no need of lookahead in Zio

ldo.c

@@ -1,5 +1,5 @@
 /*
-** $Id: ldo.c,v 2.91 2011/02/04 17:34:43 roberto Exp roberto $
+** $Id: ldo.c,v 2.92 2011/02/07 17:14:50 roberto Exp roberto $
 ** Stack and Call structure of Lua
 ** See Copyright Notice in lua.h
 */
@@ -625,10 +625,10 @@ static void f_parser (lua_State *L, void *ud) {
   Proto *tf;
   Closure *cl;
   struct SParser *p = cast(struct SParser *, ud);
-  int c = luaZ_lookahead(p->z);
+  int c = zgetc(p->z);  /* read first character */
   tf = (c == LUA_SIGNATURE[0])
            ? luaU_undump(L, p->z, &p->buff, p->name)
-           : luaY_parser(L, p->z, &p->buff, &p->dyd, p->name);
+           : luaY_parser(L, p->z, &p->buff, &p->dyd, p->name, c);
   setptvalue2s(L, L->top, tf);
   incr_top(L);
   cl = luaF_newLclosure(L, tf);

llex.c

@@ -1,5 +1,5 @@
 /*
-** $Id: llex.c,v 2.44 2011/01/26 16:30:02 roberto Exp roberto $
+** $Id: llex.c,v 2.45 2011/02/02 14:55:17 roberto Exp roberto $
 ** Lexical Analyzer
 ** See Copyright Notice in lua.h
 */
@@ -152,9 +152,11 @@ static void inclinenumber (LexState *ls) {
 }
 
 
-void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source) {
+void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source,
+                    int firstchar) {
   ls->decpoint = '.';
   ls->L = L;
+  ls->current = firstchar;
   ls->lookahead.token = TK_EOS;  /* no look-ahead token */
   ls->z = z;
   ls->fs = NULL;
@@ -164,7 +166,6 @@ void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source) {
   ls->envn = luaS_new(L, LUA_ENV);  /* create env name */
   luaS_fix(ls->envn);  /* never collect this name */
   luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER);  /* initialize buffer */
-  next(ls);  /* read first char */
 }
 
 

llex.h

@@ -1,5 +1,5 @@
 /*
-** $Id: llex.h,v 1.67 2011/02/04 17:34:43 roberto Exp roberto $
+** $Id: llex.h,v 1.68 2011/02/07 17:14:50 roberto Exp roberto $
 ** Lexical Analyzer
 ** See Copyright Notice in lua.h
 */
@@ -69,7 +69,7 @@ typedef struct LexState {
 
 LUAI_FUNC void luaX_init (lua_State *L);
 LUAI_FUNC void luaX_setinput (lua_State *L, LexState *ls, ZIO *z,
-                              TString *source);
+                              TString *source, int firstchar);
 LUAI_FUNC TString *luaX_newstring (LexState *ls, const char *str, size_t l);
 LUAI_FUNC void luaX_next (LexState *ls);
 LUAI_FUNC int luaX_lookahead (LexState *ls);

lparser.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lparser.c,v 2.105 2011/02/14 14:59:28 roberto Exp roberto $
+** $Id: lparser.c,v 2.106 2011/02/14 16:36:34 roberto Exp roberto $
 ** Lua Parser
 ** See Copyright Notice in lua.h
 */
@@ -1568,7 +1568,7 @@ static void statement (LexState *ls) {
 
 
 Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
-                    Dyndata *dyd, const char *name) {
+                    Dyndata *dyd, const char *name, int firstchar) {
   LexState lexstate;
   FuncState funcstate;
   BlockCnt bl;
@@ -1578,7 +1578,7 @@ Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
   lexstate.buff = buff;
   lexstate.dyd = dyd;
   dyd->actvar.n = dyd->gt.n = dyd->label.n = 0;
-  luaX_setinput(L, &lexstate, z, tname);
+  luaX_setinput(L, &lexstate, z, tname, firstchar);
   open_mainfunc(&lexstate, &funcstate, &bl);
   luaX_next(&lexstate);  /* read first token */
   statlist(&lexstate);  /* main body */

lparser.h

@@ -1,5 +1,5 @@
 /*
-** $Id: lparser.h,v 1.66 2011/02/04 17:34:43 roberto Exp roberto $
+** $Id: lparser.h,v 1.67 2011/02/07 17:14:50 roberto Exp roberto $
 ** Lua Parser
 ** See Copyright Notice in lua.h
 */
@@ -114,7 +114,7 @@ typedef struct FuncState {
 
