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#include "printf.h"
enum PRINTF_TYPE {
PRINTF_TYPE_STRING = 0,
PRINTF_TYPE_INT = 1,
PRINTF_TYPE_PERCENT = 2,
PRINTF_TYPE_UNKNOWN = 999
};
static enum PRINTF_TYPE get_printf_type(const char* cur)
{
while (*cur >= 0x30 && *cur < 0x3a) ++ cur;
if (*cur == 's') {
return PRINTF_TYPE_STRING;
} else if (*cur == 'd' || *cur == 'x' || *cur == 'X' || *cur == 'u') {
return PRINTF_TYPE_INT;
}
return PRINTF_TYPE_UNKNOWN;
}
static const char* printf_handle_string(
const char* fmt,
const char* next,
printf_callback_t callback,
volatile void* closure)
{
const char* cur = next;
for (; *cur != 0; ++ cur) {
callback(closure, *cur);
}
return fmt;
}
static char printf_toupper(char ch)
{
if (ch <= 0x7a && ch > 0x60) {
return ch - 0x20;
}
return ch;
}
static const char* parse_fmt(
const char* fmt,
int* out_padding,
char* out_pad_char)
{
if (*fmt == '0') {
*out_pad_char = '0';
++ fmt;
} else {
*out_pad_char = ' ';
}
int padding = 0;
while (*fmt < 0x3a && *fmt >= 0x30) {
padding *= 10;
padding += (*fmt ++) - 0x30;
}
*out_padding = padding;
return fmt;
}
static const char* mapping = "0123456789abcdef";
static const char* printf_handle_int(
const char* fmt, unsigned int next, printf_callback_t callback, volatile void* closure)
{
int base = 10;
char chars[32];
int pos = 31;
int upper = 0;
char pad_char;
int padding;
int is_unsigned = 0;
fmt = parse_fmt(fmt, &padding, &pad_char);
if (*fmt == 'x' || *fmt == 'X') {
base = 16;
is_unsigned = 1;
} else if (*fmt == 'u') {
is_unsigned = 1;
}
upper = *fmt == 'X';
int next_i = (int) next;
if (next_i < 0 && !is_unsigned) {
callback(closure, '-');
next_i *= -1;
next = (unsigned) next_i;
}
if (next == 0) {
callback(closure, '0');
} else {
while (next > 0) {
char next_ch = mapping[next % base];
if (upper) next_ch = printf_toupper(next_ch);
chars[pos --] = next_ch;
padding --;
next /= base;
}
while ((padding--) > 0) {
chars[pos --] = pad_char;
}
for (++ pos; pos < 32; ++ pos) {
callback(closure, chars[pos]);
}
}
return fmt;
}
void printf_format(
const char* fmt,
printf_callback_t callback,
volatile void* closure,
va_list ap)
{
const char* cur = fmt;
const char* next_string;
int next_int;
for (; *cur != 0; ++ cur) {
if (*cur == '%') {
// Handle the formatting here.
++ cur;
enum PRINTF_TYPE printf_type = get_printf_type(cur);
switch (printf_type) {
case PRINTF_TYPE_PERCENT:
callback(closure, '%');
break;
case PRINTF_TYPE_STRING:
next_string = va_arg(ap, const char*);
cur = printf_handle_string(cur, next_string, callback, closure);
break;
case PRINTF_TYPE_INT:
next_int = va_arg(ap, int);
cur = printf_handle_int(cur, next_int, callback, closure);
}
} else {
callback(closure, *cur);
}
}
}
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