mdw@git.distorted.org.uk Git - mLib/blob - struct/dstr-putf.c

   1 /* -*-c-*-
   2  *
   3  * `printf'-style formatting for dynamic strings
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of the mLib utilities library.
  11  *
  12  * mLib is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * mLib is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with mLib; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include "config.h"
  31
  32 #include <ctype.h>
  33 #include <math.h>
  34 #include <stdarg.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 #ifdef HAVE_FLOAT_H
  40 #  include <float.h>
  41 #endif
  42
  43 #include "dstr.h"
  44
  45 /*----- Tunable constants -------------------------------------------------*/
  46
  47 /*
  48  * For each format specifier, at least @DSTR_PUTFSTEP@ bytes are ensured
  49  * before writing the formatted result.
  50  */
  51
  52 #define DSTR_PUTFSTEP 64                /* Buffer size for @putf@ */
  53
  54 /*----- Main code ---------------------------------------------------------*/
  55
  56 /* --- @dstr_vputf@ --- *
  57  *
  58  * Arguments:   @dstr *d@ = pointer to a dynamic string block
  59  *              @const char *p@ = pointer to @printf@-style format string
  60  *              @va_list *ap@ = argument handle
  61  *
  62  * Returns:     The number of characters written to the string.
  63  *
  64  * Use:         As for @dstr_putf@, but may be used as a back-end to user-
  65  *              supplied functions with @printf@-style interfaces.
  66  */
  67
  68 int dstr_vputf(dstr *d, const char *p, va_list *ap)
  69 {
  70   const char *q = p;
  71   size_t n = d->len;
  72   size_t sz;
  73   dstr dd = DSTR_INIT;
  74
  75   while (*p) {
  76     unsigned f;
  77     int wd, prec;
  78
  79 #define f_short 1u
  80 #define f_long 2u
  81 #define f_Long 4u
  82 #define f_wd 8u
  83 #define f_prec 16u
  84
  85     /* --- Most stuff gets passed on through --- */
  86
  87     if (*p != '%') {
  88       p++;
  89       continue;
  90     }
  91
  92     /* --- Dump out what's between @q@ and @p@ --- */
  93
  94     DPUTM(d, q, p - q);
  95     p++;
  96
  97     /* --- Sort out the various silly flags and things --- */
  98
  99     DPUTC(&dd, '%');
 100     f = 0;
 101     sz = DSTR_PUTFSTEP;
 102
 103     for (;;) {
 104       switch (*p) {
 105
 106         /* --- Various simple flags --- */
 107
 108         case '+':
 109         case '-':
 110         case '#':
 111         case '0':
 112           goto putch;
 113         case 'h':
 114           f |= f_short;
 115           goto putch;
 116         case 'l':
 117           f |= f_long;
 118           goto putch;
 119         case 'L':
 120           f |= f_Long;
 121           goto putch;
 122         case 0:
 123           goto finished;
 124
 125         /* --- Field widths and precision specifiers --- */
 126
 127         {
 128           int *ip;
 129
 130         case '.':
 131           DPUTC(&dd, '.');
 132           ip = &prec;
 133           f |= f_prec;
 134           p++;
 135           goto getnum;
 136         case '*':
 137           ip = &wd;
 138           f |= f_wd;
 139           goto getnum;
 140         default:
 141           if (isdigit((unsigned char)*p)) {
 142             f |= f_wd;
 143             ip = &wd;
 144             goto getnum;
 145           }
 146           DPUTC(d, *p);
 147           goto formatted;
 148         getnum:
 149           *ip = 0;
 150           if (*p == '*') {
 151             *ip = va_arg(*ap, int);
 152             DENSURE(&dd, DSTR_PUTFSTEP);
 153             dd.len += sprintf(dd.buf + dd.len, "%i", *ip);
 154             p++;
 155           } else {
 156             *ip = *p - '0';
 157             DPUTC(&dd, *p);
 158             p++;
 159             while (isdigit((unsigned char)*p)) {
 160               DPUTC(&dd, *p);
 161               *ip = 10 * *ip + *p++ - '0';
 162             }
 163           }
 164           break;
 165         }
 166
 167         /* --- Output formatting --- */
 168
 169         case 'd': case 'i': case 'x': case 'X': case 'o': case 'u':
 170           DPUTC(&dd, *p);
 171           DPUTZ(&dd);
 172           if ((f & f_prec) && prec + 16 > sz)
 173             sz = prec + 16;
