Toward first png.

src/compression/CyclicRedundancyChecker.h

@@ -1,52 +1,20 @@
 #pragma once
 
-class CyclicRedundancyChecker
+#include "AbstractChecksumCalculator.h"
+
+class CyclicRedundancyChecker : public AbstractChecksumCalculator
 {
 public:
+    void addValue(unsigned char val) override;
 
-    void createTable()
-    {
-        unsigned long c{0};
-        for (int n = 0; n < 256; n++)
-        {
-            c = (unsigned long) n;
-            for (int k = 0; k < 8; k++)
-            {
-                if (c & 1)
-                {
-                    c = 0xedb88320L ^ (c >> 1);
-                }
-                else
-                {
-                    c = c >> 1;
-                }
-            }
-            mTable[n] = c;
-        }
-        mTableComputed = true;
-        mTableComputed = 1;
-    }
+    uint32_t getChecksum() const override;
 
-    unsigned long updateCrc(unsigned long crc, unsigned char *buf, int len)
-    {
-        unsigned long c = crc;
-        if (!mTableComputed)
-        {
-            createTable();
-        }
-        for (int n = 0; n < len; n++)
-        {
-            c = mTable[(c ^ buf[n]) & 0xff] ^ (c >> 8);
-        }
-        return c;
-    }
-
-    unsigned long doCrc(unsigned char *buf, int len)
-    {
-        return updateCrc(0xffffffffL, buf, len) ^ 0xffffffffL;
-    }
+    void reset() override;
 
 private:
+    void createTable();
     bool mTableComputed{false};
+
+    uint32_t mLastValue{0xffffffffL};
     unsigned long mTable[256];
 };