mdw@git.distorted.org.uk Git - anag/blob - util.c

   1 /* -*-c-*-
   2  *
   3  * $Id: util.c,v 1.1 2001/02/04 17:14:42 mdw Exp $
   4  *
   5  * Various useful utilities, stolen from mLib
   6  *
   7  * (c) 2001 Mark Wooding
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Anag: a simple wordgame helper.
  13  *
  14  * Anag is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * Anag is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with Anag; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: util.c,v $
  32  * Revision 1.1  2001/02/04 17:14:42  mdw
  33  * Initial checkin
  34  *
  35  */
  36
  37 /*----- Header files ------------------------------------------------------*/
  38
  39 #include "anag.h"
  40
  41 /*----- Static variables --------------------------------------------------*/
  42
  43 static const char *quis = "<unset>";
  44
  45 /*----- Error reporting ---------------------------------------------------*/
  46
  47 /* --- @ego@ --- *
  48  *
  49  * Arguments:   @const char *p@ = pointer to program name
  50  *
  51  * Returns:     ---
  52  *
  53  * Use:         Stores what the program's name is.
  54  */
  55
  56 #ifndef PATHSEP
  57 #  if defined(__riscos)
  58 #    define PATHSEP '.'
  59 #  elif defined(__unix) || defined(unix)
  60 #    define PATHSEP '/'
  61 #  else
  62 #    define PATHSEP '\\'
  63 #  endif
  64 #endif
  65
  66 void ego(const char *p)
  67 {
  68   const char *q = p;
  69   while (*q) {
  70     if (*q++ == PATHSEP)
  71       p = q;
  72   }
  73   if (*p == '-')
  74     p++;
  75   quis = p;
  76 }
  77
  78 #undef PATHSEP
  79
  80 /* --- @pquis@ --- *
  81  *
  82  * Arguments:   @FILE *fp@ = output stream to write on
  83  *              @const char *p@ = pointer to string to write
  84  *
  85  * Returns:     Zero if everything worked, EOF if not.
  86  *
  87  * Use:         Writes the string @p@ to the output stream @fp@.  Occurrences
  88  *              of the character `$' in @p@ are replaced by the program name
  89  *              as reported by @quis@.  A `$$' is replaced by a single `$'
  90  *              sign.
  91  */
  92
  93 int pquis(FILE *fp, const char *p)
  94 {
  95   size_t sz;
  96
  97   while (*p) {
  98     sz = strcspn(p, "$");
  99     if (sz) {
 100       if (fwrite(p, 1, sz, fp) < sz)
 101         return (EOF);
 102       p += sz;
 103     }
 104     if (*p == '$') {
 105       p++;
 106       if (*p == '$') {
 107         if (fputc('$', fp) == EOF)
 108           return (EOF);
 109         p++;
 110       } else {
 111         if (fputs(quis, fp) == EOF)
 112           return (EOF);
 113       }
 114     }
 115   }
 116   return (0);
 117 }
 118
 119 /* --- @die@ --- *
 120  *
 121  * Arguments:   @const char *f@ = a @printf@-style format string
 122  *              @...@ = other arguments
 123  *
 124  * Returns:     Never.
 125  *
 126  * Use:         Reports an error and exits.
 127  */
 128
 129 void die(const char *f, ...)
 130 {
 131   va_list ap;
 132   va_start(ap, f);
 133   fprintf(stderr, "%s: ", quis);
 134   vfprintf(stderr, f, ap);
 135   va_end(ap);
 136   putc('\n', stderr);
 137   exit(EXIT_FAILURE);
 138 }
 139
 140 /*----- Memory allocation -------------------------------------------------*/
 141
 142 /* --- @xmalloc@ --- *
 143  *
 144  * Arguments:   @size_t sz@ = size of block to allocate
 145  *
 146  * Returns:     Pointer to allocated block.
 147  *
 148  * Use:         Allocates memory.  If there's not enough memory, the
 149  *              program exits.
 150  */
 151
 152 void *xmalloc(size_t sz)
 153 {
 154   void *p = malloc(sz);
 155   if (!p)
 156     die("not enough memory");
 157   return (p);
 158 }
 159
 160 /* --- @xrealloc@ --- *
 161  *
 162  * Arguments:   @void *p@ = a pointer to allocated memory
 163  *              @size_t sz@ = new size of block wanted
 164  *
 165  * Returns:     Pointer to resized block.
