FIX: ICONV from UTF16 with BOM does not skip the BOM on Windows

fixes: #19

Author: Oldes

src/core/u-iconv.c

@@ -611,10 +611,21 @@ static REBYTE* get_codepage_name(REBVAL *cp)
 		return R_NONE;
 	}
 
+	REBYTE *bp;
+
 	if (cp == 1200 || cp == 1201) { // data are already wide (UTF-16LE or UTF-16BE)
-		dst_len = VAL_LEN(data) / 2;
+		dst_len = src_len / 2;
 		dst_wide = Make_Series(dst_len + 1, 2, FALSE);
-		memcpy(BIN_HEAD(dst_wide), VAL_BIN_AT(data), VAL_LEN(data));
+		bp = VAL_BIN_AT(data);
+		if ( src_len >= 2 && (
+			(0xFF == bp[0] && 0xFE == bp[1]) ||
+			(0xFE == bp[0] && 0xFF == bp[1])
+		)) { // skip BOM
+			src_len -= 2;
+			dst_len -= 1;
+			bp += 2;
+		}
+		memcpy(BIN_HEAD(dst_wide), bp, src_len);
 		dst_wide->tail = dst_len;
 		TERM_SERIES(dst_wide);
 		if (ref_to) {

src/tests/units/series-test.r3

@@ -661,6 +661,10 @@ Rebol [
 	--assert "" = iconv #{} 28592
 	--assert "" = iconv #{} 'utf8
 
+--test-- "ICONV from UTF-16 with BOM"
+	--assert "Writer" = iconv #{FEFF005700720069007400650072} 'UTF-16BE
+	--assert "Writer" = iconv #{FFFE570072006900740065007200} 'UTF-16LE
+
 
 --test-- "ICONV/TO (conversion to different codepage - binary result)"
 	bin: to binary! txt ; normaly conversion is done to UTF-8