1 /* input_file.c - Deal with Input Files - 2 Copyright (C) 1987-2016 Free Software Foundation, Inc. 3 4 This file is part of GAS, the GNU Assembler. 5 6 GAS is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3, or (at your option) 9 any later version. 10 11 GAS is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GAS; see the file COPYING. If not, write to the Free 18 Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA 19 02110-1301, USA. */ 20 21 /* Confines all details of reading source bytes to this module. 22 All O/S specific crocks should live here. 23 What we lose in "efficiency" we gain in modularity. 24 Note we don't need to #include the "as.h" file. No common coupling! */ 25 26 #include "as.h" 27 #include "input-file.h" 28 #include "safe-ctype.h" 29 30 /* This variable is non-zero if the file currently being read should be 31 preprocessed by app. It is zero if the file can be read straight in. */ 32 int preprocess = 0; 33 34 /* This code opens a file, then delivers BUFFER_SIZE character 35 chunks of the file on demand. 36 BUFFER_SIZE is supposed to be a number chosen for speed. 37 The caller only asks once what BUFFER_SIZE is, and asks before 38 the nature of the input files (if any) is known. */ 39 40 #define BUFFER_SIZE (32 * 1024) 41 42 /* We use static data: the data area is not sharable. */ 43 44 static FILE *f_in; 45 static const char *file_name; 46 47 /* Struct for saving the state of this module for file includes. */ 48 struct saved_file 49 { 50 FILE * f_in; 51 const char * file_name; 52 int preprocess; 53 char * app_save; 54 }; 55 56 /* These hooks accommodate most operating systems. */ 57 58 void 59 input_file_begin (void) 60 { 61 f_in = (FILE *) 0; 62 } 63 64 void 65 input_file_end (void) 66 { 67 } 68 69 /* Return BUFFER_SIZE. */ 70 size_t 71 input_file_buffer_size (void) 72 { 73 return (BUFFER_SIZE); 74 } 75 76 /* Push the state of our input, returning a pointer to saved info that 77 can be restored with input_file_pop (). */ 78 79 char * 80 input_file_push (void) 81 { 82 struct saved_file *saved; 83 84 saved = XNEW (struct saved_file); 85 86 saved->f_in = f_in; 87 saved->file_name = file_name; 88 saved->preprocess = preprocess; 89 if (preprocess) 90 saved->app_save = app_push (); 91 92 /* Initialize for new file. */ 93 input_file_begin (); 94 95 return (char *) saved; 96 } 97 98 void 99 input_file_pop (char *arg) 100 { 101 struct saved_file *saved = (struct saved_file *) arg; 102 103 input_file_end (); /* Close out old file. */ 104 105 f_in = saved->f_in; 106 file_name = saved->file_name; 107 preprocess = saved->preprocess; 108 if (preprocess) 109 app_pop (saved->app_save); 110 111 free (arg); 112 } 113 114 /* Open the specified file, "" means stdin. Filename must not be null. */ 115 116 void 117 input_file_open (const char *filename, 118 int pre) 119 { 120 int c; 121 char buf[80]; 122 123 preprocess = pre; 124 125 gas_assert (filename != 0); /* Filename may not be NULL. */ 126 if (filename[0]) 127 { 128 f_in = fopen (filename, FOPEN_RT); 129 file_name = filename; 130 } 131 else 132 { 133 /* Use stdin for the input file. */ 134 f_in = stdin; 135 /* For error messages. */ 136 file_name = _("{standard input}"); 137 } 138 139 if (f_in == NULL) 140 { 141 as_bad (_("can't open %s for reading: %s"), 142 file_name, xstrerror (errno)); 143 return; 144 } 145 146 c = getc (f_in); 147 148 if (ferror (f_in)) 149 { 150 as_bad (_("can't read from %s: %s"), 151 file_name, xstrerror (errno)); 152 153 fclose (f_in); 154 f_in = NULL; 155 return; 156 } 157 158 /* Check for an empty input file. */ 159 if (feof (f_in)) 160 { 161 fclose (f_in); 162 f_in = NULL; 163 return; 164 } 165 gas_assert (c != EOF); 166 167 if (c == '#') 168 { 169 /* Begins with comment, may not want to preprocess. */ 170 c = getc (f_in); 171 if (c == 'N') 172 { 173 if (fgets (buf, sizeof (buf), f_in) 174 && !strncmp (buf, "O_APP", 5) && ISSPACE (buf[5])) 175 preprocess = 0; 176 if (!strchr (buf, '\n')) 177 ungetc ('#', f_in); /* It was longer. */ 178 else 179 ungetc ('\n', f_in); 180 } 181 else if (c == 'A') 182 { 183 if (fgets (buf, sizeof (buf), f_in) 184 && !strncmp (buf, "PP", 2) && ISSPACE (buf[2])) 185 preprocess = 1; 186 if (!strchr (buf, '\n')) 187 ungetc ('#', f_in); 188 else 189 ungetc ('\n', f_in); 190 } 191 else if (c == '\n') 192 ungetc ('\n', f_in); 193 else 194 ungetc ('#', f_in); 195 } 196 else 197 ungetc (c, f_in); 198 } 199 200 /* Close input file. */ 201 202 void 203 input_file_close (void) 204 { 205 /* Don't close a null file pointer. */ 206 if (f_in != NULL) 207 fclose (f_in); 208 209 f_in = 0; 210 } 211 212 /* This function is passed to do_scrub_chars. */ 213 214 static size_t 215 input_file_get (char *buf, size_t buflen) 216 { 217 size_t size; 218 219 if (feof (f_in)) 220 return 0; 221 222 size = fread (buf, sizeof (char), buflen, f_in); 223 if (ferror (f_in)) 224 as_bad (_("can't read from %s: %s"), file_name, xstrerror (errno)); 225 return size; 226 } 227 228 /* Read a buffer from the input file. */ 229 230 char * 231 input_file_give_next_buffer (char *where /* Where to place 1st character of new buffer. */) 232 { 233 char *return_value; /* -> Last char of what we read, + 1. */ 234 size_t size; 235 236 if (f_in == (FILE *) 0) 237 return 0; 238 /* fflush (stdin); could be done here if you want to synchronise 239 stdin and stdout, for the case where our input file is stdin. 240 Since the assembler shouldn't do any output to stdout, we 241 don't bother to synch output and input. */ 242 if (preprocess) 243 size = do_scrub_chars (input_file_get, where, BUFFER_SIZE); 244 else 245 size = input_file_get (where, BUFFER_SIZE); 246 247 if (size) 248 return_value = where + size; 249 else 250 { 251 if (fclose (f_in)) 252 as_warn (_("can't close %s: %s"), file_name, xstrerror (errno)); 253 254 f_in = (FILE *) 0; 255 return_value = 0; 256 } 257 258 return return_value; 259 } 260