diff options
Diffstat (limited to 'stdio/obstream.c')
| -rw-r--r-- | stdio/obstream.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/stdio/obstream.c b/stdio/obstream.c new file mode 100644 index 0000000000..32f7220b59 --- /dev/null +++ b/stdio/obstream.c @@ -0,0 +1,187 @@ +/* Copyright (C) 1992 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., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +#include <ansidecl.h> +#include <stdio.h> +#include <obstack.h> +#include <stdarg.h> +#include <string.h> + +/* Output-room function for obstack streams. */ + +static void +DEFUN(grow, (stream, c), FILE *stream AND int c) +{ + struct obstack *const obstack = (struct obstack *) stream->__cookie; + + /* Move the end of the object back to include only the portion + of the buffer which the user has already written into. */ + obstack_blank_fast (obstack, - (stream->__put_limit - stream->__bufp)); + + if (stream->__target > obstack_object_size (obstack)) + { + /* 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 object + up to the target address. */ + + obstack_blank (obstack, + stream->__target - obstack_object_size (obstack)); + /* fseek has just flushed us, so the put limit points + to the end of the written data. */ + bzero (stream->__put_limit, + stream->__target - stream->__bufsize); + } + + if (c != EOF) + obstack_1grow (obstack, (unsigned char) c); + + /* The stream buffer always maps exactly to the object on the top + of the obstack. The start of the buffer is the start of the object. + The put limit points just past the end of the object. On fflush, the + obstack is sync'd so the end of the object points just past the last + character written to the stream. */ + + stream->__target = stream->__offset = 0; + stream->__buffer = obstack_base (obstack); + stream->__bufsize = obstack_room (obstack); + stream->__bufp = obstack_next_free (obstack); + stream->__get_limit = stream->__bufp; + + if (c == EOF) + /* This is fflush. Make the stream buffer, the object, + and the characters actually written all match. */ + stream->__put_limit = stream->__get_limit; + else + { + /* Extend the buffer (and the object) to include + the rest of the obstack chunk (which is unitialized). + Data past bufp is undefined. */ + stream->__put_limit = stream->__buffer + stream->__bufsize; + obstack_blank_fast (obstack, stream->__put_limit - stream->__bufp); + } +} + +/* Seek function for obstack streams. + There is no external state to munge. */ + +static int +DEFUN(seek, (cookie, pos, whence), + PTR cookie AND fpos_t *pos AND 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 obstack is consistent. */ + *pos += obstack_object_size ((struct obstack *) cookie); + return 0; + + default: + __libc_fatal ("obstream::seek called with bogus WHENCE\n"); + return -1; + } +} + +/* Input room function for obstack streams. + Only what has been written to the stream can be read back. */ + +static int +DEFUN(input, (stream), FILE *stream) +{ + /* Re-sync with the obstack, growing the object if necessary. */ + grow (stream, EOF); + + if (stream->__bufp < stream->__get_limit) + return (unsigned char) *stream->__bufp++; + + stream->__eof = 1; + return EOF; +} + +/* Initialize STREAM to talk to OBSTACK. */ + +static void +DEFUN(init_obstream, (stream, obstack), + FILE *stream AND struct obstack *obstack) +{ + stream->__mode.__write = 1; + stream->__mode.__read = 1; + + /* Input can read only what has been written. */ + stream->__room_funcs.__input = input; + + /* Do nothing for close. */ + stream->__io_funcs.__close = NULL; + + /* When the buffer is full, grow the obstack. */ + stream->__room_funcs.__output = grow; + + /* Seek within the object, and extend it. */ + stream->__io_funcs.__seek = seek; + stream->__target = stream->__offset = 0; + + stream->__seen = 1; + + /* Don't deallocate that buffer! */ + stream->__userbuf = 1; + + /* We don't have to initialize the buffer. + The first read attempt will call grow, which will do all the work. */ +} + +FILE * +open_obstack_stream (obstack) + struct obstack *obstack; +{ + register FILE *stream; + + stream = __newstream (); + if (stream == NULL) + return NULL; + + init_obstream (stream, obstack); + return stream; +} + +int +DEFUN(obstack_vprintf, (obstack, format, args), + struct obstack *obstack AND const char *format AND va_list args) +{ + FILE f; + bzero (&f, sizeof (f)); + init_obstream (&f, obstack); + return vfprintf (&f, format, args); +} + +int +DEFUN(obstack_printf, (obstack, format), + struct obstack *obstack AND const char *format DOTS) +{ + int result; + va_list ap; + va_start (ap, format); + result = obstack_vprintf (obstack, format, ap); + va_end (ap); + return result; +} |