summaryrefslogtreecommitdiff
path: root/Build/source/libs/luajit/LuaJIT-2.1.0-beta1/src/lj_strscan.c
blob: d3c5ba9124fa1457f3688665317ed6df88bb167c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
/*
** String scanning.
** Copyright (C) 2005-2015 Mike Pall. See Copyright Notice in luajit.h
*/

#include <math.h>

#define lj_strscan_c
#define LUA_CORE

#include "lj_obj.h"
#include "lj_char.h"
#include "lj_strscan.h"

/* -- Scanning numbers ---------------------------------------------------- */

/*
** Rationale for the builtin string to number conversion library:
**
** It removes a dependency on libc's strtod(), which is a true portability
** nightmare. Mainly due to the plethora of supported OS and toolchain
** combinations. Sadly, the various implementations
** a) are often buggy, incomplete (no hex floats) and/or imprecise,
** b) sometimes crash or hang on certain inputs,
** c) return non-standard NaNs that need to be filtered out, and
** d) fail if the locale-specific decimal separator is not a dot,
**    which can only be fixed with atrocious workarounds.
**
** Also, most of the strtod() implementations are hopelessly bloated,
** which is not just an I-cache hog, but a problem for static linkage
** on embedded systems, too.
**
** OTOH the builtin conversion function is very compact. Even though it
** does a lot more, like parsing long longs, octal or imaginary numbers
** and returning the result in different formats:
** a) It needs less than 3 KB (!) of machine code (on x64 with -Os),
** b) it doesn't perform any dynamic allocation and,
** c) it needs only around 600 bytes of stack space.
**
** The builtin function is faster than strtod() for typical inputs, e.g.
** "123", "1.5" or "1e6". Arguably, it's slower for very large exponents,
** which are not very common (this could be fixed, if needed).
**
** And most importantly, the builtin function is equally precise on all
** platforms. It correctly converts and rounds any input to a double.
** If this is not the case, please send a bug report -- but PLEASE verify
** that the implementation you're comparing to is not the culprit!
**
** The implementation quickly pre-scans the entire string first and
** handles simple integers on-the-fly. Otherwise, it dispatches to the
** base-specific parser. Hex and octal is straightforward.
**
** Decimal to binary conversion uses a fixed-length circular buffer in
** base 100. Some simple cases are handled directly. For other cases, the
** number in the buffer is up-scaled or down-scaled until the integer part
** is in the proper range. Then the integer part is rounded and converted
** to a double which is finally rescaled to the result. Denormals need
** special treatment to prevent incorrect 'double rounding'.
*/

/* Definitions for circular decimal digit buffer (base 100 = 2 digits/byte). */
#define STRSCAN_DIG	1024
#define STRSCAN_MAXDIG	800		/* 772 + extra are sufficient. */
#define STRSCAN_DDIG	(STRSCAN_DIG/2)
#define STRSCAN_DMASK	(STRSCAN_DDIG-1)

/* Helpers for circular buffer. */
#define DNEXT(a)	(((a)+1) & STRSCAN_DMASK)
#define DPREV(a)	(((a)-1) & STRSCAN_DMASK)
#define DLEN(lo, hi)	((int32_t)(((lo)-(hi)) & STRSCAN_DMASK))

#define casecmp(c, k)	(((c) | 0x20) == k)

/* Final conversion to double. */
static void strscan_double(uint64_t x, TValue *o, int32_t ex2, int32_t neg)
{
  double n;

  /* Avoid double rounding for denormals. */
  if (LJ_UNLIKELY(ex2 <= -1075 && x != 0)) {
    /* NYI: all of this generates way too much code on 32 bit CPUs. */
#if defined(__GNUC__) && LJ_64
    int32_t b = (int32_t)(__builtin_clzll(x)^63);
#else
    int32_t b = (x>>32) ? 32+(int32_t)lj_fls((uint32_t)(x>>32)) :
			  (int32_t)lj_fls((uint32_t)x);
#endif
    if ((int32_t)b + ex2 <= -1023 && (int32_t)b + ex2 >= -1075) {
      uint64_t rb = (uint64_t)1 << (-1075-ex2);
      if ((x & rb) && ((x & (rb+rb+rb-1)))) x += rb+rb;
      x = (x & ~(rb+rb-1));
    }
  }

  /* Convert to double using a signed int64_t conversion, then rescale. */
  lua_assert((int64_t)x >= 0);
  n = (double)(int64_t)x;
  if (neg) n = -n;
  if (ex2) n = ldexp(n, ex2);
  o->n = n;
}

