--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/luajit/src/lj_buf.c	Fri Jan 23 22:38:59 2026 -0800
@@ -0,0 +1,305 @@
+/*
+** Buffer handling.
+** Copyright (C) 2005-2023 Mike Pall. See Copyright Notice in luajit.h
+*/
+
+#define lj_buf_c
+#define LUA_CORE
+
+#include "lj_obj.h"
+#include "lj_gc.h"
+#include "lj_err.h"
+#include "lj_buf.h"
+#include "lj_str.h"
+#include "lj_tab.h"
+#include "lj_strfmt.h"
+
+/* -- Buffer management --------------------------------------------------- */
+
+static void buf_grow(SBuf *sb, MSize sz)
+{
+  MSize osz = sbufsz(sb), len = sbuflen(sb), nsz = osz;
+  char *b;
+  GCSize flag;
+  if (nsz < LJ_MIN_SBUF) nsz = LJ_MIN_SBUF;
+  while (nsz < sz) nsz += nsz;
+  flag = sbufflag(sb);
+  if ((flag & SBUF_FLAG_COW)) {  /* Copy-on-write semantics. */
+    lj_assertG_(G(sbufL(sb)), sb->w == sb->e, "bad SBuf COW");
+    b = (char *)lj_mem_new(sbufL(sb), nsz);
+    setsbufflag(sb, flag & ~(GCSize)SBUF_FLAG_COW);
+    setgcrefnull(sbufX(sb)->cowref);
+    memcpy(b, sb->b, osz);
+  } else {
+    b = (char *)lj_mem_realloc(sbufL(sb), sb->b, osz, nsz);
+  }
+  if ((flag & SBUF_FLAG_EXT)) {
+    sbufX(sb)->r = sbufX(sb)->r - sb->b + b;  /* Adjust read pointer, too. */
+  }
+  /* Adjust buffer pointers. */
+  sb->b = b;
+  sb->w = b + len;
+  sb->e = b + nsz;
+  if ((flag & SBUF_FLAG_BORROW)) {  /* Adjust borrowed buffer pointers. */
+    SBuf *bsb = mref(sbufX(sb)->bsb, SBuf);
+    bsb->b = b;
+    bsb->w = b + len;
+    bsb->e = b + nsz;
+  }
+}
+
+LJ_NOINLINE char *LJ_FASTCALL lj_buf_need2(SBuf *sb, MSize sz)
+{
+  lj_assertG_(G(sbufL(sb)), sz > sbufsz(sb), "SBuf overflow");
+  if (LJ_UNLIKELY(sz > LJ_MAX_BUF))
+    lj_err_mem(sbufL(sb));
+  buf_grow(sb, sz);
+  return sb->b;
+}
+
+LJ_NOINLINE char *LJ_FASTCALL lj_buf_more2(SBuf *sb, MSize sz)
+{
+  if (sbufisext(sb)) {
+    SBufExt *sbx = (SBufExt *)sb;
+    MSize len = sbufxlen(sbx);
+    if (LJ_UNLIKELY(sz > LJ_MAX_BUF || len + sz > LJ_MAX_BUF))
+      lj_err_mem(sbufL(sbx));
+    if (len + sz > sbufsz(sbx)) {  /* Must grow. */
+      buf_grow((SBuf *)sbx, len + sz);
+    } else if (sbufiscow(sb) || sbufxslack(sbx) < (sbufsz(sbx) >> 3)) {
+      /* Also grow to avoid excessive compactions, if slack < size/8. */
+      buf_grow((SBuf *)sbx, sbuflen(sbx) + sz);  /* Not sbufxlen! */
+      return sbx->w;
+    }
+    if (sbx->r != sbx->b) {  /* Compact by moving down. */
+      memmove(sbx->b, sbx->r, len);
+      sbx->r = sbx->b;
+      sbx->w = sbx->b + len;
+      lj_assertG_(G(sbufL(sbx)), len + sz <= sbufsz(sbx), "bad SBuf compact");
+    }
+  } else {
+    MSize len = sbuflen(sb);
+    lj_assertG_(G(sbufL(sb)), sz > sbufleft(sb), "SBuf overflow");
