59 lines
1.3 KiB
C
59 lines
1.3 KiB
C
#if !defined(lint) && defined(SCCSIDS)
|
|
static char sccsid[] = "@(#)fread.c 1.1 94/10/31 SMI"; /* from S5R2 3.11 */
|
|
#endif
|
|
|
|
/*LINTLIBRARY*/
|
|
/*
|
|
* This version reads directly from the buffer rather than looping on getc.
|
|
* Ptr args aren't checked for NULL because the program would be a
|
|
* catastrophic mess anyway. Better to abort than just to return NULL.
|
|
*/
|
|
#include <stdio.h>
|
|
#include "stdiom.h"
|
|
#include <errno.h>
|
|
|
|
#define MIN(x, y) (x < y ? x : y)
|
|
|
|
extern int _filbuf();
|
|
extern _bufsync();
|
|
extern char *memcpy();
|
|
|
|
int
|
|
fread(ptr, size, count, iop)
|
|
char *ptr;
|
|
int size, count;
|
|
register FILE *iop;
|
|
{
|
|
register unsigned int nleft;
|
|
register int n;
|
|
|
|
#ifdef POSIX
|
|
if ( !(iop->_flag & (_IOREAD|_IORW)) ) {
|
|
iop->_flag |= _IOERR;
|
|
errno = EBADF;
|
|
return (NULL);
|
|
}
|
|
#endif POSIX
|
|
if (size <= 0 || count <= 0) return 0;
|
|
nleft = count * size;
|
|
|
|
/* Put characters in the buffer */
|
|
/* note that the meaning of n when just starting this loop is
|
|
irrelevant. It is defined in the loop */
|
|
for ( ; ; ) {
|
|
if (iop->_cnt <= 0) { /* empty buffer */
|
|
if (_filbuf(iop) == EOF)
|
|
return (count - (nleft + size - 1)/size);
|
|
iop->_ptr--;
|
|
iop->_cnt++;
|
|
}
|
|
n = MIN(nleft, iop->_cnt);
|
|
ptr = memcpy(ptr, (char *) iop->_ptr, n) + n;
|
|
iop->_cnt -= n;
|
|
iop->_ptr += n;
|
|
_BUFSYNC(iop);
|
|
if ((nleft -= n) == 0)
|
|
return (count);
|
|
}
|
|
}
|