stdio.c

   1 #include <errno.h>
   2 #include <fcntl.h>
   3 #include <stdarg.h>
   4 #include <stdio.h>
   5 #include <unistd.h>
   6
   7 static char *putstr(char *d, char *s)
   8 {
   9         while (*s)
  10                 *d++ = *s++;
  11         return d;
  12 }
  13
  14 static int digits(unsigned long n, int base)
  15 {
  16         int i;
  17         for (i = 0; n; i++)
  18                 n /= base;
  19         return i ? i : 1;
  20 }
  21
  22 static char *digs = "0123456789abcdef";
  23
  24 static char *putint(char *s, unsigned long n, int base, int sign)
  25 {
  26         int d;
  27         int i;
  28         if (sign && n & 0x80000000) {
  29                 *s++ = '-';
  30                 n = -n;
  31         }
  32         d = digits(n, base);
  33         for (i = 0; i < d; i++) {
  34                 s[d - i - 1] = digs[n % base];
  35                 n /= base;
  36         }
  37         return s + d;
  38 }
  39
  40 int vsprintf(char *dst, char *fmt, va_list ap)
  41 {
  42         char *d = dst;
  43         char *s = fmt;
  44         while (*s) {
  45                 int c = *s++;
  46                 if (c != '%') {
  47                         *d++ = c;
  48                         continue;
  49                 }
  50                 if (*s == 'l')
  51                         s++;
  52                 switch ((c = *s++)) {
  53                 case 'd':
  54                         d = putint(d, va_arg(ap, long), 10, 1);
  55                         break;
  56                 case 'u':
  57                         d = putint(d, va_arg(ap, long), 10, 0);
  58                         break;
  59                 case 'x':
  60                 case 'p':
  61                         d = putint(d, va_arg(ap, long), 16, 0);
  62                         break;
  63                 case 'c':
  64                         *d++ = va_arg(ap, int);
  65                         break;
  66                 case 's':
  67                         d = putstr(d, va_arg(ap, char *));
  68                         break;
  69                 case '\0':
  70                         s--;
  71                         break;
  72                 default:
  73                         *d++ = c;
  74                 }
  75         }
  76         *d = '\0';
  77         return d - dst;
  78 }
  79
  80 static char buf[1 << 12];
  81
  82 static FILE _stdout = {1};
  83 static FILE _stderr = {2};
  84 FILE *stdout = &_stdout;
  85 FILE *stderr = &_stderr;
  86
  87 int printf(char *fmt, ...)
  88 {
  89         va_list ap;
  90         int ret;
  91         va_start(ap, fmt);
  92         ret = vsprintf(buf, fmt, ap);
  93         va_end(ap);
  94         return write(1, buf, ret);
  95 }
  96
  97 int fprintf(FILE *filp, char *fmt, ...)
  98 {
  99         va_list ap;
 100         int ret;
 101         va_start(ap, fmt);
 102         ret = vsprintf(buf, fmt, ap);
 103         va_end(ap);
 104         return write(filp->fd, buf, ret);
 105 }
 106
 107 int sprintf(char *dst, char *fmt, ...)
 108 {
 109         va_list ap;
 110         int ret;
 111         va_start(ap, fmt);
 112         ret = vsprintf(dst, fmt, ap);
 113         va_end(ap);
 114         return ret;
 115 }
 116
 117 void perror(char *s)
 118 {
 119         int idx = errno;
 120         if (idx >= sys_nerr)
 121                 idx = 0;
 122         fprintf(stderr, "%s: %s\n", s, sys_errlist[idx]);
 123 }
 124
 125 FILE *fopen(char *path, char *mode)
 126 {
 127         FILE *fp;
 128         int flags;
 129
 130         if (strchr(mode, '+'))
 131                 flags = O_RDWR;
 132         else
 133                 flags = *mode == 'r' ? O_RDONLY : O_WRONLY;
 134         if (*mode != 'r')
 135                 flags |= O_CREAT;
 136         if (*mode == 'w')
 137                 flags |= O_TRUNC;
 138         if (*mode == 'a')
 139                 flags |= O_APPEND;
 140
 141         fp = malloc(sizeof(*fp));
 142         fp->fd = open(path, flags, 0600);
 143         return fp;
 144 }
 145
 146 int fclose(FILE *fp)
 147 {
 148         int ret = close(fp);
 149         free(fp);
 150         return ret;
 151 }
 152
 153 void setbuf(FILE *fp, char *buf)
 154 {
 155 }