dos/printf.c

   1 /*
   2  * Oh, it's a waste of space, but oh-so-yummy for debugging.  It's just
   3  * initialization code anyway, so it doesn't take up space when we're
   4  * actually running.  This version of printf() does not include 64-bit
   5  * support.  "Live with it."
   6  *
   7  * Most of this code was shamelessly snarfed from the Linux kernel, then
   8  * modified.  It's therefore GPL.
   9  *
  10  * printf() isn't actually needed to build syslinux.com, but during
  11  * debugging it's handy.
  12  */
  13
  14 #include <stdarg.h>
  15 #include <stdio.h>
  16 #include "mystuff.h"
  17
  18 static int strnlen(const char *s, int maxlen)
  19 {
  20     const char *es = s;
  21     while (*es && maxlen) {
  22         es++;
  23         maxlen--;
  24     }
  25
  26     return (es - s);
  27 }
  28
  29 #define ZEROPAD 1               /* pad with zero */
  30 #define SIGN    2               /* unsigned/signed long */
  31 #define PLUS    4               /* show plus */
  32 #define SPACE   8               /* space if plus */
  33 #define LEFT    16              /* left justified */
  34 #define SPECIAL 32              /* 0x */
  35 #define LARGE   64              /* use 'ABCDEF' instead of 'abcdef' */
  36
  37 #define do_div(n,base) ({ \
  38 int __res; \
  39 __res = ((unsigned long) n) % (unsigned) base; \
  40 n = ((unsigned long) n) / (unsigned) base; \
  41 __res; })
  42
  43 static char *number(char *str, long num, int base, int size, int precision,
  44                     int type)
  45 {
  46     char c, sign, tmp[66];
  47     const char *digits = "0123456789abcdefghijklmnopqrstuvwxyz";
  48     int i;
  49
  50     if (type & LARGE)
  51         digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  52     if (type & LEFT)
  53         type &= ~ZEROPAD;
  54     if (base < 2 || base > 36)
  55         return 0;
  56     c = (type & ZEROPAD) ? '0' : ' ';
  57     sign = 0;
  58     if (type & SIGN) {
  59         if (num < 0) {
  60             sign = '-';
  61             num = -num;
  62             size--;
  63         } else if (type & PLUS) {
  64             sign = '+';
  65             size--;
  66         } else if (type & SPACE) {
  67             sign = ' ';
  68             size--;
  69         }
  70     }
  71     if (type & SPECIAL) {
  72         if (base == 16)
  73             size -= 2;
  74         else if (base == 8)
  75             size--;
  76     }
  77     i = 0;
  78     if (num == 0)
  79         tmp[i++] = '0';
  80     else
  81         while (num != 0)
  82             tmp[i++] = digits[do_div(num, base)];
  83     if (i > precision)
  84         precision = i;
  85     size -= precision;
  86     if (!(type & (ZEROPAD + LEFT)))
  87         while (size-- > 0)
  88             *str++ = ' ';
  89     if (sign)
  90         *str++ = sign;
  91     if (type & SPECIAL) {
  92         if (base == 8)
  93             *str++ = '0';
  94         else if (base == 16) {
  95             *str++ = '0';
  96             *str++ = digits[33];
  97         }
  98     }
  99     if (!(type & LEFT))
 100         while (size-- > 0)
 101             *str++ = c;
 102     while (i < precision--)
 103         *str++ = '0';
 104     while (i-- > 0)
 105         *str++ = tmp[i];
 106     while (size-- > 0)
 107         *str++ = ' ';
 108     return str;
 109 }
 110
 111 /* Forward decl. needed for IP address printing stuff... */
 112 int sprintf(char *buf, const char *fmt, ...);
 113
 114 int vsprintf(char *buf, const char *fmt, va_list args)
 115 {
 116     int len;
 117     unsigned long num;
 118     int i, base;
 119     char *str;
 120     const char *s;
 121
 122     int flags;                  /* flags to number() */
 123
 124     int field_width;            /* width of output field */
 125     int precision;              /* min. # of digits for integers; max
 126                                    number of chars for from string */
 127     int qualifier;              /* 'h', 'l', or 'L' for integer fields */
 128
 129     for (str = buf; *fmt; ++fmt) {
 130         if (*fmt != '%') {
 131             *str++ = *fmt;
 132             continue;
 133         }
 134
 135         /* process flags */
 136         flags = 0;
 137 repeat:
 138         ++fmt;                  /* this also skips first '%' */
 139         switch (*fmt) {
 140         case '-':
 141             flags |= LEFT;
 142             goto repeat;
 143         case '+':
 144             flags |= PLUS;
 145             goto repeat;
 146         case ' ':
 147             flags |= SPACE;
 148             goto repeat;
 149         case '#':
 150             flags |= SPECIAL;