 
 LUAI_FUNC Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
-                              Dyndata *dyd, const char *name);
+                              Dyndata *dyd, const char *name, int firstchar);
 
 
 #endif

lundump.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lundump.c,v 2.14 2010/10/25 14:33:38 roberto Exp roberto $
+** $Id: lundump.c,v 2.15 2011/02/07 19:15:24 roberto Exp roberto $
 ** load precompiled Lua chunks
 ** See Copyright Notice in lua.h
 */
@@ -180,8 +180,8 @@ static void LoadHeader(LoadState* S)
  char h[LUAC_HEADERSIZE];
  char s[LUAC_HEADERSIZE];
  luaU_header(h);
- LoadBlock(S,s,LUAC_HEADERSIZE);
- if (memcmp(h,s,LUAC_HEADERSIZE)!=0) error(S,"incompatible");
+ LoadBlock(S,s,LUAC_HEADERSIZE-1);  /* 1st char already read */
+ if (memcmp(h+1,s,LUAC_HEADERSIZE-1)!=0) error(S,"incompatible");
 }
 
 /*

lzio.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lzio.c,v 1.31 2005/06/03 20:15:29 roberto Exp roberto $
+** $Id: lzio.c,v 1.32 2011/02/17 17:34:16 roberto Exp roberto $
 ** a generic input stream interface
 ** See Copyright Notice in lua.h
 */
@@ -22,40 +22,23 @@ int luaZ_fill (ZIO *z) {
   size_t size;
   lua_State *L = z->L;
   const char *buff;
-  if (z->eoz) return EOZ;
   lua_unlock(L);
   buff = z->reader(L, z->data, &size);
   lua_lock(L);
-  if (buff == NULL || size == 0) {
-    z->eoz = 1;  /* avoid calling reader function next time */
+  if (buff == NULL || size == 0)
     return EOZ;
-  }
-  z->n = size - 1;
+  z->n = size - 1;  /* discount char being returned */
   z->p = buff;
   return char2int(*(z->p++));
 }
 
 
-int luaZ_lookahead (ZIO *z) {
-  if (z->n == 0) {
-    if (luaZ_fill(z) == EOZ)
-      return EOZ;
-    else {
-      z->n++;  /* luaZ_fill removed first byte; put back it */
-      z->p--;
-    }
-  }
-  return char2int(*z->p);
-}
-
-
 void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) {
   z->L = L;
   z->reader = reader;
   z->data = data;
   z->n = 0;
   z->p = NULL;
-  z->eoz = 0;
 }
 
 
@@ -63,8 +46,14 @@ void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) {
 size_t luaZ_read (ZIO *z, void *b, size_t n) {
   while (n) {
     size_t m;
-    if (luaZ_lookahead(z) == EOZ)
-      return n;  /* return number of missing bytes */
+    if (z->n == 0) {  /* no bytes in buffer? */
+      if (luaZ_fill(z) == EOZ)  /* try to read more */
+        return n;  /* no more input; return number of missing bytes */
+      else {
+        z->n++;  /* luaZ_fill consumed first byte; put it back */
+        z->p--;
+      }
+    }
     m = (n <= z->n) ? n : z->n;  /* min. between n and z->n */
     memcpy(b, z->p, m);
     z->n -= m;

lzio.h

@@ -1,5 +1,5 @@
 /*
-** $Id: lzio.h,v 1.22 2009/05/18 17:26:25 roberto Exp roberto $
+** $Id: lzio.h,v 1.23 2011/02/17 17:34:16 roberto Exp roberto $
 ** Buffered streams
 ** See Copyright Notice in lua.h
 */
@@ -50,7 +50,6 @@ LUAI_FUNC char *luaZ_openspace (lua_State *L, Mbuffer *buff, size_t n);
 LUAI_FUNC void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader,
                                         void *data);
 LUAI_FUNC size_t luaZ_read (ZIO* z, void* b, size_t n);	/* read next n bytes */
-LUAI_FUNC int luaZ_lookahead (ZIO *z);
 
 
 
@@ -62,7 +61,6 @@ struct Zio {
   lua_Reader reader;		/* reader function */
   void* data;			/* additional data */
   lua_State *L;			/* Lua state (for reader) */
-  int eoz;			/* true if reader has no more data */
 };