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105 lines
2.6 KiB
C
105 lines
2.6 KiB
C
/*
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* Copyright (c) 2020 Proofpoint, Inc. and its suppliers.
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* All rights reserved.
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*
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* By using this file, you agree to the terms and conditions set
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* forth in the LICENSE file which can be found at the top level of
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* the sendmail distribution.
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*
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*/
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#include <sm/gen.h>
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#include <sm/sendmail.h>
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#include <sm/ixlen.h>
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#if USE_EAI
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/*
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** legal utf-8 byte sequence
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** http://www.unicode.org/versions/Unicode6.0.0/ch03.pdf - page 94
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**
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** Code Points 1st 2s 3s 4s
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** U+0000..U+007F 00..7F
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** U+0080..U+07FF C2..DF 80..BF
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** U+0800..U+0FFF E0 A0..BF 80..BF
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** U+1000..U+CFFF E1..EC 80..BF 80..BF
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** U+D000..U+D7FF ED 80..9F 80..BF
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** U+E000..U+FFFF EE..EF 80..BF 80..BF
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** U+10000..U+3FFFF F0 90..BF 80..BF 80..BF
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** U+40000..U+FFFFF F1..F3 80..BF 80..BF 80..BF
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** U+100000..U+10FFFF F4 80..8F 80..BF 80..BF
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*/
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/*
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** based on
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** https://github.com/lemire/fastvalidate-utf-8.git
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** which is distributed under an MIT license (besides others).
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*/
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bool
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utf8_valid(b, length)
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const char *b;
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size_t length;
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{
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const unsigned char *bytes;
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size_t index;
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bytes = (const unsigned char *)b;
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index = 0;
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while (true)
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{
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unsigned char byte1;
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do { /* fast ASCII Path */
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if (index >= length)
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return true;
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byte1 = bytes[index++];
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} while (byte1 < 0x80);
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if (byte1 < 0xE0)
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{
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/* Two-byte form. */
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if (index == length)
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return false;
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if (byte1 < 0xC2 || bytes[index++] > 0xBF)
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return false;
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}
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else if (byte1 < 0xF0)
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{
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/* Three-byte form. */
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if (index + 1 >= length)
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return false;
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unsigned char byte2 = bytes[index++];
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if (byte2 > 0xBF
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/* Overlong? 5 most significant bits must not all be zero. */
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|| (byte1 == 0xE0 && byte2 < 0xA0)
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/* Check for illegal surrogate codepoints. */
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|| (byte1 == 0xED && 0xA0 <= byte2)
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/* Third byte trailing-byte test. */
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|| bytes[index++] > 0xBF)
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return false;
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}
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else
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{
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/* Four-byte form. */
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if (index + 2 >= length)
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return false;
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int byte2 = bytes[index++];
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if (byte2 > 0xBF
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/* Check that 1 <= plane <= 16. Tricky optimized form of: */
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/* if (byte1 > (byte) 0xF4 */
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/* || byte1 == (byte) 0xF0 && byte2 < (byte) 0x90 */
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/* || byte1 == (byte) 0xF4 && byte2 > (byte) 0x8F) */
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|| (((byte1 << 28) + (byte2 - 0x90)) >> 30) != 0
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/* Third byte trailing-byte test */
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|| bytes[index++] > 0xBF
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/* Fourth byte trailing-byte test */
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|| bytes[index++] > 0xBF)
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return false;
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}
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}
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/* NOTREACHED */
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return false;
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}
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#endif /* USE_EAI */
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