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#define _GNU_SOURCE
#include "stdio_impl.h"
#include <stdlib.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
struct fcookie {
void *cookie;
cookie_io_functions_t iofuncs;
};
struct cookie_FILE {
FILE f;
struct fcookie fc;
unsigned char buf[UNGET+BUFSIZ];
};
static size_t cookieread(FILE *f, unsigned char *buf, size_t len)
{
struct fcookie *fc = f->cookie;
ssize_t ret = -1;
size_t remain = len, readlen = 0;
size_t len2 = len - !!f->buf_size;
if (!fc->iofuncs.read) goto bail;
if (len2) {
ret = fc->iofuncs.read(fc->cookie, (char *) buf, len2);
if (ret <= 0) goto bail;
readlen += ret;
remain -= ret;
}
if (!f->buf_size || remain > !!f->buf_size) return readlen;
f->rpos = f->buf;
ret = fc->iofuncs.read(fc->cookie, (char *) f->rpos, f->buf_size);
if (ret <= 0) goto bail;
f->rend = f->rpos + ret;
buf[readlen++] = *f->rpos++;
return readlen;
bail:
f->flags |= ret == 0 ? F_EOF : F_ERR;
f->rpos = f->rend = f->buf;
return readlen;
}
static size_t cookiewrite(FILE *f, const unsigned char *buf, size_t len)
{
struct fcookie *fc = f->cookie;
ssize_t ret;
size_t len2 = f->wpos - f->wbase;
if (!fc->iofuncs.write) return len;
if (len2) {
f->wpos = f->wbase;
if (cookiewrite(f, f->wpos, len2) < len2) return 0;
}
ret = fc->iofuncs.write(fc->cookie, (const char *) buf, len);
if (ret < 0) {
f->wpos = f->wbase = f->wend = 0;
f->flags |= F_ERR;
return 0;
}
return ret;
}
static off_t cookieseek(FILE *f, off_t off, int whence)
{
struct fcookie *fc = f->cookie;
int res;
if (whence > 2U) {
errno = EINVAL;
return -1;
}
if (!fc->iofuncs.seek) {
errno = ENOTSUP;
return -1;
}
res = fc->iofuncs.seek(fc->cookie, &off, whence);
if (res < 0)
return res;
return off;
}
static int cookieclose(FILE *f)
{
struct fcookie *fc = f->cookie;
if (fc->iofuncs.close) return fc->iofuncs.close(fc->cookie);
return 0;
}
FILE *fopencookie(void *cookie, const char *mode, cookie_io_functions_t iofuncs)
{
struct cookie_FILE *f;
/* Check for valid initial mode character */
if (!strchr("rwa", *mode)) {
errno = EINVAL;
return 0;
}
/* Allocate FILE+fcookie+buffer or fail */
if (!(f=malloc(sizeof *f))) return 0;
/* Zero-fill only the struct, not the buffer */
memset(&f->f, 0, sizeof f->f);
/* Impose mode restrictions */
if (!strchr(mode, '+')) f->f.flags = (*mode == 'r') ? F_NOWR : F_NORD;
/* Set up our fcookie */
f->fc.cookie = cookie;
f->fc.iofuncs.read = iofuncs.read;
f->fc.iofuncs.write = iofuncs.write;
f->fc.iofuncs.seek = iofuncs.seek;
f->fc.iofuncs.close = iofuncs.close;
f->f.fd = -1;
f->f.cookie = &f->fc;
f->f.buf = f->buf + UNGET;
f->f.buf_size = BUFSIZ;
f->f.lbf = EOF;
/* Initialize op ptrs. No problem if some are unneeded. */
f->f.read = cookieread;
f->f.write = cookiewrite;
f->f.seek = cookieseek;
f->f.close = cookieclose;
/* Add new FILE to open file list */
return __ofl_add(&f->f);
}
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