cowos uses it's own cowlibc! big W

kernel/klibc/stdio.c

@@ -0,0 +1,100 @@
+#include <limits.h>
+#include <stdarg.h>
+/* #include <tty.h> */
+#include <klibc/stdio.h>
+#include <klibc/string.h>
+
+/* returns 1 for true, adhering to suckless */
+static int
+print(const char* data, size_t length)
+{
+	const unsigned char* bytes = (const unsigned char*) data;
+	for (size_t i = 0; i < length; i++) {
+		if (putchar(bytes[i]) == EOF) {
+			return 0;
+                }
+        }
+	return 1;
+}
+
+/* todo: set errno to eoverflow for some cases in which errno should not be used */
+int
+printf(const char* restrict format, ...)
+{
+	va_list parameters;
+	va_start(parameters, format);
+
+	int written = 0;
+
+	while (*format != '\0') {
+		size_t maxrem = INT_MAX - written;
+
+		if (format[0] != '%' || format[1] == '%') {
+			if (format[0] == '%')
+				format++;
+			size_t amount = 1;
+			while (format[amount] && format[amount] != '%')
+				amount++;
+			if (maxrem < amount) {
+				return -1;
+			}
+			if (!print(format, amount))
+				return -1;
+			format += amount;
+			written += amount;
+			continue;
+		}
+
+		const char* format_begun_at = format++;
+
+		if (*format == 'c') {
+			format++;
+			char c = (char) va_arg(parameters, int /* char promotes to int */);
+			if (!maxrem) {
+				return -1;
+			}
+			if (!print(&c, sizeof(c))) {
+				return -1;
+                        }
+			written++;
+		} else if (*format == 's') {
+			format++;
+			const char* str = va_arg(parameters, const char*);
+			size_t len = strlen(str);
+			if (maxrem < len) {
+				return -1;
+			}
+			if (!print(str, len)) {
+				return -1;
+                        }
+			written += len;
+		} else {
+			format = format_begun_at;
+			size_t len = strlen(format);
+			if (maxrem < len) {
+				return -1;
+			}
+			if (!print(format, len)) {
+				return -1;
+                        }
+			written += len;
+			format += len;
+		}
+	}
+
+	va_end(parameters);
+	return written;
+}
+
+/* todo: Implement stdio and the write system call. */
+int
+putchar(int ic)
+{
+	return ic;
+}
+
+int
+puts(const char* string)
+{
+        return printf("%s\n", string);
+}