+ int size = 1024;
+
+ for ( ;; )
+ {
+#if wxUSE_UNICODE_UTF8
+ BufferType tmp(str, size + 1);
+ typename BufferType::CharType *buf = tmp;
+#else
+ wxStringBuffer tmp(str, size + 1);
+ wxChar *buf = tmp;
+#endif
+
+ if ( !buf )
+ {
+ // out of memory
+
+ // in UTF-8 build, leaving uninitialized junk in the buffer
+ // could result in invalid non-empty UTF-8 string, so just
+ // reset the string to empty on failure:
+ buf[0] = '\0';
+ return -1;
+ }
+
+ // wxVsnprintf() may modify the original arg pointer, so pass it
+ // only a copy
+ va_list argptrcopy;
+ wxVaCopy(argptrcopy, argptr);
+
+#ifndef __WXWINCE__
+ // Set errno to 0 to make it determinate if wxVsnprintf fails to set it.
+ errno = 0;
+#endif
+ int len = wxVsnprintf(buf, size, format, argptrcopy);
+ va_end(argptrcopy);
+
+ // some implementations of vsnprintf() don't NUL terminate
+ // the string if there is not enough space for it so
+ // always do it manually
+ // FIXME: This really seems to be the wrong and would be an off-by-one
+ // bug except the code above allocates an extra character.
+ buf[size] = _T('\0');
+
+ // vsnprintf() may return either -1 (traditional Unix behaviour) or the
+ // total number of characters which would have been written if the
+ // buffer were large enough (newer standards such as Unix98)
+ if ( len < 0 )
+ {
+ // NB: wxVsnprintf() may call either wxCRT_VsnprintfW or
+ // wxCRT_VsnprintfA in UTF-8 build; wxUSE_WXVSNPRINTF
+ // is true if *both* of them use our own implementation,
+ // otherwise we can't be sure
+#if wxUSE_WXVSNPRINTF
+ // we know that our own implementation of wxVsnprintf() returns -1
+ // only for a format error - thus there's something wrong with
+ // the user's format string
+ buf[0] = '\0';
+ return -1;
+#else // possibly using system version
+ // assume it only returns error if there is not enough space, but
+ // as we don't know how much we need, double the current size of
+ // the buffer
+#ifndef __WXWINCE__
+ if( (errno == EILSEQ) || (errno == EINVAL) )
+ // If errno was set to one of the two well-known hard errors
+ // then fail immediately to avoid an infinite loop.
+ return -1;
+ else
+#endif // __WXWINCE__
+ // still not enough, as we don't know how much we need, double the
+ // current size of the buffer
+ size *= 2;
+#endif // wxUSE_WXVSNPRINTF/!wxUSE_WXVSNPRINTF
+ }
+ else if ( len >= size )
+ {
+#if wxUSE_WXVSNPRINTF
+ // we know that our own implementation of wxVsnprintf() returns
+ // size+1 when there's not enough space but that's not the size
+ // of the required buffer!
+ size *= 2; // so we just double the current size of the buffer
+#else
+ // some vsnprintf() implementations NUL-terminate the buffer and
+ // some don't in len == size case, to be safe always add 1
+ // FIXME: I don't quite understand this comment. The vsnprintf
+ // function is specifically defined to return the number of
+ // characters printed not including the null terminator.
+ // So OF COURSE you need to add 1 to get the right buffer size.
+ // The following line is definitely correct, no question.
+ size = len + 1;
+#endif
+ }
+ else // ok, there was enough space
+ {
+ break;
+ }
projects / wxWidgets.git / blobdiff