xref: /linux/fs/hfsplus/unicode.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15) 
1 /*
2  *  linux/fs/hfsplus/unicode.c
3  *
4  * Copyright (C) 2001
5  * Brad Boyer (flar@allandria.com)
6  * (C) 2003 Ardis Technologies <roman@ardistech.com>
7  *
8  * Handler routines for unicode strings
9  */
10 
11 #include <linux/types.h>
12 #include <linux/nls.h>
13 #include "hfsplus_fs.h"
14 #include "hfsplus_raw.h"
15 
16 /* Fold the case of a unicode char, given the 16 bit value */
17 /* Returns folded char, or 0 if ignorable */
18 static inline u16 case_fold(u16 c)
19 {
20         u16 tmp;
21 
22         tmp = hfsplus_case_fold_table[c >> 8];
23         if (tmp)
24                 tmp = hfsplus_case_fold_table[tmp + (c & 0xff)];
25         else
26                 tmp = c;
27         return tmp;
28 }
29 
30 /* Compare unicode strings, return values like normal strcmp */
31 int hfsplus_strcasecmp(const struct hfsplus_unistr *s1,
32 		       const struct hfsplus_unistr *s2)
33 {
34 	u16 len1, len2, c1, c2;
35 	const hfsplus_unichr *p1, *p2;
36 
37 	len1 = be16_to_cpu(s1->length);
38 	len2 = be16_to_cpu(s2->length);
39 	p1 = s1->unicode;
40 	p2 = s2->unicode;
41 
42 	while (1) {
43 		c1 = c2 = 0;
44 
45 		while (len1 && !c1) {
46 			c1 = case_fold(be16_to_cpu(*p1));
47 			p1++;
48 			len1--;
49 		}
50 		while (len2 && !c2) {
51 			c2 = case_fold(be16_to_cpu(*p2));
52 			p2++;
53 			len2--;
54 		}
55 
56 		if (c1 != c2)
57 			return (c1 < c2) ? -1 : 1;
58 		if (!c1 && !c2)
59 			return 0;
60 	}
61 }
62 
63 /* Compare names as a sequence of 16-bit unsigned integers */
64 int hfsplus_strcmp(const struct hfsplus_unistr *s1,
65 		   const struct hfsplus_unistr *s2)
66 {
67 	u16 len1, len2, c1, c2;
68 	const hfsplus_unichr *p1, *p2;
69 	int len;
70 
71 	len1 = be16_to_cpu(s1->length);
72 	len2 = be16_to_cpu(s2->length);
73 	p1 = s1->unicode;
74 	p2 = s2->unicode;
75 
76 	for (len = min(len1, len2); len > 0; len--) {
77 		c1 = be16_to_cpu(*p1);
78 		c2 = be16_to_cpu(*p2);
79 		if (c1 != c2)
80 			return c1 < c2 ? -1 : 1;
81 		p1++;
82 		p2++;
83 	}
84 
85 	return len1 < len2 ? -1 :
86 	       len1 > len2 ? 1 : 0;
87 }
88 
89 
90 #define Hangul_SBase	0xac00
91 #define Hangul_LBase	0x1100
92 #define Hangul_VBase	0x1161
93 #define Hangul_TBase	0x11a7
94 #define Hangul_SCount	11172
95 #define Hangul_LCount	19
96 #define Hangul_VCount	21
97 #define Hangul_TCount	28
98 #define Hangul_NCount	(Hangul_VCount * Hangul_TCount)
99 
100 
101 static u16 *hfsplus_compose_lookup(u16 *p, u16 cc)
102 {
103 	int i, s, e;
104 
105 	s = 1;
106 	e = p[1];
107 	if (!e || cc < p[s * 2] || cc > p[e * 2])
108 		return NULL;
109 	do {
110 		i = (s + e) / 2;
111 		if (cc > p[i * 2])
112 			s = i + 1;
113 		else if (cc < p[i * 2])
114 			e = i - 1;
115 		else
116 			return hfsplus_compose_table + p[i * 2 + 1];
117 	} while (s <= e);
118 	return NULL;
119 }
120 
121 int hfsplus_uni2asc(struct super_block *sb, const struct hfsplus_unistr *ustr, char *astr, int *len_p)
122 {
123 	const hfsplus_unichr *ip;
124 	struct nls_table *nls = HFSPLUS_SB(sb).nls;
125 	u8 *op;
126 	u16 cc, c0, c1;
127 	u16 *ce1, *ce2;
128 	int i, len, ustrlen, res, compose;
129 
130 	op = astr;
131 	ip = ustr->unicode;
132 	ustrlen = be16_to_cpu(ustr->length);
133 	len = *len_p;
134 	ce1 = NULL;
135 	compose = !(HFSPLUS_SB(sb).flags & HFSPLUS_SB_NODECOMPOSE);
136 
137 	while (ustrlen > 0) {
138 		c0 = be16_to_cpu(*ip++);
139 		ustrlen--;
140 		/* search for single decomposed char */
141 		if (likely(compose))
142 			ce1 = hfsplus_compose_lookup(hfsplus_compose_table, c0);
143 		if (ce1 && (cc = ce1[0])) {