/* Parse hexadecimal number. */
static StrScanFmt strscan_hex(const uint8_t *p, TValue *o,
			      StrScanFmt fmt, uint32_t opt,
			      int32_t ex2, int32_t neg, uint32_t dig)
{
  uint64_t x = 0;
  uint32_t i;

  /* Scan hex digits. */
  for (i = dig > 16 ? 16 : dig ; i; i--, p++) {
    uint32_t d = (*p != '.' ? *p : *++p); if (d > '9') d += 9;
    x = (x << 4) + (d & 15);
  }

  /* Summarize rounding-effect of excess digits. */
  for (i = 16; i < dig; i++, p++)
    x |= ((*p != '.' ? *p : *++p) != '0'), ex2 += 4;

  /* Format-specific handling. */
  switch (fmt) {
  case STRSCAN_INT:
    if (!(opt & STRSCAN_OPT_TONUM) && x < 0x80000000u+neg) {
      o->i = neg ? -(int32_t)x : (int32_t)x;
      return STRSCAN_INT;  /* Fast path for 32 bit integers. */
    }
    if (!(opt & STRSCAN_OPT_C)) { fmt = STRSCAN_NUM; break; }
    /* fallthrough */
  case STRSCAN_U32:
    if (dig > 8) return STRSCAN_ERROR;
    o->i = neg ? -(int32_t)x : (int32_t)x;
    return STRSCAN_U32;
  case STRSCAN_I64:
  case STRSCAN_U64:
    if (dig > 16) return STRSCAN_ERROR;
    o->u64 = neg ? (uint64_t)-(int64_t)x : x;
    return fmt;
  default:
    break;
  }

  /* Reduce range, then convert to double. */
  if ((x & U64x(c0000000,0000000))) { x = (x >> 2) | (x & 3); ex2 += 2; }
  strscan_double(x, o, ex2, neg);
  return fmt;
}

/* Parse octal number. */
static StrScanFmt strscan_oct(const uint8_t *p, TValue *o,
			      StrScanFmt fmt, int32_t neg, uint32_t dig)
{
  uint64_t x = 0;

  /* Scan octal digits. */
  if (dig > 22 || (dig == 22 && *p > '1')) return STRSCAN_ERROR;
  while (dig-- > 0) {
    if (!(*p >= '0' && *p <= '7')) return STRSCAN_ERROR;
    x = (x << 3) + (*p++ & 7);
  }

  /* Format-specific handling. */
  switch (fmt) {
  case STRSCAN_INT:
    if (x >= 0x80000000u+neg) fmt = STRSCAN_U32;
    /* fallthrough */
  case STRSCAN_U32:
    if ((x >> 32)) return STRSCAN_ERROR;
    o->i = neg ? -(int32_t)x : (int32_t)x;
    break;
  default:
  case STRSCAN_I64:
  case STRSCAN_U64:
    o->u64 = neg ? (uint64_t)-(int64_t)x : x;
    break;
  }
  return fmt;
}

/* Parse decimal number. */
static StrScanFmt strscan_dec(const uint8_t *p, TValue *o,
			      StrScanFmt fmt, uint32_t opt,
			      int32_t ex10, int32_t neg, uint32_t dig)
{
  uint8_t xi[STRSCAN_DDIG], *xip = xi;

  if (dig) {
    uint32_t i = dig;
    if (i > STRSCAN_MAXDIG) {
      ex10 += (int32_t)(i - STRSCAN_MAXDIG);
      i = STRSCAN_MAXDIG;
    }
    /* Scan unaligned leading digit. */
    if (((ex10^i) & 1))
      *xip++ = ((*p != '.' ? *p : *++p) & 15), i--, p++;
    /* Scan aligned double-digits. */
    for ( ; i > 1; i -= 2) {
      uint32_t d = 10 * ((*p != '.' ? *p : *++p) & 15); p++;
      *xip++ = d + ((*p != '.' ? *p : *++p) & 15); p++;
    }
    /* Scan and realign trailing digit. */
    if (i) *xip++ = 10 * ((*p != '.' ? *p : *++p) & 15), ex10--, dig++, p++;

    /* Summarize rounding-effect of excess digits. */
    if (dig > STRSCAN_MAXDIG) {
      do {
	if ((*p != '.' ? *p : *++p) != '0') { xip[-1] |= 1; break; }
	p++;
      } while (--dig > STRSCAN_MAXDIG);
      dig = STRSCAN_MAXDIG;
    } else {  /* Simplify exponent. */
      while (ex10 > 0 && dig <= 18) *xip++ = 0, ex10 -= 2, dig += 2;
    }
  } else {  /* Only got zeros. */
    ex10 = 0;
    xi[0] = 0;
  }

