* 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.
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>
#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;
- char *p;
- int r;
- size_t total;
+ size_t 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;
+ 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, ret;
+
+ 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);
+ }
+ }
+ /*
+ * 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;
}
}
- (void)memcpy((void *)p, (void *)fp->_p, resid);
- fp->_r -= resid;
- fp->_p += resid;
- FUNLOCKFILE(fp);
return (count);
}
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