merge revision(s) 55547,55551,55552,55555,55557,55559,55568,55575,55691: [Backport #12536]

	* string.c: Fix memory corruptions when using UTF-16/32 strings.
	  [Bug #12536] [ruby-dev:49699]

	* string.c (TERM_LEN_MAX): Macro for the longest TERM_FILL length,
	  the same as largest value of rb_enc_mbminlen(enc) among encodings.

	* string.c (str_new, rb_str_buf_new, str_shared_replace): Allocate
	  +TERM_LEN_MAX bytes instead of +1. This change may increase memory
	  usage.

	* string.c (rb_str_new_with_class): Use TERM_LEN of the "obj".

	* string.c (rb_str_plus, rb_str_justify): Use str_new0 which is aware
	  of termlen.

	* string.c (str_shared_replace): Copy +termlen bytes instead of +1.

	* string.c (rb_str_times): termlen should not be included in capa.

	* string.c (RESIZE_CAPA_TERM): When using RSTRING_EMBED_LEN_MAX,
	  termlen should be counted with it because embedded strings are
	  also processed by TERM_FILL.

	* string.c (rb_str_capacity, str_shared_replace, str_buf_cat): ditto.

	* string.c (rb_str_drop_bytes, rb_str_setbyte, str_byte_substr): ditto.

	* string.c (rb_str_subseq, str_substr): When RSTRING_EMBED_LEN_MAX
	  is used, TERM_LEN(str) should be considered with it because
	  embedded strings are also processed by TERM_FILL.
	  Additional fix for [Bug #12536] [ruby-dev:49699].
	  Additional fix for [Bug #12536] [ruby-dev:49699].

	* string.c (rb_usascii_str_new, rb_utf8_str_new): Specify termlen
	  which is apparently 1 for the encodings.

	* string.c (str_new0_cstr): New static function to create a String
	  object from a C string with specifying termlen.

	* string.c (rb_usascii_str_new_cstr, rb_utf8_str_new_cstr): Specify
	  termlen by using new str_new0_cstr().

	* string.c (str_new_static): Specify termlen from the given encoding
	  when creating a new String object is needed.

	* string.c (rb_tainted_str_new_with_enc): New function to create a
	  tainted String object with the given encoding. This means that
	  the termlen is correctly specified. Curretly static function.
	  The function name might be renamed to rb_tainted_enc_str_new
	  or rb_enc_tainted_str_new.

	* string.c (rb_external_str_new_with_enc): Use encoding by using the
	  above rb_tainted_str_new_with_enc().

	* string.c (str_fill_term): When termlen increases, re-allocation
	  of memory for termlen should always be needed.
	  In this fix, if possible, decrease capa instead of realloc.
	  [Bug #12536] [ruby-dev:49699]

	* string.c: Partially reverts r55547 and r55555.
	  ChangeLog about the reverted changes are also deleted in this file.
	  [Bug #12536] [ruby-dev:49699] [ruby-dev:49702]

	* string.c: Specify termlen as far as possible.
	  the termlen is correctly specified. Currently static function.

	* string.c (rb_str_change_terminator_length): New function to change
	  termlen and resize heap for the terminator. This is split from
	  rb_str_fill_terminator (str_fill_term) because filling terminator
	  and changing terminator length are different things. [Bug #12536]

	* internal.h: declaration for rb_str_change_terminator_length.

	* string.c (str_fill_term): Simplify only to zero-fill the terminator.
	  For non-shared strings, it assumes that (capa + termlen) bytes of
	  heap is allocated. This partially reverts r55557.

	* encoding.c (rb_enc_associate_index): rb_str_change_terminator_length
	  is used, and it should be called whenever the termlen is changed.

	* string.c (str_capacity): New static function to return capacity
	  of a string with the given termlen, because the termlen may
	  sometimes be different from TERM_LEN(str) especially during
	  changing termlen or filling terminator with specific termlen.

	* string.c (rb_str_capacity): Use str_capacity.

	* string.c (str_buf_cat): Fix capa size for embed string.
	  Fix bug in r55547. [Bug #12536]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@56301 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 2 insertions, 2 deletions

diff --git a/encoding.c b/encoding.c
index 1c6719c910..07b32f5f83 100644
--- a/encoding.c
+++ b/encoding.c
@@ -821,8 +821,8 @@ rb_enc_associate_index(VALUE obj, int idx)
     }
     termlen = rb_enc_mbminlen(enc);
     oldtermlen = rb_enc_mbminlen(rb_enc_from_index(oldidx));
-    if (oldtermlen < termlen && RB_TYPE_P(obj, T_STRING)) {
-	rb_str_fill_terminator(obj, termlen);
+    if (oldtermlen != termlen && RB_TYPE_P(obj, T_STRING)) {
+	rb_str_change_terminator_length(obj, oldtermlen, termlen);
     }
     enc_set_index(obj, idx);
     return obj;