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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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