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authorUlrich Drepper <drepper@redhat.com>1998-11-13 13:21:56 +0000
committerUlrich Drepper <drepper@redhat.com>1998-11-13 13:21:56 +0000
commit7f2a1e3cf8077faa2c5de78f081890302a4c8362 (patch)
treefe02a7b2be425a9609d7bc3ffddc72b5efd54f1b
parent2dc9c8cd694ef6c72c631e33ff2eb2c3d412dfe8 (diff)
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Correct and improve fread_unlocked and fwrite_unlocked optimizations.
-rw-r--r--libio/bits/stdio.h39
1 files changed, 27 insertions, 12 deletions
diff --git a/libio/bits/stdio.h b/libio/bits/stdio.h
index f47749e1d6..a3e3d6fc8d 100644
--- a/libio/bits/stdio.h
+++ b/libio/bits/stdio.h
@@ -127,32 +127,47 @@ ferror_unlocked (FILE *__stream) __THROW
 #if defined __USE_MISC && defined __GNUC__ && defined __OPTIMIZE__
 /* Perform some simple optimizations.  */
 # define fread_unlocked(ptr, size, n, stream) \
-  (__extension__ ((__builtin_constant_p (size) && __builtin_constant_p (n)    \
+  (__extension__ ((((__builtin_constant_p (size)			      \
+		     && ((size) == 0 || __builtin_constant_p (n)))	      \
+		    || (__builtin_constant_p (n) && (n) == 0))		      \
 		   && (size_t) ((size) * (n)) <= 8)			      \
 		  ? ({ char *__ptr = (char *) (ptr);			      \
 		       FILE *__stream = (stream);			      \
-		       int __c;						      \
-		       size_t __cnt = (size) * (n);			      \
-		       while (__cnt-- > 0)				      \
+		       size_t __size = (size);				      \
+		       size_t __n = (n);				      \
+		       size_t __readres = __n;				      \
+		       size_t __cnt = __size * __n + 1;			      \
+		       while (--__cnt > 0)				      \
 			 {						      \
-			   __c = _IO_getc_unlocked (__stream);		      \
+			   int __c = _IO_getc_unlocked (__stream);	      \
 			   if (__c == EOF)				      \
-			     break;					      \
+			     {						      \
+			       __readres = (__size * __n - __cnt) / __size;   \
+			       break;					      \
+			     }						      \
 			   *__ptr++ = __c;				      \
 			 }						      \
-		       ((size_t) ((size) * (n)) - __cnt) / (size); })	      \
+		       __readres; })					      \
 		  : fread_unlocked (ptr, size, n, stream)))
 
 # define fwrite_unlocked(ptr, size, n, stream) \
-  (__extension__ ((__builtin_constant_p (size) && __builtin_constant_p (n)    \
+  (__extension__ ((((__builtin_constant_p (size)			      \
+		     && ((size) == 0 || __builtin_constant_p (n)))	      \
+		    || (__builtin_constant_p (n) && (n) == 0))		      \
 		   && (size_t) ((size) * (n)) <= 8)			      \
 		  ? ({ const char *__ptr = (const char *) (ptr);	      \
 		       FILE *__stream = (stream);			      \
-		       size_t __cnt = (size) * (n);			      \
-		       while (__cnt-- > 0)				      \
+		       size_t __size = (size);				      \
+		       size_t __n = (n);				      \
+		       size_t __writeres = __n;				      \
+		       size_t __cnt = __size * __n + 1;			      \
+		       while (--__cnt > 0)				      \
 			 if (_IO_putc_unlocked (*__ptr++, __stream) == EOF)   \
-			   break;					      \
-		       ((size_t) ((size) * (n)) - __cnt) / (size); })	      \
+			   {						      \
+			     __writeres = (__size * __n - __cnt) / __size;    \
+			     break;					      \
+			   }						      \
+		       __writeres; })					      \
 		  : fwrite_unlocked (ptr, size, n, stream)))
 #endif