1351        {
1352          SV *value;
1353          char *p = dec->cur;
1354          char *e = p + 24; // only try up to 24 bytes
1355
1356          for (;;)
1357            {
1358              // the >= 0x80 is false on most architectures
1359              if (p == e || *p < 0x20 || *p >= 0x80 || *p == '\\')
1360                {
1361                  // slow path, back up and use decode_str
1362                  SV *key = decode_str (dec);
1363                  if (!key)
1364                    goto fail;
1365
1366                  decode_ws (dec); EXPECT_CH (':');
1367
1368                  decode_ws (dec);
1369                  value = decode_sv (dec);
1370                  if (!value)
1371                    {
1372                      SvREFCNT_dec (key);
1373                      goto fail;
1374                    }
1375
1376                  hv_store_ent (hv, key, value, 0);
1377                  SvREFCNT_dec (key);
1378
1379                  break;
1380                }
1381              else if (*p == '"')
1382                {
1383                  // fast path, got a simple key
1384                  char *key = dec->cur;
1385                  int len = p - key;
1386                  dec->cur = p + 1;
1387
1388                  decode_ws (dec); EXPECT_CH (':');
1389
1390                  decode_ws (dec);
1391                  value = decode_sv (dec);
1392                  if (!value)
1393                    goto fail;
1394
1395                  hv_store (hv, key, len, value, 0);
1396
1397                  break;
1398                }
1399
1400              ++p;
1401            }
1402        }
1403
1404        decode_ws (dec);
1405
1406        if (*dec->cur == '}')
1407          {
1408            ++dec->cur;
1409            break;
1410          }
1411
1412        if (*dec->cur != ',')
1413          ERR (", or } expected while parsing object/hash");
1414
1415        ++dec->cur;
1416
1417        decode_ws (dec);
1418
1419        if (*dec->cur == '}' && dec->json.flags & F_RELAXED)
1420          {
1421            ++dec->cur;
1422            break;
1423          }
1424      }
1425
1426  DEC_DEC_DEPTH;
1427  sv = newRV_noinc ((SV *)hv);
1428
1429  // check filter callbacks
1430  if (dec->json.flags & F_HOOK)
1431    {
1432      if (dec->json.cb_sk_object && HvKEYS (hv) == 1)
1433        {
1434          HE *cb, *he;
1435
1436          hv_iterinit (hv);
1437          he = hv_iternext (hv);
1438          hv_iterinit (hv);
1439
1440          // the next line creates a mortal sv each time its called.
1441          // might want to optimise this for common cases.
1442          cb = hv_fetch_ent (dec->json.cb_sk_object, hv_iterkeysv (he), 0, 0);
1443
1444          if (cb)
1445            {
1446              dSP;
1447              int count;
1448
1449              ENTER; SAVETMPS; PUSHMARK (SP);
1450              XPUSHs (HeVAL (he));
1451              sv_2mortal (sv);
1452
1453              PUTBACK; count = call_sv (HeVAL (cb), G_ARRAY); SPAGAIN;
1454
1455              if (count == 1)
1456                {
1457                  sv = newSVsv (POPs);
1458                  FREETMPS; LEAVE;
1459                  return sv;
1460                }
1461
1462              SvREFCNT_inc (sv);
1463              FREETMPS; LEAVE;
1464            }
1465        }
1466
1467      if (dec->json.cb_object)
1468        {
1469          dSP;
1470          int count;
1471
1472          ENTER; SAVETMPS; PUSHMARK (SP);
1473          XPUSHs (sv_2mortal (sv));
1474
1475          PUTBACK; count = call_sv (dec->json.cb_object, G_ARRAY); SPAGAIN;
1476
1477          if (count == 1)
1478            {
1479              sv = newSVsv (POPs);
1480              FREETMPS; LEAVE;
1481              return sv;
1482            }
1483
1484          SvREFCNT_inc (sv);
1485          FREETMPS; LEAVE;
1486        }
1487    }
1488
1489  return sv;
1490
1491fail:
1492  SvREFCNT_dec (hv);
1493  DEC_DEC_DEPTH;
1494  return 0;
1495}
1496
