--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/luajit/src/lib_buffer.c	Fri Jan 23 22:38:59 2026 -0800
@@ -0,0 +1,360 @@
+/*
+** Buffer library.
+** Copyright (C) 2005-2023 Mike Pall. See Copyright Notice in luajit.h
+*/
+
+#define lib_buffer_c
+#define LUA_LIB
+
+#include "lua.h"
+#include "lauxlib.h"
+#include "lualib.h"
+
+#include "lj_obj.h"
+
+#if LJ_HASBUFFER
+#include "lj_gc.h"
+#include "lj_err.h"
+#include "lj_buf.h"
+#include "lj_str.h"
+#include "lj_tab.h"
+#include "lj_udata.h"
+#include "lj_meta.h"
+#if LJ_HASFFI
+#include "lj_ctype.h"
+#include "lj_cdata.h"
+#include "lj_cconv.h"
+#endif
+#include "lj_strfmt.h"
+#include "lj_serialize.h"
+#include "lj_lib.h"
+
+/* -- Helper functions ---------------------------------------------------- */
+
+/* Check that the first argument is a string buffer. */
+static SBufExt *buffer_tobuf(lua_State *L)
+{
+  if (!(L->base < L->top && tvisbuf(L->base)))
+    lj_err_argtype(L, 1, "buffer");
+  return bufV(L->base);
+}
+
+/* Ditto, but for writers. */
+static LJ_AINLINE SBufExt *buffer_tobufw(lua_State *L)
+{
+  SBufExt *sbx = buffer_tobuf(L);
+  setsbufXL_(sbx, L);
+  return sbx;
+}
+
+#define buffer_toudata(sbx)	((GCudata *)(sbx)-1)
+
+/* -- Buffer methods ------------------------------------------------------ */
+
+#define LJLIB_MODULE_buffer_method
+
+LJLIB_CF(buffer_method_free)
+{
+  SBufExt *sbx = buffer_tobuf(L);
+  lj_bufx_free(L, sbx);
+  L->top = L->base+1;  /* Chain buffer object. */
+  return 1;
+}
+
+LJLIB_CF(buffer_method_reset)		LJLIB_REC(.)
+{
+  SBufExt *sbx = buffer_tobuf(L);
+  lj_bufx_reset(sbx);
+  L->top = L->base+1;  /* Chain buffer object. */
+  return 1;
+}
+
+LJLIB_CF(buffer_method_skip)		LJLIB_REC(.)
+{
+  SBufExt *sbx = buffer_tobuf(L);
+  MSize n = (MSize)lj_lib_checkintrange(L, 2, 0, LJ_MAX_BUF);
+  MSize len = sbufxlen(sbx);
+  if (n < len) {
+    sbx->r += n;
+  } else if (sbufiscow(sbx)) {
+    sbx->r = sbx->w;
+  } else {
+    sbx->r = sbx->w = sbx->b;
+  }
+  L->top = L->base+1;  /* Chain buffer object. */
+  return 1;
+}
+
+LJLIB_CF(buffer_method_set)		LJLIB_REC(.)
+{
+  SBufExt *sbx = buffer_tobuf(L);
+  GCobj *ref;
+  const char *p;
+  MSize len;
+#if LJ_HASFFI
+  if (tviscdata(L->base+1)) {
+    CTState *cts = ctype_cts(L);
+    lj_cconv_ct_tv(cts, ctype_get(cts, CTID_P_CVOID), (uint8_t *)&p,
+		   L->base+1, CCF_ARG(2));
+    len = (MSize)lj_lib_checkintrange(L, 3, 0, LJ_MAX_BUF);
+  } else
+#endif
+  {
+    GCstr *str = lj_lib_checkstrx(L, 2);
+    p = strdata(str);
+    len = str->len;
+  }
+  lj_bufx_free(L, sbx);
+  lj_bufx_set_cow(L, sbx, p, len);
+  ref = gcV(L->base+1);
+  setgcref(sbx->cowref, ref);
+  lj_gc_objbarrier(L, buffer_toudata(sbx), ref);
+  L->top = L->base+1;  /* Chain buffer object. */
+  return 1;
+}
+
+LJLIB_CF(buffer_method_put)		LJLIB_REC(.)
