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deps/g3dlite/include/G3D/Crypto.h

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+/** 
+  \file G3D/Crypto.h
+ 
+  \maintainer Morgan McGuire, http://graphics.cs.williams.edu
+ 
+
+  \created 2006-03-29
+  \edited  2011-06-21
+ */
+
+#ifndef G3D_Crypto_h
+#define G3D_Crypto_h
+
+#include "G3D/platform.h"
+#include "G3D/g3dmath.h"
+#include "G3D/System.h"
+#include <string>
+
+namespace G3D {
+
+/** See G3D::Crypto::md5 */
+class MD5Hash {
+private:
+
+    uint8   value[16];
+
+public:
+
+    MD5Hash() {
+        for (int i = 0; i < 16; ++i) {
+            value[i] = 0;
+        }
+    }
+
+    explicit MD5Hash(class BinaryInput& b);
+
+    /** Rotates the bytes once */
+    void rotateBytes() {
+        uint8 temp = value[0];
+        for (int i = 0; i < 15; ++i) {
+            value[i] = value[i + 1];
+        }
+        value[15] = temp;
+    }
+
+    /** Rotates by n bytes */
+    void rotateBytes(int n) {
+        uint8 temp[16];
+        System::memcpy(temp, value, 16);
+        for (int i = 0; i < 16; ++i) {
+            value[i] = value[(i + n) & 15];
+        }
+    }
+
+    uint8& operator[](int i) {
+        return value[i];
+    }
+
+    const uint8& operator[](int i) const {
+        return value[i];
+    }
+
+    bool operator==(const MD5Hash& other) const {
+        bool match = true;
+        for (int i = 0; i < 16; ++i) {
+            match = match && (other.value[i] == value[i]);
+        }
+        return match;
+    }
+
+    inline bool operator!=(const MD5Hash& other) const {
+        return !(*this == other);
+    }
+
+    void deserialize(class BinaryInput& b);
+
+    void serialize(class BinaryOutput& b) const;
+
+    static size_t hashCode(const MD5Hash& key) {
+        size_t h = 0;
+        for (int i = 0; i < 4; ++i) {
+            const int x = i * 4;
+            h ^= (((uint32)key.value[x + 0]) << 24) |
+                (((uint32)key.value[x + 1]) << 16) |
+                (((uint32)key.value[x + 2]) << 8) |
+                ((uint32)key.value[x + 3]);
+        }
+        return h;
+    }
+};
+
+
+/** Cryptography and hashing helper functions */
+class Crypto {
+public:
+
+    /**
+     Computes the CRC32 value of a byte array.  CRC32 is designed to be a hash
+     function that produces different values for similar strings.
+
+     This implementation is compatible with PKZIP and GZIP.
+
+     Based on http://www.gamedev.net/reference/programming/features/crc32/
+    */
+    static uint32 crc32(const void* bytes, size_t numBytes);
+
+    /**
+     Computes the MD5 hash (message digest) of a byte stream, as defined by
+     http://www.ietf.org/rfc/rfc1321.txt.
+
+     @cite Based on implementation by L. Peter Deutsch, ghost@aladdin.com
+     */
+    static MD5Hash md5(const void* bytes, size_t numBytes);
+
+    /**
+     Returns the nth prime less than 2000 in constant time.  The first prime has index
+     0 and is the number 2.
+     */
+    static int smallPrime(int n);
+
+    /** Returns 1 + the largest value that can be passed to smallPrime. */
+    static int numSmallPrimes();
+};
+
+}
+
+#endif