1497static SV *
1498decode_tag (dec_t *dec)
1499{
1500  SV *tag = 0;
1501  SV *val = 0;
1502
1503  if (!(dec->json.flags & F_ALLOW_TAGS))
1504    ERR ("malformed JSON string, neither array, object, number, string or atom");
1505
1506  ++dec->cur;
1507
1508  decode_ws (dec);
1509
1510  tag = decode_sv (dec);
1511  if (!tag)
1512    goto fail;
1513
1514  if (!SvPOK (tag))
1515    ERR ("malformed JSON string, (tag) must be a string");
1516
1517  decode_ws (dec);
1518
1519  if (*dec->cur != ')')
1520    ERR (") expected after tag");
1521
1522  ++dec->cur;
1523
1524  decode_ws (dec);
1525
1526  val = decode_sv (dec);
1527  if (!val)
1528    goto fail;
1529
1530  if (!SvROK (val) || SvTYPE (SvRV (val)) != SVt_PVAV)
1531    ERR ("malformed JSON string, tag value must be an array");
1532
1533  {
1534    AV *av = (AV *)SvRV (val);
1535    int i, len = av_len (av) + 1;
1536    HV *stash = gv_stashsv (tag, 0);
1537    SV *sv;
1538
1539    if (!stash)
1540      ERR ("cannot decode perl-object (package does not exist)");
1541
1542    GV *method = gv_fetchmethod_autoload (stash, "THAW", 0);
1543
1544    if (!method)
1545      ERR ("cannot decode perl-object (package does not have a THAW method)");
1546
1547    dSP;
1548
1549    ENTER; SAVETMPS; PUSHMARK (SP);
1550    EXTEND (SP, len + 2);
1551    // we re-bless the reference to get overload and other niceties right
1552    PUSHs (tag);
1553    PUSHs (sv_json);
1554
1555    for (i = 0; i < len; ++i)
1556      PUSHs (*av_fetch (av, i, 1));
1557
1558    PUTBACK;
1559    call_sv ((SV *)GvCV (method), G_SCALAR);
1560    SPAGAIN;
1561
1562    SvREFCNT_dec (tag);
1563    SvREFCNT_dec (val);
1564    sv = SvREFCNT_inc (POPs);
1565
1566    PUTBACK;
1567
1568    FREETMPS; LEAVE;
1569
1570    return sv;
1571  }
1572
1573fail:
1574  SvREFCNT_dec (tag);
1575  SvREFCNT_dec (val);
1576  return 0;
1577}
1578
1579static SV *
1580decode_sv (dec_t *dec)
1581{
1582  // the beauty of JSON: you need exactly one character lookahead
1583  // to parse everything.
1584  switch (*dec->cur)
1585    {
1586      case '"': ++dec->cur; return decode_str (dec);
1587      case '[': ++dec->cur; return decode_av  (dec);
1588      case '{': ++dec->cur; return decode_hv  (dec);
1589      case '(':             return decode_tag (dec);
1590
1591      case '-':
1592      case '0': case '1': case '2': case '3': case '4':
1593      case '5': case '6': case '7': case '8': case '9':
1594        return decode_num (dec);
1595
1596      case 't':
1597        if (dec->end - dec->cur >= 4 && !memcmp (dec->cur, "true", 4))
1598          {
1599            dec->cur += 4;
1600#if JSON_SLOW
1601            types_true = get_bool ("Types::Serialiser::true");
1602#endif
1603            return newSVsv (types_true);
1604          }
1605        else
1606          ERR ("'true' expected");
1607
1608        break;
1609
1610      case 'f':
1611        if (dec->end - dec->cur >= 5 && !memcmp (dec->cur, "false", 5))
1612          {
1613            dec->cur += 5;
1614#if JSON_SLOW
1615            types_false = get_bool ("Types::Serialiser::false");
1616#endif
1617            return newSVsv (types_false);
1618          }
1619        else
1620          ERR ("'false' expected");
1621
1622        break;
1623
1624      case 'n':
1625        if (dec->end - dec->cur >= 4 && !memcmp (dec->cur, "null", 4))
1626          {
1627            dec->cur += 4;
1628            return newSVsv (&PL_sv_undef);
1629          }
1630        else
1631          ERR ("'null' expected");
1632
1633        break;
1634
1635      default:
1636        ERR ("malformed JSON string, neither tag, array, object, number, string or atom");
1637        break;
1638    }
1639
1640fail:
1641  return 0;
1642}
1643
1644static SV *
1645decode_json (SV *string, JSON *json, char **offset_return)
1646{
1647  dec_t dec;
1648  SV *sv;
1649
1650  /* work around bugs in 5.10 where manipulating magic values
1651   * makes perl ignore the magic in subsequent accesses.
