/* * is_utf8 is distributed under the following terms: * * Copyright (c) 2013 Palard Julien. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include "is_utf8.hh" #include "config.h" /* Check if the given unsigned char * is a valid utf-8 sequence. Return value : If the string is valid utf-8, 0 is returned. Else the position, starting from 1, is returned. Source: http://www.unicode.org/versions/Unicode7.0.0/UnicodeStandard-7.0.pdf page 124, 3.9 "Unicode Encoding Forms", "UTF-8" Table 3-7. Well-Formed UTF-8 Byte Sequences ----------------------------------------------------------------------------- | Code Points | First Byte | Second Byte | Third Byte | Fourth Byte | | U+0000..U+007F | 00..7F | | | | | U+0080..U+07FF | C2..DF | 80..BF | | | | U+0800..U+0FFF | E0 | A0..BF | 80..BF | | | U+1000..U+CFFF | E1..EC | 80..BF | 80..BF | | | U+D000..U+D7FF | ED | 80..9F | 80..BF | | | U+E000..U+FFFF | EE..EF | 80..BF | 80..BF | | | U+10000..U+3FFFF | F0 | 90..BF | 80..BF | 80..BF | | U+40000..U+FFFFF | F1..F3 | 80..BF | 80..BF | 80..BF | | U+100000..U+10FFFF | F4 | 80..8F | 80..BF | 80..BF | ----------------------------------------------------------------------------- Returns the first erroneous byte position, and give in `faulty_bytes` the number of actually existing bytes taking part in this error. */ ssize_t is_utf8(unsigned char* str, size_t len, const char** message, int* faulty_bytes) { size_t i = 0; *message = nullptr; *faulty_bytes = 0; while (i < len) { if (str[i] == '\n') { *message = nullptr; return i; } if (str[i] <= 0x7F) /* 00..7F */ { i += 1; } else if (str[i] >= 0xC2 && str[i] <= 0xDF) /* C2..DF 80..BF */ { if (i + 1 < len) /* Expect a 2nd byte */ { if (str[i + 1] < 0x80 || str[i + 1] > 0xBF) { *message = "After a first byte between C2 and DF, expecting a " "2nd byte between 80 and BF"; *faulty_bytes = 2; return i; } } else { *message = "After a first byte between C2 and DF, expecting a 2nd " "byte."; *faulty_bytes = 1; return i; } i += 2; } else if (str[i] == 0xE0) /* E0 A0..BF 80..BF */ { if (i + 2 < len) /* Expect a 2nd and 3rd byte */ { if (str[i + 1] < 0xA0 || str[i + 1] > 0xBF) { *message = "After a first byte of E0, expecting a 2nd byte " "between A0 and BF."; *faulty_bytes = 2; return i; } if (str[i + 2] < 0x80 || str[i + 2] > 0xBF) { *message = "After a first byte of E0, expecting a 3nd byte " "between 80 and BF."; *faulty_bytes = 3; return i; } } else { *message = "After a first byte of E0, expecting two following " "bytes."; *faulty_bytes = 1; return i; } i += 3; } else if (str[i] >= 0xE1 && str[i] <= 0xEC) /* E1..EC 80..BF 80..BF */ { if (i + 2 < len) /* Expect a 2nd and 3rd byte */ { if (str[i + 1] < 0x80 || str[i + 1] > 0xBF) { *message = "After a first byte between E1 and EC, expecting the " "2nd byte between 80 and BF."; *faulty_bytes = 2; return i; } if (str[i + 2] < 0x80 || str[i + 2] > 0xBF) { *message = "After a first byte between E1 and EC, expecting the " "3rd byte between 80 and BF."; *faulty_bytes = 3; return i; } } else { *message = "After a first byte between E1 and EC, expecting two " "following bytes."; *faulty_bytes = 1; return i; } i += 3; } else if (str[i] == 0xED) /* ED 80..9F 80..BF */ { if (i + 2 < len) /* Expect a 2nd and 3rd byte */ { if (str[i + 1] < 0x80 || str[i + 1] > 0x9F) { *message = "After a first byte of ED, expecting 2nd byte " "between 80 and 9F."; *faulty_bytes = 2; return i; } if (str[i + 2] < 0x80 || str[i + 2] > 0xBF) { *message = "After a first byte of ED, expecting 3rd byte " "between 80 and BF."; *faulty_bytes = 3; return i; } } else { *message = "After a first byte of ED, expecting two following " "bytes."; *faulty_bytes = 1; return i; } i += 3; } else if (str[i] >= 0xEE && str[i] <= 0xEF) /* EE..EF 80..BF 80..BF */ { if (i + 2 < len) /* Expect a 2nd and 3rd byte */ { if (str[i + 1] < 0x80 || str[i + 1] > 0xBF) { *message = "After a first byte between EE and EF, expecting 2nd " "byte between 80 and BF."; *faulty_bytes = 2; return i; } if (str[i + 2] < 0x80 || str[i + 2] > 0xBF) { *message = "After a first byte between EE and EF, expecting 3rd " "byte between 80 and BF."; *faulty_bytes = 3; return i; } } else { *message = "After a first byte between EE and EF, two following " "bytes."; *faulty_bytes = 1; return i; } i += 3; } else if (str[i] == 0xF0) /* F0 90..BF 80..BF 80..BF */ { if (i + 3 < len) /* Expect a 2nd, 3rd 3th byte */ { if (str[i + 1] < 0x90 || str[i + 1] > 0xBF) { *message = "After a first byte of F0, expecting 2nd byte " "between 90 and BF."; *faulty_bytes = 2; return i; } if (str[i + 2] < 0x80 || str[i + 2] > 0xBF) { *message = "After a first byte of F0, expecting 3rd byte " "between 80 and BF."; *faulty_bytes = 3; return i; } if (str[i + 3] < 0x80 || str[i + 3] > 0xBF) { *message = "After a first byte of F0, expecting 4th byte " "between 80 and BF."; *faulty_bytes = 4; return i; } } else { *message = "After a first byte of F0, expecting three following " "bytes."; *faulty_bytes = 1; return i; } i += 4; } else if (str[i] >= 0xF1 && str[i] <= 0xF3) /* F1..F3 80..BF 80..BF 80..BF */ { if (i + 3 < len) /* Expect a 2nd, 3rd 3th byte */ { if (str[i + 1] < 0x80 || str[i + 1] > 0xBF) { *message = "After a first byte of F1, F2, or F3, expecting a " "2nd byte between 80 and BF."; *faulty_bytes = 2; return i; } if (str[i + 2] < 0x80 || str[i + 2] > 0xBF) { *message = "After a first byte of F1, F2, or F3, expecting a " "3rd byte between 80 and BF."; *faulty_bytes = 3; return i; } if (str[i + 3] < 0x80 || str[i + 3] > 0xBF) { *message = "After a first byte of F1, F2, or F3, expecting a " "4th byte between 80 and BF."; *faulty_bytes = 4; return i; } } else { *message = "After a first byte of F1, F2, or F3, expecting three " "following bytes."; *faulty_bytes = 1; return i; } i += 4; } else if (str[i] == 0xF4) /* F4 80..8F 80..BF 80..BF */ { if (i + 3 < len) /* Expect a 2nd, 3rd 3th byte */ { if (str[i + 1] < 0x80 || str[i + 1] > 0x8F) { *message = "After a first byte of F4, expecting 2nd byte " "between 80 and 8F."; *faulty_bytes = 2; return i; } if (str[i + 2] < 0x80 || str[i + 2] > 0xBF) { *message = "After a first byte of F4, expecting 3rd byte " "between 80 and BF."; *faulty_bytes = 3; return i; } if (str[i + 3] < 0x80 || str[i + 3] > 0xBF) { *message = "After a first byte of F4, expecting 4th byte " "between 80 and BF."; *faulty_bytes = 4; return i; } } else { *message = "After a first byte of F4, expecting three following " "bytes."; *faulty_bytes = 1; return i; } i += 4; } else { *message = "Expecting bytes in the following ranges: 00..7F C2..F4."; *faulty_bytes = 1; return i; } } return -1; }