+    if (LJ_UNLIKELY(sz > LJ_MAX_BUF || len + sz > LJ_MAX_BUF))
+      lj_err_mem(sbufL(sb));
+    buf_grow(sb, len + sz);
+  }
+  return sb->w;
+}
+
+void LJ_FASTCALL lj_buf_shrink(lua_State *L, SBuf *sb)
+{
+  char *b = sb->b;
+  MSize osz = (MSize)(sb->e - b);
+  if (osz > 2*LJ_MIN_SBUF) {
+    MSize n = (MSize)(sb->w - b);
+    b = lj_mem_realloc(L, b, osz, (osz >> 1));
+    sb->b = b;
+    sb->w = b + n;
+    sb->e = b + (osz >> 1);
+  }
+  lj_assertG_(G(sbufL(sb)), !sbufisext(sb), "YAGNI shrink SBufExt");
+}
+
+char * LJ_FASTCALL lj_buf_tmp(lua_State *L, MSize sz)
+{
+  SBuf *sb = &G(L)->tmpbuf;
+  setsbufL(sb, L);
+  return lj_buf_need(sb, sz);
+}
+
+#if LJ_HASBUFFER && LJ_HASJIT
+void lj_bufx_set(SBufExt *sbx, const char *p, MSize len, GCobj *ref)
+{
+  lua_State *L = sbufL(sbx);
+  lj_bufx_free(L, sbx);
+  lj_bufx_set_cow(L, sbx, p, len);
+  setgcref(sbx->cowref, ref);
+  lj_gc_objbarrier(L, (GCudata *)sbx - 1, ref);
+}
+
+#if LJ_HASFFI
+MSize LJ_FASTCALL lj_bufx_more(SBufExt *sbx, MSize sz)
+{
+  lj_buf_more((SBuf *)sbx, sz);
+  return sbufleft(sbx);
+}
+#endif
+#endif
+
+/* -- Low-level buffer put operations ------------------------------------- */
+
+SBuf *lj_buf_putmem(SBuf *sb, const void *q, MSize len)
+{
+  char *w = lj_buf_more(sb, len);
+  w = lj_buf_wmem(w, q, len);
+  sb->w = w;
+  return sb;
+}
+
+#if LJ_HASJIT || LJ_HASFFI
+static LJ_NOINLINE SBuf * LJ_FASTCALL lj_buf_putchar2(SBuf *sb, int c)
+{
+  char *w = lj_buf_more2(sb, 1);
+  *w++ = (char)c;
+  sb->w = w;
+  return sb;
+}
+
+SBuf * LJ_FASTCALL lj_buf_putchar(SBuf *sb, int c)
+{
+  char *w = sb->w;
+  if (LJ_LIKELY(w < sb->e)) {
+    *w++ = (char)c;
+    sb->w = w;
+    return sb;
+  }
+  return lj_buf_putchar2(sb, c);
+}
+#endif
+
+SBuf * LJ_FASTCALL lj_buf_putstr(SBuf *sb, GCstr *s)
+{
+  MSize len = s->len;
+  char *w = lj_buf_more(sb, len);
+  w = lj_buf_wmem(w, strdata(s), len);
+  sb->w = w;
+  return sb;
+}
+
+/* -- High-level buffer put operations ------------------------------------ */
+
+SBuf * LJ_FASTCALL lj_buf_putstr_reverse(SBuf *sb, GCstr *s)
+{
+  MSize len = s->len;
+  char *w = lj_buf_more(sb, len), *e = w+len;
+  const char *q = strdata(s)+len-1;
+  while (w < e)
+    *w++ = *q--;
+  sb->w = w;
+  return sb;
+}
+
+SBuf * LJ_FASTCALL lj_buf_putstr_lower(SBuf *sb, GCstr *s)
+{
+  MSize len = s->len;
+  char *w = lj_buf_more(sb, len), *e = w+len;
+  const char *q = strdata(s);
+  for (; w < e; w++, q++) {
+    uint32_t c = *(unsigned char *)q;
+#if LJ_TARGET_PPC
+    *w = c + ((c >= 'A' && c <= 'Z') << 5);
+#else
+    if (c >= 'A' && c <= 'Z') c += 0x20;
+    *w = c;
+#endif
+  }
+  sb->w = w;
+  return sb;
+}
+
+SBuf * LJ_FASTCALL lj_buf_putstr_upper(SBuf *sb, GCstr *s)