1652   * also make a copy of non-PV values, to get them into a clean
1653   * state (SvPV should do that, but it's buggy, see below).
1654   */
1655  /*SvGETMAGIC (string);*/
1656  if (SvMAGICAL (string) || !SvPOK (string))
1657    string = sv_2mortal (newSVsv (string));
1658
1659  SvUPGRADE (string, SVt_PV);
1660
1661  /* work around a bug in perl 5.10, which causes SvCUR to fail an
1662   * assertion with -DDEBUGGING, although SvCUR is documented to
1663   * return the xpv_cur field which certainly exists after upgrading.
1664   * according to nicholas clark, calling SvPOK fixes this.
1665   * But it doesn't fix it, so try another workaround, call SvPV_nolen
1666   * and hope for the best.
1667   * Damnit, SvPV_nolen still trips over yet another assertion. This
1668   * assertion business is seriously broken, try yet another workaround
1669   * for the broken -DDEBUGGING.
1670   */
1671  {
1672#ifdef DEBUGGING
1673    STRLEN offset = SvOK (string) ? sv_len (string) : 0;
1674#else
1675    STRLEN offset = SvCUR (string);
1676#endif
1677
1678    if (offset > json->max_size && json->max_size)
1679      croak ("attempted decode of JSON text of %lu bytes size, but max_size is set to %lu",
1680             (unsigned long)SvCUR (string), (unsigned long)json->max_size);
1681  }
1682
1683  if (DECODE_WANTS_OCTETS (json))
1684    sv_utf8_downgrade (string, 0);
1685  else
1686    sv_utf8_upgrade (string);
1687
1688  SvGROW (string, SvCUR (string) + 1); // should basically be a NOP
1689
1690  dec.json  = *json;
1691  dec.cur   = SvPVX (string);
1692  dec.end   = SvEND (string);
1693  dec.err   = 0;
1694  dec.depth = 0;
1695
1696  if (dec.json.cb_object || dec.json.cb_sk_object)
1697    dec.json.flags |= F_HOOK;
1698
1699  *dec.end = 0; // this should basically be a nop, too, but make sure it's there
1700
1701  decode_ws (&dec);
1702  sv = decode_sv (&dec);
1703
1704  if (offset_return)
1705    *offset_return = dec.cur;
1706
1707  if (!(offset_return || !sv))
1708    {
1709      // check for trailing garbage
1710      decode_ws (&dec);
1711
1712      if (*dec.cur)
1713        {
1714          dec.err = "garbage after JSON object";
1715          SvREFCNT_dec (sv);
1716          sv = 0;
1717        }
1718    }
1719
1720  if (!sv)
1721    {
1722      SV *uni = sv_newmortal ();
1723
1724      // horrible hack to silence warning inside pv_uni_display
1725      COP cop = *PL_curcop;
1726      cop.cop_warnings = pWARN_NONE;
1727      ENTER;
1728      SAVEVPTR (PL_curcop);
1729      PL_curcop = &cop;
1730      pv_uni_display (uni, dec.cur, dec.end - dec.cur, 20, UNI_DISPLAY_QQ);
1731      LEAVE;
1732
1733      croak ("%s, at character offset %d (before \"%s\")",
1734             dec.err,
1735             (int)ptr_to_index (string, dec.cur),
1736             dec.cur != dec.end ? SvPV_nolen (uni) : "(end of string)");
1737    }
1738
1739  sv = sv_2mortal (sv);
1740
1741  if (!(dec.json.flags & F_ALLOW_NONREF) && !SvROK (sv))
1742    croak ("JSON text must be an object or array (but found number, string, true, false or null, use allow_nonref to allow this)");
1743
1744  return sv;
1745}
1746
1747/////////////////////////////////////////////////////////////////////////////
1748// incremental parser
1749
1750static void
1751incr_parse (JSON *self)
1752{
1753  const char *p = SvPVX (self->incr_text) + self->incr_pos;
1754
1755  // the state machine here is a bit convoluted and could be simplified a lot
1756  // but this would make it slower, so...
