1/* input_file.c - Deal with Input Files -
2   Copyright 1987, 1990, 1991, 1992, 1993, 1994, 1995, 1999, 2000, 2001,
3   2002, 2003, 2005, 2006
4   Free Software Foundation, Inc.
5
6   This file is part of GAS, the GNU Assembler.
7
8   GAS is free software; you can redistribute it and/or modify
9   it under the terms of the GNU General Public License as published by
10   the Free Software Foundation; either version 2, or (at your option)
11   any later version.
12
13   GAS is distributed in the hope that it will be useful,
14   but WITHOUT ANY WARRANTY; without even the implied warranty of
15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16   GNU General Public License for more details.
17
18   You should have received a copy of the GNU General Public License
19   along with GAS; see the file COPYING.  If not, write to the Free
20   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
21   02110-1301, USA.  */
22
23/* Confines all details of reading source bytes to this module.
24   All O/S specific crocks should live here.
25   What we lose in "efficiency" we gain in modularity.
26   Note we don't need to #include the "as.h" file. No common coupling!  */
27
28#include "as.h"
29#include "input-file.h"
30#include "safe-ctype.h"
31
32static int input_file_get (char *, int);
33
34/* This variable is non-zero if the file currently being read should be
35   preprocessed by app.  It is zero if the file can be read straight in.  */
36int preprocess = 0;
37
38/* This code opens a file, then delivers BUFFER_SIZE character
39   chunks of the file on demand.
40   BUFFER_SIZE is supposed to be a number chosen for speed.
41   The caller only asks once what BUFFER_SIZE is, and asks before
42   the nature of the input files (if any) is known.  */
43
44#define BUFFER_SIZE (32 * 1024)
45
46/* We use static data: the data area is not sharable.  */
47
48static FILE *f_in;
49static char *file_name;
50
51/* Struct for saving the state of this module for file includes.  */
52struct saved_file
53  {
54    FILE * f_in;
55    char * file_name;
56    int    preprocess;
57    char * app_save;
58  };
59
60/* These hooks accommodate most operating systems.  */
61
62void
63input_file_begin (void)
64{
65  f_in = (FILE *) 0;
66}
67
68void
69input_file_end (void)
70{
71}
72
73/* Return BUFFER_SIZE.  */
74unsigned int
75input_file_buffer_size (void)
76{
77  return (BUFFER_SIZE);
78}
79
80/* Push the state of our input, returning a pointer to saved info that
81   can be restored with input_file_pop ().  */
82
83char *
84input_file_push (void)
85{
86  register struct saved_file *saved;
87
88  saved = (struct saved_file *) xmalloc (sizeof *saved);
89
90  saved->f_in = f_in;
91  saved->file_name = file_name;
92  saved->preprocess = preprocess;
93  if (preprocess)
94    saved->app_save = app_push ();
95
96  /* Initialize for new file.  */
97  input_file_begin ();
98
99  return (char *) saved;
100}
101
102void
103input_file_pop (char *arg)
104{
105  register struct saved_file *saved = (struct saved_file *) arg;
106
107  input_file_end ();		/* Close out old file.  */
108
109  f_in = saved->f_in;
110  file_name = saved->file_name;
111  preprocess = saved->preprocess;
112  if (preprocess)
113    app_pop (saved->app_save);
114
115  free (arg);
116}
117
118void
119input_file_open (char *filename, /* "" means use stdin. Must not be 0.  */
120		 int pre)
121{
122  int c;
123  char buf[80];
124
125  preprocess = pre;
126
127  assert (filename != 0);	/* Filename may not be NULL.  */
128  if (filename[0])
129    {
130      f_in = fopen (filename, FOPEN_RT);
131      file_name = filename;
132    }
133  else
134    {
135      /* Use stdin for the input file.  */
136      f_in = stdin;
137      /* For error messages.  */
138      file_name = _("{standard input}");
139    }
140
141  if (f_in == NULL)
142    {
143      as_bad (_("can't open %s for reading: %s"),
144	      file_name, xstrerror (errno));
145      return;
146    }
147
148  c = getc (f_in);
149
150  if (ferror (f_in))
151    {
152      as_bad (_("can't read from %s: %s"),
153	      file_name, xstrerror (errno));
154
155      fclose (f_in);
156      f_in = NULL;
157      return;
158    }
159
160  if (c == '#')
161    {
162      /* Begins with comment, may not want to preprocess.  */
163      c = getc (f_in);
164      if (c == 'N')
165	{
166	  if (fgets (buf, sizeof (buf), f_in)
167	      && !strncmp (buf, "O_APP", 5) && ISSPACE (buf[5]))
168	    preprocess = 0;
169	  if (!strchr (buf, '\n'))
170	    ungetc ('#', f_in);	/* It was longer.  */
171	  else
172	    ungetc ('\n', f_in);
173	}
174      else if (c == 'A')
175	{
176	  if (fgets (buf, sizeof (buf), f_in)
177	      && !strncmp (buf, "PP", 2) && ISSPACE (buf[2]))
178	    preprocess = 1;
179	  if (!strchr (buf, '\n'))
180	    ungetc ('#', f_in);
181	  else
182	    ungetc ('\n', f_in);
183	}
184      else if (c == '\n')
185	ungetc ('\n', f_in);
186      else
187	ungetc ('#', f_in);
188    }
189  else
190    ungetc (c, f_in);
191}
192
193/* Close input file.  */
194
195void
196input_file_close (void)
197{
198  /* Don't close a null file pointer.  */
199  if (f_in != NULL)
200    fclose (f_in);
201
202  f_in = 0;
203}
204
205/* This function is passed to do_scrub_chars.  */
206
207static int
208input_file_get (char *buf, int buflen)
209{
210  int size;
211
212  size = fread (buf, sizeof (char), buflen, f_in);
213  if (size < 0)
214    {
215      as_bad (_("can't read from %s: %s"), file_name, xstrerror (errno));
216      size = 0;
217    }
218  return size;
219}
220
221/* Read a buffer from the input file.  */
222
223char *
224input_file_give_next_buffer (char *where /* Where to place 1st character of new buffer.  */)
225{
226  char *return_value;		/* -> Last char of what we read, + 1.  */
227  register int size;
228
229  if (f_in == (FILE *) 0)
230    return 0;
231  /* fflush (stdin); could be done here if you want to synchronise
232     stdin and stdout, for the case where our input file is stdin.
233     Since the assembler shouldn't do any output to stdout, we
234     don't bother to synch output and input.  */
235  if (preprocess)
236    size = do_scrub_chars (input_file_get, where, BUFFER_SIZE);
237  else
238    size = fread (where, sizeof (char), BUFFER_SIZE, f_in);
239  if (size < 0)
240    {
241      as_bad (_("can't read from %s: %s"), file_name, xstrerror (errno));
242      size = 0;
243    }
244  if (size)
245    return_value = where + size;
246  else
247    {
248      if (fclose (f_in))
249	as_warn (_("can't close %s: %s"), file_name, xstrerror (errno));
250
251      f_in = (FILE *) 0;
252      return_value = 0;
253    }
254
255  return return_value;
256}
257