Simlify a string conversion from WCS to MBS on Windows.

diff --git a/libarchive/archive_string.c b/libarchive/archive_string.c
index ecdb01f0c8039247f07f676d29fdeb481c58f1b9..bf9f904bc2d5517bbc00086b5d2b9d799a3cb041 100644 (file)
--- a/libarchive/archive_string.c
+++ b/libarchive/archive_string.c
@@ -535,6 +535,7 @@ archive_wstring_append_from_mbs_in_codepage(struct archive_wstring *dest,
                }
        } else {
                DWORD mbflag;
+               size_t buffsize;
 
                if (sc == NULL)
                        mbflag = 0;
@@ -546,41 +547,24 @@ archive_wstring_append_from_mbs_in_codepage(struct archive_wstring *dest,
                } else
                        mbflag = MB_PRECOMPOSED;
 
-               if (length == 0) {
-                       /*
-                        * We do not need to convert any characters but make
-                        * sure `dest' has a valid buffer(no NULL pointer).
-                        */
-                       if (NULL == archive_wstring_ensure(dest,
-                           dest->length + 1))
+               buffsize = dest->length + length + 1;
+               do {
+                       /* Allocate memory for WCS. */
+                       if (NULL == archive_wstring_ensure(dest, buffsize))
                                return (-1);
-                       dest->s[dest->length] = L'\0';
-                       return (0);
-               }
-
-               /*
-                * Count how many bytes are needed for WCS.
-                */
-               count = MultiByteToWideChar(from_cp,
-                   mbflag, s, length, NULL, 0);
-               if (count == 0) {
-                       if (dest->s == NULL) {
-                               if (NULL == archive_wstring_ensure(dest,
-                                   dest->length + 1))
-                                       return (-1);
+                       /* Convert MBS to WCS. */
+                       count = MultiByteToWideChar(from_cp,
+                           mbflag, s, length, dest->s + dest->length,
+                           (dest->buffer_length >> 1) -1);
+                       if (count == 0 &&
+                           GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
+                               /* Expand the WCS buffer. */
+                               buffsize = dest->buffer_length << 1;
+                               continue;
                        }
-                       dest->s[dest->length] = L'\0';
-                       return (-1);
-               }
-               /* Allocate memory for WCS. */
-               if (NULL == archive_wstring_ensure(dest,
-                   dest->length + count + 1))
-                       return (-1);
-               /* Convert MBS to WCS. */
-               count = MultiByteToWideChar(from_cp,
-                   mbflag, s, length, dest->s + dest->length, count);
-               if (count == 0)
-                       ret = -1;
+                       if (count == 0 && length != 0)
+                               ret = -1;
+               } while (0);
        }
        dest->length += count;
        dest->s[dest->length] = L'\0';