add zstd fast levels from 1 to 7

zstd supports negative compression levels (`--fast=XXX` param in zstd CLI), so add them here also
commit_hash:ed7231a6f341cd120dfea0d4b0b481962df835ab

Author: tobo

library/cpp/blockcodecs/codecs/zstd/zstd.cpp

@@ -5,36 +5,38 @@
 #define ZSTD_STATIC_LINKING_ONLY
 #include <contrib/libs/zstd/include/zstd.h>
 
+#include <utility>
+
 using namespace NBlockCodecs;
 
 namespace {
     struct TZStd08Codec: public TAddLengthCodec<TZStd08Codec> {
-        inline TZStd08Codec(unsigned level)
+        TZStd08Codec(int level, TString name)
             : Level(level)
-            , MyName(TStringBuf("zstd08_") + ToString(Level))
+            , MyName(std::move(name))
         {
         }
 
-        static inline size_t CheckError(size_t ret, const char* what) {
-            if (ZSTD_isError(ret)) {
+        static size_t CheckError(size_t ret, const char* what) {
+            if (Y_UNLIKELY(ZSTD_isError(ret))) {
                 ythrow yexception() << what << TStringBuf(" zstd error: ") << ZSTD_getErrorName(ret);
             }
 
             return ret;
         }
 
-        static inline size_t DoMaxCompressedLength(size_t l) noexcept {
+        static size_t DoMaxCompressedLength(size_t l) noexcept {
             return ZSTD_compressBound(l);
         }
 
-        inline size_t DoCompress(const TData& in, void* out) const {
+        size_t DoCompress(const TData& in, void* out) const {
             return CheckError(ZSTD_compress(out, DoMaxCompressedLength(in.size()), in.data(), in.size(), Level), "compress");
         }
 
-        inline void DoDecompress(const TData& in, void* out, size_t dsize) const {
+        static void DoDecompress(const TData& in, void* out, size_t dsize) {
             const size_t res = CheckError(ZSTD_decompress(out, dsize, in.data(), in.size()), "decompress");
 
-            if (res != dsize) {
+            if (Y_UNLIKELY(res != dsize)) {
                 ythrow TDecompressError(dsize, res);
             }
         }
@@ -43,15 +45,20 @@ namespace {
             return MyName;
         }
 
-        const unsigned Level;
+        const int Level;
         const TString MyName;
     };
 
     struct TZStd08Registrar {
         TZStd08Registrar() {
             for (int i = 1; i <= ZSTD_maxCLevel(); ++i) {
-                RegisterCodec(MakeHolder<TZStd08Codec>(i));
-                RegisterAlias("zstd_" + ToString(i), "zstd08_" + ToString(i));
+                const TString name = "zstd08_"sv + ToString(i);
+                RegisterCodec(MakeHolder<TZStd08Codec>(i, name));
+                RegisterAlias("zstd_"sv + ToString(i), name);
+            }
+
+            for (int i = 1; i <= 7; ++i) {
+                RegisterCodec(MakeHolder<TZStd08Codec>(-i, "zstd_fast_"sv + ToString(i)));
             }
         }
     };