clean up allocation/setup logic for fmemopen

rather than manually performing pointer arithmetic to carve multiple
objects out of one allocation, use a containing struct that
encompasses them all.
This commit is contained in:
Rich Felker 2018-04-18 14:57:10 -04:00
parent 4245a233c1
commit 0b043c7b70
1 changed files with 31 additions and 21 deletions

View File

@ -9,6 +9,12 @@ struct cookie {
int mode;
};
struct mem_FILE {
FILE f;
struct cookie c;
unsigned char buf[UNGET+BUFSIZ], buf2[];
};
static off_t mseek(FILE *f, off_t off, int whence)
{
ssize_t base;
@ -72,8 +78,7 @@ static int mclose(FILE *m)
FILE *fmemopen(void *restrict buf, size_t size, const char *restrict mode)
{
FILE *f;
struct cookie *c;
struct mem_FILE *f;
int plus = !!strchr(mode, '+');
if (!size || !strchr("rwa", *mode)) {
@ -86,29 +91,34 @@ FILE *fmemopen(void *restrict buf, size_t size, const char *restrict mode)
return 0;
}
f = calloc(sizeof *f + sizeof *c + UNGET + BUFSIZ + (buf?0:size), 1);
f = malloc(sizeof *f + (buf?0:size));
if (!f) return 0;
f->cookie = c = (void *)(f+1);
f->fd = -1;
f->lbf = EOF;
f->buf = (unsigned char *)(c+1) + UNGET;
f->buf_size = BUFSIZ;
if (!buf) buf = f->buf + BUFSIZ;
memset(&f->f, 0, sizeof f->f);
f->f.cookie = &f->c;
f->f.fd = -1;
f->f.lbf = EOF;
f->f.buf = f->buf + UNGET;
f->f.buf_size = sizeof f->buf - UNGET;
if (!buf) {
buf = f->buf2;;
memset(buf, 0, size);
}
c->buf = buf;
c->size = size;
c->mode = *mode;
memset(&f->c, 0, sizeof f->c);
f->c.buf = buf;
f->c.size = size;
f->c.mode = *mode;
if (!plus) f->flags = (*mode == 'r') ? F_NOWR : F_NORD;
if (*mode == 'r') c->len = size;
else if (*mode == 'a') c->len = c->pos = strnlen(buf, size);
if (!plus) f->f.flags = (*mode == 'r') ? F_NOWR : F_NORD;
if (*mode == 'r') f->c.len = size;
else if (*mode == 'a') f->c.len = f->c.pos = strnlen(buf, size);
f->read = mread;
f->write = mwrite;
f->seek = mseek;
f->close = mclose;
f->f.read = mread;
f->f.write = mwrite;
f->f.seek = mseek;
f->f.close = mclose;
if (!libc.threaded) f->lock = -1;
if (!libc.threaded) f->f.lock = -1;
return __ofl_add(f);
return __ofl_add(&f->f);
}