From d0542c15808825e8a57571432660e87b464beb17 Mon Sep 17 00:00:00 2001
From: Robert <robert.altner@einweckglas.com>
Date: Wed, 6 Sep 2023 00:12:39 +0200
Subject: [PATCH] add atoi function

---
 src/kernel/include/stdlib.h |  2 ++
 src/kernel/lib/stdlib.c     | 29 +++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/src/kernel/include/stdlib.h b/src/kernel/include/stdlib.h
index e97d284..c2535ad 100644
--- a/src/kernel/include/stdlib.h
+++ b/src/kernel/include/stdlib.h
@@ -1,6 +1,8 @@
 #ifndef _CLIPPER_STDLIB_H_
 #define _CLIPPER_STDLIB_H_
 
+int atoi(const char* str);
+
 char* itoa(int value, char* buffer, int base);
 char* utoa(unsigned int value, char* buffer, int base);
 
diff --git a/src/kernel/lib/stdlib.c b/src/kernel/lib/stdlib.c
index 9b5c1d4..b2e4471 100644
--- a/src/kernel/lib/stdlib.c
+++ b/src/kernel/lib/stdlib.c
@@ -1,5 +1,34 @@
 #include "stdlib.h"
 
+int atoi(const char* str) {
+	// Blled away whitespace
+	while(*str++ == ' ');
+	str--;
+
+	int val = 0;
+	int factor = 1;
+
+	if (*str == '+') { 
+		str++; 
+	} else if (*str == '-') {
+		factor = -1;
+		str++;
+	}
+
+	const char* start = str;
+	while (*str >= '0' && *str <= '9') {
+		str++;
+	}
+
+	int power_of_ten = 1;
+	while (start < str) {
+		val += power_of_ten * ((*(--str)) - '0');
+		power_of_ten *= 10;
+	}
+
+	return factor * val;
+}
+
 char* itoa(int value, char* buffer, int base) {
 	char* ptr;
 	char* value_start;