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#include <init/stdlib.h>
#include <shared/syscalls.h>
#include <stdarg.h>
int __tty_fd;
int printf(const char *fmt, ...) {
const char *seg = fmt; // beginning of the current segment
int total = 0;
va_list argp;
va_start(argp, fmt);
if (__tty_fd < 0) return 0;
for (;;) {
char c = *fmt++;
switch (c) {
case '\0':
// TODO don't assume that stdout is @ fd 0
_syscall_write(0, seg, fmt - seg - 1, 0);
return total + (fmt - seg - 1);
case '%':
_syscall_write(0, seg, fmt - seg - 1, 0);
total += fmt - seg - 1;
size_t pad_len = 0;
parse_fmt:
c = *fmt++;
switch (c) {
case '0':
pad_len = *fmt++ - '0'; // can skip over the null byte, idc
goto parse_fmt;
case 'c':
char c = va_arg(argp, int);
_syscall_write(0, &c, 1, 0);
total += 1;
break;
case 's':
const char *s = va_arg(argp, char*);
if (s) {
_syscall_write(0, s, strlen(s), 0);
total += strlen(s);
}
break;
case 'x':
unsigned int n = va_arg(argp, int);
size_t i = 4; // nibbles * 4
while (n >> i && i < (sizeof(int) * 8))
i += 4;
if (i < pad_len * 4)
i = pad_len * 4;
while (i > 0) {
i -= 4;
char h = '0' + ((n >> i) & 0xf);
if (h > '9') h += 'a' - '9' - 1;
_syscall_write(0, &h, 1, 0);
total++;
}
break;
}
seg = fmt;
break;
}
}
}
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