144 			/* start of a possibly decomposed Hangul char */
145 			if (cc != 0xffff)
146 				goto done;
147 			if (!ustrlen)
148 				goto same;
149 			c1 = be16_to_cpu(*ip) - Hangul_VBase;
150 			if (c1 < Hangul_VCount) {
151 				/* compose the Hangul char */
152 				cc = (c0 - Hangul_LBase) * Hangul_VCount;
153 				cc = (cc + c1) * Hangul_TCount;
154 				cc += Hangul_SBase;
155 				ip++;
156 				ustrlen--;
157 				if (!ustrlen)
158 					goto done;
159 				c1 = be16_to_cpu(*ip) - Hangul_TBase;
160 				if (c1 > 0 && c1 < Hangul_TCount) {
161 					cc += c1;
162 					ip++;
163 					ustrlen--;
164 				}
165 				goto done;
166 			}
167 		}
168 		while (1) {
169 			/* main loop for common case of not composed chars */
170 			if (!ustrlen)
171 				goto same;
172 			c1 = be16_to_cpu(*ip);
173 			if (likely(compose))
174 				ce1 = hfsplus_compose_lookup(hfsplus_compose_table, c1);
175 			if (ce1)
176 				break;
177 			switch (c0) {
178 			case 0:
179 				c0 = 0x2400;
180 				break;
181 			case '/':
182 				c0 = ':';
183 				break;
184 			}
185 			res = nls->uni2char(c0, op, len);
186 			if (res < 0) {
187 				if (res == -ENAMETOOLONG)
188 					goto out;
189 				*op = '?';
190 				res = 1;
191 			}
192 			op += res;
193 			len -= res;
194 			c0 = c1;
195 			ip++;
196 			ustrlen--;
197 		}
198 		ce2 = hfsplus_compose_lookup(ce1, c0);
199 		if (ce2) {
200 			i = 1;
201 			while (i < ustrlen) {
202 				ce1 = hfsplus_compose_lookup(ce2, be16_to_cpu(ip[i]));
203 				if (!ce1)
204 					break;
205 				i++;
206 				ce2 = ce1;
207 			}
208 			if ((cc = ce2[0])) {
209 				ip += i;
210 				ustrlen -= i;
211 				goto done;
212 			}
213 		}
214 	same:
215 		switch (c0) {
216 		case 0:
217 			cc = 0x2400;
218 			break;
219 		case '/':
220 			cc = ':';
221 			break;
222 		default:
223 			cc = c0;
224 		}
225 	done:
226 		res = nls->uni2char(cc, op, len);
227 		if (res < 0) {
228 			if (res == -ENAMETOOLONG)
229 				goto out;
230 			*op = '?';
231 			res = 1;
232 		}
233 		op += res;
234 		len -= res;
235 	}
236 	res = 0;
237 out:
238 	*len_p = (char *)op - astr;
239 	return res;
240 }
241 
242 int hfsplus_asc2uni(struct super_block *sb, struct hfsplus_unistr *ustr, const char *astr, int len)
243 {
244 	struct nls_table *nls = HFSPLUS_SB(sb).nls;
245 	int size, off, decompose;
246 	wchar_t c;
247 	u16 outlen = 0;
248 
249 	decompose = !(HFSPLUS_SB(sb).flags & HFSPLUS_SB_NODECOMPOSE);
250 
251 	while (outlen < HFSPLUS_MAX_STRLEN && len > 0) {
252 		size = nls->char2uni(astr, len, &c);
253 		if (size <= 0) {
254 			c = '?';
255 			size = 1;
256 		}
257 		astr += size;
258 		len -= size;
259 		switch (c) {
260 		case 0x2400:
261 			c = 0;
262 			break;
263 		case ':':
264 			c = '/';
265 			break;
266 		}
267 		if (c >= 0xc0 && decompose) {
268 			off = hfsplus_decompose_table[(c >> 12) & 0xf];
269 			if (!off)
270 				goto done;
271 			if (off == 0xffff) {
272 				goto done;
273 			}
274 			off = hfsplus_decompose_table[off + ((c >> 8) & 0xf)];
275 			if (!off)
276 				goto done;
277 			off = hfsplus_decompose_table[off + ((c >> 4) & 0xf)];
278 			if (!off)
279 				goto done;
280 			off = hfsplus_decompose_table[off + (c & 0xf)];
281 			size = off & 3;
282 			if (!size)
283 				goto done;
284 			off /= 4;
285 			if (outlen + size > HFSPLUS_MAX_STRLEN)
286 				break;
287 			do {
288 				ustr->unicode[outlen++] = cpu_to_be16(hfsplus_decompose_table[off++]);
289 			} while (--size > 0);
290 			continue;
291 		}
292 	done:
293 		ustr->unicode[outlen++] = cpu_to_be16(c);
294 	}
295 	ustr->length = cpu_to_be16(outlen);
296 	if (len > 0)
297 		return -ENAMETOOLONG;
298 	return 0;
299 }
300