options/ansi: Impl tolower, strcasecmp and strcoll

options/ansi/generic/ctype-stubs.cpp

@@ -48,9 +48,12 @@ int isxdigit(int c) {
 }
 
 int tolower(int c) {
-	__ensure(!"Not implemented");
-	__builtin_unreachable();
+	// TODO: this really needs to be redesigned and support other charsets.
+	if(c >= 'A' && c <= 'Z')
+		return c - 'A' + 'a';
+	return c;
 }
+
 int toupper(int c) {
 	// TODO: this really needs to be redesigned and support other charsets.
 	if(c >= 'a' && c <= 'z')

options/ansi/generic/string-stubs.cpp

@@ -80,10 +80,12 @@ int strcmp(const char *a, const char *b) {
 		i++;
 	}
 }
+
 int strcoll(const char *a, const char *b) {
-	__ensure(!"Not implemented");
-	__builtin_unreachable();
+	// TODO: strcoll should take "LC_COLLATE" into account.
+	return strcmp(a, b);
 }
+
 int strncmp(const char *a, const char *b, size_t max_size) {
 	size_t i = 0;
 	while(true) {

options/posix/generic/strings-stubs.cpp

@@ -1,16 +1,30 @@
 
 #include <strings.h>
 
+#include <ctype.h>
 #include <bits/ensure.h>
 
 int ffs(int word) {
 	__ensure(!"Not implemented");
 	__builtin_unreachable();
 }
+
 int strcasecmp(const char *a, const char *b) {
-	__ensure(!"Not implemented");
-	__builtin_unreachable();
+	size_t i = 0;
+	while(true) {
+		unsigned char a_byte = tolower(a[i]);
+		unsigned char b_byte = tolower(b[i]);
+		if(!a_byte && !b_byte)
+			return 0;
+		// If only one char is null, one of the following cases applies.
+		if(a_byte < b_byte)
+			return -1;
+		if(a_byte > b_byte)
+			return 1;
+		i++;
+	}
 }
+
 int strncasecmp(const char *a, const char *b, size_t size) {
 	__ensure(!"Not implemented");
 	__builtin_unreachable();