From 59c88f846d1dcd901a4420651aedf27816618923 Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 24 Feb 2021 11:14:44 -0300
Subject: Broadening the use of branch hints

More uses of macros 'likely'/'unlikely' (renamed to
'l_likely'/'l_unlikely'), both in range (extended to the
libraries) and in scope (extended to hooks, stack growth).
---
 liolib.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

(limited to 'liolib.c')

diff --git a/liolib.c b/liolib.c
index 79516724..b08397da 100644
--- a/liolib.c
+++ b/liolib.c
@@ -186,7 +186,7 @@ static int f_tostring (lua_State *L) {
 
 static FILE *tofile (lua_State *L) {
   LStream *p = tolstream(L);
-  if (isclosed(p))
+  if (l_unlikely(isclosed(p)))
     luaL_error(L, "attempt to use a closed file");
   lua_assert(p->f);
   return p->f;
@@ -261,7 +261,7 @@ static LStream *newfile (lua_State *L) {
 static void opencheck (lua_State *L, const char *fname, const char *mode) {
   LStream *p = newfile(L);
   p->f = fopen(fname, mode);
-  if (p->f == NULL)
+  if (l_unlikely(p->f == NULL))
     luaL_error(L, "cannot open file '%s' (%s)", fname, strerror(errno));
 }
 
@@ -309,7 +309,7 @@ static FILE *getiofile (lua_State *L, const char *findex) {
   LStream *p;
   lua_getfield(L, LUA_REGISTRYINDEX, findex);
   p = (LStream *)lua_touserdata(L, -1);
-  if (isclosed(p))
+  if (l_unlikely(isclosed(p)))
     luaL_error(L, "default %s file is closed", findex + IOPREF_LEN);
   return p->f;
 }
@@ -436,7 +436,7 @@ typedef struct {
 ** Add current char to buffer (if not out of space) and read next one
 */
 static int nextc (RN *rn) {
-  if (rn->n >= L_MAXLENNUM) {  /* buffer overflow? */
+  if (l_unlikely(rn->n >= L_MAXLENNUM)) {  /* buffer overflow? */
     rn->buff[0] = '\0';  /* invalidate result */
     return 0;  /* fail */
   }
@@ -499,8 +499,8 @@ static int read_number (lua_State *L, FILE *f) {
   ungetc(rn.c, rn.f);  /* unread look-ahead char */
   l_unlockfile(rn.f);
   rn.buff[rn.n] = '\0';  /* finish string */
-  if (lua_stringtonumber(L, rn.buff))  /* is this a valid number? */
-    return 1;  /* ok */
+  if (l_likely(lua_stringtonumber(L, rn.buff)))
+    return 1;  /* ok, it is a valid number */
   else {  /* invalid format */
    lua_pushnil(L);  /* "result" to be removed */
    return 0;  /* read fails */
@@ -676,7 +676,8 @@ static int g_write (lua_State *L, FILE *f, int arg) {
       status = status && (fwrite(s, sizeof(char), l, f) == l);
     }
   }
-  if (status) return 1;  /* file handle already on stack top */
+  if (l_likely(status))
+    return 1;  /* file handle already on stack top */
   else return luaL_fileresult(L, status, NULL);
 }
 
@@ -703,7 +704,7 @@ static int f_seek (lua_State *L) {
   luaL_argcheck(L, (lua_Integer)offset == p3, 3,
                   "not an integer in proper range");
   op = l_fseek(f, offset, mode[op]);
-  if (op)
+  if (l_unlikely(op))
     return luaL_fileresult(L, 0, NULL);  /* error */
   else {
     lua_pushinteger(L, (lua_Integer)l_ftell(f));
-- 
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