--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/luajit/src/lj_buf.h	Fri Jan 23 22:38:59 2026 -0800
@@ -0,0 +1,198 @@
+/*
+** Buffer handling.
+** Copyright (C) 2005-2023 Mike Pall. See Copyright Notice in luajit.h
+*/
+
+#ifndef _LJ_BUF_H
+#define _LJ_BUF_H
+
+#include "lj_obj.h"
+#include "lj_gc.h"
+#include "lj_str.h"
+
+/* Resizable string buffers. */
+
+/* The SBuf struct definition is in lj_obj.h:
+**   char *w;	Write pointer.
+**   char *e;	End pointer.
+**   char *b;	Base pointer.
+**   MRef L;	lua_State, used for buffer resizing. Extension bits in 3 LSB.
+*/
+
+/* Extended string buffer. */
+typedef struct SBufExt {
+  SBufHeader;
+  union {
+    GCRef cowref;	/* Copy-on-write object reference. */
+    MRef bsb;		/* Borrowed string buffer. */
+  };
+  char *r;		/* Read pointer. */
+  GCRef dict_str;	/* Serialization string dictionary table. */
+  GCRef dict_mt;	/* Serialization metatable dictionary table. */
+  int depth;		/* Remaining recursion depth. */
+} SBufExt;
+
+#define sbufsz(sb)		((MSize)((sb)->e - (sb)->b))
+#define sbuflen(sb)		((MSize)((sb)->w - (sb)->b))
+#define sbufleft(sb)		((MSize)((sb)->e - (sb)->w))
+#define sbufxlen(sbx)		((MSize)((sbx)->w - (sbx)->r))
+#define sbufxslack(sbx)		((MSize)((sbx)->r - (sbx)->b))
+
+#define SBUF_MASK_FLAG		(7)
+#define SBUF_MASK_L		(~(GCSize)SBUF_MASK_FLAG)
+#define SBUF_FLAG_EXT		1	/* Extended string buffer. */
+#define SBUF_FLAG_COW		2	/* Copy-on-write buffer. */
+#define SBUF_FLAG_BORROW	4	/* Borrowed string buffer. */
+
+#define sbufL(sb) \
+  ((lua_State *)(void *)(uintptr_t)(mrefu((sb)->L) & SBUF_MASK_L))
+#define setsbufL(sb, l)		(setmref((sb)->L, (l)))
+#define setsbufXL(sb, l, flag) \
+  (setmrefu((sb)->L, (GCSize)(uintptr_t)(void *)(l) + (flag)))
+#define setsbufXL_(sb, l) \
+  (setmrefu((sb)->L, (GCSize)(uintptr_t)(void *)(l) | (mrefu((sb)->L) & SBUF_MASK_FLAG)))
+
+#define sbufflag(sb)		(mrefu((sb)->L))
+#define sbufisext(sb)		(sbufflag((sb)) & SBUF_FLAG_EXT)
+#define sbufiscow(sb)		(sbufflag((sb)) & SBUF_FLAG_COW)
+#define sbufisborrow(sb)	(sbufflag((sb)) & SBUF_FLAG_BORROW)
+#define sbufiscoworborrow(sb)	(sbufflag((sb)) & (SBUF_FLAG_COW|SBUF_FLAG_BORROW))
+#define sbufX(sb) \
+  (lj_assertG_(G(sbufL(sb)), sbufisext(sb), "not an SBufExt"), (SBufExt *)(sb))
+#define setsbufflag(sb, flag)	(setmrefu((sb)->L, (flag)))
+
+#define tvisbuf(o) \
+  (LJ_HASBUFFER && tvisudata(o) && udataV(o)->udtype == UDTYPE_BUFFER)
+#define bufV(o)		check_exp(tvisbuf(o), ((SBufExt *)uddata(udataV(o))))
+
+/* Buffer management */
+LJ_FUNC char *LJ_FASTCALL lj_buf_need2(SBuf *sb, MSize sz);
+LJ_FUNC char *LJ_FASTCALL lj_buf_more2(SBuf *sb, MSize sz);
+LJ_FUNC void LJ_FASTCALL lj_buf_shrink(lua_State *L, SBuf *sb);
+LJ_FUNC char * LJ_FASTCALL lj_buf_tmp(lua_State *L, MSize sz);
+
+static LJ_AINLINE void lj_buf_init(lua_State *L, SBuf *sb)
+{
+  setsbufL(sb, L);
+  sb->w = sb->e = sb->b = NULL;
+}
+
+static LJ_AINLINE void lj_buf_reset(SBuf *sb)
+{
+  sb->w = sb->b;
+}
+
+static LJ_AINLINE SBuf *lj_buf_tmp_(lua_State *L)
+{
+  SBuf *sb = &G(L)->tmpbuf;
+  setsbufL(sb, L);
+  lj_buf_reset(sb);
+  return sb;
