/*	tigersum - a command line utility to calculate the tiger hash from input.
	Copyright (C) 2014  Michele "King_DuckZ" Santullo

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import std.stdio;
import std.string;
import std.array, std.range;
import std.algorithm;

private extern(C) void tiger (char* parMessage, ulong parLength, out ulong[3] parOut, char parPadding);
private extern(C) void tiger_init (out ulong[3] parOut);
private extern(C) void tiger_chunk (char* parMessage, ulong parLength, out ulong[3] parOut);
private extern(C) void tiger_last_chunk (char* parMessage, ulong parBuffLength, ulong parTotalLength, out ulong[3] parOut, char parPadding);

private ulong swapLong (ulong parNum) {
	parNum = (parNum & 0x00000000FFFFFFFF) << 32 | (parNum & 0xFFFFFFFF00000000) >> 32;
	parNum = (parNum & 0x0000FFFF0000FFFF) << 16 | (parNum & 0xFFFF0000FFFF0000) >> 16;
	parNum = (parNum & 0x00FF00FF00FF00FF) << 8  | (parNum & 0xFF00FF00FF00FF00) >> 8;
	return parNum;
}

public ulong[3] getTiger (in string parData, bool parV2) {
	char[] unaligned = new char[parData.length + ulong.alignof - 1];
	size_t offset = ((cast(size_t)unaligned.ptr + (ulong.alignof - 1)) & ~cast(size_t)(ulong.alignof - 1)) - cast(size_t)unaligned.ptr;
	assert(offset >= 0 && offset < ulong.alignof);
	assert(offset + parData.length <= unaligned.length);

	char padding = (parV2 ? 0x80 : 0x01);
	char[] aligned = unaligned[offset .. offset + parData.length];
	aligned[] = parData[];
	assert((cast(size_t)aligned.ptr & cast(size_t)(ulong.alignof - 1)) == 0);
	ulong[3] retval;
	tiger(aligned.ptr, aligned.length, retval, padding);
	return retval;
}

public ulong[3] getTiger (ref File parData, bool parV2) {
	const auto buff_length = 64 * 128;
	char[] unaligned = new char[buff_length + ulong.alignof - 1];
	size_t offset = ((cast(size_t)unaligned.ptr + (ulong.alignof - 1)) & ~cast(size_t)(ulong.alignof - 1)) - cast(size_t)unaligned.ptr;
	assert(offset >= 0 && offset < ulong.alignof);

	assert(offset + buff_length <= unaligned.length);
	char[] aligned = unaligned[offset .. buff_length];
	assert(aligned.length == buff_length);

	ulong[3] retval;
	auto data_left = parData.size;
	tiger_init(retval);
	while (data_left >= buff_length) {
		parData.rawRead(aligned);
		tiger_chunk(aligned.ptr, buff_length, retval);
		data_left -= buff_length;
	}

	const char padding = (parV2 ? 0x80 : 0x01);
	if (data_left) {
		parData.rawRead(aligned[0 .. data_left]);
		const ulong proc_length = data_left & ~0x3fUL;
		tiger_chunk(aligned.ptr, proc_length, retval);
		tiger_last_chunk(aligned.ptr + proc_length, data_left - proc_length, parData.size, retval, padding);
	}
	else {
		tiger_last_chunk(null, 0, parData.size, retval, padding);
	}

	return retval;
}

public string tigerToString (in ulong[3] parTiger) {
	return format("%016x%016x%016x", swapLong(parTiger[0]), swapLong(parTiger[1]), swapLong(parTiger[2]));
}

unittest {
	assert("67e6ae8e9e968999f70a23e72aeaa9251cbc7c78a7916636" == tigerToString(getTiger("a", true)));
	assert("f68d7bc5af4b43a06e048d7829560d4a9415658bb0b1f3bf" == tigerToString(getTiger("abc", true)));
	assert("e29419a1b5fa259de8005e7de75078ea81a542ef2552462d" == tigerToString(getTiger("message digest", true)));
	assert("f5b6b6a78c405c8547e91cd8624cb8be83fc804a474488fd" == tigerToString(getTiger("abcdefghijklmnopqrstuvwxyz", true)));
	assert("a6737f3997e8fbb63d20d2df88f86376b5fe2d5ce36646a9" == tigerToString(getTiger("abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq", true)));
	assert("ea9ab6228cee7b51b77544fca6066c8cbb5bbae6319505cd" == tigerToString(getTiger("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789", true)));
	assert("d85278115329ebaa0eec85ecdc5396fda8aa3a5820942fff" == tigerToString(getTiger(replicate("1234567890", 8), true)));
	assert("e068281f060f551628cc5715b9d0226796914d45f7717cf4" == tigerToString(getTiger(replicate("a", 1000000), true)));

	assert("2aab1484e8c158f2bfb8c5ff41b57a525129131c957b5f93" == tigerToString(getTiger("abc", false)));
	assert("dd00230799f5009fec6debc838bb6a27df2b9d6f110c7937" == tigerToString(getTiger("Tiger", false)));
	assert("f71c8583902afb879edfe610f82c0d4786a3a534504486b5" == tigerToString(getTiger("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+-", false)));
	assert("48ceeb6308b87d46e95d656112cdf18d97915f9765658957" == tigerToString(getTiger("ABCDEFGHIJKLMNOPQRSTUVWXYZ=abcdefghijklmnopqrstuvwxyz+0123456789", false)));
	assert("8a866829040a410c729ad23f5ada711603b3cdd357e4c15e" == tigerToString(getTiger("Tiger - A Fast New Hash Function, by Ross Anderson and Eli Biham", false)));
	assert("ce55a6afd591f5ebac547ff84f89227f9331dab0b611c889" == tigerToString(getTiger("Tiger - A Fast New Hash Function, by Ross Anderson and Eli Biham, proceedings of Fast Software Encryption 3, Cambridge.", false)));
	assert("631abdd103eb9a3d245b6dfd4d77b257fc7439501d1568dd" == tigerToString(getTiger("Tiger - A Fast New Hash Function, by Ross Anderson and Eli Biham, proceedings of Fast Software Encryption 3, Cambridge, 1996.", false)));
	assert("c54034e5b43eb8005848a7e0ae6aac76e4ff590ae715fd25" == tigerToString(getTiger("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+-ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+-", false)));
}