diff options
Diffstat (limited to 'lib/libc/stdio/open_memstream.c')
| -rw-r--r-- | lib/libc/stdio/open_memstream.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/lib/libc/stdio/open_memstream.c b/lib/libc/stdio/open_memstream.c new file mode 100644 index 0000000..aa50822 --- /dev/null +++ b/lib/libc/stdio/open_memstream.c @@ -0,0 +1,209 @@ +/*- + * Copyright (c) 2013 Advanced Computing Technologies LLC + * Written by: John H. Baldwin <jhb@FreeBSD.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "namespace.h" +#include <assert.h> +#include <errno.h> +#include <limits.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <wchar.h> +#include "un-namespace.h" + +/* XXX: There is no FPOS_MAX. This assumes fpos_t is an off_t. */ +#define FPOS_MAX OFF_MAX + +struct memstream { + char **bufp; + size_t *sizep; + ssize_t len; + fpos_t offset; +}; + +static int +memstream_grow(struct memstream *ms, fpos_t newoff) +{ + char *buf; + ssize_t newsize; + + if (newoff < 0 || newoff >= SSIZE_MAX) + newsize = SSIZE_MAX - 1; + else + newsize = newoff; + if (newsize > ms->len) { + buf = realloc(*ms->bufp, newsize + 1); + if (buf != NULL) { +#ifdef DEBUG + fprintf(stderr, "MS: %p growing from %zd to %zd\n", + ms, ms->len, newsize); +#endif + memset(buf + ms->len + 1, 0, newsize - ms->len); + *ms->bufp = buf; + ms->len = newsize; + return (1); + } + return (0); + } + return (1); +} + +static void +memstream_update(struct memstream *ms) +{ + + assert(ms->len >= 0 && ms->offset >= 0); + *ms->sizep = ms->len < ms->offset ? ms->len : ms->offset; +} + +static int +memstream_write(void *cookie, const char *buf, int len) +{ + struct memstream *ms; + ssize_t tocopy; + + ms = cookie; + if (!memstream_grow(ms, ms->offset + len)) + return (-1); + tocopy = ms->len - ms->offset; + if (len < tocopy) + tocopy = len; + memcpy(*ms->bufp + ms->offset, buf, tocopy); + ms->offset += tocopy; + memstream_update(ms); +#ifdef DEBUG + fprintf(stderr, "MS: write(%p, %d) = %zd\n", ms, len, tocopy); +#endif + return (tocopy); +} + +static fpos_t +memstream_seek(void *cookie, fpos_t pos, int whence) +{ + struct memstream *ms; +#ifdef DEBUG + fpos_t old; +#endif + + ms = cookie; +#ifdef DEBUG + old = ms->offset; +#endif + switch (whence) { + case SEEK_SET: + /* _fseeko() checks for negative offsets. */ + assert(pos >= 0); + ms->offset = pos; + break; + case SEEK_CUR: + /* This is only called by _ftello(). */ + assert(pos == 0); + break; + case SEEK_END: + if (pos < 0) { + if (pos + ms->len < 0) { +#ifdef DEBUG + fprintf(stderr, + "MS: bad SEEK_END: pos %jd, len %zd\n", + (intmax_t)pos, ms->len); +#endif + errno = EINVAL; + return (-1); + } + } else { + if (FPOS_MAX - ms->len < pos) { +#ifdef DEBUG + fprintf(stderr, + "MS: bad SEEK_END: pos %jd, len %zd\n", + (intmax_t)pos, ms->len); +#endif + errno = EOVERFLOW; + return (-1); + } + } + ms->offset = ms->len + pos; + break; + } + memstream_update(ms); +#ifdef DEBUG + fprintf(stderr, "MS: seek(%p, %jd, %d) %jd -> %jd\n", ms, (intmax_t)pos, + whence, (intmax_t)old, (intmax_t)ms->offset); +#endif + return (ms->offset); +} + +static int +memstream_close(void *cookie) +{ + + free(cookie); + return (0); +} + +FILE * +open_memstream(char **bufp, size_t *sizep) +{ + struct memstream *ms; + int save_errno; + FILE *fp; + + if (bufp == NULL || sizep == NULL) { + errno = EINVAL; + return (NULL); + } + *bufp = calloc(1, 1); + if (*bufp == NULL) + return (NULL); + ms = malloc(sizeof(*ms)); + if (ms == NULL) { + save_errno = errno; + free(*bufp); + *bufp = NULL; + errno = save_errno; + return (NULL); + } + ms->bufp = bufp; + ms->sizep = sizep; + ms->len = 0; + ms->offset = 0; + memstream_update(ms); + fp = funopen(ms, NULL, memstream_write, memstream_seek, + memstream_close); + if (fp == NULL) { + save_errno = errno; + free(ms); + free(*bufp); + *bufp = NULL; + errno = save_errno; + return (NULL); + } + fwide(fp, -1); + return (fp); +} |