1757
1758  for (;;)
1759    {
1760      //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
1761      switch (self->incr_mode)
1762        {
1763          // only used for initial whitespace skipping
1764          case INCR_M_WS:
1765            for (;;)
1766              {
1767                if (*p > 0x20)
1768                  {
1769                    if (*p == '#')
1770                      {
1771                        self->incr_mode = INCR_M_C0;
1772                        goto incr_m_c;
1773                      }
1774                    else
1775                      {
1776                        self->incr_mode = INCR_M_JSON;
1777                        goto incr_m_json;
1778                      }
1779                  }
1780                else if (!*p)
1781                  goto interrupt;
1782
1783                ++p;
1784              }
1785
1786          // skip a single char inside a string (for \\-processing)
1787          case INCR_M_BS:
1788            if (!*p)
1789              goto interrupt;
1790
1791            ++p;
1792            self->incr_mode = INCR_M_STR;
1793            goto incr_m_str;
1794
1795          // inside #-style comments
1796          case INCR_M_C0:
1797          case INCR_M_C1:
1798          incr_m_c:
1799            for (;;)
1800              {
1801                if (*p == '\n')
1802                  {
1803                    self->incr_mode = self->incr_mode == INCR_M_C0 ? INCR_M_WS : INCR_M_JSON;
1804                    break;
1805                  }
1806                else if (!*p)
1807                  goto interrupt;
1808
1809                ++p;
1810              }
1811
1812            break;
1813
1814          // inside a string
1815          case INCR_M_STR:
1816          incr_m_str:
1817            for (;;)
1818              {
1819                if (*p == '"')
1820                  {
1821                    ++p;
1822                    self->incr_mode = INCR_M_JSON;
1823
1824                    if (!self->incr_nest)
1825                      goto interrupt;
1826
1827                    goto incr_m_json;
1828                  }
1829                else if (*p == '\\')
1830                  {
1831                    ++p; // "virtually" consumes character after \
1832
1833                    if (!*p) // if at end of string we have to switch modes
1834                      {
1835                        self->incr_mode = INCR_M_BS;
1836                        goto interrupt;
1837                      }
1838                  }
1839                else if (!*p)
1840                  goto interrupt;
1841
1842                ++p;
1843              }
1844
1845          // after initial ws, outside string
1846          case INCR_M_JSON:
1847          incr_m_json:
1848            for (;;)
1849              {
1850                switch (*p++)
1851                  {
1852                    case 0:
1853                      --p;
1854                      goto interrupt;
1855
1856                    case 0x09:
1857                    case 0x0a:
1858                    case 0x0d:
1859                    case 0x20:
1860                      if (!self->incr_nest)
1861                        {
1862                          --p; // do not eat the whitespace, let the next round do it
1863                          goto interrupt;
1864                        }
1865                      break;
1866
1867                    case '"':
1868                      self->incr_mode = INCR_M_STR;
1869                      goto incr_m_str;
1870
1871                    case '[':
1872                    case '{':
1873                    case '(':
1874                      if (++self->incr_nest > self->max_depth)
