vendor: 引入 Lua 4.0.1 官方源码 + 移植评估文档 (lua_4.0 分支)

- Lua 4.0 是首个引入 lua_State* 的版本, 但 API 与 5.x 代际差异大
- 桥接层适配要点与工作量评估见 doc/ADAPTATION-lua40.md
- 本分支暂不承诺可编译, 后续按需移植

lib/lua/lzio.c

@@ -1,70 +1,78 @@
 /*
-** $Id: lzio.c $
-** Buffered streams
+** $Id: lzio.c,v 1.13 2000/06/12 13:52:05 roberto Exp $
+** a generic input stream interface
 ** See Copyright Notice in lua.h
 */
 
-#define lzio_c
-#define LUA_CORE
-
-#include "lprefix.h"
 
 
+#include <stdio.h>
 #include <string.h>
 
 #include "lua.h"
 
-#include "lapi.h"
-#include "llimits.h"
-#include "lmem.h"
-#include "lstate.h"
 #include "lzio.h"
 
 
-int luaZ_fill (ZIO *z) {
-  size_t size;
-  lua_State *L = z->L;
-  const char *buff;
-  lua_unlock(L);
-  buff = z->reader(L, z->data, &size);
-  lua_lock(L);
-  if (buff == NULL || size == 0)
-    return EOZ;
-  z->n = size - 1;  /* discount char being returned */
-  z->p = buff;
-  return cast_uchar(*(z->p++));
+
+/* ----------------------------------------------------- memory buffers --- */
+
+static int zmfilbuf (ZIO* z) {
+  (void)z;  /* to avoid warnings */
+  return EOZ;
 }
 
 
-void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) {
-  z->L = L;
-  z->reader = reader;
-  z->data = data;
+ZIO* zmopen (ZIO* z, const char* b, size_t size, const char *name) {
+  if (b==NULL) return NULL;
+  z->n = size;
+  z->p = (const unsigned char *)b;
+  z->filbuf = zmfilbuf;
+  z->u = NULL;
+  z->name = name;
+  return z;
+}
+
+/* ------------------------------------------------------------ strings --- */
+
+ZIO* zsopen (ZIO* z, const char* s, const char *name) {
+  if (s==NULL) return NULL;
+  return zmopen(z, s, strlen(s), name);
+}
+
+/* -------------------------------------------------------------- FILEs --- */
+
+static int zffilbuf (ZIO* z) {
+  size_t n;
+  if (feof((FILE *)z->u)) return EOZ;
+  n = fread(z->buffer, 1, ZBSIZE, (FILE *)z->u);
+  if (n==0) return EOZ;
+  z->n = n-1;
+  z->p = z->buffer;
+  return *(z->p++);
+}
+
+
+ZIO* zFopen (ZIO* z, FILE* f, const char *name) {
+  if (f==NULL) return NULL;
   z->n = 0;
-  z->p = NULL;
+  z->p = z->buffer;
+  z->filbuf = zffilbuf;
+  z->u = f;
+  z->name = name;
+  return z;
 }
 
 
 /* --------------------------------------------------------------- read --- */
-
-static int checkbuffer (ZIO *z) {
-  if (z->n == 0) {  /* no bytes in buffer? */
-    if (luaZ_fill(z) == EOZ)  /* try to read more */
-      return 0;  /* no more input */
-    else {
-      z->n++;  /* luaZ_fill consumed first byte; put it back */
-      z->p--;
-    }
-  }
-  return 1;  /* now buffer has something */
-}
-
-
-size_t luaZ_read (ZIO *z, void *b, size_t n) {
+size_t zread (ZIO *z, void *b, size_t n) {
   while (n) {
     size_t m;
-    if (!checkbuffer(z))
-      return n;  /* no more input; return number of missing bytes */
+    if (z->n == 0) {
+      if (z->filbuf(z) == EOZ)
+        return n;  /* return number of missing bytes */
+      zungetc(z);  /* put result from `filbuf' in the buffer */
+    }
     m = (n <= z->n) ? n : z->n;  /* min. between n and z->n */
     memcpy(b, z->p, m);
     z->n -= m;
@@ -74,16 +82,3 @@ size_t luaZ_read (ZIO *z, void *b, size_t n) {
   }
   return 0;
 }
-
-
-const void *luaZ_getaddr (ZIO* z, size_t n) {
-  const void *res;
-  if (!checkbuffer(z))
-    return NULL;  /* no more input */
-  if (z->n < n)  /* not enough bytes? */
-    return NULL;  /* block not whole; cannot give an address */
-  res = z->p;  /* get block address */
-  z->n -= n;  /* consume these bytes */
-  z->p += n;
-  return res;
-}