+{
+  SBufExt *sbx = buffer_tobufw(L);
+  ptrdiff_t arg, narg = L->top - L->base;
+  for (arg = 1; arg < narg; arg++) {
+    cTValue *o = &L->base[arg], *mo = NULL;
+  retry:
+    if (tvisstr(o)) {
+      lj_buf_putstr((SBuf *)sbx, strV(o));
+    } else if (tvisint(o)) {
+      lj_strfmt_putint((SBuf *)sbx, intV(o));
+    } else if (tvisnum(o)) {
+      lj_strfmt_putfnum((SBuf *)sbx, STRFMT_G14, numV(o));
+    } else if (tvisbuf(o)) {
+      SBufExt *sbx2 = bufV(o);
+      if (sbx2 == sbx) lj_err_arg(L, (int)(arg+1), LJ_ERR_BUFFER_SELF);
+      lj_buf_putmem((SBuf *)sbx, sbx2->r, sbufxlen(sbx2));
+    } else if (!mo && !tvisnil(mo = lj_meta_lookup(L, o, MM_tostring))) {
+      /* Call __tostring metamethod inline. */
+      copyTV(L, L->top++, mo);
+      copyTV(L, L->top++, o);
+      lua_call(L, 1, 1);
+      o = &L->base[arg];  /* The stack may have been reallocated. */
+      copyTV(L, &L->base[arg], L->top-1);
+      L->top = L->base + narg;
+      goto retry;  /* Retry with the result. */
+    } else {
+      lj_err_argtype(L, (int)(arg+1), "string/number/__tostring");
+    }
+    /* Probably not useful to inline other __tostring MMs, e.g. FFI numbers. */
+  }
+  L->top = L->base+1;  /* Chain buffer object. */
+  lj_gc_check(L);
+  return 1;
+}
+
+LJLIB_CF(buffer_method_putf)		LJLIB_REC(.)
+{
+  SBufExt *sbx = buffer_tobufw(L);
+  lj_strfmt_putarg(L, (SBuf *)sbx, 2, 2);
+  L->top = L->base+1;  /* Chain buffer object. */
+  lj_gc_check(L);
+  return 1;
+}
+
+LJLIB_CF(buffer_method_get)		LJLIB_REC(.)
+{
+  SBufExt *sbx = buffer_tobuf(L);
+  ptrdiff_t arg, narg = L->top - L->base;
+  if (narg == 1) {
+    narg++;
+    setnilV(L->top++);  /* get() is the same as get(nil). */
+  }
+  for (arg = 1; arg < narg; arg++) {
+    TValue *o = &L->base[arg];
+    MSize n = tvisnil(o) ? LJ_MAX_BUF :
+	      (MSize) lj_lib_checkintrange(L, (int)(arg+1), 0, LJ_MAX_BUF);
+    MSize len = sbufxlen(sbx);
+    if (n > len) n = len;
+    setstrV(L, o, lj_str_new(L, sbx->r, n));
+    sbx->r += n;
+  }
+  if (sbx->r == sbx->w && !sbufiscow(sbx)) sbx->r = sbx->w = sbx->b;
+  lj_gc_check(L);
+  return (int)(narg-1);
+}
+
+#if LJ_HASFFI
+LJLIB_CF(buffer_method_putcdata)	LJLIB_REC(.)
+{
+  SBufExt *sbx = buffer_tobufw(L);
+  const char *p;
+  MSize len;
+  if (tviscdata(L->base+1)) {
+    CTState *cts = ctype_cts(L);
+    lj_cconv_ct_tv(cts, ctype_get(cts, CTID_P_CVOID), (uint8_t *)&p,
+		   L->base+1, CCF_ARG(2));
+  } else {
+    lj_err_argtype(L, 2, "cdata");
+  }
+  len = (MSize)lj_lib_checkintrange(L, 3, 0, LJ_MAX_BUF);
+  lj_buf_putmem((SBuf *)sbx, p, len);
+  L->top = L->base+1;  /* Chain buffer object. */
+  return 1;
+}
+
+LJLIB_CF(buffer_method_reserve)		LJLIB_REC(.)
+{
+  SBufExt *sbx = buffer_tobufw(L);
+  MSize sz = (MSize)lj_lib_checkintrange(L, 2, 0, LJ_MAX_BUF);
+  GCcdata *cd;
+  lj_buf_more((SBuf *)sbx, sz);
+  ctype_loadffi(L);
+  cd = lj_cdata_new_(L, CTID_P_UINT8, CTSIZE_PTR);
+  *(void **)cdataptr(cd) = sbx->w;
+  setcdataV(L, L->top++, cd);
+  setintV(L->top++, sbufleft(sbx));
+  return 2;
+}
+
+LJLIB_CF(buffer_method_commit)		LJLIB_REC(.)
+{
+  SBufExt *sbx = buffer_tobuf(L);
+  MSize len = (MSize)lj_lib_checkintrange(L, 2, 0, LJ_MAX_BUF);
+  if (len > sbufleft(sbx)) lj_err_arg(L, 2, LJ_ERR_NUMRNG);
+  sbx->w += len;
+  L->top = L->base+1;  /* Chain buffer object. */
+  return 1;
+}
+
+LJLIB_CF(buffer_method_ref)		LJLIB_REC(.)
+{
+  SBufExt *sbx = buffer_tobuf(L);
+  GCcdata *cd;
+  ctype_loadffi(L);
+  cd = lj_cdata_new_(L, CTID_P_UINT8, CTSIZE_PTR);
+  *(void **)cdataptr(cd) = sbx->r;
+  setcdataV(L, L->top++, cd);
+  setintV(L->top++, sbufxlen(sbx));
+  return 2;
+}
+#endif
+
+LJLIB_CF(buffer_method_encode)		LJLIB_REC(.)
