#include <cstdio>
#include <cmath>
#include <ctime>
#include <map>
#include <string>

// char* word_list[] = { ... };
// int word_list_len = xxx;
#include "words.h"

typedef unsigned int uint32_t;
typedef uint32_t (*hash_func_t)(const char*);

uint32_t FNV32(const char* string)
{
	const unsigned char* p = reinterpret_cast<const unsigned char*>(string);

	uint32_t hash = 0x811c9dc5;

	while (*p)
	{
		hash *= 0x01000193;
		hash ^= *p++;
	}

	return hash;
}

uint32_t FNV10(const char* string)
{
	return FNV32(string) & 0x3ff;
}

uint32_t FNV10x(const char* string)
{
	uint32_t hash = FNV32(string);
	return ((hash >> 10) ^ hash) & 0x3ff;
}

uint32_t CRC32(const char* string)
{
	static const uint32_t table[] =
	{
		0x00000000U, 0x77073096U, 0xee0e612cU, 0x990951baU, 0x076dc419U,
		0x706af48fU, 0xe963a535U, 0x9e6495a3U, 0x0edb8832U, 0x79dcb8a4U,
		0xe0d5e91eU, 0x97d2d988U, 0x09b64c2bU, 0x7eb17cbdU, 0xe7b82d07U,
		0x90bf1d91U, 0x1db71064U, 0x6ab020f2U, 0xf3b97148U, 0x84be41deU,
		0x1adad47dU, 0x6ddde4ebU, 0xf4d4b551U, 0x83d385c7U, 0x136c9856U,
		0x646ba8c0U, 0xfd62f97aU, 0x8a65c9ecU, 0x14015c4fU, 0x63066cd9U,
		0xfa0f3d63U, 0x8d080df5U, 0x3b6e20c8U, 0x4c69105eU, 0xd56041e4U,
		0xa2677172U, 0x3c03e4d1U, 0x4b04d447U, 0xd20d85fdU, 0xa50ab56bU,
		0x35b5a8faU, 0x42b2986cU, 0xdbbbc9d6U, 0xacbcf940U, 0x32d86ce3U,
		0x45df5c75U, 0xdcd60dcfU, 0xabd13d59U, 0x26d930acU, 0x51de003aU,
		0xc8d75180U, 0xbfd06116U, 0x21b4f4b5U, 0x56b3c423U, 0xcfba9599U,
		0xb8bda50fU, 0x2802b89eU, 0x5f058808U, 0xc60cd9b2U, 0xb10be924U,
		0x2f6f7c87U, 0x58684c11U, 0xc1611dabU, 0xb6662d3dU, 0x76dc4190U,
		0x01db7106U, 0x98d220bcU, 0xefd5102aU, 0x71b18589U, 0x06b6b51fU,
		0x9fbfe4a5U, 0xe8b8d433U, 0x7807c9a2U, 0x0f00f934U, 0x9609a88eU,
		0xe10e9818U, 0x7f6a0dbbU, 0x086d3d2dU, 0x91646c97U, 0xe6635c01U,
		0x6b6b51f4U, 0x1c6c6162U, 0x856530d8U, 0xf262004eU, 0x6c0695edU,
		0x1b01a57bU, 0x8208f4c1U, 0xf50fc457U, 0x65b0d9c6U, 0x12b7e950U,
		0x8bbeb8eaU, 0xfcb9887cU, 0x62dd1ddfU, 0x15da2d49U, 0x8cd37cf3U,
		0xfbd44c65U, 0x4db26158U, 0x3ab551ceU, 0xa3bc0074U, 0xd4bb30e2U,
		0x4adfa541U, 0x3dd895d7U, 0xa4d1c46dU, 0xd3d6f4fbU, 0x4369e96aU,
		0x346ed9fcU, 0xad678846U, 0xda60b8d0U, 0x44042d73U, 0x33031de5U,
		0xaa0a4c5fU, 0xdd0d7cc9U, 0x5005713cU, 0x270241aaU, 0xbe0b1010U,
		0xc90c2086U, 0x5768b525U, 0x206f85b3U, 0xb966d409U, 0xce61e49fU,
		0x5edef90eU, 0x29d9c998U, 0xb0d09822U, 0xc7d7a8b4U, 0x59b33d17U,
