gas/input-file.c

   1 /* input_file.c - Deal with Input Files -
   2    Copyright 1987, 1990, 1991, 1992, 1993, 1994, 1995, 1999, 2000, 2001,
   3    2002, 2003, 2005
   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 <stdio.h>
  29 #include <string.h>
  30 #include <errno.h>
  31 #include "as.h"
  32 #include "input-file.h"
  33 #include "safe-ctype.h"
  34
  35 static int input_file_get (char *, int);
  36
  37 /* This variable is non-zero if the file currently being read should be
  38    preprocessed by app.  It is zero if the file can be read straight in.  */
  39 int preprocess = 0;
  40
  41 /* This code opens a file, then delivers BUFFER_SIZE character
  42    chunks of the file on demand.
  43    BUFFER_SIZE is supposed to be a number chosen for speed.
  44    The caller only asks once what BUFFER_SIZE is, and asks before
  45    the nature of the input files (if any) is known.  */
  46
  47 #define BUFFER_SIZE (32 * 1024)
  48
  49 /* We use static data: the data area is not sharable.  */
  50
  51 static FILE *f_in;
  52 static char *file_name;
  53
  54 /* Struct for saving the state of this module for file includes.  */
  55 struct saved_file
  56   {
  57     FILE * f_in;
  58     char * file_name;
  59     int    preprocess;
  60     char * app_save;
  61   };
  62 \f
  63 /* These hooks accommodate most operating systems.  */
  64
  65 void
  66 input_file_begin (void)
  67 {
  68   f_in = (FILE *) 0;
  69 }
  70
  71 void
  72 input_file_end (void)
  73 {
  74 }
  75
  76 /* Return BUFFER_SIZE.  */
  77 unsigned int
  78 input_file_buffer_size (void)
  79 {
  80   return (BUFFER_SIZE);
  81 }
  82
  83 /* Push the state of our input, returning a pointer to saved info that
  84    can be restored with input_file_pop ().  */
  85
  86 char *
  87 input_file_push (void)
  88 {
  89   register struct saved_file *saved;
  90
  91   saved = (struct saved_file *) xmalloc (sizeof *saved);
  92
  93   saved->f_in = f_in;
  94   saved->file_name = file_name;
  95   saved->preprocess = preprocess;
  96   if (preprocess)
  97     saved->app_save = app_push ();
  98
  99   /* Initialize for new file.  */
 100   input_file_begin ();
 101
 102   return (char *) saved;
 103 }
 104
 105 void
 106 input_file_pop (char *arg)
 107 {
 108   register struct saved_file *saved = (struct saved_file *) arg;
 109
 110   input_file_end ();            /* Close out old file.  */
 111
 112   f_in = saved->f_in;
 113   file_name = saved->file_name;
 114   preprocess = saved->preprocess;
 115   if (preprocess)
 116     app_pop (saved->app_save);
 117
 118   free (arg);
 119 }
 120 \f
 121 void
 122 input_file_open (char *filename, /* "" means use stdin. Must not be 0.  */
 123                  int pre)
 124 {
 125   int c;
 126   char buf[80];
 127
 128   preprocess = pre;
 129
 130   assert (filename != 0);       /* Filename may not be NULL.  */
 131   if (filename[0])
 132     {
 133       f_in = fopen (filename, FOPEN_RT);
 134       file_name = filename;
 135     }
 136   else
 137     {
 138       /* Use stdin for the input file.  */
 139       f_in = stdin;
 140       /* For error messages.  */
 141       file_name = _("{standard input}");
 142     }
 143
 144   if (f_in == NULL)
 145     {
 146       bfd_set_error (bfd_error_system_call);
 147       as_perror (_("Can't open %s for reading"), file_name);
 148       return;
 149     }
 150
 151   c = getc (f_in);
 152
 153   if (ferror (f_in))
 154     {
 155       bfd_set_error (bfd_error_system_call);
 156       as_perror (_("Can't open %s for reading"), file_name);
 157
 158       fclose (f_in);
 159       f_in = NULL;
 160       return;
 161     }
 162
 163   if (c == '#')
 164     {
 165       /* Begins with comment, may not want to preprocess.  */
 166       c = getc (f_in);
 167       if (c == 'N')
 168         {
 169           fgets (buf, 80, f_in);
 170           if (!strncmp (buf, "O_APP", 5) && ISSPACE (buf[5]))
 171             preprocess = 0;
 172           if (!strchr (buf, '\n'))
 173             ungetc ('#', f_in); /* It was longer.  */
 174           else
 175             ungetc ('\n', f_in);
 176         }
 177       else if (c == 'A')
 178         {
 179           fgets (buf, 80, f_in);
 180           if (!strncmp (buf, "PP", 2) && ISSPACE (buf[2]))
 181             preprocess = 1;
 182           if (!strchr (buf, '\n'))
 183             ungetc ('#', f_in);
 184           else
 185             ungetc ('\n', f_in);
 186         }
 187       else if (c == '\n')
 188         ungetc ('\n', f_in);
 189       else
 190         ungetc ('#', f_in);
 191     }
 192   else
 193     ungetc (c, f_in);
 194 }
 195
 196 /* Close input file.  */
 197
 198 void
 199 input_file_close (void)
 200 {
 201   /* Don't close a null file pointer.  */
 202   if (f_in != NULL)
 203     fclose (f_in);
 204
 205   f_in = 0;
 206 }
 207
 208 /* This function is passed to do_scrub_chars.  */
 209
 210 static int
 211 input_file_get (char *buf, int buflen)
 212 {
 213   int size;
 214
 215   size = fread (buf, sizeof (char), buflen, f_in);
 216   if (size < 0)
 217     {
 218       bfd_set_error (bfd_error_system_call);
 219       as_perror (_("Can't read from %s"), file_name);
 220       size = 0;
 221     }
 222   return size;
 223 }
 224
 225 /* Read a buffer from the input file.  */
 226
 227 char *
 228 input_file_give_next_buffer (char *where /* Where to place 1st character of new buffer.  */)
 229 {
 230   char *return_value;           /* -> Last char of what we read, + 1.  */
 231   register int size;
 232
 233   if (f_in == (FILE *) 0)
 234     return 0;
 235   /* fflush (stdin); could be done here if you want to synchronise
 236      stdin and stdout, for the case where our input file is stdin.
 237      Since the assembler shouldn't do any output to stdout, we
 238      don't bother to synch output and input.  */
 239   if (preprocess)
 240     size = do_scrub_chars (input_file_get, where, BUFFER_SIZE);
 241   else
 242     size = fread (where, sizeof (char), BUFFER_SIZE, f_in);
 243   if (size < 0)
 244     {
 245       bfd_set_error (bfd_error_system_call);
 246       as_perror (_("Can't read from %s"), file_name);
 247       size = 0;
 248     }
 249   if (size)
 250     return_value = where + size;
 251   else
 252     {
 253       if (fclose (f_in))
 254         {
 255           bfd_set_error (bfd_error_system_call);
 256           as_perror (_("Can't close %s"), file_name);
 257         }
 258       f_in = (FILE *) 0;
 259       return_value = 0;
 260     }
 261
 262   return return_value;
 263 }