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/*
* 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.
*/
utf8_scan_result
is_utf8(const unsigned char* str,
size_t len,
const char** message,
int* faulty_bytes,
nonstd::optional<unsigned char> terminator)
{
bool has_ansi = false;
ssize_t i = 0;
*message = nullptr;
*faulty_bytes = 0;
while (i < len) {
if (str[i] == '\x1b') {
has_ansi = true;
}
if (terminator && str[i] == terminator.value()) {
*message = nullptr;
return {i, has_ansi};
}
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, has_ansi};
}
} else {
*message
= "After a first byte between C2 and DF, expecting a 2nd "
"byte.";
*faulty_bytes = 1;
return {i, has_ansi};
}
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, has_ansi};
}
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, has_ansi};
}
} else {
*message
= "After a first byte of E0, expecting two following "
"bytes.";
*faulty_bytes = 1;
return {i, has_ansi};
}
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, has_ansi};
}
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, has_ansi};
}
} else {
*message
= "After a first byte between E1 and EC, expecting two "
"following bytes.";
*faulty_bytes = 1;
return {i, has_ansi};
}
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, has_ansi};
}
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, has_ansi};
}
} else {
*message
= "After a first byte of ED, expecting two following "
"bytes.";
*faulty_bytes = 1;
return {i, has_ansi};
}
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, has_ansi};
}
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, has_ansi};
}
} else {
*message
= "After a first byte between EE and EF, two following "
"bytes.";
*faulty_bytes = 1;
return {i, has_ansi};
}
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, has_ansi};
}
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, has_ansi};
}
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, has_ansi};
}
} else {
*message
= "After a first byte of F0, expecting three following "
"bytes.";
*faulty_bytes = 1;
return {i, has_ansi};
}
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, has_ansi};
}
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, has_ansi};
}
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, has_ansi};
}
} else {
*message
= "After a first byte of F1, F2, or F3, expecting three "
"following bytes.";
*faulty_bytes = 1;
return {i, has_ansi};
}
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, has_ansi};
}
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, has_ansi};
}
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, has_ansi};
}
} else {
*message
= "After a first byte of F4, expecting three following "
"bytes.";
*faulty_bytes = 1;
return {i, has_ansi};
}
i += 4;
} else {
*message
= "Expecting bytes in the following ranges: 00..7F C2..F4.";
*faulty_bytes = 1;
return {i, has_ansi};
}
}
return {-1, has_ansi};
}
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