1875                        croak (ERR_NESTING_EXCEEDED);
1876                      break;
1877
1878                    case ']':
1879                    case '}':
1880                      if (--self->incr_nest <= 0)
1881                        goto interrupt;
1882                      break;
1883
1884                    case ')':
1885                      --self->incr_nest;
1886                      break;
1887
1888                    case '#':
1889                      self->incr_mode = INCR_M_C1;
1890                      goto incr_m_c;
1891                  }
1892              }
1893        }
1894
1895      modechange:
1896        ;
1897    }
1898
1899interrupt:
1900  self->incr_pos = p - SvPVX (self->incr_text);
1901  //printf ("interrupt<%.*s>\n", self->incr_pos, SvPVX(self->incr_text));//D
1902  //printf ("return pos %d mode %d nest %d\n", self->incr_pos, self->incr_mode, self->incr_nest);//D
1903}
1904
1905/////////////////////////////////////////////////////////////////////////////
1906// XS interface functions
1907
1908MODULE = JSON::XS		PACKAGE = JSON::XS
1909
1910BOOT:
1911{
1912	int i;
1913
1914        for (i = 0; i < 256; ++i)
1915          decode_hexdigit [i] =
1916            i >= '0' && i <= '9' ? i - '0'
1917            : i >= 'a' && i <= 'f' ? i - 'a' + 10
1918            : i >= 'A' && i <= 'F' ? i - 'A' + 10
1919            : -1;
1920
1921	json_stash          = gv_stashpv ("JSON::XS"                  , 1);
1922	types_boolean_stash = gv_stashpv ("Types::Serialiser::Boolean", 1);
1923
1924        types_true  = get_bool ("Types::Serialiser::true");
1925        types_false = get_bool ("Types::Serialiser::false");
1926
1927        sv_json = newSVpv ("JSON", 0);
1928        SvREADONLY_on (sv_json);
1929
1930        CvNODEBUG_on (get_cv ("JSON::XS::incr_text", 0)); /* the debugger completely breaks lvalue subs */
1931}
1932
1933PROTOTYPES: DISABLE
1934
1935void CLONE (...)
1936	CODE:
1937        json_stash          = 0;
1938        types_boolean_stash = 0;
1939
1940void new (char *klass)
1941	PPCODE:
1942{
1943	SV *pv = NEWSV (0, sizeof (JSON));
1944        SvPOK_only (pv);
1945        json_init ((JSON *)SvPVX (pv));
1946        XPUSHs (sv_2mortal (sv_bless (
1947           newRV_noinc (pv),
1948           strEQ (klass, "JSON::XS") ? JSON_STASH : gv_stashpv (klass, 1)
1949        )));
1950}
1951
1952void ascii (JSON *self, int enable = 1)
1953	ALIAS:
1954        ascii           = F_ASCII
1955        latin1          = F_LATIN1
1956        utf8            = F_UTF8
1957        indent          = F_INDENT
1958        canonical       = F_CANONICAL
1959        space_before    = F_SPACE_BEFORE
1960        space_after     = F_SPACE_AFTER
1961        pretty          = F_PRETTY
1962        allow_nonref    = F_ALLOW_NONREF
1963        shrink          = F_SHRINK
1964        allow_blessed   = F_ALLOW_BLESSED
1965        convert_blessed = F_CONV_BLESSED
1966        relaxed         = F_RELAXED
1967        allow_unknown   = F_ALLOW_UNKNOWN
1968        allow_tags      = F_ALLOW_TAGS
1969	PPCODE:
1970{
1971        if (enable)
1972          self->flags |=  ix;
1973        else
1974          self->flags &= ~ix;
1975
1976        XPUSHs (ST (0));
1977}
1978
1979void get_ascii (JSON *self)
1980	ALIAS:
1981        get_ascii           = F_ASCII
1982        get_latin1          = F_LATIN1
1983        get_utf8            = F_UTF8
1984        get_indent          = F_INDENT
1985        get_canonical       = F_CANONICAL
1986        get_space_before    = F_SPACE_BEFORE
1987        get_space_after     = F_SPACE_AFTER
1988        get_allow_nonref    = F_ALLOW_NONREF
1989        get_shrink          = F_SHRINK
1990        get_allow_blessed   = F_ALLOW_BLESSED
