[ps] Check for end-of-stream after advancing character.

Whilst writing the base85 stream we advance an extra character if we spot
a '~', however we need to be paranoid that we have not stepped beyond the
end of the data for this write.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/cairo-ps-surface.c b/src/cairo-ps-surface.c
index 77c30355..b20c5b10 100644
--- a/src/cairo-ps-surface.c
+++ b/src/cairo-ps-surface.c
@@ -1583,7 +1583,10 @@ _string_array_stream_write (cairo_output_stream_t *base,
 	    _cairo_output_stream_write (stream->output, &c, 1);
 	    stream->column++;
 	    stream->string_size++;
-	    length--;
+
+	    if (length-- == 0)
+		break;
+
 	    c = *data++;
 	}
 	_cairo_output_stream_write (stream->output, &c, 1);