/*
 * linux/fs/hfs/string.c
 *
 * Copyright (C) 1995-1997  Paul H. Hargrove
 * This file may be distributed under the terms of the GNU Public License.
 *
 * This file contains the string comparison function for the
 * Macintosh character set.
 *
 * The code in this file is derived from code which is copyright
 * 1986, 1989, 1990 by Abacus Research and Development, Inc. (ARDI)
 * It is used here by the permission of ARDI's president Cliff Matthews.
 *
 * If you discover bugs in this code please notify both the author of the
 * Linux HFS file system: hargrove@sccm.stanford.edu (Paul H. Hargrove)
 * and the author of ARDI's HFS code: ctm@ardi.com (Clifford T. Matthews)
 *
 * "XXX" in a comment is a note to myself to consider changing something.
 */

#include "hfs.h"

/*================ File-local variables ================*/

/*
 * unsigned char caseorder[]
 *
 * Defines the lexical ordering of characters on the Macintosh
 *
 * Composition of the 'casefold' and 'order' tables from ARDI's code
 * with the entry for 0x20 changed to match that for 0xCA to remove
 * special case for those two characters.
 */
static unsigned char caseorder[256] = {
0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,0x0F,
0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F,
0x20,0x22,0x23,0x28,0x29,0x2A,0x2B,0x2C,0x2F,0x30,0x31,0x32,0x33,0x34,0x35,0x36,
0x37,0x38,0x39,0x3A,0x3B,0x3C,0x3D,0x3E,0x3F,0x40,0x41,0x42,0x43,0x44,0x45,0x46,
0x47,0x48,0x57,0x59,0x5D,0x5F,0x66,0x68,0x6A,0x6C,0x72,0x74,0x76,0x78,0x7A,0x7E,
0x8C,0x8E,0x90,0x92,0x95,0x97,0x9E,0xA0,0xA2,0xA4,0xA7,0xA9,0xAA,0xAB,0xAC,0xAD,
0x4E,0x48,0x57,0x59,0x5D,0x5F,0x66,0x68,0x6A,0x6C,0x72,0x74,0x76,0x78,0x7A,0x7E,
0x8C,0x8E,0x90,0x92,0x95,0x97,0x9E,0xA0,0xA2,0xA4,0xA7,0xAF,0xB0,0xB1,0xB2,0xB3,
0x4A,0x4C,0x5A,0x60,0x7B,0x7F,0x98,0x4F,0x49,0x51,0x4A,0x4B,0x4C,0x5A,0x60,0x63,
0x64,0x65,0x6E,0x6F,0x70,0x71,0x7B,0x84,0x85,0x86,0x7F,0x80,0x9A,0x9B,0x9C,0x98,
0xB4,0xB5,0xB6,0xB7,0xB8,0xB9,0xBA,0x94,0xBB,0xBC,0xBD,0xBE,0xBF,0xC0,0x4D,0x81,
0xC1,0xC2,0xC3,0xC4,0xC5,0xC6,0xC7,0xC8,0xC9,0xCA,0xCB,0x55,0x8A,0xCC,0x4D,0x81,
0xCD,0xCE,0xCF,0xD0,0xD1,0xD2,0xD3,0x26,0x27,0xD4,0x20,0x49,0x4B,0x80,0x82,0x82,
0xD5,0xD6,0x24,0x25,0x2D,0x2E,0xD7,0xD8,0xA6,0xD9,0xDA,0xDB,0xDC,0xDD,0xDE,0xDF,
0xE0,0xE1,0xE2,0xE3,0xE4,0xE5,0xE6,0xE7,0xE8,0xE9,0xEA,0xEB,0xEC,0xED,0xEE,0xEF,
0xF0,0xF1,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,0xF8,0xF9,0xFA,0xFB,0xFC,0xFD,0xFE,0xFF
};

