Get chopn_inplace working, and puzzle over strlen/bufused differences.

git-svn-id: https://svn.parrot.org/parrot/branches/strings@35630 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

pseudocode/Encodings.pm

@@ -1,6 +1,6 @@
 class ParrotEncoding::Base::Fixed {
     our $.width;
-    method string_length($str) { return $str.bufused / $str.encoding.width; }
+    method string_length($str) { return $str.strlen / $str.encoding.width; }
 
     method string_char_iterate($str, $callback, $parameter) {
         for (0..self.string_length($str)-1) { 
@@ -20,6 +20,8 @@ class ParrotEncoding::Base::Fixed {
             $callback($str.encoding.grapheme_at_index($str,$_), $parameter); 
         }
     }
+
+    method chopn_inplace($str, $n) { $str.strlen -= $n * $.width }
 }
 
 class ParrotEncoding::Base::Variable {

pseudocode/ParrotString.pm

@@ -85,7 +85,9 @@ sub Parrot_string_grapheme_substr($src, $offset, $len) { ... }
 sub Parrot_string_replace($src, $offset, $len, $replacement) { ... }
 sub Parrot_string_grapheme_replace($src, $offset, $len, $replacement) { ... }
 sub Parrot_string_chopn($src, $count) { ... }
-sub Parrot_string_chopn_inplace($src, $count) { ... }
+sub Parrot_string_chopn_inplace($str, $count) {
+    return $str.encoding.chopn_inplace($str, $count);
+}
 
 sub Parrot_string_grapheme_chopn($src, $count) { 
     return Parrot_string_replace($src, Parrot_string_grapheme_length($src) - $count, $count, undef);

pseudocode/t/create.t

@@ -1,12 +1,15 @@
 use Test;
 use ParrotString;
-plan 8;
+plan 10;
 
 my $str = Parrot_string_new_init("flurble", 4, ParrotCharset::ASCII, ParrotEncoding::Byte);
 ok($str.charset ~~ ParrotCharset::ASCII, "Charset set properly");
-is(Parrot_string_grapheme_length($str), 4, "String length correct");
+is(Parrot_string_grapheme_length($str), 4, "Grapheme length correct");
 is(Parrot_string_byte_length($str), 4, "String length correct");
 is(Parrot_string_index($str, 1), ord("l"), "String indexing");
+Parrot_string_chopn_inplace($str, 2);
+is(Parrot_string_grapheme_length($str), 2, "Grapheme length correct post-chop");
+is(Parrot_string_byte_length($str), 2, "String length correct post-chop");
 
 $str = Parrot_string_new_init("\xce\xb3\xce\xb5\xce\xb9\xce\xac \xcf\x83\xce\xbf\xcf\x85 \xce\xba\xcf\x8c\xcf\x83\xce\xbc\xce\xbf\xcf\x82", 28, ParrotCharset::Unicode, ParrotEncoding::UTF8);
 ok($str.charset ~~ ParrotCharset::Unicode, "We're unicode");