		0x2eb40d81U, 0xb7bd5c3bU, 0xc0ba6cadU, 0xedb88320U, 0x9abfb3b6U,
		0x03b6e20cU, 0x74b1d29aU, 0xead54739U, 0x9dd277afU, 0x04db2615U,
		0x73dc1683U, 0xe3630b12U, 0x94643b84U, 0x0d6d6a3eU, 0x7a6a5aa8U,
		0xe40ecf0bU, 0x9309ff9dU, 0x0a00ae27U, 0x7d079eb1U, 0xf00f9344U,
		0x8708a3d2U, 0x1e01f268U, 0x6906c2feU, 0xf762575dU, 0x806567cbU,
		0x196c3671U, 0x6e6b06e7U, 0xfed41b76U, 0x89d32be0U, 0x10da7a5aU,
		0x67dd4accU, 0xf9b9df6fU, 0x8ebeeff9U, 0x17b7be43U, 0x60b08ed5U,
		0xd6d6a3e8U, 0xa1d1937eU, 0x38d8c2c4U, 0x4fdff252U, 0xd1bb67f1U,
		0xa6bc5767U, 0x3fb506ddU, 0x48b2364bU, 0xd80d2bdaU, 0xaf0a1b4cU,
		0x36034af6U, 0x41047a60U, 0xdf60efc3U, 0xa867df55U, 0x316e8eefU,
		0x4669be79U, 0xcb61b38cU, 0xbc66831aU, 0x256fd2a0U, 0x5268e236U,
		0xcc0c7795U, 0xbb0b4703U, 0x220216b9U, 0x5505262fU, 0xc5ba3bbeU,
		0xb2bd0b28U, 0x2bb45a92U, 0x5cb36a04U, 0xc2d7ffa7U, 0xb5d0cf31U,
		0x2cd99e8bU, 0x5bdeae1dU, 0x9b64c2b0U, 0xec63f226U, 0x756aa39cU,
		0x026d930aU, 0x9c0906a9U, 0xeb0e363fU, 0x72076785U, 0x05005713U,
		0x95bf4a82U, 0xe2b87a14U, 0x7bb12baeU, 0x0cb61b38U, 0x92d28e9bU,
		0xe5d5be0dU, 0x7cdcefb7U, 0x0bdbdf21U, 0x86d3d2d4U, 0xf1d4e242U,
		0x68ddb3f8U, 0x1fda836eU, 0x81be16cdU, 0xf6b9265bU, 0x6fb077e1U,
		0x18b74777U, 0x88085ae6U, 0xff0f6a70U, 0x66063bcaU, 0x11010b5cU,
		0x8f659effU, 0xf862ae69U, 0x616bffd3U, 0x166ccf45U, 0xa00ae278U,
		0xd70dd2eeU, 0x4e048354U, 0x3903b3c2U, 0xa7672661U, 0xd06016f7U,
		0x4969474dU, 0x3e6e77dbU, 0xaed16a4aU, 0xd9d65adcU, 0x40df0b66U,
		0x37d83bf0U, 0xa9bcae53U, 0xdebb9ec5U, 0x47b2cf7fU, 0x30b5ffe9U,
		0xbdbdf21cU, 0xcabac28aU, 0x53b39330U, 0x24b4a3a6U, 0xbad03605U,
		0xcdd70693U, 0x54de5729U, 0x23d967bfU, 0xb3667a2eU, 0xc4614ab8U,
		0x5d681b02U, 0x2a6f2b94U, 0xb40bbe37U, 0xc30c8ea1U, 0x5a05df1bU,
		0x2d02ef8dU
	};

	const unsigned char* p = reinterpret_cast<const unsigned char*>(string);

	uint32_t hash = 0xffffffffU;

	while (*p)
	{
		hash = table[(hash ^ *p++) & 0xff] ^ (hash >> 8);
	}

	return hash ^ 0xffffffffU;
}

uint32_t CRC10(const char* string)
{
	return CRC32(string) & 0x3ff;
}

class CollisionTester
{
	typedef std::map<uint32_t, std::string> Map;

	const hash_func_t hash_func;
	const char* const name;

	Map history;
	int coll_count;

public:

	CollisionTester(hash_func_t hash_func, const char* name)
	:	hash_func(hash_func), name(name), coll_count(0)
	{
	}

	void AddWord(const char* word)
	{
		uint32_t hash = hash_func(word);