/*
 * unsigned char casefold[]
 *
 * Defines the mapping to lowercase characters on the Macintosh
 *
 * "Inverse" of the 'casefold' from ARDI's code.
 */
static unsigned char casefold[256] = {
0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,0x0F,
0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F,
0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,0x28,0x29,0x2A,0x2B,0x2C,0x2D,0x2E,0x2F,
0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0x3A,0x3B,0x3C,0x3D,0x3E,0x3F,
0x40,0x61,0x62,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F,
0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7A,0x5B,0x5C,0x5D,0x5E,0x5F,
0x41,0x61,0x62,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F,
0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7A,0x7B,0x7C,0x7D,0x7E,0x7F,
0x8A,0x8C,0x8D,0x8E,0x96,0x9A,0x9F,0x87,0x88,0x89,0x8A,0x8B,0x8C,0x8D,0x8E,0x8F,
0x90,0x91,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9A,0x9B,0x9C,0x9D,0x9E,0x9F,
0xA0,0xA1,0xA2,0xA3,0xA4,0xA5,0xA6,0xA7,0xA8,0xA9,0xAA,0xAB,0xAC,0xAD,0xBE,0xBF,
0xB0,0xB1,0xB2,0xB3,0xB4,0xB5,0xB6,0xB7,0xB8,0xB9,0xBA,0xBB,0xBC,0xBD,0xBE,0xBF,
0xC0,0xC1,0xC2,0xC3,0xC4,0xC5,0xC6,0xC7,0xC8,0xC9,0xCA,0x88,0x8B,0x9B,0xCF,0xCF,
0xD0,0xD1,0xD2,0xD3,0xD4,0xD5,0xD6,0xD7,0xD8,0xD9,0xDA,0xDB,0xDC,0xDD,0xDE,0xDF,
0xE0,0xE1,0xE2,0xE3,0xE4,0xE5,0xE6,0xE7,0xE8,0xE9,0xEA,0xEB,0xEC,0xED,0xEE,0xEF,
0xF0,0xF1,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,0xF8,0xF9,0xFA,0xFB,0xFC,0xFD,0xFE,0xFF
};

/*================ Global functions ================*/

/*
 * Hash a string to an integer in a case-independent way
 */
unsigned int hfs_strhash(const struct hfs_name *cname)
{
	/* Currently just sum of the 'order' of first and last characters */
	return ((unsigned int)caseorder[cname->Name[0]] +
		(unsigned int)caseorder[cname->Name[cname->Len - 1]]);
}

/*
 * Compare two strings in the HFS filename character ordering
 * Returns positive, negative, or zero, not just 0 or (+/-)1
 *
 * Equivalent to ARDI's call:
 *	ROMlib_RelString(s1+1, s2+1, true, false, (s1[0]<<16) | s2[0])
 */
int hfs_strcmp(const struct hfs_name *s1, const struct hfs_name *s2)
{
	int len, tmp;
	const unsigned char *p1, *p2;

	if (!s1 || !s2) {
		return 0;
	}

	len = (s1->Len > s2->Len) ? s2->Len : s1->Len;
	p1 = s1->Name;
	p2 = s2->Name;

	while (len--) {
		if ((tmp = (int)caseorder[*(p1++)]-(int)caseorder[*(p2++)])) {
			return tmp;
		}
	}
	return s1->Len - s2->Len;
}

/*
 * Test for equality of two strings in the HFS filename character ordering.
 */
int hfs_streq(const struct hfs_name *s1, const struct hfs_name *s2)
{
	int len;
	const unsigned char *p1, *p2;

	if (!s1 || !s2 || (s1->Len != s2->Len)) {
		return 0;
	}

	len = s1->Len;
	p1 = s1->Name;
	p2 = s2->Name;

	while (len--) {
		if (caseorder[*(p1++)] != caseorder[*(p2++)]) {
			return 0;
		}
	}
	return 1;
}

/*
 * Convert a string to the Macintosh version of lower case.
 */
void hfs_tolower(unsigned char *p, int len)
{
	while (len--) {
		*p = casefold[*p];
		++p;
	}
}