+{
+  MSize len = s->len;
+  char *w = lj_buf_more(sb, len), *e = w+len;
+  const char *q = strdata(s);
+  for (; w < e; w++, q++) {
+    uint32_t c = *(unsigned char *)q;
+#if LJ_TARGET_PPC
+    *w = c - ((c >= 'a' && c <= 'z') << 5);
+#else
+    if (c >= 'a' && c <= 'z') c -= 0x20;
+    *w = c;
+#endif
+  }
+  sb->w = w;
+  return sb;
+}
+
+SBuf *lj_buf_putstr_rep(SBuf *sb, GCstr *s, int32_t rep)
+{
+  MSize len = s->len;
+  if (rep > 0 && len) {
+    uint64_t tlen = (uint64_t)rep * len;
+    char *w;
+    if (LJ_UNLIKELY(tlen > LJ_MAX_STR))
+      lj_err_mem(sbufL(sb));
+    w = lj_buf_more(sb, (MSize)tlen);
+    if (len == 1) {  /* Optimize a common case. */
+      uint32_t c = strdata(s)[0];
+      do { *w++ = c; } while (--rep > 0);
+    } else {
+      const char *e = strdata(s) + len;
+      do {
+	const char *q = strdata(s);
+	do { *w++ = *q++; } while (q < e);
+      } while (--rep > 0);
+    }
+    sb->w = w;
+  }
+  return sb;
+}
+
+SBuf *lj_buf_puttab(SBuf *sb, GCtab *t, GCstr *sep, int32_t i, int32_t e)
+{
+  MSize seplen = sep ? sep->len : 0;
+  if (i <= e) {
+    for (;;) {
+      cTValue *o = lj_tab_getint(t, i);
+      char *w;
+      if (!o) {
+      badtype:  /* Error: bad element type. */
+	sb->w = (char *)(intptr_t)i;  /* Store failing index. */
+	return NULL;
+      } else if (tvisstr(o)) {
+	MSize len = strV(o)->len;
+	w = lj_buf_wmem(lj_buf_more(sb, len + seplen), strVdata(o), len);
+      } else if (tvisint(o)) {
+	w = lj_strfmt_wint(lj_buf_more(sb, STRFMT_MAXBUF_INT+seplen), intV(o));
+      } else if (tvisnum(o)) {
+	w = lj_buf_more(lj_strfmt_putfnum(sb, STRFMT_G14, numV(o)), seplen);
+      } else {
+	goto badtype;
+      }
+      if (i++ == e) {
+	sb->w = w;
+	break;
+      }
+      if (seplen) w = lj_buf_wmem(w, strdata(sep), seplen);
+      sb->w = w;
+    }
+  }
+  return sb;
+}
+
+/* -- Miscellaneous buffer operations ------------------------------------- */
+
+GCstr * LJ_FASTCALL lj_buf_tostr(SBuf *sb)
+{
+  return lj_str_new(sbufL(sb), sb->b, sbuflen(sb));
+}
+
+/* Concatenate two strings. */
+GCstr *lj_buf_cat2str(lua_State *L, GCstr *s1, GCstr *s2)
+{
+  MSize len1 = s1->len, len2 = s2->len;
+  char *buf = lj_buf_tmp(L, len1 + len2);
+  memcpy(buf, strdata(s1), len1);
+  memcpy(buf+len1, strdata(s2), len2);
+  return lj_str_new(L, buf, len1 + len2);
+}
+
+/* Read ULEB128 from buffer. */
+uint32_t LJ_FASTCALL lj_buf_ruleb128(const char **pp)
+{
+  const uint8_t *w = (const uint8_t *)*pp;
+  uint32_t v = *w++;
+  if (LJ_UNLIKELY(v >= 0x80)) {
+    int sh = 0;
+    v &= 0x7f;
+    do { v |= ((*w & 0x7f) << (sh += 7)); } while (*w++ >= 0x80);
+  }
+  *pp = (const char *)w;
+  return v;
+}
+