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/* Copyright (C) 2004 Manuel Novoa III <mjn3@codepoet.org>
*
* GNU Library General Public License (LGPL) version 2 or later.
*
* Dedicated to Toni. See uClibc/DEDICATION.mjn3 for details.
*/
#include <features.h>
#ifdef __USE_GNU
#include "_stdio.h"
#ifndef __UCLIBC_HAS_GLIBC_CUSTOM_STREAMS__
#error no custom streams!
#endif
#define COOKIE ((__oms_cookie *) cookie)
#define MEMSTREAM_BUFSIZ 256
typedef struct {
char *buf;
size_t len;
size_t pos;
size_t eof;
char **bufloc;
size_t *sizeloc;
} __oms_cookie;
/* Nothing to do here, as memstreams are write-only. */
/* static ssize_t oms_read(void *cookie, char *buf, size_t bufsize) */
/* { */
/* } */
static ssize_t oms_write(register void *cookie, const char *buf, size_t bufsize)
{
register char *newbuf;
size_t count;
/* Note: we already know bufsize < SSIZE_MAX... */
count = COOKIE->len - COOKIE->pos - 1;
assert(COOKIE->pos < COOKIE->len); /* Always nul-terminate! */
if (bufsize > count) {
newbuf = realloc(COOKIE->buf, COOKIE->len + bufsize - count);
if (newbuf) {
*COOKIE->bufloc = COOKIE->buf = newbuf;
COOKIE->len += (bufsize - count);
} else {
bufsize = count;
if (count == 0) {
__set_errno(EFBIG); /* TODO: check glibc errno setting... */
return -1;
}
}
}
memcpy(COOKIE->buf + COOKIE->pos, buf, bufsize);
COOKIE->pos += bufsize;
if (COOKIE->pos > COOKIE->eof) {
*COOKIE->sizeloc = COOKIE->eof = COOKIE->pos;
COOKIE->buf[COOKIE->eof] = 0; /* Need to nul-terminate. */
}
return bufsize;
}
static int oms_seek(register void *cookie, __offmax_t *pos, int whence)
{
__offmax_t p = *pos;
register char *buf;
size_t leastlen;
/* Note: fseek already checks that whence is legal, so don't check here
* unless debugging. */
assert(((unsigned int) whence) <= 2);
if (whence != SEEK_SET) {
p += (whence == SEEK_CUR) ? COOKIE->pos : /* SEEK_END */ COOKIE->eof;
}
/* Note: glibc only allows seeking in the buffer. We'll actually restrict
* to the data. */
/* Check for offset < 0, offset >= too big (need nul), or overflow... */
if (((uintmax_t) p) >= SIZE_MAX - 1) {
return -1;
}
leastlen = ((size_t) p) + 1; /* New pos + 1 for nul if necessary. */
if (leastlen >= COOKIE->len) { /* Need to grow buffer... */
buf = realloc(COOKIE->buf, leastlen);
if (buf) {
*COOKIE->bufloc = COOKIE->buf = buf;
COOKIE->len = leastlen;
memset(buf + COOKIE->eof, 0, leastlen - COOKIE->eof); /* 0-fill */
} else {
/* TODO: check glibc errno setting... */
return -1;
}
}
*pos = COOKIE->pos = --leastlen;
if (leastlen > COOKIE->eof) {
memset(COOKIE->buf + COOKIE->eof, 0, leastlen - COOKIE->eof);
*COOKIE->sizeloc = COOKIE->eof;
}
return 0;
}
static int oms_close(void *cookie)
{
free(cookie);
return 0;
}
#undef COOKIE
static const cookie_io_functions_t _oms_io_funcs = {
NULL, oms_write, oms_seek, oms_close
};
/* TODO: If we have buffers enabled, it might be worthwile to add a pointer
* to the FILE in the cookie and operate directly on the buffer itself
* (ie replace the FILE buffer with the cookie buffer and update FILE bufstart,
* etc. whenever we seek). */
FILE *open_memstream(char **bufloc, size_t *sizeloc)
{
register __oms_cookie *cookie;
register FILE *fp;
if ((cookie = malloc(sizeof(__oms_cookie))) != NULL) {
if ((cookie->buf = malloc(cookie->len = MEMSTREAM_BUFSIZ)) == NULL) {
goto EXIT_cookie;
}
*cookie->buf = 0; /* Set nul terminator for buffer. */
*(cookie->bufloc = bufloc) = cookie->buf;
*(cookie->sizeloc = sizeloc) = cookie->eof = cookie->pos = 0;
#ifndef __BCC__
fp = fopencookie(cookie, "w", _oms_io_funcs);
#else
fp = fopencookie(cookie, "w", &_oms_io_funcs);
#endif
/* Note: We don't need to worry about locking fp in the thread case
* as the only possible access would be a close or flush with
* nothing currently in the FILE's write buffer. */
if (fp != NULL) {
__STDIO_STREAM_VALIDATE(fp);
return fp;
}
free(cookie->buf);
}
EXIT_cookie:
free(cookie);
return NULL;
}
libc_hidden_def(open_memstream)
#endif
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