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authorsonots <sonots@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2017-06-21 07:43:26 +0000
committersonots <sonots@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2017-06-21 07:43:26 +0000
commit2cf26ae662667618fa91d7b3adbbf515361e3d84 (patch)
tree7cb10b195876d2defb42961be4823620ab550e65
parent6980bf408cd23d0f9ba7c56921a72b41d8686edd (diff)
downloadruby-2cf26ae662667618fa91d7b3adbbf515361e3d84.tar.gz
string.c: add String#delete_prefix and String#delete_prefix!
to remove leading substr [Feature #12694] [fix GH-1632] * string.c (rb_str_delete_prefix_bang): add a new method to remove prefix destuctively. * string.c (rb_str_delete_prefix): add a new method to remove prefix non-destuctively. * test/ruby/test_string.rb: add tests. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59132 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
-rw-r--r--NEWS2
-rw-r--r--string.c68
-rw-r--r--test/ruby/test_string.rb95
3 files changed, 165 insertions, 0 deletions
diff --git a/NEWS b/NEWS
index 3f9f620850..d423e8abbd 100644
--- a/NEWS
+++ b/NEWS
@@ -85,6 +85,8 @@ with all sufficient information, see the ChangeLog file or Redmine
(same as "literal".freeze in Ruby 2.1+) [Feature #13295]
* String#{casecmp,casecmp?} now return nil for non-string arguments
instead of raising a TypeError. [Bug #13312]
+ * String##delete_prefix is added to remove prefix [Feature #12694]
+ * String#delete_prefix! is added to remove prefix destructively [Feature #12694]
=== Stdlib updates (outstanding ones only)
diff --git a/string.c b/string.c
index 052e0197a1..072f1329ee 100644
--- a/string.c
+++ b/string.c
@@ -9191,6 +9191,72 @@ rb_str_end_with(int argc, VALUE *argv, VALUE str)
return Qfalse;
}
+static long
+deleted_prefix_length(VALUE str, VALUE prefix)
+{
+ char *strptr, *prefixptr;
+ long olen, prefixlen;
+
+ StringValue(prefix);
+ if (is_broken_string(prefix)) return 0;
+ rb_enc_check(str, prefix);
+
+ /* return 0 if not start with prefix */
+ prefixlen = RSTRING_LEN(prefix);
+ if (prefixlen <= 0) return 0;
+ olen = RSTRING_LEN(str);
+ if (olen < prefixlen) return 0;
+ strptr = RSTRING_PTR(str);
+ prefixptr = RSTRING_PTR(prefix);
+ if (memcmp(strptr, prefixptr, prefixlen) != 0) return 0;
+
+ return prefixlen;
+}
+
+/*
+ * call-seq:
+ * str.delete_prefix!(prefix) -> self or nil
+ *
+ * Deletes leading <code>prefix</code> from <i>str</i>, returning
+ * <code>nil</code> if no change was made.
+ *
+ * "hello".delete_prefix!("hel") #=> "lo"
+ * "hello".delete_prefix!("llo") #=> nil
+ */
+
+static VALUE
+rb_str_delete_prefix_bang(VALUE str, VALUE prefix)
+{
+ long prefixlen;
+ str_modify_keep_cr(str);
+
+ prefixlen = deleted_prefix_length(str, prefix);
+ if (prefixlen <= 0) return Qnil;
+
+ return rb_str_drop_bytes(str, prefixlen);
+}
+
+/*
+ * call-seq:
+ * str.delete_prefix(prefix) -> new_str
+ *
+ * Returns a copy of <i>str</i> with leading <code>prefix</code> deleted.
