/*
 * This file is part of John the Ripper password cracker,
 * Copyright (c) 2012 magnum
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted.
 *
 * There's ABSOLUTELY NO WARRANTY, express or implied.
 */

/* ------ Contains (at least) prepare(), valid() and split() ------ */

/* ------- Check if the ciphertext if a valid SHA-512 crypt ------- */
static int valid(char * ciphertext, struct fmt_main * self) {
	char *pos, *start;

	if (strncmp(ciphertext, "$6$", 3))
			return 0;

	ciphertext += 3;

	if (!strncmp(ciphertext, ROUNDS_PREFIX,
			sizeof(ROUNDS_PREFIX) - 1)) {
		const char *num = ciphertext + sizeof(ROUNDS_PREFIX) - 1;
		char *endp;
		if (!strtoul(num, &endp, 10))
					return 0;
		if (*endp == '$')
			ciphertext = endp + 1;
			}
	for (pos = ciphertext; *pos && *pos != '$'; pos++);
	if (!*pos || pos < ciphertext || pos > &ciphertext[SALT_LENGTH]) return 0;

	start = ++pos;
	while (atoi64[ARCH_INDEX(*pos)] != 0x7F) pos++;
	if (*pos || pos - start != CIPHERTEXT_LENGTH) return 0;
	return 1;
}

/* ------- To binary functions ------- */
#define TO_BINARY(b1, b2, b3) \
	value = (ARCH_WORD_32)atoi64[ARCH_INDEX(pos[0])] | \
		((ARCH_WORD_32)atoi64[ARCH_INDEX(pos[1])] << 6) | \
		((ARCH_WORD_32)atoi64[ARCH_INDEX(pos[2])] << 12) | \
		((ARCH_WORD_32)atoi64[ARCH_INDEX(pos[3])] << 18); \
	pos += 4; \
	out[b1] = value >> 16; \
	out[b2] = value >> 8; \
	out[b3] = value;

static void * get_binary(char * ciphertext) {
	static ARCH_WORD_32 outbuf[BINARY_SIZE/4];
	ARCH_WORD_32 value;
	char *pos = strrchr(ciphertext, '$') + 1;
	unsigned char *out = (unsigned char*)outbuf;
	int i = 0;

	do {
		TO_BINARY(i, (i+21)%63, (i+42)%63);
		i = (i+22)%63;
	} while (i != 21);
	value = (ARCH_WORD_32)atoi64[ARCH_INDEX(pos[0])] |
		((ARCH_WORD_32)atoi64[ARCH_INDEX(pos[1])] << 6);
	out[63] = value;
	return (void *)out;
}