Add CRC checksums to EBG and turns data

include/util/connectivity_checksum.hpp

@@ -0,0 +1,90 @@
+#ifndef CONNECTIVITY_CHECKSUM_HPP
+#define CONNECTIVITY_CHECKSUM_HPP
+
+#include <zlib.h>
+
+#include <boost/assert.hpp>
+
+#include <array>
+#include <climits>
+#include <cstdint>
+
+namespace osrm
+{
+namespace util
+{
+
+struct ConnectivityChecksum
+{
+    ConnectivityChecksum() : checksum(0), length(0), byte_number(0), bit_number(0) {}
+
+    void process_byte(unsigned char byte)
+    {
+        BOOST_ASSERT(byte_number < buffer.size());
+
+        if (bit_number > 0)
+        {
+            bit_number = 0;
+            ++byte_number;
+            ++length;
+        }
+        flush_bytes();
+
+        buffer[byte_number] = byte;
+        ++byte_number;
+        ++length;
+        flush_bytes();
+
+        buffer[byte_number] = 0;
+    }
+
+    void process_bit(bool bit)
+    {
+        BOOST_ASSERT(byte_number < buffer.size());
+        BOOST_ASSERT(bit_number < CHAR_BIT);
+
+        buffer[byte_number] = (buffer[byte_number] << 1) | static_cast<unsigned char>(bit);
+        if (++bit_number >= CHAR_BIT)
+        {
+            bit_number = 0;
+            ++byte_number;
+            ++length;
+            flush_bytes();
+            buffer[byte_number] = 0;
+        }
+    }
+
+    std::uint32_t update_checksum(std::uint32_t current)
+    {
+        if (bit_number > 0)
+        {
+            ++byte_number;
+            ++length;
+        }
+        checksum = crc32(checksum, buffer.data(), byte_number);
+        checksum = crc32_combine(current, checksum, length);
+        length = byte_number = bit_number = 0;
+        buffer[byte_number] = 0;
+        return checksum;
+    }
+
+  private:
+    void flush_bytes()
+    {
+        if (byte_number >= buffer.size())
+        {
+            checksum = crc32(checksum, buffer.data(), buffer.size());
+            byte_number = 0;
+        }
+    }
+
+    std::array<unsigned char, 64> buffer;
+    std::uint32_t checksum;
+    std::size_t length;
+    std::size_t byte_number;
+    unsigned char bit_number;
+};
+}
+}
+
+#endif