+}
+
+static LJ_AINLINE void lj_buf_free(global_State *g, SBuf *sb)
+{
+  lj_assertG(!sbufisext(sb), "bad free of SBufExt");
+  lj_mem_free(g, sb->b, sbufsz(sb));
+}
+
+static LJ_AINLINE char *lj_buf_need(SBuf *sb, MSize sz)
+{
+  if (LJ_UNLIKELY(sz > sbufsz(sb)))
+    return lj_buf_need2(sb, sz);
+  return sb->b;
+}
+
+static LJ_AINLINE char *lj_buf_more(SBuf *sb, MSize sz)
+{
+  if (LJ_UNLIKELY(sz > sbufleft(sb)))
+    return lj_buf_more2(sb, sz);
+  return sb->w;
+}
+
+/* Extended buffer management */
+static LJ_AINLINE void lj_bufx_init(lua_State *L, SBufExt *sbx)
+{
+  memset(sbx, 0, sizeof(SBufExt));
+  setsbufXL(sbx, L, SBUF_FLAG_EXT);
+}
+
+static LJ_AINLINE void lj_bufx_set_borrow(lua_State *L, SBufExt *sbx, SBuf *sb)
+{
+  setsbufXL(sbx, L, SBUF_FLAG_EXT | SBUF_FLAG_BORROW);
+  setmref(sbx->bsb, sb);
+  sbx->r = sbx->w = sbx->b = sb->b;
+  sbx->e = sb->e;
+}
+
+static LJ_AINLINE void lj_bufx_set_cow(lua_State *L, SBufExt *sbx,
+				       const char *p, MSize len)
+{
+  setsbufXL(sbx, L, SBUF_FLAG_EXT | SBUF_FLAG_COW);
+  sbx->r = sbx->b = (char *)p;
+  sbx->w = sbx->e = (char *)p + len;
+}
+
+static LJ_AINLINE void lj_bufx_reset(SBufExt *sbx)
+{
+  if (sbufiscow(sbx)) {
+    setmrefu(sbx->L, (mrefu(sbx->L) & ~(GCSize)SBUF_FLAG_COW));
+    setgcrefnull(sbx->cowref);
+    sbx->b = sbx->e = NULL;
+  }
+  sbx->r = sbx->w = sbx->b;
+}
+
+static LJ_AINLINE void lj_bufx_free(lua_State *L, SBufExt *sbx)
+{
+  if (!sbufiscoworborrow(sbx)) lj_mem_free(G(L), sbx->b, sbufsz(sbx));
+  setsbufXL(sbx, L, SBUF_FLAG_EXT);
+  setgcrefnull(sbx->cowref);
+  sbx->r = sbx->w = sbx->b = sbx->e = NULL;
+}
+
+#if LJ_HASBUFFER && LJ_HASJIT
+LJ_FUNC void lj_bufx_set(SBufExt *sbx, const char *p, MSize len, GCobj *o);
+#if LJ_HASFFI
+LJ_FUNC MSize LJ_FASTCALL lj_bufx_more(SBufExt *sbx, MSize sz);
+#endif
+#endif
+
+/* Low-level buffer put operations */
+LJ_FUNC SBuf *lj_buf_putmem(SBuf *sb, const void *q, MSize len);
+#if LJ_HASJIT || LJ_HASFFI
+LJ_FUNC SBuf * LJ_FASTCALL lj_buf_putchar(SBuf *sb, int c);
+#endif
+LJ_FUNC SBuf * LJ_FASTCALL lj_buf_putstr(SBuf *sb, GCstr *s);
+
+static LJ_AINLINE char *lj_buf_wmem(char *p, const void *q, MSize len)
+{
+  return (char *)memcpy(p, q, len) + len;
+}
+
+static LJ_AINLINE void lj_buf_putb(SBuf *sb, int c)
+{
+  char *w = lj_buf_more(sb, 1);
+  *w++ = (char)c;
+  sb->w = w;
+}
+
+/* High-level buffer put operations */
+LJ_FUNCA SBuf * LJ_FASTCALL lj_buf_putstr_reverse(SBuf *sb, GCstr *s);
+LJ_FUNCA SBuf * LJ_FASTCALL lj_buf_putstr_lower(SBuf *sb, GCstr *s);
+LJ_FUNCA SBuf * LJ_FASTCALL lj_buf_putstr_upper(SBuf *sb, GCstr *s);
+LJ_FUNC SBuf *lj_buf_putstr_rep(SBuf *sb, GCstr *s, int32_t rep);
+LJ_FUNC SBuf *lj_buf_puttab(SBuf *sb, GCtab *t, GCstr *sep,
+			    int32_t i, int32_t e);
+
+/* Miscellaneous buffer operations */
+LJ_FUNCA GCstr * LJ_FASTCALL lj_buf_tostr(SBuf *sb);
+LJ_FUNC GCstr *lj_buf_cat2str(lua_State *L, GCstr *s1, GCstr *s2);
+LJ_FUNC uint32_t LJ_FASTCALL lj_buf_ruleb128(const char **pp);
+
+static LJ_AINLINE GCstr *lj_buf_str(lua_State *L, SBuf *sb)
+{
+  return lj_str_new(L, sb->b, sbuflen(sb));
+}
+
+#endif