+ *
+ * "hello".delete_prefix("hel") #=> "lo"
+ * "hello".delete_prefix("llo") #=> "hello"
+ */
+
+static VALUE
+rb_str_delete_prefix(VALUE str, VALUE prefix)
+{
+ long prefixlen;
+
+ prefixlen = deleted_prefix_length(str, prefix);
+ if (prefixlen <= 0) return rb_str_dup(str);
+
+ return rb_str_subseq(str, prefixlen, RSTRING_LEN(str) - prefixlen);
+}
+
void
rb_str_setter(VALUE val, ID id, VALUE *var)
{
@@ -10346,6 +10412,7 @@ Init_String(void)
rb_define_method(rb_cString, "strip", rb_str_strip, 0);
rb_define_method(rb_cString, "lstrip", rb_str_lstrip, 0);
rb_define_method(rb_cString, "rstrip", rb_str_rstrip, 0);
+ rb_define_method(rb_cString, "delete_prefix", rb_str_delete_prefix, 1);
rb_define_method(rb_cString, "sub!", rb_str_sub_bang, -1);
rb_define_method(rb_cString, "gsub!", rb_str_gsub_bang, -1);
@@ -10354,6 +10421,7 @@ Init_String(void)
rb_define_method(rb_cString, "strip!", rb_str_strip_bang, 0);
rb_define_method(rb_cString, "lstrip!", rb_str_lstrip_bang, 0);
rb_define_method(rb_cString, "rstrip!", rb_str_rstrip_bang, 0);
+ rb_define_method(rb_cString, "delete_prefix!", rb_str_delete_prefix_bang, 1);
rb_define_method(rb_cString, "tr", rb_str_tr, 2);
rb_define_method(rb_cString, "tr_s", rb_str_tr_s, 2);
diff --git a/test/ruby/test_string.rb b/test/ruby/test_string.rb
index 0fd0538d00..a12af416ab 100644
--- a/test/ruby/test_string.rb
+++ b/test/ruby/test_string.rb
@@ -2416,6 +2416,101 @@ CODE
assert_equal("\u3042", s4)
end
+ def test_delete_prefix
+ assert_raise(TypeError) { 'hello'.delete_prefix(nil) }
+ assert_raise(TypeError) { 'hello'.delete_prefix(1) }
+ assert_raise(TypeError) { 'hello'.delete_prefix(/hel/) }
+
+ s = S("hello")
+ assert_equal("lo", s.delete_prefix('hel'))
+ assert_equal("hello", s)
+
+ s = S("hello")
+ assert_equal("hello", s.delete_prefix('lo'))
+ assert_equal("hello", s)
+
+ s = S("\u{3053 3093 306b 3061 306f}")
+ assert_equal("\u{306b 3061 306f}", s.delete_prefix("\u{3053 3093}"))
+ assert_equal("\u{3053 3093 306b 3061 306f}", s)
+
+ s = S("\u{3053 3093 306b 3061 306f}")
+ assert_equal("\u{3053 3093 306b 3061 306f}", s.delete_prefix('hel'))
+ assert_equal("\u{3053 3093 306b 3061 306f}", s)
+
+ s = S("hello")
+ assert_equal("hello", s.delete_prefix("\u{3053 3093}"))
+ assert_equal("hello", s)
+
+ # skip if argument is a broken string
+ s = S("\xe3\x81\x82")
+ assert_equal("\xe3\x81\x82", s.delete_prefix("\xe3"))
+ assert_equal("\xe3\x81\x82", s)
+
+ # clear coderange
+ s = S("\u{3053 3093}hello")
+ assert_not_predicate(s, :ascii_only?)
+ assert_predicate(s.delete_prefix("\u{3053 3093}"), :ascii_only?)
+
+ # argument should be converted to String
+ klass = Class.new {|klass| def to_str; 'a'; end }
+ s = S("abba")
+ assert_equal("bba", s.delete_prefix(klass.new))
+ assert_equal("abba", s)
+ end
+
+ def test_delete_prefix_bang
+ assert_raise(TypeError) { 'hello'.delete_prefix!(nil) }
+ assert_raise(TypeError) { 'hello'.delete_prefix!(1) }
+ assert_raise(TypeError) { 'hello'.delete_prefix!(/hel/) }
+
+ s = S("hello")
+ assert_equal("lo", s.delete_prefix!('hel'))
+ assert_equal("lo", s)
+
+ s = S("hello")
+ assert_equal(nil, s.delete_prefix!('lo'))
+ assert_equal("hello", s)
+
+ s = S("\u{3053 3093 306b 3061 306f}")
+ assert_equal("\u{306b 3061 306f}", s.delete_prefix!("\u{3053 3093}"))
+ assert_equal("\u{306b 3061 306f}", s)
+
+ s = S("\u{3053 3093 306b 3061 306f}")
+ assert_equal(nil, s.delete_prefix!('hel'))
+ assert_equal("\u{3053 3093 306b 3061 306f}", s)
+
+ s = S("hello")
+ assert_equal(nil, s.delete_prefix!("\u{3053 3093}"))
+ assert_equal("hello", s)
+
+ # skip if argument is a broken string
+ s = S("\xe3\x81\x82")
+ assert_equal(nil, s.delete_prefix!("\xe3"))
+ assert_equal("\xe3\x81\x82", s)
+
+ # clear coderange
+ s = S("\u{3053 3093}hello")
+ assert_not_predicate(s, :ascii_only?)
+ assert_predicate(s.delete_prefix!("\u{3053 3093}"), :ascii_only?)
+
+ # argument should be converted to String
+ klass = Class.new {|klass| def to_str; 'a'; end }
+ s = S("abba")
+ assert_equal("bba", s.delete_prefix!(klass.new))
+ assert_equal("bba", s)
+
+ s = S("ax").freeze
+ assert_raise_with_message(RuntimeError, /frozen/) {s.delete_prefix!("a")}
+
+ s = S("ax")
+ o = Struct.new(:s).new(s)
+ def o.to_str
+ s.freeze
+ "a"
+ end
+ assert_raise_with_message(RuntimeError, /frozen/) {s.delete_prefix!(o)}
+ end
+
=begin
def test_symbol_table_overflow
assert_in_out_err([], <<-INPUT, [], /symbol table overflow \(symbol [a-z]{8}\) \(RuntimeError\)/)