intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 74 insertions, 0 deletions

diff --git a/library/cpp/compproto/compressor.h b/library/cpp/compproto/compressor.h
new file mode 100644
index 00000000000..14b335e13ca
--- /dev/null
+++ b/library/cpp/compproto/compressor.h
@@ -0,0 +1,74 @@
+#pragma once
+
+#include <util/system/defaults.h>
+
+namespace NCompProto {
+    struct TEmpty {
+    };
+
+    struct TTable {
+        TTable() {
+            for (size_t i = 0; i < 64; ++i) {
+                CodeBase[i] = 0;
+                CodeMask[i] = 0;
+                Length[i] = 0;
+                PrefLength[i] = 0;
+                Id[i] = 0;
+            }
+        }
+        ui32 CodeBase[64];
+        ui32 CodeMask[64];
+        ui8 Length[64];
+        ui8 PrefLength[64];
+        ui8 Id[64];
+        enum {
+            PAGE_BOUND = 4096,
+#ifdef WITH_VALGRIND
+            SAFE_MODE = 1,
+#else
+#if defined(__has_feature)
+#if __has_feature(address_sanitizer)
+            SAFE_MODE = 1,
+#else
+            SAFE_MODE = 0,
+#endif
+#else
+            SAFE_MODE = 0,
+#endif
+#endif
+        };
+        ui32 inline Decompress(const ui8* codes, ui64& offset) const {
+            codes += (offset >> 3);
+            size_t pageOff = size_t(codes) % PAGE_BOUND;
+            size_t readOff = offset & 7;
+            if (pageOff > PAGE_BOUND - 8 || SAFE_MODE) {
+                size_t off = 8;
+                ui64 res = codes[0];
+                ++codes;
+                ui64 indexCur = ((res + 0x0000) >> readOff) & 63;
+                ui64 indexAlt = ((res + 0xff00) >> readOff) & 63;
+                if (Id[indexCur] != Id[indexAlt]) {
+                    res += (ui64(codes[0]) << off);
+                    ++codes;
+                    off += 8;
+                    indexCur = (res >> readOff) & 63;
+                }
+                ui64 index = indexCur;
+                ui64 length = Length[index];
+                while (off < readOff + length) {
+                    res += (ui64(codes[0]) << off);
+                    ++codes;
+                    off += 8;
+                }
+                offset += length;
+                ui64 code = res >> readOff;
+                return (((ui32)(code >> PrefLength[index])) & CodeMask[index]) + CodeBase[index];
+            }
+            ui64 code = ((const ui64*)(codes))[0] >> readOff;
+            ui64 index = code & 63;
+            offset += Length[index];
+            return (((ui32)(code >> PrefLength[index])) & CodeMask[index]) + CodeBase[index];
+        }
+    };
+
+}