 151             goto repeat;
 152         case '0':
 153             flags |= ZEROPAD;
 154             goto repeat;
 155         }
 156
 157         /* get field width */
 158         field_width = -1;
 159         if (isdigit(*fmt))
 160             field_width = skip_atou(&fmt);
 161         else if (*fmt == '*') {
 162             ++fmt;
 163             /* it's the next argument */
 164             field_width = va_arg(args, int);
 165             if (field_width < 0) {
 166                 field_width = -field_width;
 167                 flags |= LEFT;
 168             }
 169         }
 170
 171         /* get the precision */
 172         precision = -1;
 173         if (*fmt == '.') {
 174             ++fmt;
 175             if (isdigit(*fmt))
 176                 precision = skip_atou(&fmt);
 177             else if (*fmt == '*') {
 178                 ++fmt;
 179                 /* it's the next argument */
 180                 precision = va_arg(args, int);
 181             }
 182             if (precision < 0)
 183                 precision = 0;
 184         }
 185
 186         /* get the conversion qualifier */
 187         qualifier = -1;
 188         if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
 189             qualifier = *fmt;
 190             ++fmt;
 191         }
 192
 193         /* default base */
 194         base = 10;
 195
 196         switch (*fmt) {
 197         case 'c':
 198             if (!(flags & LEFT))
 199                 while (--field_width > 0)
 200                     *str++ = ' ';
 201             *str++ = (unsigned char)va_arg(args, int);
 202             while (--field_width > 0)
 203                 *str++ = ' ';
 204             continue;
 205
 206         case 's':
 207             s = va_arg(args, char *);
 208             len = strnlen(s, precision);
 209
 210             if (!(flags & LEFT))
 211                 while (len < field_width--)
 212                     *str++ = ' ';
 213             for (i = 0; i < len; ++i)
 214                 *str++ = *s++;
 215             while (len < field_width--)
 216                 *str++ = ' ';
 217             continue;
 218
 219         case 'p':
 220             if (field_width == -1) {
 221                 field_width = 2 * sizeof(void *);
 222                 flags |= ZEROPAD;
 223             }
 224             str = number(str,
 225                          (unsigned long)va_arg(args, void *), 16,
 226                          field_width, precision, flags);
 227             continue;
 228
 229         case 'n':
 230             if (qualifier == 'l') {
 231                 long *ip = va_arg(args, long *);
 232                 *ip = (str - buf);
 233             } else {
 234                 int *ip = va_arg(args, int *);
 235                 *ip = (str - buf);
 236             }
 237             continue;
 238
 239         case '%':
 240             *str++ = '%';
 241             continue;
 242
 243             /* integer number formats - set up the flags and "break" */
 244         case 'o':
 245             base = 8;
 246             break;
 247
 248         case 'X':
 249             flags |= LARGE;
 250         case 'x':
 251             base = 16;
 252             break;
 253
 254         case 'd':
 255         case 'i':
 256             flags |= SIGN;
 257         case 'u':
 258             break;
 259
 260         default:
 261             *str++ = '%';
 262             if (*fmt)
 263                 *str++ = *fmt;
 264             else
 265                 --fmt;
 266             continue;
 267         }
 268         if (qualifier == 'l')
 269             num = va_arg(args, unsigned long);
 270         else if (qualifier == 'h') {
 271             num = (unsigned short)va_arg(args, int);
 272             if (flags & SIGN)
 273                 num = (short)num;
 274         } else if (flags & SIGN)
 275             num = va_arg(args, int);
 276         else
 277             num = va_arg(args, unsigned int);
 278         str = number(str, num, base, field_width, precision, flags);
 279     }
 280     *str = '\0';
 281     return str - buf;
 282 }
 283
 284 int sprintf(char *buf, const char *fmt, ...)
 285 {
 286     va_list args;
 287     int i;
 288
 289     va_start(args, fmt);
 290     i = vsprintf(buf, fmt, args);
 291     va_end(args);
 292     return i;
 293 }
 294
 295 int printf(const char *fmt, ...)
 296 {
 297     char printf_buf[1024];
 298     va_list args;
 299     int printed;
 300
 301     va_start(args, fmt);
 302     printed = vsprintf(printf_buf, fmt, args);
 303     va_end(args);
 304
 305     puts(printf_buf);
 306
 307     return printed;
 308 }