xplist: Improve writing of large PLIST_DATA nodes by growing buffer in advance

Instead of letting the buffer grow by just the amount of bytes currently
transformed to base64 - which is basically line by line - we now calculate
the size of the output blob in advance and grow the buffer accordingly.
This will reduce the amount of reallocs to just one, which is especially
important for large data blobs.
While this is a general improvement for all platforms, it is on platforms
like Windows where realloc() can be REALLY slow; converting a 20mb blob to
XML can easily take up to a minute (due to the several hundred thousand
calls to realloc()). With this commit, it will be fast again.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/xplist.c b/src/xplist.c
index 0e9b007..7f20ef2 100644
--- a/src/xplist.c
+++ b/src/xplist.c
@@ -294,6 +294,7 @@ static void node_to_xml(node_t* node, bytearray_t **outbuf, uint32_t depth)
             uint32_t maxread = ((76 - indent*8) / 4) * 3;
             size_t count = 0;
             size_t b64count = 0;
+            str_buf_grow(*outbuf, (node_data->length / 3 * 4) + 4 + (((node_data->length / maxread) + 1) * (indent+1)));
             while (j < node_data->length) {
                 for (i = 0; i < indent; i++) {
                     str_buf_append(*outbuf, "\t", 1);