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 <uchar.h> 31 #include <wchar.h> 32 33 #include "private/bionic_mbstate.h" 34 35 size_t c32rtomb(char* s, char32_t c32, mbstate_t* ps) { 36 static mbstate_t __private_state; 37 mbstate_t* state = (ps == NULL) ? &__private_state : ps; 38 39 if (s == NULL) { 40 // Equivalent to c32rtomb(buf, U'\0', ps). 41 return mbstate_reset_and_return(1, state); 42 } 43 44 // POSIX states that if char32_t is a null wide character, a null byte shall 45 // be stored, preceded by any shift sequence needed to restore the initial 46 // shift state. Since shift states are not supported, only the null byte is 47 // stored. 48 if (c32 == U'\0') { 49 *s = '\0'; 50 return mbstate_reset_and_return(1, state); 51 } 52 53 if (!mbsinit(state)) { 54 return mbstate_reset_and_return_illegal(EILSEQ, state); 55 } 56 57 if ((c32 & ~0x7f) == 0) { 58 // Fast path for plain ASCII characters. 59 *s = c32; 60 return 1; 61 } 62 63 // Determine the number of octets needed to represent this character. 64 // We always output the shortest sequence possible. Also specify the 65 // first few bits of the first octet, which contains the information 66 // about the sequence length. 67 uint8_t lead; 68 size_t length; 69 if ((c32 & ~0x7f) == 0) { 70 lead = 0; 71 length = 1; 72 } else if ((c32 & ~0x7ff) == 0) { 73 lead = 0xc0; 74 length = 2; 75 } else if ((c32 & ~0xffff) == 0) { 76 lead = 0xe0; 77 length = 3; 78 } else if ((c32 & ~0x1fffff) == 0) { 79 lead = 0xf0; 80 length = 4; 81 } else { 82 errno = EILSEQ; 83 return __MB_ERR_ILLEGAL_SEQUENCE; 84 } 85 86 // Output the octets representing the character in chunks 87 // of 6 bits, least significant last. The first octet is 88 // a special case because it contains the sequence length 89 // information. 90 for (size_t i = length - 1; i > 0; i--) { 91 s[i] = (c32 & 0x3f) | 0x80; 92 c32 >>= 6; 93 } 94 *s = (c32 & 0xff) | lead; 95 96 return length; 97 } 98