1991        get_convert_blessed = F_CONV_BLESSED
1992        get_relaxed         = F_RELAXED
1993        get_allow_unknown   = F_ALLOW_UNKNOWN
1994        get_allow_tags      = F_ALLOW_TAGS
1995	PPCODE:
1996        XPUSHs (boolSV (self->flags & ix));
1997
1998void max_depth (JSON *self, U32 max_depth = 0x80000000UL)
1999	PPCODE:
2000        self->max_depth = max_depth;
2001        XPUSHs (ST (0));
2002
2003U32 get_max_depth (JSON *self)
2004	CODE:
2005        RETVAL = self->max_depth;
2006	OUTPUT:
2007        RETVAL
2008
2009void max_size (JSON *self, U32 max_size = 0)
2010	PPCODE:
2011        self->max_size = max_size;
2012        XPUSHs (ST (0));
2013
2014int get_max_size (JSON *self)
2015	CODE:
2016        RETVAL = self->max_size;
2017	OUTPUT:
2018        RETVAL
2019
2020void filter_json_object (JSON *self, SV *cb = &PL_sv_undef)
2021	PPCODE:
2022{
2023        SvREFCNT_dec (self->cb_object);
2024        self->cb_object = SvOK (cb) ? newSVsv (cb) : 0;
2025
2026        XPUSHs (ST (0));
2027}
2028
2029void filter_json_single_key_object (JSON *self, SV *key, SV *cb = &PL_sv_undef)
2030	PPCODE:
2031{
2032	if (!self->cb_sk_object)
2033          self->cb_sk_object = newHV ();
2034
2035        if (SvOK (cb))
2036          hv_store_ent (self->cb_sk_object, key, newSVsv (cb), 0);
2037        else
2038          {
2039            hv_delete_ent (self->cb_sk_object, key, G_DISCARD, 0);
2040
2041            if (!HvKEYS (self->cb_sk_object))
2042              {
2043                SvREFCNT_dec (self->cb_sk_object);
2044                self->cb_sk_object = 0;
2045              }
2046          }
2047
2048        XPUSHs (ST (0));
2049}
2050
2051void encode (JSON *self, SV *scalar)
2052	PPCODE:
2053        PUTBACK; scalar = encode_json (scalar, self); SPAGAIN;
2054        XPUSHs (scalar);
2055
2056void decode (JSON *self, SV *jsonstr)
2057	PPCODE:
2058        PUTBACK; jsonstr = decode_json (jsonstr, self, 0); SPAGAIN;
2059        XPUSHs (jsonstr);
2060
2061void decode_prefix (JSON *self, SV *jsonstr)
2062	PPCODE:
2063{
2064	SV *sv;
2065        char *offset;
2066        PUTBACK; sv = decode_json (jsonstr, self, &offset); SPAGAIN;
2067        EXTEND (SP, 2);
2068        PUSHs (sv);
2069        PUSHs (sv_2mortal (newSVuv (ptr_to_index (jsonstr, offset))));
2070}
2071
2072void incr_parse (JSON *self, SV *jsonstr = 0)
2073	PPCODE:
2074{
2075	if (!self->incr_text)
2076          self->incr_text = newSVpvn ("", 0);
2077
2078        /* if utf8-ness doesn't match the decoder, need to upgrade/downgrade */
2079        if (!DECODE_WANTS_OCTETS (self) == !SvUTF8 (self->incr_text))
2080          if (DECODE_WANTS_OCTETS (self))
2081            {
2082              if (self->incr_pos)
2083                self->incr_pos = utf8_length ((U8 *)SvPVX (self->incr_text),
2084                                              (U8 *)SvPVX (self->incr_text) + self->incr_pos);
2085
2086              sv_utf8_downgrade (self->incr_text, 0);
2087            }
2088          else
2089            {
2090              sv_utf8_upgrade (self->incr_text);
2091
2092              if (self->incr_pos)
2093                self->incr_pos = utf8_hop ((U8 *)SvPVX (self->incr_text), self->incr_pos)
2094                                 - (U8 *)SvPVX (self->incr_text);
2095            }
2096
2097        // append data, if any
2098        if (jsonstr)
2099          {
2100            /* make sure both strings have same encoding */
2101            if (SvUTF8 (jsonstr) != SvUTF8 (self->incr_text))
2102              if (SvUTF8 (jsonstr))
2103                sv_utf8_downgrade (jsonstr, 0);
2104              else
2105                sv_utf8_upgrade (jsonstr);
2106
