bfd/
[binutils.git] / gas / input-file.c
blob709c972c9af029d027595bf0b6f944e5a04ec6d0
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, 2007, 2009
4 Free Software Foundation, Inc.
6 This file is part of GAS, the GNU Assembler.
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 3, or (at your option)
11 any later version.
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.
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. */
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! */
28 #include "as.h"
29 #include "input-file.h"
30 #include "safe-ctype.h"
32 static int input_file_get (char *, int);
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. */
36 int preprocess = 0;
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. */
44 #define BUFFER_SIZE (32 * 1024)
46 /* We use static data: the data area is not sharable. */
48 static FILE *f_in;
49 static char *file_name;
51 /* Struct for saving the state of this module for file includes. */
52 struct saved_file
54 FILE * f_in;
55 char * file_name;
56 int preprocess;
57 char * app_save;
60 /* These hooks accommodate most operating systems. */
62 void
63 input_file_begin (void)
65 f_in = (FILE *) 0;
68 void
69 input_file_end (void)
73 /* Return BUFFER_SIZE. */
74 unsigned int
75 input_file_buffer_size (void)
77 return (BUFFER_SIZE);
80 /* Push the state of our input, returning a pointer to saved info that
81 can be restored with input_file_pop (). */
83 char *
84 input_file_push (void)
86 register struct saved_file *saved;
88 saved = (struct saved_file *) xmalloc (sizeof *saved);
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 ();
96 /* Initialize for new file. */
97 input_file_begin ();
99 return (char *) saved;
102 void
103 input_file_pop (char *arg)
105 register struct saved_file *saved = (struct saved_file *) arg;
107 input_file_end (); /* Close out old file. */
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);
115 free (arg);
118 void
119 input_file_open (char *filename, /* "" means use stdin. Must not be 0. */
120 int pre)
122 int c;
123 char buf[80];
125 preprocess = pre;
127 gas_assert (filename != 0); /* Filename may not be NULL. */
128 if (filename[0])
130 f_in = fopen (filename, FOPEN_RT);
131 file_name = filename;
133 else
135 /* Use stdin for the input file. */
136 f_in = stdin;
137 /* For error messages. */
138 file_name = _("{standard input}");
141 if (f_in == NULL)
143 as_bad (_("can't open %s for reading: %s"),
144 file_name, xstrerror (errno));
145 return;
148 c = getc (f_in);
150 if (ferror (f_in))
152 as_bad (_("can't read from %s: %s"),
153 file_name, xstrerror (errno));
155 fclose (f_in);
156 f_in = NULL;
157 return;
160 /* Check for an empty input file. */
161 if (feof (f_in))
163 fclose (f_in);
164 f_in = NULL;
165 return;
167 gas_assert (c != EOF);
169 if (c == '#')
171 /* Begins with comment, may not want to preprocess. */
172 c = getc (f_in);
173 if (c == 'N')
175 if (fgets (buf, sizeof (buf), f_in)
176 && !strncmp (buf, "O_APP", 5) && ISSPACE (buf[5]))
177 preprocess = 0;
178 if (!strchr (buf, '\n'))
179 ungetc ('#', f_in); /* It was longer. */
180 else
181 ungetc ('\n', f_in);
183 else if (c == 'A')
185 if (fgets (buf, sizeof (buf), f_in)
186 && !strncmp (buf, "PP", 2) && ISSPACE (buf[2]))
187 preprocess = 1;
188 if (!strchr (buf, '\n'))
189 ungetc ('#', f_in);
190 else
191 ungetc ('\n', f_in);
193 else if (c == '\n')
194 ungetc ('\n', f_in);
195 else
196 ungetc ('#', f_in);
198 else
199 ungetc (c, f_in);
202 /* Close input file. */
204 void
205 input_file_close (void)
207 /* Don't close a null file pointer. */
208 if (f_in != NULL)
209 fclose (f_in);
211 f_in = 0;
214 /* This function is passed to do_scrub_chars. */
216 static int
217 input_file_get (char *buf, int buflen)
219 int size;
221 if (feof (f_in))
222 return 0;
224 size = fread (buf, sizeof (char), buflen, f_in);
225 if (size < 0)
227 as_bad (_("can't read from %s: %s"), file_name, xstrerror (errno));
228 size = 0;
230 return size;
233 /* Read a buffer from the input file. */
235 char *
236 input_file_give_next_buffer (char *where /* Where to place 1st character of new buffer. */)
238 char *return_value; /* -> Last char of what we read, + 1. */
239 int size;
241 if (f_in == (FILE *) 0)
242 return 0;
243 /* fflush (stdin); could be done here if you want to synchronise
244 stdin and stdout, for the case where our input file is stdin.
245 Since the assembler shouldn't do any output to stdout, we
246 don't bother to synch output and input. */
247 if (preprocess)
248 size = do_scrub_chars (input_file_get, where, BUFFER_SIZE);
249 else
251 if (feof (f_in))
252 size = 0;
253 else
254 size = fread (where, sizeof (char), BUFFER_SIZE, f_in);
257 if (size < 0)
259 as_bad (_("can't read from %s: %s"), file_name, xstrerror (errno));
260 size = 0;
262 if (size)
263 return_value = where + size;
264 else
266 if (fclose (f_in))
267 as_warn (_("can't close %s: %s"), file_name, xstrerror (errno));
269 f_in = (FILE *) 0;
270 return_value = 0;
273 return return_value;