From 21973c01ab5da205aa261cc41d0639642b8aaf15 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Fri, 18 Dec 2015 06:40:00 +0000
Subject: stringio.c: strio_unget_bytes

* ext/stringio/stringio.c (strio_unget_bytes): extract from
  strio_ungetbyte to share with strio_ungetc.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53185 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ext/stringio/stringio.c | 52 ++++++++++++++++++++-----------------------------
 1 file changed, 21 insertions(+), 31 deletions(-)

(limited to 'ext/stringio')

diff --git a/ext/stringio/stringio.c b/ext/stringio/stringio.c
index 23d7deba02..28e629599f 100644
--- a/ext/stringio/stringio.c
+++ b/ext/stringio/stringio.c
@@ -29,6 +29,7 @@ struct StringIO {
 };
 
 static void strio_init(int, VALUE *, struct StringIO *, VALUE);
+static VALUE strio_unget_bytes(struct StringIO *, const char *, long);
 
 #define IS_STRIO(obj) (rb_typeddata_is_kind_of((obj), &strio_data_type))
 #define error_inval(msg) (errno = EINVAL, rb_sys_fail(msg))
@@ -723,19 +724,17 @@ static VALUE
 strio_ungetc(VALUE self, VALUE c)
 {
     struct StringIO *ptr = readable(self);
-    long lpos, clen;
-    char *p, *pend;
     rb_encoding *enc, *enc2;
 
-    if (NIL_P(c)) return Qnil;
     check_modifiable(ptr);
+    if (NIL_P(c)) return Qnil;
     if (FIXNUM_P(c)) {
 	int cc = FIX2INT(c);
 	char buf[16];
 
 	enc = rb_enc_get(ptr->string);
 	rb_enc_mbcput(cc, buf, enc);
-	c = rb_enc_str_new(buf, rb_enc_codelen(cc, enc), enc);
+	return strio_unget_bytes(ptr, buf, rb_enc_codelen(cc, enc));
     }
     else {
 	SafeStringValue(c);
@@ -744,29 +743,10 @@ strio_ungetc(VALUE self, VALUE c)
 	if (enc != enc2 && enc != rb_ascii8bit_encoding()) {
 	    c = rb_str_conv_enc(c, enc2, enc);
 	}
+	strio_unget_bytes(ptr, RSTRING_PTR(c), RSTRING_LEN(c));
+	RB_GC_GUARD(c);
+	return Qnil;
     }
-    if (RSTRING_LEN(ptr->string) < ptr->pos) {
-	long len = RSTRING_LEN(ptr->string);
-	rb_str_resize(ptr->string, ptr->pos - 1);
-	memset(RSTRING_PTR(ptr->string) + len, 0, ptr->pos - len - 1);
-	rb_str_concat(ptr->string, c);
-	ptr->pos--;
-    }
-    else {
-	/* get logical position */
-	lpos = 0; p = RSTRING_PTR(ptr->string); pend = p + ptr->pos;
-	for (;;) {
-	    clen = rb_enc_mbclen(p, pend, enc);
-	    if (p+clen >= pend) break;
-	    p += clen;
-	    lpos++;
-	}
-	clen = p - RSTRING_PTR(ptr->string);
-	rb_str_update(ptr->string, lpos, ptr->pos ? 1 : 0, c);
-	ptr->pos = clen;
-    }
-
-    return Qnil;
 }
 
 /*
@@ -780,21 +760,32 @@ strio_ungetbyte(VALUE self, VALUE c)
 {
     struct StringIO *ptr = readable(self);
     char buf[1], *cp = buf;
-    long pos = ptr->pos, cl = 1, len, rest;
-    VALUE str = ptr->string;
-    char *s;
+    long cl = 1;
 
+    check_modifiable(ptr);
     if (NIL_P(c)) return Qnil;
     if (FIXNUM_P(c)) {
 	buf[0] = (char)FIX2INT(c);
+	return strio_unget_bytes(ptr, buf, 1);
     }
     else {
 	SafeStringValue(c);
 	cp = RSTRING_PTR(c);
 	cl = RSTRING_LEN(c);
 	if (cl == 0) return Qnil;
+	strio_unget_bytes(ptr, cp, cl);
+	RB_GC_GUARD(c);
+	return Qnil;
     }
-    check_modifiable(ptr);
+}
+
+static VALUE
+strio_unget_bytes(struct StringIO *ptr, const char *cp, long cl)
+{
+    long pos = ptr->pos, len, rest;
+    VALUE str = ptr->string;
+    char *s;
+
     len = RSTRING_LEN(str);
     rest = pos - len;
     if (cl > pos) {
@@ -816,7 +807,6 @@ strio_ungetbyte(VALUE self, VALUE c)
     }
     memcpy(s + pos, cp, cl);
     ptr->pos = pos;
-    RB_GC_GUARD(c);
     return Qnil;
 }
 
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