fs/hfs/string.c

0001 /*
0002  *  linux/fs/hfs/string.c
0003  *
0004  * Copyright (C) 1995-1997  Paul H. Hargrove
0005  * (C) 2003 Ardis Technologies <roman@ardistech.com>
0006  * This file may be distributed under the terms of the GNU General Public License.
0007  *
0008  * This file contains the string comparison function for the
0009  * Macintosh character set.
0010  *
0011  * The code in this file is derived from code which is copyright
0012  * 1986, 1989, 1990 by Abacus Research and Development, Inc. (ARDI)
0013  * It is used here by the permission of ARDI's president Cliff Matthews.
0014  */
0015
0016 #include "hfs_fs.h"
0017 #include <linux/dcache.h>
0018
0019 /*================ File-local variables ================*/
0020
0021 /*
0022  * unsigned char caseorder[]
0023  *
0024  * Defines the lexical ordering of characters on the Macintosh
0025  *
0026  * Composition of the 'casefold' and 'order' tables from ARDI's code
0027  * with the entry for 0x20 changed to match that for 0xCA to remove
0028  * special case for those two characters.
0029  */
0030 static unsigned char caseorder[256] = {
0031     0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,0x0F,
0032     0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F,
0033     0x20,0x22,0x23,0x28,0x29,0x2A,0x2B,0x2C,0x2F,0x30,0x31,0x32,0x33,0x34,0x35,0x36,
0034     0x37,0x38,0x39,0x3A,0x3B,0x3C,0x3D,0x3E,0x3F,0x40,0x41,0x42,0x43,0x44,0x45,0x46,
0035     0x47,0x48,0x57,0x59,0x5D,0x5F,0x66,0x68,0x6A,0x6C,0x72,0x74,0x76,0x78,0x7A,0x7E,
0036     0x8C,0x8E,0x90,0x92,0x95,0x97,0x9E,0xA0,0xA2,0xA4,0xA7,0xA9,0xAA,0xAB,0xAC,0xAD,
0037     0x4E,0x48,0x57,0x59,0x5D,0x5F,0x66,0x68,0x6A,0x6C,0x72,0x74,0x76,0x78,0x7A,0x7E,
0038     0x8C,0x8E,0x90,0x92,0x95,0x97,0x9E,0xA0,0xA2,0xA4,0xA7,0xAF,0xB0,0xB1,0xB2,0xB3,
0039     0x4A,0x4C,0x5A,0x60,0x7B,0x7F,0x98,0x4F,0x49,0x51,0x4A,0x4B,0x4C,0x5A,0x60,0x63,
0040     0x64,0x65,0x6E,0x6F,0x70,0x71,0x7B,0x84,0x85,0x86,0x7F,0x80,0x9A,0x9B,0x9C,0x98,
0041     0xB4,0xB5,0xB6,0xB7,0xB8,0xB9,0xBA,0x94,0xBB,0xBC,0xBD,0xBE,0xBF,0xC0,0x4D,0x81,
0042     0xC1,0xC2,0xC3,0xC4,0xC5,0xC6,0xC7,0xC8,0xC9,0xCA,0xCB,0x55,0x8A,0xCC,0x4D,0x81,
0043     0xCD,0xCE,0xCF,0xD0,0xD1,0xD2,0xD3,0x26,0x27,0xD4,0x20,0x49,0x4B,0x80,0x82,0x82,
0044     0xD5,0xD6,0x24,0x25,0x2D,0x2E,0xD7,0xD8,0xA6,0xD9,0xDA,0xDB,0xDC,0xDD,0xDE,0xDF,
0045     0xE0,0xE1,0xE2,0xE3,0xE4,0xE5,0xE6,0xE7,0xE8,0xE9,0xEA,0xEB,0xEC,0xED,0xEE,0xEF,
0046     0xF0,0xF1,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,0xF8,0xF9,0xFA,0xFB,0xFC,0xFD,0xFE,0xFF
0047 };
0048
0049 /*================ Global functions ================*/
0050
0051 /*
0052  * Hash a string to an integer in a case-independent way
0053  */
0054 int hfs_hash_dentry(const struct dentry *dentry, struct qstr *this)
0055 {
0056     const unsigned char *name = this->name;
0057     unsigned int hash, len = this->len;
0058
0059     if (len > HFS_NAMELEN)
0060         len = HFS_NAMELEN;
0061
0062     hash = init_name_hash(dentry);
0063     for (; len; len--)
0064         hash = partial_name_hash(caseorder[*name++], hash);
0065     this->hash = end_name_hash(hash);
0066     return 0;
0067 }
0068
0069 /*
0070  * Compare two strings in the HFS filename character ordering
0071  * Returns positive, negative, or zero, not just 0 or (+/-)1
0072  *
0073  * Equivalent to ARDI's call:
0074  *  ROMlib_RelString(s1+1, s2+1, true, false, (s1[0]<<16) | s2[0])
0075  */
0076 int hfs_strcmp(const unsigned char *s1, unsigned int len1,
0077            const unsigned char *s2, unsigned int len2)
0078 {
0079     int len, tmp;
0080
0081     len = (len1 > len2) ? len2 : len1;
0082
0083     while (len--) {
0084         tmp = (int)caseorder[*(s1++)] - (int)caseorder[*(s2++)];
0085         if (tmp)
0086             return tmp;
0087     }
0088     return len1 - len2;
0089 }
0090
0091 /*
0092  * Test for equality of two strings in the HFS filename character ordering.
0093  * return 1 on failure and 0 on success
0094  */
0095 int hfs_compare_dentry(const struct dentry *dentry,
0096         unsigned int len, const char *str, const struct qstr *name)
0097 {
0098     const unsigned char *n1, *n2;
0099
0100     if (len >= HFS_NAMELEN) {
0101         if (name->len < HFS_NAMELEN)
0102             return 1;
0103         len = HFS_NAMELEN;
0104     } else if (len != name->len)
0105         return 1;
0106
0107     n1 = str;
0108     n2 = name->name;
0109     while (len--) {
0110         if (caseorder[*n1++] != caseorder[*n2++])
0111             return 1;
0112     }
0113     return 0;
0114 }