1 files changed, 63 insertions, 0 deletions
diff --git a/src/kernel/lib/stdio/vsprintf.c b/src/kernel/lib/stdio/vsprintf.c
new file mode 100644
index 0000000..6584ed1
--- /dev/null
+++ b/src/kernel/lib/stdio/vsprintf.c
@@ -0,0 +1,63 @@
+#include <lib/stdlib.h>
+#include <stdarg.h>
+#include <stdint.h>
+
+static void append(char *dest, char *src, int index)
+{
+	for (int i = index; i < strlen(src) + index; i++)
+		dest[i] = src[i - index];
+	dest[index + strlen(src)] = 0;
+}
+
+int vsprintf(char *str, const char *fmt, va_list args)
+{
+	u8 ready_to_format = 0;
+
+	int i = 0;
+	char buf = 0;
+	char format_buffer[20] = "\0";
+
+	for (; *fmt; fmt++) {
+		if (ready_to_format) {
+			ready_to_format = 0;
+
+			if (*fmt == '%') {
+				str[i] = '%';
+				continue;
+			}
+
+			buf = *fmt;
+			if (buf == 's') {
+				char *string = va_arg(args, char *);
+				append(str, string, i);
+				i = strlen(str);
+			} else if (buf == 'x') {
+				itoa_base((u32)va_arg(args, int), format_buffer, 16);
+				append(str, format_buffer, i);
+				i = strlen(str);
+			} else if (buf == 'd') {
+				itoa_base(va_arg(args, int), format_buffer, 10);
+				append(str, format_buffer, i);
+				i = strlen(str);
+			} else if (buf == 'o') {
+				itoa_base(va_arg(args, int), format_buffer, 8);
+				append(str, format_buffer, i);
+				i = strlen(str);
+			} else if (buf == 'c') {
+				str[i] = (char)va_arg(args, int);
+				i++;
+			}
+		} else {
+			if (*fmt == '%')
+				ready_to_format = 1;
+			else {
+				str[i] = *fmt;
+				i++;
+			}
+		}
+
+		format_buffer[0] = '\0';
+	}
+
+	return strlen(str);
+}
+\ No newline at end of file