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#include "printf.h"
#include <stdarg.h>
void print(const char *s);
typedef struct pstream {
char *buffer;
int remain;
int added;
} pstream_t;
static void addchar(pstream_t *p, char c)
{
if (p->remain) {
*p->buffer++ = c;
--p->remain;
}
++p->added;
}
void print_str(pstream_t *p, const char *s)
{
while (*s)
addchar(p, *s++);
}
static char digits[16] = "0123456789abcdef";
void print_int(pstream_t *ps, long n, int base)
{
char buf[sizeof(long) * 3 + 2], *p = buf;
int s = 0, i;
if (n < 0) {
n = -n;
s = 1;
}
while (n) {
*p++ = digits[n % base];
n /= base;
}
if (s)
*p++ = '-';
if (p == buf)
*p++ = '0';
for (i = 0; i < (p - buf) / 2; ++i) {
char tmp;
tmp = buf[i];
buf[i] = p[-1-i];
p[-1-i] = tmp;
}
*p = 0;
print_str(ps, buf);
}
void print_unsigned(pstream_t *ps, unsigned long n, int base)
{
char buf[sizeof(long) * 3 + 1], *p = buf;
int i;
while (n) {
*p++ = digits[n % base];
n /= base;
}
if (p == buf)
*p++ = '0';
for (i = 0; i < (p - buf) / 2; ++i) {
char tmp;
tmp = buf[i];
buf[i] = p[-1-i];
p[-1-i] = tmp;
}
*p = 0;
print_str(ps, buf);
}
int vsnprintf(char *buf, int size, const char *fmt, va_list va)
{
int n;
pstream_t s;
s.buffer = buf;
s.remain = size - 1;
s.added = 0;
while (*fmt) {
char f = *fmt++;
if (f != '%') {
addchar(&s, f);
continue;
}
f = *fmt++;
switch (f) {
case '%':
addchar(&s, '%');
break;
case '\0':
--fmt;
break;
case 'd':
print_int(&s, va_arg(va, int), 10);
break;
case 'x':
print_unsigned(&s, va_arg(va, int), 16);
break;
case 'p':
print_str(&s, "0x");
print_unsigned(&s, (unsigned long)va_arg(va, void *), 16);
break;
case 's':
print_str(&s, va_arg(va, const char *));
break;
default:
addchar(&s, f);
break;
}
}
*s.buffer = 0;
++s.added;
return s.added;
}
int snprintf(char *buf, int size, const char *fmt, ...)
{
va_list va;
int r;
va_start(va, fmt);
r = vsnprintf(buf, size, fmt, va);
va_end(va);
return r;
}
int printf(const char *fmt, ...)
{
va_list va;
char buf[2000];
int r;
va_start(va, fmt);
r = vsnprintf(buf, sizeof buf, fmt, va);
va_end(va);
print(buf);
return r;
}
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