gas/input-file.c

   1 /* input_file.c - Deal with Input Files -
   2    Copyright (C) 1987, 90, 91, 92, 93, 94, 95, 98, 99, 2000
   3    Free Software Foundation, Inc.
   4
   5    This file is part of GAS, the GNU Assembler.
   6
   7    GAS is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2, or (at your option)
  10    any later version.
  11
  12    GAS is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GAS; see the file COPYING.  If not, write to the Free
  19    Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20    02111-1307, USA.  */
  21
  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
  29 #include <stdio.h>
  30 #include <string.h>
  31
  32 #include "as.h"
  33 #include "input-file.h"
  34
  35 static int input_file_get PARAMS ((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    */
  40 int preprocess = 0;
  41
  42 /*
  43  * This code opens a file, then delivers BUFFER_SIZE character
  44  * chunks of the file on demand.
  45  * BUFFER_SIZE is supposed to be a number chosen for speed.
  46  * The caller only asks once what BUFFER_SIZE is, and asks before
  47  * the nature of the input files (if any) is known.
  48  */
  49
  50 #define BUFFER_SIZE (32 * 1024)
  51
  52 /*
  53  * We use static data: the data area is not sharable.
  54  */
  55
  56 static FILE *f_in;
  57 static char *file_name;
  58
  59 /* Struct for saving the state of this module for file includes.  */
  60 struct saved_file {
  61   FILE *f_in;
  62   char *file_name;
  63   int preprocess;
  64   char *app_save;
  65 };
  66 \f
  67 /* These hooks accomodate most operating systems.  */
  68
  69 void
  70 input_file_begin ()
  71 {
  72   f_in = (FILE *) 0;
  73 }
  74
  75 void
  76 input_file_end ()
  77 {
  78 }
  79
  80 /* Return BUFFER_SIZE.  */
  81 unsigned int
  82 input_file_buffer_size ()
  83 {
  84   return (BUFFER_SIZE);
  85 }
  86
  87 int
  88 input_file_is_open ()
  89 {
  90   return f_in != (FILE *) 0;
  91 }
  92
  93 /* Push the state of our input, returning a pointer to saved info that
  94    can be restored with input_file_pop ().  */
  95 char *
  96 input_file_push ()
  97 {
  98   register struct saved_file *saved;
  99
 100   saved = (struct saved_file *) xmalloc (sizeof *saved);
 101
 102   saved->f_in = f_in;
 103   saved->file_name = file_name;
 104   saved->preprocess = preprocess;
 105   if (preprocess)
 106     saved->app_save = app_push ();
 107
 108   input_file_begin ();          /* Initialize for new file */
 109
 110   return (char *) saved;
 111 }
 112
 113 void
 114 input_file_pop (arg)
 115      char *arg;
 116 {
 117   register struct saved_file *saved = (struct saved_file *) arg;
 118
 119   input_file_end ();            /* Close out old file */
 120
 121   f_in = saved->f_in;
 122   file_name = saved->file_name;
 123   preprocess = saved->preprocess;
 124   if (preprocess)
 125     app_pop (saved->app_save);
 126
 127   free (arg);
 128 }
 129 \f
 130 void
 131 input_file_open (filename, pre)
 132      char *filename;            /* "" means use stdin. Must not be 0.  */
 133      int pre;
 134 {
 135   int c;
 136   char buf[80];
 137
 138   preprocess = pre;
 139
 140   assert (filename != 0);       /* Filename may not be NULL.  */
 141   if (filename[0])
 142     {                           /* We have a file name. Suck it and see.  */
 143       f_in = fopen (filename, "r");
 144       file_name = filename;
 145     }
 146   else
 147     {                           /* use stdin for the input file.  */
 148       f_in = stdin;
 149       file_name = _("{standard input}");        /* For error messages.  */
 150     }
 151   if (f_in == (FILE *) 0)
 152     {
 153       as_bad (_("Can't open %s for reading."), file_name);
 154       as_perror ("%s", file_name);
 155       return;
 156     }
 157
 158   c = getc (f_in);
 159   if (c == '#')
 160     {                           /* Begins with comment, may not want to preprocess */
 161       c = getc (f_in);
 162       if (c == 'N')
 163         {
 164           fgets (buf, 80, f_in);
 165           if (!strcmp (buf, "O_APP\n"))
 166             preprocess = 0;
 167           if (!strchr (buf, '\n'))
 168             ungetc ('#', f_in); /* It was longer */
 169           else
 170             ungetc ('\n', f_in);
 171         }
 172       else if (c == '\n')
 173         ungetc ('\n', f_in);
 174       else
 175         ungetc ('#', f_in);
 176     }
 177   else
 178     ungetc (c, f_in);
 179 }
 180
 181 /* Close input file.  */
 182 void
 183 input_file_close ()
 184 {
 185   if (f_in != NULL)
 186     {
 187       fclose (f_in);
 188     }                           /* don't close a null file pointer */
 189   f_in = 0;
 190 }
 191
 192 /* This function is passed to do_scrub_chars.  */
 193
 194 static int
 195 input_file_get (buf, buflen)
 196      char *buf;
 197      int buflen;
 198 {
 199   int size;
 200
 201   size = fread (buf, sizeof (char), buflen, f_in);
 202   if (size < 0)
 203     {
 204       as_perror (_("Can't read from %s"), file_name);
 205       size = 0;
 206     }
 207   return size;
 208 }
 209
 210 /* Read a buffer from the input file.  */
 211
 212 char *
 213 input_file_give_next_buffer (where)
 214      char *where;               /* Where to place 1st character of new buffer.  */
 215 {
 216   char *return_value;           /* -> Last char of what we read, + 1.  */
 217   register int size;
 218
 219   if (f_in == (FILE *) 0)
 220     return 0;
 221   /*
 222    * fflush (stdin); could be done here if you want to synchronise
 223    * stdin and stdout, for the case where our input file is stdin.
 224    * Since the assembler shouldn't do any output to stdout, we
 225    * don't bother to synch output and input.
 226    */
 227   if (preprocess)
 228     size = do_scrub_chars (input_file_get, where, BUFFER_SIZE);
 229   else
 230     size = fread (where, sizeof (char), BUFFER_SIZE, f_in);
 231   if (size < 0)
 232     {
 233       as_perror (_("Can't read from %s"), file_name);
 234       size = 0;
 235     }
 236   if (size)
 237     return_value = where + size;
 238   else
 239     {
 240       if (fclose (f_in))
 241         as_perror (_("Can't close %s"), file_name);
 242       f_in = (FILE *) 0;
 243       return_value = 0;
 244     }
 245   return (return_value);
 246 }