lib/vsprintf.c

   1 /*
   2  *  linux/lib/vsprintf.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 /* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */
   8 /*
   9  * Wirzenius wrote this portably, Torvalds fucked it up :-)
  10  */
  11
  12 #include <stdarg.h>
  13 #include <linux/types.h>
  14 #include <linux/string.h>
  15 #include <linux/ctype.h>
  16
  17 unsigned long simple_strtoul(const char *cp,char **endp,unsigned int base)
  18 {
  19         unsigned long result = 0,value;
  20
  21         if (!base) {
  22                 base = 10;
  23                 if (*cp == '0') {
  24                         base = 8;
  25                         cp++;
  26                         if ((*cp == 'x') && isxdigit(cp[1])) {
  27                                 cp++;
  28                                 base = 16;
  29                         }
  30                 }
  31         }
  32         while (isxdigit(*cp) && (value = isdigit(*cp) ? *cp-'0' : (islower(*cp)
  33             ? toupper(*cp) : *cp)-'A'+10) < base) {
  34                 result = result*base + value;
  35                 cp++;
  36         }
  37         if (endp)
  38                 *endp = (char *)cp;
  39         return result;
  40 }
  41
  42 long simple_strtol(const char *cp,char **endp,unsigned int base)
  43 {
  44         if(*cp=='-')
  45                 return -simple_strtoul(cp+1,endp,base);
  46         return simple_strtoul(cp,endp,base);
  47 }
  48
  49 /* we use this so that we can do without the ctype library */
  50 #define is_digit(c)     ((c) >= '0' && (c) <= '9')
  51
  52 static int skip_atoi(const char **s)
  53 {
  54         int i=0;
  55
  56         while (is_digit(**s))
  57                 i = i*10 + *((*s)++) - '0';
  58         return i;
  59 }
  60
  61 #define ZEROPAD 1               /* pad with zero */
  62 #define SIGN    2               /* unsigned/signed long */
  63 #define PLUS    4               /* show plus */
  64 #define SPACE   8               /* space if plus */
  65 #define LEFT    16              /* left justified */
  66 #define SPECIAL 32              /* 0x */
  67 #define LARGE   64              /* use 'ABCDEF' instead of 'abcdef' */
  68
  69 #define do_div(n,base) ({ \
  70 int __res; \
  71 __res = ((unsigned long) n) % (unsigned) base; \
  72 n = ((unsigned long) n) / (unsigned) base; \
  73 __res; })
  74
  75 static char * number(char * str, long num, int base, int size, int precision
  76         ,int type)
  77 {
  78         char c,sign,tmp[66];
  79         const char *digits="0123456789abcdefghijklmnopqrstuvwxyz";
  80         int i;
  81
  82         if (type & LARGE)
  83                 digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  84         if (type & LEFT)
  85                 type &= ~ZEROPAD;
  86         if (base < 2 || base > 36)
  87                 return 0;
  88         c = (type & ZEROPAD) ? '0' : ' ';
  89         sign = 0;
  90         if (type & SIGN) {
  91                 if (num < 0) {
  92                         sign = '-';
  93                         num = -num;
  94                         size--;
  95                 } else if (type & PLUS) {
  96                         sign = '+';
  97                         size--;
  98                 } else if (type & SPACE) {
  99                         sign = ' ';
 100                         size--;
 101                 }
 102         }
 103         if (type & SPECIAL) {
 104                 if (base == 16)
 105                         size -= 2;
 106                 else if (base == 8)
 107                         size--;
 108         }
 109         i = 0;
 110         if (num == 0)
 111                 tmp[i++]='0';
 112         else while (num != 0)
 113                 tmp[i++] = digits[do_div(num,base)];
 114         if (i > precision)
 115                 precision = i;
 116         size -= precision;
 117         if (!(type&(ZEROPAD+LEFT)))
 118                 while(size-->0)
 119                         *str++ = ' ';
 120         if (sign)
 121                 *str++ = sign;
 122         if (type & SPECIAL) {
 123                 if (base==8)
 124                         *str++ = '0';
 125                 else if (base==16) {
 126                         *str++ = '0';
 127                         *str++ = digits[33];
 128                 }
 129         }
 130         if (!(type & LEFT))
 131                 while (size-- > 0)
 132                         *str++ = c;
 133         while (i < precision--)
 134                 *str++ = '0';
 135         while (i-- > 0)
 136                 *str++ = tmp[i];
 137         while (size-- > 0)
 138                 *str++ = ' ';
 139         return str;
 140 }
 141
 142 /* Forward decl. needed for IP address printing stuff... */
 143 int sprintf(char * buf, const char *fmt, ...);
 144
 145 int vsprintf(char *buf, const char *fmt, va_list args)
 146 {
 147         int len;
 148         unsigned long num;
 149         int i, base;
 150         char * str;
 151         const char *s;
 152
 153         int flags;              /* flags to number() */
 154
 155         int field_width;        /* width of output field */
 156         int precision;          /* min. # of digits for integers; max
 157                                    number of chars for from string */
 158         int qualifier;          /* 'h', 'l', or 'L' for integer fields */
 159
 160         for (str=buf ; *fmt ; ++fmt) {
 161                 if (*fmt != '%') {
 162                         *str++ = *fmt;
 163                         continue;
 164                 }
 165
 166                 /* process flags */
 167                 flags = 0;
 168                 repeat:
 169                         ++fmt;          /* this also skips first '%' */
 170                         switch (*fmt) {
 171                                 case '-': flags |= LEFT; goto repeat;