2107            /* and then just blindly append */
2108            {
2109              STRLEN len;
2110              const char *str = SvPV (jsonstr, len);
2111              STRLEN cur = SvCUR (self->incr_text);
2112
2113              if (SvLEN (self->incr_text) <= cur + len)
2114                SvGROW (self->incr_text, cur + (len < (cur >> 2) ? cur >> 2 : len) + 1);
2115
2116              Move (str, SvEND (self->incr_text), len, char);
2117              SvCUR_set (self->incr_text, SvCUR (self->incr_text) + len);
2118              *SvEND (self->incr_text) = 0; // this should basically be a nop, too, but make sure it's there
2119            }
2120          }
2121
2122        if (GIMME_V != G_VOID)
2123          do
2124            {
2125              SV *sv;
2126              char *offset;
2127
2128              if (!INCR_DONE (self))
2129                {
2130                  incr_parse (self);
2131
2132                  if (self->incr_pos > self->max_size && self->max_size)
2133                    croak ("attempted decode of JSON text of %lu bytes size, but max_size is set to %lu",
2134                           (unsigned long)self->incr_pos, (unsigned long)self->max_size);
2135
2136                  if (!INCR_DONE (self))
2137                    {
2138                      // as an optimisation, do not accumulate white space in the incr buffer
2139                      if (self->incr_mode == INCR_M_WS && self->incr_pos)
2140                        {
2141                          self->incr_pos = 0;
2142                          SvCUR_set (self->incr_text, 0);
2143                        }
2144
2145                      break;
2146                    }
2147                }
2148
2149              PUTBACK; sv = decode_json (self->incr_text, self, &offset); SPAGAIN;
2150              XPUSHs (sv);
2151
2152              self->incr_pos -= offset - SvPVX (self->incr_text);
2153              self->incr_nest = 0;
2154              self->incr_mode = 0;
2155
2156              sv_chop (self->incr_text, offset);
2157            }
2158          while (GIMME_V == G_ARRAY);
2159}
2160
2161SV *incr_text (JSON *self)
2162	ATTRS: lvalue
2163	CODE:
2164{
2165        if (self->incr_pos)
2166          croak ("incr_text can not be called when the incremental parser already started parsing");
2167
2168        RETVAL = self->incr_text ? SvREFCNT_inc (self->incr_text) : &PL_sv_undef;
2169}
2170	OUTPUT:
2171        RETVAL
2172
2173void incr_skip (JSON *self)
2174	CODE:
2175{
2176        if (self->incr_pos)
2177          {
2178            sv_chop (self->incr_text, SvPV_nolen (self->incr_text) + self->incr_pos);
2179            self->incr_pos  = 0;
2180            self->incr_nest = 0;
2181            self->incr_mode = 0;
2182          }
2183}
2184
2185void incr_reset (JSON *self)
2186	CODE:
2187{
2188	SvREFCNT_dec (self->incr_text);
2189        self->incr_text = 0;
2190        self->incr_pos  = 0;
2191        self->incr_nest = 0;
2192        self->incr_mode = 0;
2193}
2194
2195void DESTROY (JSON *self)
2196	CODE:
2197        SvREFCNT_dec (self->cb_sk_object);
2198        SvREFCNT_dec (self->cb_object);
2199        SvREFCNT_dec (self->incr_text);
2200
2201PROTOTYPES: ENABLE
2202
2203void encode_json (SV *scalar)
2204	PPCODE:
2205{
2206        JSON json;
2207        json_init (&json);
2208        json.flags |= F_UTF8;
2209        PUTBACK; scalar = encode_json (scalar, &json); SPAGAIN;
2210        XPUSHs (scalar);
2211}
2212
2213void decode_json (SV *jsonstr)
2214	PPCODE:
2215{
2216        JSON json;
2217        json_init (&json);
2218        json.flags |= F_UTF8;
2219        PUTBACK; jsonstr = decode_json (jsonstr, &json, 0); SPAGAIN;
2220        XPUSHs (jsonstr);
2221}
2222
2223