commit f98cb5d3552666ede73137d998162094d5a31a1a Author: Nick Mathewson nickm@torproject.org Date: Tue Feb 6 10:36:59 2018 -0500

Use "static-only" zstd functions to estimate memory usage.

These should provide better and more accurate results when we can use them; we fall back to the old approach when we can't. --- src/common/compress_zstd.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/common/compress_zstd.c b/src/common/compress_zstd.c index 799448744..02469ced9 100644 --- a/src/common/compress_zstd.c +++ b/src/common/compress_zstd.c @@ -139,9 +139,11 @@ struct tor_zstd_compress_state_t {

#ifdef HAVE_ZSTD /** Return an approximate number of bytes stored in memory to hold the - * Zstandard compression/decompression state. */ + * Zstandard compression/decompression state. This is a fake estimate + * based on inspecting the zstd source: tor_zstd_state_size_precalc() is + * more accurate when it's allowed to use "static-only" functions */ static size_t -tor_zstd_state_size_precalc(int compress, int preset) +tor_zstd_state_size_precalc_fake(int compress, int preset) { tor_assert(preset > 0);

@@ -198,6 +200,24 @@ tor_zstd_state_size_precalc(int compress, int preset)

return memory_usage; } + +/** Return an approximate number of bytes stored in memory to hold the + * Zstandard compression/decompression state. */ +static size_t +tor_zstd_state_size_precalc(int compress, int preset) +{ +#ifdef ZSTD_STATIC_LINKING_ONLY + if (tor_zstd_can_use_static_apis()) { + if (compress) { + return ZSTD_estimateCStreamSize(preset); + } else { + /* Could use DStream, but that takes a windowSize. */ + return ZSTD_estimateDCtxSize(); + } + } +#endif + return tor_zstd_state_size_precalc_fake(compress, preset); +} #endif /* defined(HAVE_ZSTD) */

/** Construct and return a tor_zstd_compress_state_t object using