1 /*
2 * Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26
27 /**
28 * Determine length of this Standard UTF-8 in Modified UTF-8.
29 * Validation is done of the basic UTF encoding rules, returns
30 * length (no change) when errors are detected in the UTF encoding.
31 *
32 * Note: Accepts Modified UTF-8 also, no verification on the
33 * correctness of Standard UTF-8 is done. e,g, 0xC080 input is ok.
34 */
35 int
modifiedUtf8LengthOfUtf8(char * string,int length)36 modifiedUtf8LengthOfUtf8(char* string, int length) {
37 int new_length;
38 int i;
39
40 new_length = 0;
41 for ( i = 0 ; i < length ; i++ ) {
42 unsigned byte;
43
44 byte = (unsigned char)string[i];
45 if ( (byte & 0x80) == 0 ) { /* 1byte encoding */
46 new_length++;
47 if ( byte == 0 ) {
48 new_length++; /* We gain one byte in length on NULL bytes */
49 }
50 } else if ( (byte & 0xE0) == 0xC0 ) { /* 2byte encoding */
51 /* Check encoding of following bytes */
52 if ( (i+1) >= length || (string[i+1] & 0xC0) != 0x80 ) {
53 break; /* Error condition */
54 }
55 i++; /* Skip next byte */
56 new_length += 2;
57 } else if ( (byte & 0xF0) == 0xE0 ) { /* 3byte encoding */
58 /* Check encoding of following bytes */
59 if ( (i+2) >= length || (string[i+1] & 0xC0) != 0x80
60 || (string[i+2] & 0xC0) != 0x80 ) {
61 break; /* Error condition */
62 }
63 i += 2; /* Skip next two bytes */
64 new_length += 3;
65 } else if ( (byte & 0xF8) == 0xF0 ) { /* 4byte encoding */
66 /* Check encoding of following bytes */
67 if ( (i+3) >= length || (string[i+1] & 0xC0) != 0x80
68 || (string[i+2] & 0xC0) != 0x80
69 || (string[i+3] & 0xC0) != 0x80 ) {
70 break; /* Error condition */
71 }
72 i += 3; /* Skip next 3 bytes */
73 new_length += 6; /* 4byte encoding turns into 2 3byte ones */
74 } else {
75 break; /* Error condition */
76 }
77 }
78 if ( i != length ) {
79 /* Error in finding new length, return old length so no conversion */
80 /* FIXUP: ERROR_MESSAGE? */
81 return length;
82 }
83 return new_length;
84 }
85
86 /*
87 * Convert Standard UTF-8 to Modified UTF-8.
88 * Assumes the UTF-8 encoding was validated by modifiedLength() above.
89 *
90 * Note: Accepts Modified UTF-8 also, no verification on the
91 * correctness of Standard UTF-8 is done. e,g, 0xC080 input is ok.
92 */
93 void
convertUtf8ToModifiedUtf8(char * string,int length,char * new_string,int new_length)94 convertUtf8ToModifiedUtf8(char *string, int length, char *new_string, int new_length)
95 {
96 int i;
97 int j;
98
99 j = 0;
100 for ( i = 0 ; i < length ; i++ ) {
101 unsigned byte1;
102
103 byte1 = (unsigned char)string[i];
104
105 /* NULL bytes and bytes starting with 11110xxx are special */
106 if ( (byte1 & 0x80) == 0 ) { /* 1byte encoding */
107 if ( byte1 == 0 ) {
108 /* Bits out: 11000000 10000000 */
109 new_string[j++] = (char)0xC0;
110 new_string[j++] = (char)0x80;
111 } else {
112 /* Single byte */
113 new_string[j++] = byte1;
114 }
115 } else if ( (byte1 & 0xE0) == 0xC0 ) { /* 2byte encoding */
116 new_string[j++] = byte1;
117 new_string[j++] = string[++i];
118 } else if ( (byte1 & 0xF0) == 0xE0 ) { /* 3byte encoding */
119 new_string[j++] = byte1;
120 new_string[j++] = string[++i];
121 new_string[j++] = string[++i];
122 } else if ( (byte1 & 0xF8) == 0xF0 ) { /* 4byte encoding */
123 /* Beginning of 4byte encoding, turn into 2 3byte encodings */
124 unsigned byte2, byte3, byte4, u21;
125
126 /* Bits in: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx */
127 byte2 = (unsigned char)string[++i];
128 byte3 = (unsigned char)string[++i];
129 byte4 = (unsigned char)string[++i];
130 /* Reconstruct full 21bit value */
131 u21 = (byte1 & 0x07) << 18;
132 u21 += (byte2 & 0x3F) << 12;
133 u21 += (byte3 & 0x3F) << 6;
134 u21 += (byte4 & 0x3F);
135 /* Bits out: 11101101 1010xxxx 10xxxxxx */
136 new_string[j++] = (char)0xED;
137 new_string[j++] = 0xA0 + (((u21 >> 16) - 1) & 0x0F);
138 new_string[j++] = 0x80 + ((u21 >> 10) & 0x3F);
139 /* Bits out: 11101101 1011xxxx 10xxxxxx */
140 new_string[j++] = (char)0xED;
141 new_string[j++] = 0xB0 + ((u21 >> 6) & 0x0F);
142 new_string[j++] = byte4;
143 }
144 }
145 new_string[j] = 0;
146 }
147