aboutsummaryrefslogtreecommitdiff
path: root/gas/input-file.c
blob: aae20a8ca6e255839a308f846dbb5f87b34e7d04 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
/* input_file.c - Deal with Input Files -
   Copyright (C) 1987-2021 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 3, 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, 51 Franklin Street - Fifth Floor, Boston, MA
   02110-1301, 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 "as.h"
#include "input-file.h"
#include "safe-ctype.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 const char *file_name;

/* Struct for saving the state of this module for file includes.  */
struct saved_file
  {
    FILE * f_in;
    const char * file_name;
    int    preprocess;
    char * app_save;
  };

/* These hooks accommodate most operating systems.  */

void
input_file_begin (void)
{
  f_in = (FILE *) 0;
}

void
input_file_end (void)
{
}

/* Return BUFFER_SIZE.  */
size_t
input_file_buffer_size (void)
{
  return (BUFFER_SIZE);
}

/* Push the state of our input, returning a pointer to saved info that
   can be restored with input_file_pop ().  */

char *
input_file_push (void)
{
  struct saved_file *saved;

  saved = XNEW (struct saved_file);

  saved->f_in = f_in;
  saved->file_name = file_name;
  saved->preprocess = preprocess;
  if (preprocess)
    saved->app_save = app_push ();

  /* Initialize for new file.  */
  input_file_begin ();

  return (char *) saved;
}

void
input_file_pop (char *arg)
{
  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);
}

/* Open the specified file, "" means stdin.  Filename must not be null.  */

void
input_file_open (const char *filename,
		 int pre)
{
  int c;
  char buf[80];

  preprocess = pre;

  gas_assert (filename != 0);	/* Filename may not be NULL.  */
  if (filename[0])
    {
      f_in = fopen (filename, FOPEN_RT);
      file_name = filename;
    }
  else
    {
      /* Use stdin for the input file.  */
      f_in = stdin;
      /* For error messages.  */
      file_name = _("{standard input}");
    }

  if (f_in == NULL)
    {
      as_bad (_("can't open %s for reading: %s"),
	      file_name, xstrerror (errno));
      return;
    }

  c = getc (f_in);

  if (ferror (f_in))
    {
      as_bad (_("can't read from %s: %s"),
	      file_name, xstrerror (errno));

      fclose (f_in);
      f_in = NULL;
      return;
    }

  /* Check for an empty input file.  */
  if (feof (f_in))
    {
      fclose (f_in);
      f_in = NULL;
      return;
    }
  gas_assert (c != EOF);

  if (c == '#')
    {
      /* Begins with comment, may not want to preprocess.  */
      c = getc (f_in);
      if (c == 'N')
	{
	  if (fgets (buf, sizeof (buf), f_in)
	      && !strncmp (buf, "O_APP", 5) && ISSPACE (buf[5]))
	    preprocess = 0;
	  if (!strchr (buf, '\n'))
	    ungetc ('#', f_in);	/* It was longer.  */
	  else
	    ungetc ('\n', f_in);
	}
      else if (c == 'A')
	{
	  if (fgets (buf, sizeof (buf), f_in)
	      && !strncmp (buf, "PP", 2) && ISSPACE (buf[2]))
	    preprocess = 1;
	  if (!strchr (buf, '\n'))
	    ungetc ('#', f_in);
	  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 (void)
{
  /* Don't close a null file pointer.  */
  if (f_in != NULL)
    fclose (f_in);

  f_in = 0;
}

/* This function is passed to do_scrub_chars.  */

static size_t
input_file_get (char *buf, size_t buflen)
{
  size_t size;

  if (feof (f_in))
    return 0;

  size = fread (buf, sizeof (char), buflen, f_in);
  if (ferror (f_in))
    as_bad (_("can't read from %s: %s"), file_name, xstrerror (errno));
  return size;
}

/* Read a buffer from the input file.  */

char *
input_file_give_next_buffer (char *where /* Where to place 1st character of new buffer.  */)
{
  char *return_value;		/* -> Last char of what we read, + 1.  */
  size_t 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)
    size = do_scrub_chars (input_file_get, where, BUFFER_SIZE);
  else
    size = input_file_get (where, BUFFER_SIZE);

  if (size)
    return_value = where + size;
  else
    {
      if (fclose (f_in))
	as_warn (_("can't close %s: %s"), file_name, xstrerror (errno));

      f_in = (FILE *) 0;
      return_value = 0;
    }

  return return_value;
}