lib/sysutil/kprintf.c

   1 /*      printf() - system services printf()             Author: Kees J. Bot
   2  *                                                              15 Jan 1994
   3  */
   4 #define nil 0
   5 #include <stdarg.h>
   6 #include <stddef.h>
   7 #include <limits.h>
   8
   9 #define isdigit(c)      ((unsigned) ((c) - '0') <  (unsigned) 10)
  10
  11 #if !__STDC__
  12 /* Classic C stuff, ignore. */
  13 void kputc();
  14 int printf(fmt) char *fmt;
  15 #else
  16
  17 /* Printf() uses kputc() to print characters. */
  18 void kputc(int c);
  19
  20 #define count_kputc(c) do { charcount++; kputc(c); } while(0)
  21
  22 int printf(const char *fmt, ...)
  23 #endif
  24 {
  25         int c, charcount = 0;
  26         enum { LEFT, RIGHT } adjust;
  27         enum { LONG, INT } intsize;
  28         int fill;
  29         int width, max, len, base;
  30         static char X2C_tab[]= "0123456789ABCDEF";
  31         static char x2c_tab[]= "0123456789abcdef";
  32         char *x2c;
  33         char *p;
  34         long i;
  35         unsigned long u;
  36         char temp[8 * sizeof(long) / 3 + 2];
  37
  38         va_list argp;
  39
  40         va_start(argp, fmt);
  41
  42         while ((c= *fmt++) != 0) {
  43                 if (c != '%') {
  44                         /* Ordinary character. */
  45                         count_kputc(c);
  46                         continue;
  47                 }
  48
  49                 /* Format specifier of the form:
  50                  *      %[adjust][fill][width][.max]keys
  51                  */
  52                 c= *fmt++;
  53
  54                 adjust= RIGHT;
  55                 if (c == '-') {
  56                         adjust= LEFT;
  57                         c= *fmt++;
  58                 }
  59
  60                 fill= ' ';
  61                 if (c == '0') {
  62                         fill= '0';
  63                         c= *fmt++;
  64                 }
  65
  66                 width= 0;
  67                 if (c == '*') {
  68                         /* Width is specified as an argument, e.g. %*d. */
  69                         width= va_arg(argp, int);
  70                         c= *fmt++;
  71                 } else
  72                 if (isdigit(c)) {
  73                         /* A number tells the width, e.g. %10d. */
  74                         do {
  75                                 width= width * 10 + (c - '0');
  76                         } while (isdigit(c= *fmt++));
  77                 }
  78
  79                 max= INT_MAX;
  80                 if (c == '.') {
  81                         /* Max field length coming up. */
  82                         if ((c= *fmt++) == '*') {
  83                                 max= va_arg(argp, int);
  84                                 c= *fmt++;
  85                         } else
  86                         if (isdigit(c)) {
  87                                 max= 0;
  88                                 do {
  89                                         max= max * 10 + (c - '0');
  90                                 } while (isdigit(c= *fmt++));
  91                         }
  92                 }
  93
  94                 /* Set a few flags to the default. */
  95                 x2c= x2c_tab;
  96                 i= 0;
  97                 base= 10;
  98                 intsize= INT;
  99                 if (c == 'l' || c == 'L') {
 100                         /* "Long" key, e.g. %ld. */
 101                         intsize= LONG;
 102                         c= *fmt++;
 103                 }
 104                 if (c == 0) break;
 105
 106                 switch (c) {
 107                         /* Decimal. */
 108                 case 'd':
 109                         i= intsize == LONG ? va_arg(argp, long)
 110                                                 : va_arg(argp, int);
 111                         u= i < 0 ? -i : i;
 112                         goto int2ascii;
 113
 114                         /* Octal. */
 115                 case 'o':
 116                         base= 010;
 117                         goto getint;
 118
 119                         /* Pointer, interpret as %X or %lX. */
 120                 case 'p':
 121                         if (sizeof(char *) > sizeof(int)) intsize= LONG;
 122
 123                         /* Hexadecimal.  %X prints upper case A-F, not %lx. */
 124                 case 'X':
 125                         x2c= X2C_tab;
 126                 case 'x':
 127                         base= 0x10;
 128                         goto getint;
 129
 130                         /* Unsigned decimal. */
 131                 case 'u':
 132                 getint:
 133                         u= intsize == LONG ? va_arg(argp, unsigned long)
 134                                                 : va_arg(argp, unsigned int);
 135                 int2ascii:
 136                         p= temp + sizeof(temp)-1;
 137                         *p= 0;
 138                         do {
 139                                 *--p= x2c[(ptrdiff_t) (u % base)];
 140                         } while ((u /= base) > 0);
 141                         goto string_length;
 142
 143                         /* A character. */
 144                 case 'c':
 145                         p= temp;
 146                         *p= va_arg(argp, int);
 147                         len= 1;
 148                         goto string_print;
 149
 150                         /* Simply a percent. */
 151                 case '%':
 152                         p= temp;
 153                         *p= '%';
 154                         len= 1;
 155                         goto string_print;
 156
 157                         /* A string.  The other cases will join in here. */
 158                 case 's':
 159                         p= va_arg(argp, char *);
 160
 161                 string_length:
 162                         for (len= 0; p[len] != 0 && len < max; len++) {}
 163
 164                 string_print:
 165                         width -= len;
 166                         if (i < 0) width--;
 167                         if (fill == '0' && i < 0) count_kputc('-');
 168                         if (adjust == RIGHT) {
 169                                 while (width > 0) { count_kputc(fill); width--; }
 170                         }
 171                         if (fill == ' ' && i < 0) count_kputc('-');
 172                         while (len > 0) { count_kputc((unsigned char) *p++); len--; }
 173                         while (width > 0) { count_kputc(fill); width--; }
 174                         break;
 175
 176                         /* Unrecognized format key, echo it back. */
 177                 default:
 178                         count_kputc('%');
 179                         count_kputc(c);
 180                 }
 181         }
 182
 183         /* Mark the end with a null (should be something else, like -1). */
 184         kputc(0);
 185         va_end(argp);
 186         return charcount;
 187 }
 188
 189 /*
 190  * $PchId: kprintf.c,v 1.5 1996/04/11 06:59:05 philip Exp $
 191  */