+{
+  SBufExt *sbx = buffer_tobufw(L);
+  cTValue *o = lj_lib_checkany(L, 2);
+  lj_serialize_put(sbx, o);
+  lj_gc_check(L);
+  L->top = L->base+1;  /* Chain buffer object. */
+  return 1;
+}
+
+LJLIB_CF(buffer_method_decode)		LJLIB_REC(.)
+{
+  SBufExt *sbx = buffer_tobufw(L);
+  setnilV(L->top++);
+  sbx->r = lj_serialize_get(sbx, L->top-1);
+  lj_gc_check(L);
+  return 1;
+}
+
+LJLIB_CF(buffer_method___gc)
+{
+  SBufExt *sbx = buffer_tobuf(L);
+  lj_bufx_free(L, sbx);
+  return 0;
+}
+
+LJLIB_CF(buffer_method___tostring)	LJLIB_REC(.)
+{
+  SBufExt *sbx = buffer_tobuf(L);
+  setstrV(L, L->top-1, lj_str_new(L, sbx->r, sbufxlen(sbx)));
+  lj_gc_check(L);
+  return 1;
+}
+
+LJLIB_CF(buffer_method___len)		LJLIB_REC(.)
+{
+  SBufExt *sbx = buffer_tobuf(L);
+  setintV(L->top-1, (int32_t)sbufxlen(sbx));
+  return 1;
+}
+
+LJLIB_PUSH("buffer") LJLIB_SET(__metatable)
+LJLIB_PUSH(top-1) LJLIB_SET(__index)
+
+/* -- Buffer library functions -------------------------------------------- */
+
+#define LJLIB_MODULE_buffer
+
+LJLIB_PUSH(top-2) LJLIB_SET(!)  /* Set environment. */
+
+LJLIB_CF(buffer_new)
+{
+  MSize sz = 0;
+  int targ = 1;
+  GCtab *env, *dict_str = NULL, *dict_mt = NULL;
+  GCudata *ud;
+  SBufExt *sbx;
+  if (L->base < L->top && !tvistab(L->base)) {
+    targ = 2;
+    if (!tvisnil(L->base))
+      sz = (MSize)lj_lib_checkintrange(L, 1, 0, LJ_MAX_BUF);
+  }
+  if (L->base+targ-1 < L->top) {
+    GCtab *options = lj_lib_checktab(L, targ);
+    cTValue *opt_dict, *opt_mt;
+    opt_dict = lj_tab_getstr(options, lj_str_newlit(L, "dict"));
+    if (opt_dict && tvistab(opt_dict)) {
+      dict_str = tabV(opt_dict);
+      lj_serialize_dict_prep_str(L, dict_str);
+    }
+    opt_mt = lj_tab_getstr(options, lj_str_newlit(L, "metatable"));
+    if (opt_mt && tvistab(opt_mt)) {
+      dict_mt = tabV(opt_mt);
+      lj_serialize_dict_prep_mt(L, dict_mt);
+    }
+  }
+  env = tabref(curr_func(L)->c.env);
+  ud = lj_udata_new(L, sizeof(SBufExt), env);
+  ud->udtype = UDTYPE_BUFFER;
+  /* NOBARRIER: The GCudata is new (marked white). */
+  setgcref(ud->metatable, obj2gco(env));
+  setudataV(L, L->top++, ud);
+  sbx = (SBufExt *)uddata(ud);
+  lj_bufx_init(L, sbx);
+  setgcref(sbx->dict_str, obj2gco(dict_str));
+  setgcref(sbx->dict_mt, obj2gco(dict_mt));
+  if (sz > 0) lj_buf_need2((SBuf *)sbx, sz);
+  lj_gc_check(L);
+  return 1;
+}
+
+LJLIB_CF(buffer_encode)			LJLIB_REC(.)
+{
+  cTValue *o = lj_lib_checkany(L, 1);
+  setstrV(L, L->top++, lj_serialize_encode(L, o));
+  lj_gc_check(L);
+  return 1;
+}
+
+LJLIB_CF(buffer_decode)			LJLIB_REC(.)
+{
+  GCstr *str = lj_lib_checkstrx(L, 1);
+  setnilV(L->top++);
+  lj_serialize_decode(L, L->top-1, str);
+  lj_gc_check(L);
+  return 1;
+}
+
+/* ------------------------------------------------------------------------ */
+
+#include "lj_libdef.h"
+
+int luaopen_string_buffer(lua_State *L)
+{
+  LJ_LIB_REG(L, NULL, buffer_method);
+  lua_getfield(L, -1, "__tostring");
+  lua_setfield(L, -2, "tostring");
+  LJ_LIB_REG(L, NULL, buffer);
+  return 1;
+}
+
+#endif