fs/hfs/string.c

   1 /*
   2  *  linux/fs/hfs/string.c
   3  *
   4  * Copyright (C) 1995-1997  Paul H. Hargrove
   5  * (C) 2003 Ardis Technologies <roman@ardistech.com>
   6  * This file may be distributed under the terms of the GNU General Public License.
   7  *
   8  * This file contains the string comparison function for the
   9  * Macintosh character set.
  10  *
  11  * The code in this file is derived from code which is copyright
  12  * 1986, 1989, 1990 by Abacus Research and Development, Inc. (ARDI)
  13  * It is used here by the permission of ARDI's president Cliff Matthews.
  14  */
  15
  16 #include "hfs_fs.h"
  17 #include <linux/dcache.h>
  18
  19 /*================ File-local variables ================*/
  20
  21 /*
  22  * unsigned char caseorder[]
  23  *
  24  * Defines the lexical ordering of characters on the Macintosh
  25  *
  26  * Composition of the 'casefold' and 'order' tables from ARDI's code
  27  * with the entry for 0x20 changed to match that for 0xCA to remove
  28  * special case for those two characters.
  29  */
  30 static unsigned char caseorder[256] = {
  31         0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,0x0F,
  32         0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F,
  33         0x20,0x22,0x23,0x28,0x29,0x2A,0x2B,0x2C,0x2F,0x30,0x31,0x32,0x33,0x34,0x35,0x36,
  34         0x37,0x38,0x39,0x3A,0x3B,0x3C,0x3D,0x3E,0x3F,0x40,0x41,0x42,0x43,0x44,0x45,0x46,
  35         0x47,0x48,0x57,0x59,0x5D,0x5F,0x66,0x68,0x6A,0x6C,0x72,0x74,0x76,0x78,0x7A,0x7E,
  36         0x8C,0x8E,0x90,0x92,0x95,0x97,0x9E,0xA0,0xA2,0xA4,0xA7,0xA9,0xAA,0xAB,0xAC,0xAD,
  37         0x4E,0x48,0x57,0x59,0x5D,0x5F,0x66,0x68,0x6A,0x6C,0x72,0x74,0x76,0x78,0x7A,0x7E,
  38         0x8C,0x8E,0x90,0x92,0x95,0x97,0x9E,0xA0,0xA2,0xA4,0xA7,0xAF,0xB0,0xB1,0xB2,0xB3,
  39         0x4A,0x4C,0x5A,0x60,0x7B,0x7F,0x98,0x4F,0x49,0x51,0x4A,0x4B,0x4C,0x5A,0x60,0x63,
  40         0x64,0x65,0x6E,0x6F,0x70,0x71,0x7B,0x84,0x85,0x86,0x7F,0x80,0x9A,0x9B,0x9C,0x98,
  41         0xB4,0xB5,0xB6,0xB7,0xB8,0xB9,0xBA,0x94,0xBB,0xBC,0xBD,0xBE,0xBF,0xC0,0x4D,0x81,
  42         0xC1,0xC2,0xC3,0xC4,0xC5,0xC6,0xC7,0xC8,0xC9,0xCA,0xCB,0x55,0x8A,0xCC,0x4D,0x81,
  43         0xCD,0xCE,0xCF,0xD0,0xD1,0xD2,0xD3,0x26,0x27,0xD4,0x20,0x49,0x4B,0x80,0x82,0x82,
  44         0xD5,0xD6,0x24,0x25,0x2D,0x2E,0xD7,0xD8,0xA6,0xD9,0xDA,0xDB,0xDC,0xDD,0xDE,0xDF,
  45         0xE0,0xE1,0xE2,0xE3,0xE4,0xE5,0xE6,0xE7,0xE8,0xE9,0xEA,0xEB,0xEC,0xED,0xEE,0xEF,
  46         0xF0,0xF1,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,0xF8,0xF9,0xFA,0xFB,0xFC,0xFD,0xFE,0xFF
  47 };
  48
  49 /*================ Global functions ================*/
  50
  51 /*
  52  * Hash a string to an integer in a case-independent way
  53  */
  54 int hfs_hash_dentry(struct dentry *dentry, struct qstr *this)
  55 {
  56         const unsigned char *name = this->name;
  57         unsigned int hash, len = this->len;
  58
  59         if (len > HFS_NAMELEN)
  60                 len = HFS_NAMELEN;
  61
  62         hash = init_name_hash();
  63         for (; len; len--)
  64                 hash = partial_name_hash(caseorder[*name++], hash);
  65         this->hash = end_name_hash(hash);
  66         return 0;
  67 }
  68
  69 /*
  70  * Compare two strings in the HFS filename character ordering
  71  * Returns positive, negative, or zero, not just 0 or (+/-)1
  72  *
  73  * Equivalent to ARDI's call:
  74  *      ROMlib_RelString(s1+1, s2+1, true, false, (s1[0]<<16) | s2[0])
  75  */
  76 int hfs_strcmp(const unsigned char *s1, unsigned int len1,
  77                const unsigned char *s2, unsigned int len2)
  78 {
  79         int len, tmp;
  80
  81         len = (len1 > len2) ? len2 : len1;
  82
  83         while (len--) {
  84                 tmp = (int)caseorder[*(s1++)] - (int)caseorder[*(s2++)];
  85                 if (tmp)
  86                         return tmp;
  87         }
  88         return len1 - len2;
  89 }
  90
  91 /*
  92  * Test for equality of two strings in the HFS filename character ordering.
  93  * return 1 on failure and 0 on success
  94  */
  95 int hfs_compare_dentry(struct dentry *dentry, struct qstr *s1, struct qstr *s2)
  96 {
  97         const unsigned char *n1, *n2;
  98         int len;
  99
 100         len = s1->len;
 101         if (len >= HFS_NAMELEN) {
 102                 if (s2->len < HFS_NAMELEN)
 103                         return 1;
 104                 len = HFS_NAMELEN;
 105         } else if (len != s2->len)
 106                 return 1;
 107
 108         n1 = s1->name;
 109         n2 = s2->name;
 110         while (len--) {
 111                 if (caseorder[*n1++] != caseorder[*n2++])
 112                         return 1;
 113         }
 114         return 0;
 115 }