| /* Copyright (C) 1991, 92, 94, 95, 96, 97 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Library General Public License as |
| published by the Free Software Foundation; either version 2 of the |
| License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Library General Public License for more details. |
| |
| You should have received a copy of the GNU Library General Public |
| License along with the GNU C Library; see the file COPYING.LIB. If not, |
| write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <errno.h> |
| |
| struct memstream_info |
| { |
| char **buffer; |
| size_t *bufsize; |
| }; |
| |
| /* Enlarge STREAM's buffer. */ |
| static void |
| enlarge_buffer (register FILE *stream, int c) |
| { |
| struct memstream_info *info = (struct memstream_info *) stream->__cookie; |
| size_t need; |
| |
| if (stream->__put_limit != stream->__buffer) |
| /* Record how much has actually been written into the buffer. */ |
| *info->bufsize = stream->__bufp - stream->__buffer; |
| |
| if (stream->__target != -1 |
| && stream->__target > *info->bufsize) |
| /* Our target (where the buffer maps to) is always zero except when |
| the user just did a SEEK_END fseek. If he sought within the |
| buffer, we need do nothing and will zero the target below. If he |
| sought past the end of the object, grow and zero-fill the buffer |
| up to the target address. */ |
| need = stream->__target; |
| else |
| need = *info->bufsize; |
| |
| /* We always need an extra character in the buffer. Either we are |
| writing C, or we are flushing and need to write a NUL terminator. */ |
| ++need; |
| |
| if (stream->__bufsize < need) |
| { |
| /* Enlarge the buffer. */ |
| char *newbuf; |
| size_t newsize; |
| if (stream->__bufsize * 2 < need) |
| newsize = need; |
| else |
| newsize = stream->__bufsize * 2; |
| newbuf = (char *) realloc ((void *) stream->__buffer, newsize); |
| if (newbuf == NULL) |
| { |
| stream->__error = 1; |
| return; |
| } |
| *info->buffer = stream->__buffer = newbuf; |
| stream->__bufsize = newsize; |
| } |
| |
| stream->__target = stream->__offset = 0; |
| stream->__get_limit = stream->__bufp = stream->__buffer + *info->bufsize; |
| stream->__put_limit = stream->__buffer + stream->__bufsize; |
| |
| need -= stream->__bufp - stream->__buffer + 1; |
| if (need > 0) |
| { |
| /* We are extending the buffer after an fseek; zero-fill new space. */ |
| memset (stream->__bufp, '\0', need); |
| stream->__bufp += need; |
| } |
| |
| if (c != EOF) |
| *stream->__bufp++ = (unsigned char) c; |
| else |
| *stream->__bufp = '\0'; |
| } |
| |
| /* Seek function for memstreams. |
| There is no external state to munge. */ |
| |
| static int |
| seek (void *cookie, fpos_t *pos, int whence) |
| { |
| switch (whence) |
| { |
| case SEEK_SET: |
| case SEEK_CUR: |
| return 0; |
| |
| case SEEK_END: |
| /* Return the position relative to the end of the object. |
| fseek has just flushed us, so the info is consistent. */ |
| *pos += *((struct memstream_info *) cookie)->bufsize; |
| return 0; |
| |
| default: |
| __libc_fatal ("memstream::seek called with bogus WHENCE\n"); |
| return -1; |
| } |
| } |
| |
| static int |
| free_info (void *cookie) |
| { |
| #if 0 |
| struct memstream_info *info = (struct memstream_info *) cookie; |
| char *buf; |
| |
| buf = (char *) realloc ((PTR) *info->buffer, *info->bufsize); |
| if (buf != NULL) |
| *info->buffer = buf; |
| #endif |
| |
| free (cookie); |
| |
| return 0; |
| } |
| |
| /* Open a stream that writes into a malloc'd buffer that is expanded as |
| necessary. *BUFLOC and *SIZELOC are updated with the buffer's location |
| and the number of characters written on fflush or fclose. */ |
| FILE * |
| open_memstream (bufloc, sizeloc) |
| char **bufloc; |
| size_t *sizeloc; |
| { |
| FILE *stream; |
| struct memstream_info *info; |
| |
| if (bufloc == NULL || sizeloc == NULL) |
| { |
| __set_errno (EINVAL); |
| return NULL; |
| } |
| |
| stream = fmemopen ((char *) NULL, BUFSIZ, "w+"); |
| if (stream == NULL) |
| return NULL; |
| |
| info = (struct memstream_info *) malloc (sizeof (struct memstream_info)); |
| if (info == NULL) |
| { |
| int save = errno; |
| (void) fclose (stream); |
| __set_errno (save); |
| return NULL; |
| } |
| |
| stream->__room_funcs.__output = enlarge_buffer; |
| stream->__io_funcs.__seek = seek; |
| stream->__io_funcs.__close = free_info; |
| stream->__cookie = (void *) info; |
| stream->__userbuf = 1; |
| |
| info->buffer = bufloc; |
| info->bufsize = sizeloc; |
| |
| *bufloc = stream->__buffer; |
| |
| return stream; |
| } |