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#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include "stdio.h"
#define PERMS 0666
FILE _iob[OPN_MAX] = {
{0, (char *) NULL, (char *) NULL, {1, 0, 0, 1, 0, 0}, 0},
{0, (char *) NULL, (char *) NULL, {0, 1, 0, 1, 0, 0}, 1},
{0, (char *) NULL, (char *) NULL, {0, 1, 1, 0, 0, 0}, 2},
};
FILE *fopen(char *name, char *mode)
{
int fd;
FILE *fp;
if (*mode != 'r' && *mode != 'w' && *mode != 'a')
return NULL;
for (fp = _iob; fp < _iob + OPN_MAX; ++fp)
if (fp->flag.is_read == 0 && fp->flag.is_write == 0)
break;
if (fp == _iob + OPN_MAX)
return NULL;
if (*mode == 'w') {
fd = creat(name, PERMS);
} else if (*mode == 'a') {
if ((fd = open(name, O_WRONLY)) == -1)
fd = creat(name, PERMS);
lseek(fd, 0L, 2);
} else {
fd = open(name, O_RDONLY);
}
if (fd == -1)
return NULL;
fp->fd = fd;
fp->cnt = 0;
fp->base = NULL;
fp->flag.is_unbuf = 0;
fp->flag.is_buf = 1;
fp->flag.is_eof = 0;
fp->flag.is_err = 0;
if (*mode == 'r') {
fp->flag.is_read = 1;
fp->flag.is_write = 0;
} else {
fp->flag.is_write = 1;
fp->flag.is_read = 0;
}
return fp;
}
int _fillbuf(FILE *fp)
{
int bufsize;
if (fp->flag.is_read == 0 ||
fp->flag.is_err == 1 ||
fp->flag.is_eof == 1)
return EOF;
bufsize = (fp->flag.is_unbuf == 1) ? 1 : BUFSIZ;
if (fp->base == NULL)
if ((fp->base = (char *) malloc(bufsize)) == NULL)
return EOF;
fp->ptr = fp->base;
fp->cnt = read(fp->fd, fp->base, bufsize);
if (--fp->cnt < 0) {
if (fp->cnt == -1)
fp->flag.is_eof = 1;
else
fp->flag.is_err = 1;
fp->cnt = 0;
return EOF;
}
return (unsigned char) *fp->ptr++;
}
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