intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 90 insertions, 0 deletions

diff --git a/library/cpp/digest/old_crc/crc.h b/library/cpp/digest/old_crc/crc.h
new file mode 100644
index 0000000000..4a3ce6d05e
--- /dev/null
+++ b/library/cpp/digest/old_crc/crc.h
@@ -0,0 +1,90 @@
+#pragma once
+
+#include <util/system/defaults.h>
+
+#define CRC16INIT 0
+#define CRC32INIT 0
+#define CRC64INIT ULL(0xFFFFFFFFFFFFFFFF)
+
+// CCITT CRC-16
+inline ui16 crc16(const char* buf, size_t buflen, ui32 crcinit = CRC16INIT) {
+    ui32 crc = 0xFFFF & ((crcinit >> 8) ^ (crcinit << 8));
+    const char* end = buf + buflen;
+    extern const ui32* crctab16;
+
+    while (buf < end) {
+        crc = (crc >> 8) ^ crctab16[(crc ^ *buf) & 0xFF];
+        ++buf;
+    }
+    return (ui16)(0xFFFF & ((crc >> 8) ^ (crc << 8)));
+}
+
+struct IdTR {
+    Y_FORCE_INLINE static ui8 T(ui8 a) {
+        return a;
+    }
+};
+
+// CCITT CRC-32
+template <class TR>
+inline ui32 crc32(const char* buf, size_t buflen, ui32 crcinit = CRC32INIT) {
+    ui32 crc = crcinit ^ 0xFFFFFFFF;
+    const char* end = buf + buflen;
+    extern const ui32* crctab32;
+
+    while (buf < end) {
+        crc = (crc >> 8) ^ crctab32[(crc ^ TR::T((ui8)*buf)) & 0xFF];
+        ++buf;
+    }
+
+    return crc ^ 0xFFFFFFFF;
+}
+
+inline ui32 crc32(const char* buf, size_t buflen, ui32 crcinit = CRC32INIT) {
+    return crc32<IdTR>(buf, buflen, crcinit);
+}
+
+inline ui32 crc32(const void* buf, size_t buflen, ui32 crcinit = CRC32INIT) {
+    return crc32((const char*)buf, buflen, crcinit);
+}
+
+// Copyright (C) Sewell Development Corporation, 1994 - 1998.
+inline ui64 crc64(const void* buf, size_t buflen, ui64 crcinit = CRC64INIT) {
+    const unsigned char* ptr = (const unsigned char*)buf;
+    extern const ui64* crctab64;
+
+    while (buflen--) {
+        crcinit = crctab64[((crcinit >> 56) ^ *ptr++)] ^ (crcinit << 8);
+    }
+    return crcinit;
+}
+
+namespace NCrcPrivate {
+    template <unsigned N>
+    struct TCrcHelper;
+
+#define DEF_CRC_FUNC(t)                                                          \
+    template <>                                                                  \
+    struct TCrcHelper<t> {                                                       \
+        static const ui##t Init = CRC##t##INIT;                                  \
+        static inline ui##t Crc(const void* buf, size_t buflen, ui##t crcinit) { \
+            return crc##t((const char*)buf, buflen, crcinit);                    \
+        }                                                                        \
+    };
+
+    DEF_CRC_FUNC(16)
+    DEF_CRC_FUNC(32)
+    DEF_CRC_FUNC(64)
+
+#undef DEF_CRC_FUNC
+}
+
+template <class T>
+static inline T Crc(const void* buf, size_t len, T init) {
+    return (T)NCrcPrivate::TCrcHelper<8 * sizeof(T)>::Crc(buf, len, init);
+}
+
+template <class T>
+static inline T Crc(const void* buf, size_t len) {
+    return Crc<T>(buf, len, (T)NCrcPrivate::TCrcHelper<8 * sizeof(T)>::Init);
+}