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stdio/FreeBSD/fread.c Libc-320 Libc-1353.100.2
--- Libc/Libc-320/stdio/FreeBSD/fread.c
+++ Libc/Libc-1353.100.2/stdio/FreeBSD/fread.c
@@ -13,10 +13,6 @@
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *	This product includes software developed by the University of
- *	California, Berkeley and its contributors.
  * 4. Neither the name of the University nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
@@ -38,7 +34,7 @@
 static char sccsid[] = "@(#)fread.c	8.2 (Berkeley) 12/11/93";
 #endif /* LIBC_SCCS and not lint */
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: src/lib/libc/stdio/fread.c,v 1.12 2002/10/12 16:13:37 mike Exp $");
+__FBSDID("$FreeBSD: src/lib/libc/stdio/fread.c,v 1.16 2009/07/12 13:09:43 ed Exp $");
 
 #include "namespace.h"
 #include <stdio.h>
@@ -47,45 +43,124 @@
 #include "local.h"
 #include "libc_private.h"
 
+/*
+ * MT-safe version
+ */
+
 size_t
-fread(buf, size, count, fp)
-	void * __restrict buf;
-	size_t size, count;
-	FILE * __restrict fp;
+fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp)
 {
-	size_t resid;
+	size_t ret;
+
+	FLOCKFILE(fp);
+	ret = __fread(buf, size, count, fp);
+	FUNLOCKFILE(fp);
+	return (ret);
+}
+
+/*
+ * The maximum amount to read to avoid integer overflow.  INT_MAX is odd,
+ * so it make sense to make it even.  We subtract (BUFSIZ - 1) to get a
+ * whole number of BUFSIZ chunks.
+ */
+#define MAXREAD	(INT_MAX - (BUFSIZ - 1))
+
+/* __fread0: int sized, with size = 1 */
+static inline int
+__fread0(void * __restrict buf, int count, FILE * __restrict fp)
+{
+	int resid;
 	char *p;
-	int r;
-	size_t total;
+	int r, ret;
 
-	/*
-	 * The ANSI standard requires a return value of 0 for a count
-	 * or a size of 0.  Peculiarily, it imposes no such requirements
-	 * on fwrite; it only requires fread to be broken.
-	 */
-	if ((resid = count * size) == 0)
-		return (0);
-	FLOCKFILE(fp);
-	ORIENT(fp, -1);
-	if (fp->_r < 0)
-		fp->_r = 0;
-	total = resid;
+	resid = count;
 	p = buf;
+	/* first deal with anything left in buffer, plus any ungetc buffers */
 	while (resid > (r = fp->_r)) {
 		(void)memcpy((void *)p, (void *)fp->_p, (size_t)r);
 		fp->_p += r;
 		/* fp->_r = 0 ... done in __srefill */
 		p += r;
 		resid -= r;
-		if (__srefill(fp)) {
+		if ((ret = __srefill0(fp)) > 0)
+			break;
+		else if (ret) {
 			/* no more input: return partial result */
-			FUNLOCKFILE(fp);
-			return ((total - resid) / size);
+			return (count - resid);
 		}
 	}
-	(void)memcpy((void *)p, (void *)fp->_p, resid);
-	fp->_r -= resid;
-	fp->_p += resid;
-	FUNLOCKFILE(fp);
+	/*
+	 * 5980080: don't use optimization if __SMBF not set (meaning setvbuf
+	 * was called, and the buffer belongs to the user).
+	 * 6180417: but for unbuffered (__SMBF is not set), so specifically
+	 * test for it.
+	 */
+	if ((fp->_flags & (__SMBF | __SNBF)) && resid > fp->_bf._size) {
+		struct __sbuf save;
+		size_t n;
+
+		save = fp->_bf;
+		fp->_bf._base = (unsigned char *)p;
+		fp->_bf._size = resid;
+		while (fp->_bf._size > 0) {
+			if ((ret = __srefill1(fp)) != 0) {
+				/* no more input: return partial result */
+				resid = fp->_bf._size;
+				fp->_bf = save;
+				fp->_p = fp->_bf._base;
+				/* fp->_r = 0;  already set in __srefill1 */
+				return (count - resid);
+			}
+			fp->_bf._base += fp->_r;
+			fp->_bf._size -= fp->_r;
+		}
+		fp->_bf = save;
+		n = fp->_bf._size * ((resid - 1) / fp->_bf._size);
+		r = resid - n;
+		(void)memcpy((void *)fp->_bf._base, (void *)(p + n), (size_t)r);
+		fp->_p = fp->_bf._base + r;
+		fp->_r = 0;
+	} else {
+		while (resid > (r = fp->_r)) {
+			(void)memcpy((void *)p, (void *)fp->_p, (size_t)r);
+			fp->_p += r;
+			/* fp->_r = 0 ... done in __srefill */
+			p += r;
+			resid -= r;
+			if (__srefill1(fp)) {
+				/* no more input: return partial result */
+				return (count - resid);
+			}
+		}
+		(void)memcpy((void *)p, (void *)fp->_p, resid);
+		fp->_r -= resid;
+		fp->_p += resid;
+	}
 	return (count);
 }
+
+size_t
+__fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp)
+{
+	size_t resid;
+	int r, ret;
+	size_t total;
+
+	/*
+	 * ANSI and SUSv2 require a return value of 0 if size or count are 0.
+	 */
+	if ((resid = count * size) == 0)
+		return (0);
+	ORIENT(fp, -1);
+	if (fp->_r < 0)
+		fp->_r = 0;
+
+	for (total = resid; resid > 0; buf += r, resid -= r) {
+		r = resid > INT_MAX ? MAXREAD : (int)resid;
+		if ((ret = __fread0(buf, r, fp)) != r) {
+			count = (total - resid + ret) / size;
+			break;
+		}
+	}
+	return (count);
+}