  /* Fast path for numbers in integer format (but handles e.g. 1e6, too). */
  if (dig <= 20 && ex10 == 0) {
    uint8_t *xis;
    uint64_t x = xi[0];
    double n;
    for (xis = xi+1; xis < xip; xis++) x = x * 100 + *xis;
    if (!(dig == 20 && (xi[0] > 18 || (int64_t)x >= 0))) {  /* No overflow? */
      /* Format-specific handling. */
      switch (fmt) {
      case STRSCAN_INT:
	if (!(opt & STRSCAN_OPT_TONUM) && x < 0x80000000u+neg) {
	  o->i = neg ? -(int32_t)x : (int32_t)x;
	  return STRSCAN_INT;  /* Fast path for 32 bit integers. */
	}
	if (!(opt & STRSCAN_OPT_C)) { fmt = STRSCAN_NUM; goto plainnumber; }
	/* fallthrough */
      case STRSCAN_U32:
	if ((x >> 32) != 0) return STRSCAN_ERROR;
	o->i = neg ? -(int32_t)x : (int32_t)x;
	return STRSCAN_U32;
      case STRSCAN_I64:
      case STRSCAN_U64:
	o->u64 = neg ? (uint64_t)-(int64_t)x : x;
	return fmt;
      default:
      plainnumber:  /* Fast path for plain numbers < 2^63. */
	if ((int64_t)x < 0) break;
	n = (double)(int64_t)x;
	if (neg) n = -n;
	o->n = n;
	return fmt;
      }
    }
  }

  /* Slow non-integer path. */
  if (fmt == STRSCAN_INT) {
    if ((opt & STRSCAN_OPT_C)) return STRSCAN_ERROR;
    fmt = STRSCAN_NUM;
  } else if (fmt > STRSCAN_INT) {
    return STRSCAN_ERROR;
  }
  {
    uint32_t hi = 0, lo = (uint32_t)(xip-xi);
    int32_t ex2 = 0, idig = (int32_t)lo + (ex10 >> 1);

    lua_assert(lo > 0 && (ex10 & 1) == 0);

    /* Handle simple overflow/underflow. */
    if (idig > 310/2) { if (neg) setminfV(o); else setpinfV(o); return fmt; }
    else if (idig < -326/2) { o->n = neg ? -0.0 : 0.0; return fmt; }

    /* Scale up until we have at least 17 or 18 integer part digits. */
    while (idig < 9 && idig < DLEN(lo, hi)) {
      uint32_t i, cy = 0;
      ex2 -= 6;
      for (i = DPREV(lo); ; i = DPREV(i)) {
	uint32_t d = (xi[i] << 6) + cy;
	cy = (((d >> 2) * 5243) >> 17); d = d - cy * 100;  /* Div/mod 100. */
	xi[i] = (uint8_t)d;
	if (i == hi) break;
	if (d == 0 && i == DPREV(lo)) lo = i;
      }
      if (cy) {
	hi = DPREV(hi);
	if (xi[DPREV(lo)] == 0) lo = DPREV(lo);
	else if (hi == lo) { lo = DPREV(lo); xi[DPREV(lo)] |= xi[lo]; }
	xi[hi] = (uint8_t)cy; idig++;
      }
    }

    /* Scale down until no more than 17 or 18 integer part digits remain. */
    while (idig > 9) {
      uint32_t i = hi, cy = 0;
      ex2 += 6;
      do {
	cy += xi[i];
	xi[i] = (cy >> 6);
	cy = 100 * (cy & 0x3f);
	if (xi[i] == 0 && i == hi) hi = DNEXT(hi), idig--;
	i = DNEXT(i);
      } while (i != lo);
      while (cy) {
	if (hi == lo) { xi[DPREV(lo)] |= 1; break; }
	xi[lo] = (cy >> 6); lo = DNEXT(lo);
	cy = 100 * (cy & 0x3f);
      }
    }

    /* Collect integer part digits and convert to rescaled double. */
    {
      uint64_t x = xi[hi];
      uint32_t i;
      for (i = DNEXT(hi); --idig > 0 && i != lo; i = DNEXT(i))
	x = x * 100 + xi[i];
      if (i == lo) {
	while (--idig >= 0) x = x * 100;
      } else {  /* Gather round bit from remaining digits. */
	x <<= 1; ex2--;
	do {
	  if (xi[i]) { x |= 1; break; }
	  i = DNEXT(i);
	} while (i != lo);
      }
      strscan_double(x, o, ex2, neg);
    }
  }
  return fmt;
}