 172                                 case '+': flags |= PLUS; goto repeat;
 173                                 case ' ': flags |= SPACE; goto repeat;
 174                                 case '#': flags |= SPECIAL; goto repeat;
 175                                 case '0': flags |= ZEROPAD; goto repeat;
 176                                 }
 177
 178                 /* get field width */
 179                 field_width = -1;
 180                 if (is_digit(*fmt))
 181                         field_width = skip_atoi(&fmt);
 182                 else if (*fmt == '*') {
 183                         ++fmt;
 184                         /* it's the next argument */
 185                         field_width = va_arg(args, int);
 186                         if (field_width < 0) {
 187                                 field_width = -field_width;
 188                                 flags |= LEFT;
 189                         }
 190                 }
 191
 192                 /* get the precision */
 193                 precision = -1;
 194                 if (*fmt == '.') {
 195                         ++fmt;
 196                         if (is_digit(*fmt))
 197                                 precision = skip_atoi(&fmt);
 198                         else if (*fmt == '*') {
 199                                 ++fmt;
 200                                 /* it's the next argument */
 201                                 precision = va_arg(args, int);
 202                         }
 203                         if (precision < 0)
 204                                 precision = 0;
 205                 }
 206
 207                 /* get the conversion qualifier */
 208                 qualifier = -1;
 209                 if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
 210                         qualifier = *fmt;
 211                         ++fmt;
 212                 }
 213
 214                 /* default base */
 215                 base = 10;
 216
 217                 switch (*fmt) {
 218                 case 'c':
 219                         if (!(flags & LEFT))
 220                                 while (--field_width > 0)
 221                                         *str++ = ' ';
 222                         *str++ = (unsigned char) va_arg(args, int);
 223                         while (--field_width > 0)
 224                                 *str++ = ' ';
 225                         continue;
 226
 227                 case 's':
 228                         s = va_arg(args, char *);
 229                         if (!s)
 230                                 s = "<NULL>";
 231
 232                         len = strnlen(s, precision);
 233
 234                         if (!(flags & LEFT))
 235                                 while (len < field_width--)
 236                                         *str++ = ' ';
 237                         for (i = 0; i < len; ++i)
 238                                 *str++ = *s++;
 239                         while (len < field_width--)
 240                                 *str++ = ' ';
 241                         continue;
 242
 243                 case 'p':
 244                         if (field_width == -1) {
 245                                 field_width = 2*sizeof(void *);
 246                                 flags |= ZEROPAD;
 247                         }
 248                         str = number(str,
 249                                 (unsigned long) va_arg(args, void *), 16,
 250                                 field_width, precision, flags);
 251                         continue;
 252
 253
 254                 case 'n':
 255                         if (qualifier == 'l') {
 256                                 long * ip = va_arg(args, long *);
 257                                 *ip = (str - buf);
 258                         } else {
 259                                 int * ip = va_arg(args, int *);
 260                                 *ip = (str - buf);
 261                         }
 262                         continue;
 263
 264                 case '%':
 265                         *str++ = '%';
 266                         continue;
 267
 268                 /* integer number formats - set up the flags and "break" */
 269                 case 'o':
 270                         base = 8;
 271                         break;
 272
 273                 case 'X':
 274                         flags |= LARGE;
 275                 case 'x':
 276                         base = 16;
 277                         break;
 278
 279                 case 'd':
 280                 case 'i':
 281                         flags |= SIGN;
 282                 case 'u':
 283                         break;
 284
 285                 default:
 286                         *str++ = '%';
 287                         if (*fmt)
 288                                 *str++ = *fmt;
 289                         else
 290                                 --fmt;
 291                         continue;
 292                 }
 293                 if (qualifier == 'l')
 294                         num = va_arg(args, unsigned long);
 295                 else if (qualifier == 'h') {
 296                         num = (unsigned short) va_arg(args, int);
 297                         if (flags & SIGN)
 298                                 num = (short) num;
 299                 } else if (flags & SIGN)
 300                         num = va_arg(args, int);
 301                 else
 302                         num = va_arg(args, unsigned int);
 303                 str = number(str, num, base, field_width, precision, flags);
 304         }
 305         *str = '\0';
 306         return str-buf;
 307 }
 308
 309 int sprintf(char * buf, const char *fmt, ...)
 310 {
 311         va_list args;
 312         int i;
 313
 314         va_start(args, fmt);
 315         i=vsprintf(buf,fmt,args);
 316         va_end(args);
 317         return i;
 318 }