		Map::iterator it = history.find(hash);

		if (it == history.end())
		{
			history[hash] = word;
		}
		else
		{
			printf("%s: %s == %s (%x)\n", name, word, it->second.c_str(), hash);
			++coll_count;
		}
	}

	void ShowResult() const
	{
		printf("%s: %d collisions.\n", name, coll_count);
	}
};

class DistTester
{
	const int bucket_num;
	const hash_func_t hash_func;
	const char* const name;

	int word_count;
	int* buckets;

public:

	DistTester(int bucket_num, hash_func_t hash_func, const char* name)
	:	bucket_num(bucket_num),
		hash_func(hash_func),
		name(name),
		word_count(0),
		buckets(new int [bucket_num])
	{
		std::fill(buckets, buckets + bucket_num, 0);
	}

	~DistTester()
	{
		delete [] buckets;
	}

	void AddWord(const char* word)
	{
		++buckets[hash_func(word)];
		++word_count;
	}

	void ShowResult()
	{
		float est = static_cast<float>(word_count) / bucket_num;
		float var = 0;

		for (int i = 0; i < bucket_num; ++i)
		{
			float d = buckets[i] - est;
			var += d * d / est;
		}

		float chi2 = (var - bucket_num) / sqrt(static_cast<float>(bucket_num));
		printf("%s: chi2 = %f\n", name, chi2);
	}
};

void DoCollisionTest1(CollisionTester& tester)
{
	for (int i = 0; i < word_list_len; ++i)
	{
		tester.AddWord(word_list[i]);
	}

	tester.ShowResult();
}

void DoCollisionTest2(CollisionTester& tester)
{
	for (int i = 0; i < word_list_len; ++i)
	{
		for (int offs = 1000; offs <= 10000; offs += 1000)
		{
			std::string temp = word_list[i];
			temp += "_";
			temp += word_list[(i + offs) % word_list_len];
			tester.AddWord(temp.c_str());
		}
	}

	tester.ShowResult();
}

void DoCollisionTest3(CollisionTester& tester)
{
	for (int i = 0; i < word_list_len; ++i)
	{
		for (int sfx = 0; sfx < 10; ++sfx)
		{
			std::string temp = word_list[i];
			temp += ('0' + sfx);
			tester.AddWord(temp.c_str());
		}
	}

	tester.ShowResult();
}

void DoDistTest(DistTester& tester)
{
	for (int i = 0; i < word_list_len; ++i)
	{
		tester.AddWord(word_list[i]);
	}

	tester.ShowResult();
}

uint32_t CRCWorkload()
{
	uint32_t sum = 0;

	for (int i = 0; i < word_list_len; ++i)
	{
		sum += CRC32(word_list[i]);
	}

	return sum;
}

uint32_t FNVWorkload()
{
	uint32_t sum = 0;

	for (int i = 0; i < word_list_len; ++i)
	{
		sum += FNV32(word_list[i]);
	}

	return sum;
}

void DoSpeedTest(uint32_t (*work_func)(), const char* name)
{
	uint32_t sum = work_func();

	clock_t begin = clock();

	for (int i = 0; i < 1000; ++i)
	{
		sum += work_func();
	}

	clock_t end = clock();

	printf("%s: %ld clocks (%x)\n", name, end - begin, sum);
}

int main(int argc, char* argv[])
{
	DoCollisionTest1(CollisionTester(CRC32, "CRC32"));
	DoCollisionTest1(CollisionTester(FNV32, "FNV32"));

	DoCollisionTest2(CollisionTester(CRC32, "CRC32"));
	DoCollisionTest2(CollisionTester(FNV32, "FNV32"));

	DoCollisionTest3(CollisionTester(CRC32, "CRC32"));
	DoCollisionTest3(CollisionTester(FNV32, "FNV32"));

	DoDistTest(DistTester(1024, CRC10, "CRC10"));
	DoDistTest(DistTester(1024, FNV10, "FNV10"));
	DoDistTest(DistTester(1024, FNV10x, "FNV10x"));

	DoSpeedTest(CRCWorkload, "CRC32");
	DoSpeedTest(FNVWorkload, "FNV32");

	puts("Done.");
	getchar();

	return 0;
}