/* Parse binary number. */
static StrScanFmt strscan_bin(const uint8_t *p, TValue *o,
			      StrScanFmt fmt, uint32_t opt,
			      int32_t ex2, int32_t neg, uint32_t dig)
{
  uint64_t x = 0;
  uint32_t i;

  if (ex2 || dig > 64) return STRSCAN_ERROR;

  /* Scan binary digits. */
  for (i = dig; i; i--, p++) {
    if ((*p & ~1) != '0') return STRSCAN_ERROR;
    x = (x << 1) | (*p & 1);
  }

  /* Format-specific handling. */
  switch (fmt) {
  case STRSCAN_INT:
    if (!(opt & STRSCAN_OPT_TONUM) && x < 0x80000000u+neg) {
      o->i = neg ? -(int32_t)x : (int32_t)x;
      return STRSCAN_INT;  /* Fast path for 32 bit integers. */
    }
    if (!(opt & STRSCAN_OPT_C)) { fmt = STRSCAN_NUM; break; }
    /* fallthrough */
  case STRSCAN_U32:
    if (dig > 32) return STRSCAN_ERROR;
    o->i = neg ? -(int32_t)x : (int32_t)x;
    return STRSCAN_U32;
  case STRSCAN_I64:
  case STRSCAN_U64:
    o->u64 = neg ? (uint64_t)-(int64_t)x : x;
    return fmt;
  default:
    break;
  }

  /* Reduce range, then convert to double. */
  if ((x & U64x(c0000000,0000000))) { x = (x >> 2) | (x & 3); ex2 += 2; }
  strscan_double(x, o, ex2, neg);
  return fmt;
}

/* Scan string containing a number. Returns format. Returns value in o. */
StrScanFmt lj_strscan_scan(const uint8_t *p, TValue *o, uint32_t opt)
{
  int32_t neg = 0;

  /* Remove leading space, parse sign and non-numbers. */
  if (LJ_UNLIKELY(!lj_char_isdigit(*p))) {
    while (lj_char_isspace(*p)) p++;
    if (*p == '+' || *p == '-') neg = (*p++ == '-');
    if (LJ_UNLIKELY(*p >= 'A')) {  /* Parse "inf", "infinity" or "nan". */
      TValue tmp;
      setnanV(&tmp);
      if (casecmp(p[0],'i') && casecmp(p[1],'n') && casecmp(p[2],'f')) {
	if (neg) setminfV(&tmp); else setpinfV(&tmp);
	p += 3;
	if (casecmp(p[0],'i') && casecmp(p[1],'n') && casecmp(p[2],'i') &&
	    casecmp(p[3],'t') && casecmp(p[4],'y')) p += 5;
      } else if (casecmp(p[0],'n') && casecmp(p[1],'a') && casecmp(p[2],'n')) {
	p += 3;
      }
      while (lj_char_isspace(*p)) p++;
      if (*p) return STRSCAN_ERROR;
      o->u64 = tmp.u64;
      return STRSCAN_NUM;
    }
  }

  /* Parse regular number. */
  {
    StrScanFmt fmt = STRSCAN_INT;
    int cmask = LJ_CHAR_DIGIT;
    int base = (opt & STRSCAN_OPT_C) && *p == '0' ? 0 : 10;
    const uint8_t *sp, *dp = NULL;
    uint32_t dig = 0, hasdig = 0, x = 0;
    int32_t ex = 0;

    /* Determine base and skip leading zeros. */
    if (LJ_UNLIKELY(*p <= '0')) {
      if (*p == '0') {
	if (casecmp(p[1], 'x'))
	  base = 16, cmask = LJ_CHAR_XDIGIT, p += 2;
	else if (casecmp(p[1], 'b'))
	  base = 2, cmask = LJ_CHAR_DIGIT, p += 2;
      }
      for ( ; ; p++) {
	if (*p == '0') {
	  hasdig = 1;
	} else if (*p == '.') {
	  if (dp) return STRSCAN_ERROR;
	  dp = p;
	} else {
	  break;
	}
      }
    }

    /* Preliminary digit and decimal point scan. */
    for (sp = p; ; p++) {
      if (LJ_LIKELY(lj_char_isa(*p, cmask))) {
	x = x * 10 + (*p & 15);  /* For fast path below. */
	dig++;
      } else if (*p == '.') {
	if (dp) return STRSCAN_ERROR;
	dp = p;
      } else {
	break;
      }
    }
    if (!(hasdig | dig)) return STRSCAN_ERROR;

    /* Handle decimal point. */
    if (dp) {
      fmt = STRSCAN_NUM;
      if (dig) {
	ex = (int32_t)(dp-(p-1)); dp = p-1;
	while (ex < 0 && *dp-- == '0') ex++, dig--;  /* Skip trailing zeros. */
	if (base == 16) ex *= 4;
      }
    }

