stdio.c

   1 #include <errno.h>
   2 #include <fcntl.h>
   3 #include <stdarg.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8
   9 static char *putstr(char *d, char *s)
  10 {
  11         while (*s)
  12                 *d++ = *s++;
  13         return d;
  14 }
  15
  16 static int digits(unsigned long n, int base)
  17 {
  18         int i;
  19         for (i = 0; n; i++)
  20                 n /= base;
  21         return i ? i : 1;
  22 }
  23
  24 static char *digs = "0123456789abcdef";
  25
  26 static char *putint(char *s, unsigned long n, int base, int sign)
  27 {
  28         int d;
  29         int i;
  30         if (sign && n & 0x80000000) {
  31                 *s++ = '-';
  32                 n = -n;
  33         }
  34         d = digits(n, base);
  35         for (i = 0; i < d; i++) {
  36                 s[d - i - 1] = digs[n % base];
  37                 n /= base;
  38         }
  39         return s + d;
  40 }
  41
  42 int vsprintf(char *dst, char *fmt, va_list ap)
  43 {
  44         char *d = dst;
  45         char *s = fmt;
  46         while (*s) {
  47                 int c = *s++;
  48                 if (c != '%') {
  49                         *d++ = c;
  50                         continue;
  51                 }
  52                 if (*s == 'l')
  53                         s++;
  54                 switch ((c = *s++)) {
  55                 case 'd':
  56                         d = putint(d, va_arg(ap, long), 10, 1);
  57                         break;
  58                 case 'u':
  59                         d = putint(d, va_arg(ap, long), 10, 0);
  60                         break;
  61                 case 'x':
  62                 case 'p':
  63                         d = putint(d, va_arg(ap, long), 16, 0);
  64                         break;
  65                 case 'c':
  66                         *d++ = va_arg(ap, int);
  67                         break;
  68                 case 's':
  69                         d = putstr(d, va_arg(ap, char *));
  70                         break;
  71                 case '\0':
  72                         s--;
  73                         break;
  74                 default:
  75                         *d++ = c;
  76                 }
  77         }
  78         *d = '\0';
  79         return d - dst;
  80 }
  81
  82 static char buf[1 << 12];
  83
  84 static FILE _stdout = {1};
  85 static FILE _stderr = {2};
  86 FILE *stdout = &_stdout;
  87 FILE *stderr = &_stderr;
  88
  89 int printf(char *fmt, ...)
  90 {
  91         va_list ap;
  92         int ret;
  93         va_start(ap, fmt);
  94         ret = vsprintf(buf, fmt, ap);
  95         va_end(ap);
  96         return write(1, buf, ret);
  97 }
  98
  99 int fprintf(FILE *filp, char *fmt, ...)
 100 {
 101         va_list ap;
 102         int ret;
 103         va_start(ap, fmt);
 104         ret = vsprintf(buf, fmt, ap);
 105         va_end(ap);
 106         return write(filp->fd, buf, ret);
 107 }
 108
 109 int sprintf(char *dst, char *fmt, ...)
 110 {
 111         va_list ap;
 112         int ret;
 113         va_start(ap, fmt);
 114         ret = vsprintf(dst, fmt, ap);
 115         va_end(ap);
 116         return ret;
 117 }
 118
 119 void perror(char *s)
 120 {
 121         int idx = errno;
 122         if (idx >= sys_nerr)
 123                 idx = 0;
 124         fprintf(stderr, "%s: %s\n", s, sys_errlist[idx]);
 125 }
 126
 127 FILE *fopen(char *path, char *mode)
 128 {
 129         FILE *fp;
 130         int flags;
 131
 132         if (strchr(mode, '+'))
 133                 flags = O_RDWR;
 134         else
 135                 flags = *mode == 'r' ? O_RDONLY : O_WRONLY;
 136         if (*mode != 'r')
 137                 flags |= O_CREAT;
 138         if (*mode == 'w')
 139                 flags |= O_TRUNC;
 140         if (*mode == 'a')
 141                 flags |= O_APPEND;
 142
 143         fp = malloc(sizeof(*fp));
 144         fp->fd = open(path, flags, 0600);
 145         return fp;
 146 }
 147
 148 int fclose(FILE *fp)
 149 {
 150         int ret = close(fp->fd);
 151         free(fp);
 152         return ret;
 153 }
 154
 155 void setbuf(FILE *fp, char *buf)
 156 {
 157 }