| /* $OpenBSD: open_memstream.c,v 1.6 2015/08/31 02:53:57 guenther Exp $ */ |
| |
| /* |
| * Copyright (c) 2011 Martin Pieuchot <mpi@openbsd.org> |
| * |
| * Permission to use, copy, modify, and distribute this software for any |
| * purpose with or without fee is hereby granted, provided that the above |
| * copyright notice and this permission notice appear in all copies. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
| * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
| * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| */ |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <stdint.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include "local.h" |
| |
| #define MINIMUM(a, b) (((a) < (b)) ? (a) : (b)) |
| |
| struct state { |
| char *string; /* actual stream */ |
| char **pbuf; /* point to the stream */ |
| size_t *psize; /* point to min(pos, len) */ |
| size_t pos; /* current position */ |
| size_t size; /* number of allocated char */ |
| size_t len; /* length of the data */ |
| }; |
| |
| static int |
| memstream_write(void *v, const char *b, int l) |
| { |
| struct state *st = v; |
| char *p; |
| size_t i, end; |
| |
| end = (st->pos + l); |
| |
| if (end >= st->size) { |
| /* 1.6 is (very) close to the golden ratio. */ |
| size_t sz = st->size * 8 / 5; |
| |
| if (sz < end + 1) |
| sz = end + 1; |
| p = realloc(st->string, sz); |
| if (!p) |
| return (-1); |
| bzero(p + st->size, sz - st->size); |
| *st->pbuf = st->string = p; |
| st->size = sz; |
| } |
| |
| for (i = 0; i < l; i++) |
| st->string[st->pos + i] = b[i]; |
| st->pos += l; |
| |
| if (st->pos > st->len) { |
| st->len = st->pos; |
| st->string[st->len] = '\0'; |
| } |
| |
| *st->psize = st->pos; |
| |
| return (i); |
| } |
| |
| static fpos_t |
| memstream_seek(void *v, fpos_t off, int whence) |
| { |
| struct state *st = v; |
| ssize_t base = 0; |
| |
| switch (whence) { |
| case SEEK_SET: |
| break; |
| case SEEK_CUR: |
| base = st->pos; |
| break; |
| case SEEK_END: |
| base = st->len; |
| break; |
| } |
| |
| if (off > SIZE_MAX - base || off < -base) { |
| errno = EOVERFLOW; |
| return (-1); |
| } |
| |
| st->pos = base + off; |
| *st->psize = MINIMUM(st->pos, st->len); |
| |
| return (st->pos); |
| } |
| |
| static int |
| memstream_close(void *v) |
| { |
| struct state *st = v; |
| |
| free(st); |
| |
| return (0); |
| } |
| |
| FILE * |
| open_memstream(char **pbuf, size_t *psize) |
| { |
| struct state *st; |
| FILE *fp; |
| |
| if (pbuf == NULL || psize == NULL) { |
| errno = EINVAL; |
| return (NULL); |
| } |
| |
| if ((st = malloc(sizeof(*st))) == NULL) |
| return (NULL); |
| |
| if ((fp = __sfp()) == NULL) { |
| free(st); |
| return (NULL); |
| } |
| |
| st->size = BUFSIZ; |
| if ((st->string = calloc(1, st->size)) == NULL) { |
| free(st); |
| fp->_flags = 0; |
| return (NULL); |
| } |
| |
| *st->string = '\0'; |
| st->pos = 0; |
| st->len = 0; |
| st->pbuf = pbuf; |
| st->psize = psize; |
| |
| *pbuf = st->string; |
| *psize = st->len; |
| |
| fp->_flags = __SWR; |
| fp->_file = -1; |
| fp->_cookie = st; |
| fp->_read = NULL; |
| fp->_write = memstream_write; |
| fp->_seek = memstream_seek; |
| fp->_close = memstream_close; |
| _SET_ORIENTATION(fp, -1); |
| |
| return (fp); |
| } |
| DEF_WEAK(open_memstream); |