--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/luajit/src/lj_strscan.c	Thu Jan 22 20:10:30 2026 -0800
@@ -0,0 +1,558 @@
+/*
+** String scanning.
+** Copyright (C) 2005-2023 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)
+#define STRSCAN_MAXEXP	(1 << 20)
+
+/* 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__) || defined(__clang__)) && 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. */
+  lj_assertX((int64_t)x >= 0, "bad double conversion");
+  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 &&
+	!(x == 0 && neg)) {
+      o->i = neg ? (int32_t)(~x+1u) : (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+1u) : (int32_t)x;
+    return STRSCAN_U32;
+  case STRSCAN_I64:
+  case STRSCAN_U64:
+    if (dig > 16) return STRSCAN_ERROR;
+    o->u64 = neg ? ~x+1u : 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)(~(uint32_t)x+1u) : (int32_t)x;
+    break;
+  default:
+  case STRSCAN_I64:
+  case STRSCAN_U64:
+    o->u64 = neg ? ~x+1u : 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+1u) : (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+1u) : (int32_t)x;
+	return STRSCAN_U32;
+      case STRSCAN_I64:
+      case STRSCAN_U64:
+	o->u64 = neg ? ~x+1u : 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);
+
+    lj_assertX(lo > 0 && (ex10 & 1) == 0, "bad lo %d ex10 %d", lo, ex10);
+
+    /* 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+1u) : (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+1u) : (int32_t)x;
+    return STRSCAN_U32;
+  case STRSCAN_I64:
+  case STRSCAN_U64:
+    o->u64 = neg ? ~x+1u : 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, MSize len, TValue *o,
+			   uint32_t opt)
+{
+  int32_t neg = 0;
+  const uint8_t *pe = p + len;
+
+  /* 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 || p < pe) 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) {
+      if (base == 2) return STRSCAN_ERROR;
+      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 (ex <= -STRSCAN_MAXEXP) return STRSCAN_ERROR;
+	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)) {
+	xx = xx * 10 + (*p & 15);
+	if (xx >= STRSCAN_MAXEXP) return STRSCAN_ERROR;
+	p++;
+      }
+      ex += negx ? (int32_t)(~xx+1u) : (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;
+    }
+    if (p < pe) 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))) {
+      if ((opt & STRSCAN_OPT_TONUM)) {
+	o->n = neg ? -(double)x : (double)x;
+	return STRSCAN_NUM;
+      } else if (x == 0 && neg) {
+	o->n = -0.0;
+	return STRSCAN_NUM;
+      } else {
+	o->i = neg ? (int32_t)(~x+1u) : (int32_t)x;
+	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) && !tvismzero(o)) {
+      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), str->len, o,
+				   STRSCAN_OPT_TONUM);
+  lj_assertX(fmt == STRSCAN_ERROR || fmt == STRSCAN_NUM, "bad scan format");
+  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), str->len, o,
+				   STRSCAN_OPT_TOINT);
+  lj_assertX(fmt == STRSCAN_ERROR || fmt == STRSCAN_NUM || fmt == STRSCAN_INT,
+	     "bad scan format");
+  if (fmt == STRSCAN_INT) setitype(o, LJ_TISNUM);
+  return (fmt != STRSCAN_ERROR);
+}
+#endif
+
+#undef DNEXT
+#undef DPREV
+#undef DLEN
+