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/* input_file.c - Deal with Input Files -
Copyright (C) 1987, 1990, 1991, 1992 Free Software Foundation, Inc.
This file is part of GAS, the GNU Assembler.
GAS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GAS 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with GAS; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
/*
* Confines all details of reading source bytes to this module.
* All O/S specific crocks should live here.
* What we lose in "efficiency" we gain in modularity.
* Note we don't need to #include the "as.h" file. No common coupling!
*/
#include <stdio.h>
#include <assert.h>
#include <string.h>
#include "as.h"
#include "input-file.h"
/* This variable is non-zero if the file currently being read should be
preprocessed by app. It is zero if the file can be read straight in.
*/
int preprocess = 0;
/*
* This code opens a file, then delivers BUFFER_SIZE character
* chunks of the file on demand.
* BUFFER_SIZE is supposed to be a number chosen for speed.
* The caller only asks once what BUFFER_SIZE is, and asks before
* the nature of the input files (if any) is known.
*/
#define BUFFER_SIZE (32 * 1024)
/*
* We use static data: the data area is not sharable.
*/
static FILE *f_in;
static char *file_name;
/* Struct for saving the state of this module for file includes. */
struct saved_file
{
FILE *f_in;
char *file_name;
int preprocess;
char *app_save;
};
/* These hooks accomodate most operating systems. */
void
input_file_begin ()
{
f_in = (FILE *) 0;
}
void
input_file_end ()
{
}
/* Return BUFFER_SIZE. */
unsigned int
input_file_buffer_size ()
{
return (BUFFER_SIZE);
}
int
input_file_is_open ()
{
return f_in != (FILE *) 0;
}
/* Push the state of our input, returning a pointer to saved info that
can be restored with input_file_pop (). */
char *
input_file_push ()
{
register struct saved_file *saved;
saved = (struct saved_file *) xmalloc (sizeof *saved);
saved->f_in = f_in;
saved->file_name = file_name;
saved->preprocess = preprocess;
if (preprocess)
saved->app_save = app_push ();
input_file_begin (); /* Initialize for new file */
return (char *) saved;
}
void
input_file_pop (arg)
char *arg;
{
register struct saved_file *saved = (struct saved_file *) arg;
input_file_end (); /* Close out old file */
f_in = saved->f_in;
file_name = saved->file_name;
preprocess = saved->preprocess;
if (preprocess)
app_pop (saved->app_save);
free (arg);
}
void
input_file_open (filename, pre)
char *filename; /* "" means use stdin. Must not be 0. */
int pre;
{
int c;
char buf[80];
preprocess = pre;
assert (filename != 0); /* Filename may not be NULL. */
if (filename[0])
{ /* We have a file name. Suck it and see. */
f_in = fopen (filename, FOPEN_RT);
file_name = filename;
}
else
{ /* use stdin for the input file. */
f_in = stdin;
file_name = "{standard input}"; /* For error messages. */
}
if (f_in == (FILE *) 0)
{
as_perror ("Can't open %s for reading", file_name);
return;
}
c = getc (f_in);
if (c == '#')
{ /* Begins with comment, may not want to preprocess */
c = getc (f_in);
if (c == 'N')
{
fgets (buf, 80, f_in);
if (!strcmp (buf, "O_APP\n"))
preprocess = 0;
if (!strchr (buf, '\n'))
ungetc ('#', f_in); /* It was longer */
else
ungetc ('\n', f_in);
}
else if (c == '\n')
ungetc ('\n', f_in);
else
ungetc ('#', f_in);
}
else
ungetc (c, f_in);
}
/* Close input file. */
void
input_file_close ()
{
if (f_in != NULL)
{
fclose (f_in);
} /* don't close a null file pointer */
f_in = 0;
} /* input_file_close() */
char *
input_file_give_next_buffer (where)
char *where; /* Where to place 1st character of new buffer. */
{
char *return_value; /* -> Last char of what we read, + 1. */
register int size;
if (f_in == (FILE *) 0)
return 0;
/*
* fflush (stdin); could be done here if you want to synchronise
* stdin and stdout, for the case where our input file is stdin.
* Since the assembler shouldn't do any output to stdout, we
* don't bother to synch output and input.
*/
if (preprocess)
{
char *p;
int n;
int ch;
extern FILE *scrub_file;
scrub_file = f_in;
for (p = where, n = BUFFER_SIZE; n; --n)
{
ch = do_scrub_next_char (scrub_from_file, scrub_to_file);
if (ch == EOF)
break;
*p++ = ch;
}
size = BUFFER_SIZE - n;
}
else
size = fread (where, sizeof (char), BUFFER_SIZE, f_in);
if (size < 0)
{
as_perror ("Can't read from %s", file_name);
size = 0;
}
if (size)
return_value = where + size;
else
{
if (fclose (f_in))
as_perror ("Can't close %s", file_name);
f_in = (FILE *) 0;
return_value = 0;
}
return (return_value);
}
/* end of input-file.c */
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