lib/tiny-printf.c

   1 /*
   2  * Tiny printf version for SPL
   3  *
   4  * Copied from:
   5  * http://www.sparetimelabs.com/printfrevisited/printfrevisited.php
   6  *
   7  * Copyright (C) 2004,2008  Kustaa Nyholm
   8  *
   9  * SPDX-License-Identifier:     LGPL-2.1+
  10  */
  11
  12 #include <common.h>
  13 #include <stdarg.h>
  14 #include <serial.h>
  15
  16 static char *bf;
  17 static char zs;
  18
  19 static void out(char c)
  20 {
  21         *bf++ = c;
  22 }
  23
  24 static void out_dgt(char dgt)
  25 {
  26         out(dgt + (dgt < 10 ? '0' : 'a' - 10));
  27         zs = 1;
  28 }
  29
  30 static void div_out(unsigned int *num, unsigned int div)
  31 {
  32         unsigned char dgt = 0;
  33
  34         while (*num >= div) {
  35                 *num -= div;
  36                 dgt++;
  37         }
  38
  39         if (zs || dgt > 0)
  40                 out_dgt(dgt);
  41 }
  42
  43 int printf(const char *fmt, ...)
  44 {
  45         va_list va;
  46         char ch;
  47         char *p;
  48         unsigned int num;
  49         char buf[12];
  50         unsigned int div;
  51
  52         va_start(va, fmt);
  53
  54         while ((ch = *(fmt++))) {
  55                 if (ch != '%') {
  56                         putc(ch);
  57                 } else {
  58                         char lz = 0;
  59                         char w = 0;
  60
  61                         ch = *(fmt++);
  62                         if (ch == '0') {
  63                                 ch = *(fmt++);
  64                                 lz = 1;
  65                         }
  66
  67                         if (ch >= '0' && ch <= '9') {
  68                                 w = 0;
  69                                 while (ch >= '0' && ch <= '9') {
  70                                         w = (w * 10) + ch - '0';
  71                                         ch = *fmt++;
  72                                 }
  73                         }
  74                         bf = buf;
  75                         p = bf;
  76                         zs = 0;
  77
  78                         switch (ch) {
  79                         case 0:
  80                                 goto abort;
  81                         case 'u':
  82                         case 'd':
  83                                 num = va_arg(va, unsigned int);
  84                                 if (ch == 'd' && (int)num < 0) {
  85                                         num = -(int)num;
  86                                         out('-');
  87                                 }
  88                                 for (div = 1000000000; div; div /= 10)
  89                                         div_out(&num, div);
  90                                 break;
  91                         case 'x':
  92                                 num = va_arg(va, unsigned int);
  93                                 for (div = 0x10000000; div; div /= 0x10)
  94                                         div_out(&num, div);
  95                                 break;
  96                         case 'c':
  97                                 out((char)(va_arg(va, int)));
  98                                 break;
  99                         case 's':
 100                                 p = va_arg(va, char*);
 101                                 break;
 102                         case '%':
 103                                 out('%');
 104                         default:
 105                                 break;
 106                         }
 107
 108                         *bf = 0;
 109                         bf = p;
 110                         while (*bf++ && w > 0)
 111                                 w--;
 112                         while (w-- > 0)
 113                                 putc(lz ? '0' : ' ');
 114                         while ((ch = *p++))
 115                                 putc(ch);
 116                 }
 117         }
 118
 119 abort:
 120         va_end(va);
 121         return 0;
 122 }