    /* Parse exponent. */
    if (base >= 10 && casecmp(*p, (uint32_t)(base == 16 ? 'p' : 'e'))) {
      uint32_t xx;
      int negx = 0;
      fmt = STRSCAN_NUM; p++;
      if (*p == '+' || *p == '-') negx = (*p++ == '-');
      if (!lj_char_isdigit(*p)) return STRSCAN_ERROR;
      xx = (*p++ & 15);
      while (lj_char_isdigit(*p)) {
	if (xx < 65536) xx = xx * 10 + (*p & 15);
	p++;
      }
      ex += negx ? -(int32_t)xx : (int32_t)xx;
    }

    /* Parse suffix. */
    if (*p) {
      /* I (IMAG), U (U32), LL (I64), ULL/LLU (U64), L (long), UL/LU (ulong). */
      /* NYI: f (float). Not needed until cp_number() handles non-integers. */
      if (casecmp(*p, 'i')) {
	if (!(opt & STRSCAN_OPT_IMAG)) return STRSCAN_ERROR;
	p++; fmt = STRSCAN_IMAG;
      } else if (fmt == STRSCAN_INT) {
	if (casecmp(*p, 'u')) p++, fmt = STRSCAN_U32;
	if (casecmp(*p, 'l')) {
	  p++;
	  if (casecmp(*p, 'l')) p++, fmt += STRSCAN_I64 - STRSCAN_INT;
	  else if (!(opt & STRSCAN_OPT_C)) return STRSCAN_ERROR;
	  else if (sizeof(long) == 8) fmt += STRSCAN_I64 - STRSCAN_INT;
	}
	if (casecmp(*p, 'u') && (fmt == STRSCAN_INT || fmt == STRSCAN_I64))
	  p++, fmt += STRSCAN_U32 - STRSCAN_INT;
	if ((fmt == STRSCAN_U32 && !(opt & STRSCAN_OPT_C)) ||
	    (fmt >= STRSCAN_I64 && !(opt & STRSCAN_OPT_LL)))
	  return STRSCAN_ERROR;
      }
      while (lj_char_isspace(*p)) p++;
      if (*p) return STRSCAN_ERROR;
    }

    /* Fast path for decimal 32 bit integers. */
    if (fmt == STRSCAN_INT && base == 10 &&
	(dig < 10 || (dig == 10 && *sp <= '2' && x < 0x80000000u+neg))) {
      int32_t y = neg ? -(int32_t)x : (int32_t)x;
      if ((opt & STRSCAN_OPT_TONUM)) {
	o->n = (double)y;
	return STRSCAN_NUM;
      } else {
	o->i = y;
	return STRSCAN_INT;
      }
    }

    /* Dispatch to base-specific parser. */
    if (base == 0 && !(fmt == STRSCAN_NUM || fmt == STRSCAN_IMAG))
      return strscan_oct(sp, o, fmt, neg, dig);
    if (base == 16)
      fmt = strscan_hex(sp, o, fmt, opt, ex, neg, dig);
    else if (base == 2)
      fmt = strscan_bin(sp, o, fmt, opt, ex, neg, dig);
    else
      fmt = strscan_dec(sp, o, fmt, opt, ex, neg, dig);

    /* Try to convert number to integer, if requested. */
    if (fmt == STRSCAN_NUM && (opt & STRSCAN_OPT_TOINT)) {
      double n = o->n;
      int32_t i = lj_num2int(n);
      if (n == (lua_Number)i) { o->i = i; return STRSCAN_INT; }
    }
    return fmt;
  }
}

int LJ_FASTCALL lj_strscan_num(GCstr *str, TValue *o)
{
  StrScanFmt fmt = lj_strscan_scan((const uint8_t *)strdata(str), o,
				   STRSCAN_OPT_TONUM);
  lua_assert(fmt == STRSCAN_ERROR || fmt == STRSCAN_NUM);
  return (fmt != STRSCAN_ERROR);
}

#if LJ_DUALNUM
int LJ_FASTCALL lj_strscan_number(GCstr *str, TValue *o)
{
  StrScanFmt fmt = lj_strscan_scan((const uint8_t *)strdata(str), o,
				   STRSCAN_OPT_TOINT);
  lua_assert(fmt == STRSCAN_ERROR || fmt == STRSCAN_NUM || fmt == STRSCAN_INT);
  if (fmt == STRSCAN_INT) setitype(o, LJ_TISNUM);
  return (fmt != STRSCAN_ERROR);
}
#endif

#undef DNEXT
#undef DPREV
#undef DLEN