 174           if ((f & f_wd) && wd + 1> sz)
 175             sz = wd + 1;
 176           DENSURE(d, sz);
 177           if (f & f_long)
 178             d->len += sprintf(d->buf + d->len, dd.buf,
 179                               va_arg(*ap, unsigned long));
 180           else
 181             d->len += sprintf(d->buf + d->len, dd.buf,
 182                               va_arg(*ap, unsigned int));
 183           goto formatted;
 184
 185         case 'e': case 'E': case 'f': case 'F': case 'g': case 'G':
 186 #ifdef HAVE_FLOAT_H
 187           DPUTC(&dd, *p);
 188           DPUTZ(&dd);
 189           if (*p == 'f') {
 190             size_t mx = (f & f_Long ? LDBL_MAX_10_EXP : DBL_MAX_10_EXP) + 16;
 191             if (mx > sz)
 192               sz = mx;
 193           }
 194           if (!(f & f_prec))
 195             prec = 6;
 196           else
 197             sz += prec + 16;
 198           if ((f & f_wd) && wd + 1 > sz)
 199             sz = wd + 1;
 200           DENSURE(d, sz);
 201           if (f & f_Long)
 202             d->len += sprintf(d->buf + d->len, dd.buf,
 203                               va_arg(*ap, long double));
 204           else
 205             d->len += sprintf(d->buf + d->len, dd.buf,
 206                               va_arg(*ap, double));
 207           goto formatted;
 208 #else
 209           DPUTS(d, "<no float support>");
 210 #endif
 211
 212         case 'c':
 213           DPUTC(&dd, *p);
 214           DPUTZ(&dd);
 215           if ((f & f_wd) && wd + 1> sz)
 216             sz = wd + 1;
 217           DENSURE(d, sz);
 218           d->len += sprintf(d->buf + d->len, dd.buf,
 219                             va_arg(*ap, unsigned));
 220           goto formatted;
 221
 222         case 's': {
 223           const char *s = va_arg(*ap, const char *);
 224           sz = strlen(s);
 225           DPUTC(&dd, *p);
 226           DPUTZ(&dd);
 227           if (f & f_prec)
 228             sz = prec;
 229           if ((f & f_wd) && wd > sz)
 230             sz = wd;
 231           DENSURE(d, sz + 1);
 232           d->len += sprintf(d->buf + d->len, dd.buf, s);
 233           goto formatted;
 234         }
 235
 236         case 'p':
 237           DPUTC(&dd, *p);
 238           DPUTZ(&dd);
 239           if ((f & f_prec) && prec + 16 > sz)
 240             sz = prec + 16;
 241           if ((f & f_wd) && wd + 1> sz)
 242             sz = wd + 1;
 243           DENSURE(d, sz);
 244           d->len += sprintf(d->buf + d->len, dd.buf,
 245                             va_arg(*ap, const void *));
 246           goto formatted;
 247
 248         case 'n':
 249           if (f & f_long)
 250             *va_arg(*ap, long *) = (long)(d->len - n);
 251           else if (f & f_short)
 252             *va_arg(*ap, short *) = (short)(d->len - n);
 253           else
 254             *va_arg(*ap, int *) = (int)(d->len - n);
 255           goto formatted;
 256
 257         /* --- Other random stuff --- */
 258
 259         putch:
 260           DPUTC(&dd, *p);
 261           p++;
 262           break;
 263       }
 264     }
 265
 266   formatted:
 267     DRESET(&dd);
 268     q = ++p;
 269
 270 #undef f_short
 271 #undef f_long
 272 #undef f_Long
 273 #undef f_wd
 274 #undef f_prec
 275   }
 276
 277   DPUTM(d, q, p - q);
 278 finished:
 279   DPUTZ(d);
 280   DDESTROY(&dd);
 281   return (d->len - n);
 282 }
 283
 284 /* --- @dstr_putf@ --- *
 285  *
 286  * Arguments:   @dstr *d@ = pointer to a dynamic string block
 287  *              @const char *p@ = pointer to @printf@-style format string
 288  *              @...@ = argument handle
 289  *
 290  * Returns:     The number of characters written to the string.
 291  *
 292  * Use:         Writes a piece of text to a dynamic string, doing @printf@-
 293  *              style substitutions as it goes.  Intended to be robust if
 294  *              faced with malicious arguments, but not if the format string
 295  *              itself is malicious.
 296  */
 297
 298 int dstr_putf(dstr *d, const char *p, ...)
 299 {
 300   int n;
 301   va_list ap;
 302   va_start(ap, p);
 303   n = dstr_vputf(d, p, &ap);
 304   va_end(ap);
 305   return (n);
 306 }
 307
 308 /*----- That's all, folks -------------------------------------------------*/