1 /* 2 * Copyright (C) 2014 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <errno.h> 30 #include <sys/param.h> 31 #include <uchar.h> 32 #include <wchar.h> 33 34 #include "private/bionic_mbstate.h" 35 36 size_t mbrtoc32(char32_t* pc32, const char* s, size_t n, mbstate_t* ps) { 37 static mbstate_t __private_state; 38 mbstate_t* state = (ps == nullptr) ? &__private_state : ps; 39 40 // We should never get to a state which has all 4 bytes of the sequence set. 41 // Full state verification is done when decoding the sequence (after we have 42 // all the bytes). 43 if (mbstate_get_byte(state, 3) != 0) { 44 return mbstate_reset_and_return_illegal(EINVAL, state); 45 } 46 47 if (s == nullptr) { 48 s = ""; 49 n = 1; 50 pc32 = nullptr; 51 } 52 53 if (n == 0) { 54 return 0; 55 } 56 57 uint8_t ch; 58 if (mbsinit(state) && (((ch = static_cast<uint8_t>(*s)) & ~0x7f) == 0)) { 59 // Fast path for plain ASCII characters. 60 if (pc32 != nullptr) { 61 *pc32 = ch; 62 } 63 return (ch != '\0' ? 1 : 0); 64 } 65 66 // Determine the number of octets that make up this character 67 // from the first octet, and a mask that extracts the 68 // interesting bits of the first octet. We already know 69 // the character is at least two bytes long. 70 size_t length; 71 int mask; 72 73 // We also specify a lower bound for the character code to 74 // detect redundant, non-"shortest form" encodings. For 75 // example, the sequence C0 80 is _not_ a legal representation 76 // of the null character. This enforces a 1-to-1 mapping 77 // between character codes and their multibyte representations. 78 char32_t lower_bound; 79 80 // The first byte in the state (if any) tells the length. 81 size_t bytes_so_far = mbstate_bytes_so_far(state); 82 ch = bytes_so_far > 0 ? mbstate_get_byte(state, 0) : static_cast<uint8_t>(*s); 83 if ((ch & 0x80) == 0) { 84 mask = 0x7f; 85 length = 1; 86 lower_bound = 0; 87 } else if ((ch & 0xe0) == 0xc0) { 88 mask = 0x1f; 89 length = 2; 90 lower_bound = 0x80; 91 } else if ((ch & 0xf0) == 0xe0) { 92 mask = 0x0f; 93 length = 3; 94 lower_bound = 0x800; 95 } else if ((ch & 0xf8) == 0xf0) { 96 mask = 0x07; 97 length = 4; 98 lower_bound = 0x10000; 99 } else { 100 // Malformed input; input is not UTF-8. See RFC 3629. 101 return mbstate_reset_and_return_illegal(EILSEQ, state); 102 } 103 104 // Fill in the state. 105 size_t bytes_wanted = length - bytes_so_far; 106 size_t i; 107 for (i = 0; i < MIN(bytes_wanted, n); i++) { 108 if (!mbsinit(state) && ((*s & 0xc0) != 0x80)) { 109 // Malformed input; bad characters in the middle of a character. 110 return mbstate_reset_and_return_illegal(EILSEQ, state); 111 } 112 mbstate_set_byte(state, bytes_so_far + i, *s++); 113 } 114 if (i < bytes_wanted) { 115 return __MB_ERR_INCOMPLETE_SEQUENCE; 116 } 117 118 // Decode the octet sequence representing the character in chunks 119 // of 6 bits, most significant first. 120 char32_t c32 = mbstate_get_byte(state, 0) & mask; 121 for (i = 1; i < length; i++) { 122 c32 <<= 6; 123 c32 |= mbstate_get_byte(state, i) & 0x3f; 124 } 125 126 if (c32 < lower_bound) { 127 // Malformed input; redundant encoding. 128 return mbstate_reset_and_return_illegal(EILSEQ, state); 129 } 130 if ((c32 >= 0xd800 && c32 <= 0xdfff) || (c32 > 0x10ffff)) { 131 // Malformed input; invalid code points. 132 return mbstate_reset_and_return_illegal(EILSEQ, state); 133 } 134 if (pc32 != nullptr) { 135 *pc32 = c32; 136 } 137 return mbstate_reset_and_return(c32 == U'\0' ? 0 : bytes_wanted, state); 138 } 139
