* string.c (tr_trans): should not be affected by the encoding of

  replacement unless actually modified.  [ruby-talk:328967]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@22505 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 19 insertions, 6 deletions

diff --git a/string.c b/string.c
index da36213f7c..46cd729894 100644
--- a/string.c
+++ b/string.c
@@ -4791,8 +4791,10 @@ tr_trans(VALUE str, VALUE src, VALUE repl, int sflag)
 	char *buf = ALLOC_N(char, max), *t = buf;
 
 	while (s < send) {
-	    c0 = c = rb_enc_codepoint(s, send, enc);
-	    tlen = clen = rb_enc_codelen(c, enc);
+	    int may_modify = 0;
+	    c0 = c = rb_enc_codepoint(s, send, e1);
+	    clen = rb_enc_codelen(c, e1);
+	    tlen = enc == e1 ? clen : rb_enc_codelen(c, enc);
 
 	    s += clen;
 	    if (c < 256) {
@@ -4819,6 +4821,7 @@ tr_trans(VALUE str, VALUE src, VALUE repl, int sflag)
 	    else {
 		save = -1;
 		c = c0;
+		if (enc != e1) may_modify = 1;
 	    }
 	    while (t - buf + tlen >= max) {
 		offset = t - buf;
@@ -4827,6 +4830,9 @@ tr_trans(VALUE str, VALUE src, VALUE repl, int sflag)
 		t = buf + offset;
 	    }
 	    rb_enc_mbcput(c, t, enc);
+	    if (may_modify && memcmp(s, t, tlen) != 0) {
+		modify = 1;
+	    }
 	    t += tlen;
 	}
 	*t = '\0';
@@ -4858,8 +4864,10 @@ tr_trans(VALUE str, VALUE src, VALUE repl, int sflag)
 	char *buf = ALLOC_N(char, max), *t = buf;
 
 	while (s < send) {
-	    c0 = c = rb_enc_codepoint(s, send, enc);
-	    tlen = clen = rb_enc_codelen(c, enc);
+	    int may_modify = 0;
+	    c0 = c = rb_enc_codepoint(s, send, e1);
+	    clen = rb_enc_codelen(c, e1);
+	    tlen = enc == e1 ? clen : rb_enc_codelen(c, enc);
 
 	    if (c < 256) {
 		c = trans[c];
@@ -4881,8 +4889,8 @@ tr_trans(VALUE str, VALUE src, VALUE repl, int sflag)
 		modify = 1;
 	    }
 	    else {
-		modify = 1;
 		c = c0;
+		if (enc != e1) may_modify = 1;
 	    }
 	    while (t - buf + tlen >= max) {
 		offset = t - buf;
@@ -4890,7 +4898,12 @@ tr_trans(VALUE str, VALUE src, VALUE repl, int sflag)
 		REALLOC_N(buf, char, max);
 		t = buf + offset;
 	    }
-	    if (s != t) rb_enc_mbcput(c, t, enc);
+	    if (s != t) {
+		rb_enc_mbcput(c, t, enc);
+		if (may_modify && memcmp(s, t, tlen) != 0) {
+		    modify = 1;
+		}
+	    }
 	    s += clen;
 	    t += tlen;
 	}