Added stdarg.h

This commit is contained in:
2024-08-26 21:15:35 +02:00
parent 2ca858465c
commit f79603c778
3 changed files with 18 additions and 6 deletions
+8 -6
View File
@@ -3,10 +3,12 @@
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
// TODO: Support negative numbers
int printf(const char* fmt, ...) {
unsigned int* argPtr = (unsigned int*)&fmt + 1; // First arg after fmt
va_list args;
va_start(args, fmt);
// Printing buffer
static char* buffer;
@@ -35,23 +37,22 @@ int printf(const char* fmt, ...) {
} else if (state == '%') {
switch (c) {
case 'd': // Decimal number
strcat(buffer, itoa(*argPtr++, 10));
strcat(buffer, itoa(va_arg(args, int), 10));
len += strlen(&buffer[len]); // Add the remaining length
break;
case 'x': // Hex number
strcat(buffer, itoa(*argPtr++, 16));
strcat(buffer, itoa(va_arg(args, int), 16));
len += strlen(&buffer[len]);
break;
case 's': // String
char* s = *(char**)argPtr++;
char* s = va_arg(args, char*);
while (*s != '\0') {
buffer[len++] = *s++;
}
break;
case 'c': // Char
buffer[len++] = *(char*)argPtr;
argPtr++;
buffer[len++] = va_arg(args, char);
break;
default: // This looks insane
buffer[len++] = '%';
@@ -66,6 +67,7 @@ int printf(const char* fmt, ...) {
buffer[len] = '\0';
write(1, buffer, len);
free(buffer);
va_end(args);
return 0;
}
+10
View File
@@ -0,0 +1,10 @@
#ifndef STDARG_H
#define STDARG_H
typedef char* va_list;
#define va_start(ap, paramn) (void)((ap) = (char*)(&(paramn) + 1))
#define va_end(ap) (void)((ap) = 0)
#define va_arg(ap, type) (((type*)((ap) = ((ap) + sizeof(type))))[-1])
#endif