Add function to check if a given compression method is supported.

This patch adds support for checking if a given `compress_method_t` is
supported by the currently running Tor instance using
`tor_compress_supports_method()`.

See: https://bugs.torproject.org/21662

1 files changed, 5 insertions, 1 deletions

diff --git a/src/common/compress.h b/src/common/compress.h
index 1fd4325b7e..87306f5fb9 100644
--- a/src/common/compress.h
+++ b/src/common/compress.h
@@ -13,7 +13,8 @@
 
 /** Enumeration of what kind of compression to use.  Only ZLIB_METHOD and
  * GZIP_METHOD is guaranteed to be supported by the compress/uncompress
- * functions here. */
+ * functions here. Call tor_compress_supports_method() to check if a given
+ * compression schema is supported by Tor. */
 typedef enum {
   NO_METHOD=0,
   GZIP_METHOD=1,
@@ -51,6 +52,9 @@ tor_compress_memory_level(compression_level_t level);
 int
 tor_compress_is_compression_bomb(size_t size_in, size_t size_out);
 
+int
+tor_compress_supports_method(compress_method_t method);
+
 size_t
 tor_compress_get_total_allocation(void);