 166  *
 167  * Use:         Resizes an allocated block.  If there's not enough memory,
 168  *              the program exits.
 169  */
 170
 171 void *xrealloc(void *p, size_t sz)
 172 {
 173   p = realloc(p, sz);
 174   if (!p)
 175     die("not enough memory");
 176   return (p);
 177 }
 178
 179 /*----- Dynamic string handling -------------------------------------------*/
 180
 181 #define DSTR_INITSZ 64
 182
 183 /* --- @dstr_destroy@ --- *
 184  *
 185  * Arguments:   @dstr *d@ = pointer to a dynamic string block
 186  *
 187  * Returns:     ---
 188  *
 189  * Use:         Reclaims the space used by a dynamic string.
 190  */
 191
 192 void dstr_destroy(dstr *d) { free(d->buf); d->len = 0; d->sz = 0; }
 193
 194 /* --- @dstr_reset@ --- *
 195  *
 196  * Arguments:   @dstr *d@ = pointer to a dynamic string block
 197  *
 198  * Returns:     ---
 199  *
 200  * Use:         Resets a string so that new data gets put at the beginning.
 201  */
 202
 203 void dstr_reset(dstr *d) { d->len = 0; }
 204
 205 /* --- @dstr_ensure@ --- *
 206  *
 207  * Arguments:   @dstr *d@ = pointer to a dynamic string block
 208  *              @size_t sz@ = amount of free space to ensure
 209  *
 210  * Returns:     ---
 211  *
 212  * Use:         Ensures that at least @sz@ bytes are available in the
 213  *              given string.
 214  */
 215
 216 void dstr_ensure(dstr *d, size_t sz)
 217 {
 218   size_t rq = d->len + sz;
 219   size_t nsz;
 220
 221   /* --- If we have enough space, just leave it --- */
 222
 223   if (rq <= d->sz)
 224     return;
 225
 226   /* --- Grow the buffer --- */
 227
 228   nsz = d->sz;
 229
 230   if (nsz == 0)
 231     nsz = (DSTR_INITSZ >> 1);
 232   do nsz <<= 1; while (nsz < rq);
 233
 234   if (d->buf)
 235     d->buf = xrealloc(d->buf, nsz);
 236   else
 237     d->buf = xmalloc(nsz);
 238   d->sz = nsz;
 239 }
 240
 241 /* --- @dstr_putline@ --- *
 242  *
 243  * Arguments:   @dstr *d@ = pointer to a dynamic string block
 244  *              @FILE *fp@ = a stream to read from
 245  *
 246  * Returns:     The number of characters read into the buffer, or @EOF@ if
 247  *              end-of-file was reached before any characters were read.
 248  *
 249  * Use:         Appends the next line from the given input stream to the
 250  *              string.  A trailing newline is not added; a trailing null
 251  *              byte is appended, as for @dstr_putz@.
 252  */
 253
 254 int dstr_putline(dstr *d, FILE *fp)
 255 {
 256   size_t left = d->sz - d->len;
 257   size_t off = d->len;
 258   int rd = 0;
 259   int ch;
 260
 261   for (;;) {
 262
 263     /* --- Read the next byte --- */
 264
 265     ch = getc(fp);
 266
 267     /* --- End-of-file when no characters read is special --- */
 268
 269     if (ch == EOF && !rd)
 270       return (EOF);
 271
 272     /* --- Make sure there's some buffer space --- */
 273
 274     if (!left) {
 275       d->len = off;
 276       dstr_ensure(d, 1);
 277       left = d->sz - off;
 278     }
 279
 280     /* --- End-of-file or newline ends the loop --- */
 281
 282     if (ch == EOF || ch == '\n') {
 283       d->buf[off] = 0;
 284       d->len = off;
 285       return rd;
 286     }
 287
 288     /* --- Append the character and continue --- */
 289
 290     d->buf[off++] = ch;
 291     left--; rd++;
 292   }
 293 }
 294
 295 /*----- That's all, folks -------------------------------------------------*/