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 */ 35int 36modifiedUtf8LengthOfUtf8(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 */ 93void 94convertUtf8ToModifiedUtf8(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