win32.c: fix wrong trimming

* win32/win32.c (wstr_to_mbstr, mbstr_to_wstr): fix wrong trimming.
  WideCharToMultiByte() and MultiByteToWideChar() do not count
  NUL-terminator in the size for conversion result, unless the input
  length is -1.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42384 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 16 insertions, 8 deletions

diff --git a/win32/win32.c b/win32/win32.c
index 0a03d7bcca..ab2b64a5e4 100644
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -1954,10 +1954,14 @@ static char *
 wstr_to_mbstr(UINT cp, const WCHAR *wstr, int clen, long *plen)
 {
     char *ptr;
-    int len = WideCharToMultiByte(cp, 0, wstr, clen, NULL, 0, NULL, NULL) - 1;
-    if (!(ptr = malloc(len + 1))) return 0;
-    WideCharToMultiByte(cp, 0, wstr, clen, ptr, len + 1, NULL, NULL);
-    if (plen) *plen = len;
+    int len = WideCharToMultiByte(cp, 0, wstr, clen, NULL, 0, NULL, NULL);
+    if (!(ptr = malloc(len))) return 0;
+    WideCharToMultiByte(cp, 0, wstr, clen, ptr, len, NULL, NULL);
+    if (plen) {
+	/* exclude NUL only if NUL-terminated string */
+	if (clen == -1) --len;
+	*plen = len;
+    }
     return ptr;
 }
 
@@ -1966,10 +1970,14 @@ static WCHAR *
 mbstr_to_wstr(UINT cp, const char *str, int clen, long *plen)
 {
     WCHAR *ptr;
-    int len = MultiByteToWideChar(cp, 0, str, clen, NULL, 0) - 1;
-    if (!(ptr = malloc(sizeof(WCHAR) * (len + 1)))) return 0;
-    MultiByteToWideChar(cp, 0, str, clen, ptr, len + 1);
-    if (plen) *plen = len;
+    int len = MultiByteToWideChar(cp, 0, str, clen, NULL, 0);
+    if (!(ptr = malloc(sizeof(WCHAR) * len))) return 0;
+    MultiByteToWideChar(cp, 0, str, clen, ptr, len);
+    if (plen) {
+	/* exclude NUL only if NUL-terminated string */
+	if (clen == -1) --len;
+	*plen = len;
+    }
     return ptr;
 }