| #include "stdio_impl.h" |
| |
| struct cookie { |
| char **bufp; |
| size_t *sizep; |
| size_t pos; |
| char *buf; |
| size_t len; |
| size_t space; |
| }; |
| |
| static off_t ms_seek(FILE *f, off_t off, int whence) |
| { |
| ssize_t base; |
| struct cookie *c = f->cookie; |
| if (whence>2U) { |
| fail: |
| errno = EINVAL; |
| return -1; |
| } |
| base = (size_t [3]){0, c->pos, c->len}[whence]; |
| if (off < -base || off > SSIZE_MAX-base) goto fail; |
| return c->pos = base+off; |
| } |
| |
| static size_t ms_write(FILE *f, const unsigned char *buf, size_t len) |
| { |
| struct cookie *c = f->cookie; |
| size_t len2 = f->wpos - f->wbase; |
| char *newbuf; |
| if (len2) { |
| f->wpos = f->wbase; |
| if (ms_write(f, f->wbase, len2) < len2) return 0; |
| } |
| if (len + c->pos >= c->space) { |
| len2 = 2*c->space+1 | c->pos+len+1; |
| newbuf = realloc(c->buf, len2); |
| if (!newbuf) return 0; |
| *c->bufp = c->buf = newbuf; |
| memset(c->buf + c->space, 0, len2 - c->space); |
| c->space = len2; |
| } |
| memcpy(c->buf+c->pos, buf, len); |
| c->pos += len; |
| if (c->pos >= c->len) c->len = c->pos; |
| *c->sizep = c->pos; |
| return len; |
| } |
| |
| static int ms_close(FILE *f) |
| { |
| return 0; |
| } |
| |
| FILE *open_memstream(char **bufp, size_t *sizep) |
| { |
| FILE *f; |
| struct cookie *c; |
| if (!(f=malloc(sizeof *f + sizeof *c + BUFSIZ))) return 0; |
| memset(f, 0, sizeof *f + sizeof *c); |
| f->cookie = c = (void *)(f+1); |
| |
| c->bufp = bufp; |
| c->sizep = sizep; |
| c->pos = c->len = c->space = 0; |
| c->buf = 0; |
| |
| f->flags = F_NORD; |
| f->fd = -1; |
| f->buf = (void *)(c+1); |
| f->buf_size = BUFSIZ; |
| f->lbf = EOF; |
| f->write = ms_write; |
| f->seek = ms_seek; |
| f->close = ms_close; |
| |
| if (!libc.threaded) { |
| f->lock = -1; |
| f->next = libc.ofl_head; |
| if (libc.ofl_head) libc.ofl_head->prev = f; |
| libc.ofl_head = f; |
| } |
| |
| return f; |
| } |