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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
- typedef struct {
- size_t pos;
- size_t len;
- size_t eof;
- int dynbuf;
- unsigned char *buf;
- FILE *fp;
- } __fmo_cookie;
- #define COOKIE ((__fmo_cookie *) cookie)
- static ssize_t fmo_read(register void *cookie, char *buf, size_t bufsize)
- {
- size_t count = COOKIE->len - COOKIE->pos;
- /* Note: 0 < bufsize < SSIZE_MAX because of _stdio_READ. */
- if (!count) { /* EOF! */
- return 0;
- }
- if (bufsize > count) {
- bufsize = count;
- }
- memcpy(buf, COOKIE->buf + COOKIE->pos, bufsize);
- COOKIE->pos += bufsize;
- return bufsize;
- }
- static ssize_t fmo_write(register void *cookie, const char *buf, size_t bufsize)
- {
- size_t count;
- /* Note: bufsize < SSIZE_MAX because of _stdio_WRITE. */
- /* If appending, need to seek to end of file!!!! */
- if (COOKIE->fp->__modeflags & __FLAG_APPEND) {
- COOKIE->pos = COOKIE->eof;
- }
- count = COOKIE->len - COOKIE->pos;
- if (bufsize > count) {
- bufsize = count;
- if (count == 0) { /* We're at the end of the buffer... */
- __set_errno(EFBIG);
- return -1;
- }
- }
- memcpy(COOKIE->buf + COOKIE->pos, buf, bufsize);
- COOKIE->pos += bufsize;
- if (COOKIE->pos > COOKIE->eof) {
- COOKIE->eof = COOKIE->pos;
- if (bufsize < count) { /* New eof and still room in buffer? */
- *(COOKIE->buf + COOKIE->pos) = 0;
- }
- }
- return bufsize;
- }
- /* glibc doesn't allow seeking, but it has in-buffer seeks... we don't. */
- static int fmo_seek(register void *cookie, __offmax_t *pos, int whence)
- {
- __offmax_t p = *pos;
- /* 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 > eof, or offset overflow... */
- if (((uintmax_t) p) > COOKIE->eof) {
- return -1;
- }
- COOKIE->pos = *pos = p;
- return 0;
- }
- static int fmo_close(register void *cookie)
- {
- if (COOKIE->dynbuf) {
- free(COOKIE->buf);
- }
- free(cookie);
- return 0;
- }
- #undef COOKIE
- static const cookie_io_functions_t _fmo_io_funcs = {
- fmo_read, fmo_write, fmo_seek, fmo_close
- };
- /* TODO: If we have buffers enabled, it might be worthwile to add a pointer
- * to the FILE in the cookie and have read, write, and seek operate directly
- * on the buffer itself (ie replace the FILE buffer with the cookie buffer
- * and update FILE bufstart, etc. whenever we seek). */
- FILE *fmemopen(void *s, size_t len, const char *modes)
- {
- FILE *fp;
- register __fmo_cookie *cookie;
- size_t i;
- if ((cookie = malloc(sizeof(__fmo_cookie))) != NULL) {
- cookie->len = len;
- cookie->eof = cookie->pos = 0; /* pos and eof adjusted below. */
- cookie->dynbuf = 0;
- if (((cookie->buf = s) == NULL) && (len > 0)) {
- if ((cookie->buf = malloc(len)) == NULL) {
- goto EXIT_cookie;
- }
- cookie->dynbuf = 1;
- *cookie->buf = 0; /* If we're appending, treat as empty file. */
- }
- #ifndef __BCC__
- fp = fopencookie(cookie, modes, _fmo_io_funcs);
- #else
- fp = fopencookie(cookie, modes, &_fmo_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) {
- cookie->fp = fp;
- if (fp->__modeflags & __FLAG_READONLY) {
- cookie->eof = len;
- }
- if ((fp->__modeflags & __FLAG_APPEND) && (len > 0)) {
- for (i = 0 ; i < len ; i++) {
- if (cookie->buf[i] == 0) {
- break;
- }
- }
- cookie->eof = cookie->pos = i; /* Adjust eof and pos. */
- }
- __STDIO_STREAM_VALIDATE(fp);
- return fp;
- }
- }
- if (!s) {
- free(cookie->buf);
- }
- EXIT_cookie:
- free(cookie);
- return NULL;
- }
- #endif
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