first commit

charset.h

@@ -0,0 +1,15 @@
+#ifndef CHARSET_H
+#define CHARSET_H
+
+#include <stddef.h>
+
+/*
+ * Convert input (UTF-8, UTF-16 with BOM, or ISO-8859-1) to ISO-8859-1.
+ * Unmappable characters (> U+00FF) are replaced with '?'.
+ * Returns number of bytes written (excluding null terminator).
+ * Output is always null-terminated.
+ */
+int to_iso8859_1(const unsigned char *in, size_t in_len,
+                 char *out, size_t out_size);
+
+#endif