Miguel Freitas
11 years ago
4 changed files with 356 additions and 3 deletions
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// Copyright 2006 Nemanja Trifunovic
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/*
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Permission is hereby granted, free of charge, to any person or organization |
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obtaining a copy of the software and accompanying documentation covered by |
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this license (the "Software") to use, reproduce, display, distribute, |
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execute, and transmit the Software, and to prepare derivative works of the |
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Software, and to permit third-parties to whom the Software is furnished to |
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do so, all subject to the following: |
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The copyright notices in the Software and this entire statement, including |
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the above license grant, this restriction and the following disclaimer, |
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must be included in all copies of the Software, in whole or in part, and |
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all derivative works of the Software, unless such copies or derivative |
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works are solely in the form of machine-executable object code generated by |
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a source language processor. |
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT |
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SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE |
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FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, |
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ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
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DEALINGS IN THE SOFTWARE. |
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*/ |
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#ifndef UTF8_FOR_CPP_CORE_H_2675DCD0_9480_4c0c_B92A_CC14C027B731 |
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#define UTF8_FOR_CPP_CORE_H_2675DCD0_9480_4c0c_B92A_CC14C027B731 |
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#include <iterator> |
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#include <stdint.h> |
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namespace utf8 |
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{ |
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// The typedefs for 8-bit, 16-bit and 32-bit unsigned integers
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// You may need to change them to match your system.
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// These typedefs have the same names as ones from cstdint, or boost/cstdint
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//typedef unsigned char uint8_t;
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//typedef unsigned short uint16_t;
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//typedef unsigned int uint32_t;
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// Helper code - not intended to be directly called by the library users. May be changed at any time
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namespace internal |
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{ |
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// Unicode constants
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// Leading (high) surrogates: 0xd800 - 0xdbff
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// Trailing (low) surrogates: 0xdc00 - 0xdfff
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const uint16_t LEAD_SURROGATE_MIN = 0xd800u; |
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const uint16_t LEAD_SURROGATE_MAX = 0xdbffu; |
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const uint16_t TRAIL_SURROGATE_MIN = 0xdc00u; |
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const uint16_t TRAIL_SURROGATE_MAX = 0xdfffu; |
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const uint16_t LEAD_OFFSET = LEAD_SURROGATE_MIN - (0x10000 >> 10); |
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const uint32_t SURROGATE_OFFSET = 0x10000u - (LEAD_SURROGATE_MIN << 10) - TRAIL_SURROGATE_MIN; |
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// Maximum valid value for a Unicode code point
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const uint32_t CODE_POINT_MAX = 0x0010ffffu; |
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template<typename octet_type> |
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inline uint8_t mask8(octet_type oc) |
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{ |
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return static_cast<uint8_t>(0xff & oc); |
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} |
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template<typename u16_type> |
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inline uint16_t mask16(u16_type oc) |
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{ |
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return static_cast<uint16_t>(0xffff & oc); |
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} |
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template<typename octet_type> |
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inline bool is_trail(octet_type oc) |
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{ |
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return ((utf8::internal::mask8(oc) >> 6) == 0x2); |
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} |
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template <typename u16> |
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inline bool is_lead_surrogate(u16 cp) |
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{ |
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return (cp >= LEAD_SURROGATE_MIN && cp <= LEAD_SURROGATE_MAX); |
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} |
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template <typename u16> |
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inline bool is_trail_surrogate(u16 cp) |
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{ |
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return (cp >= TRAIL_SURROGATE_MIN && cp <= TRAIL_SURROGATE_MAX); |
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} |
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template <typename u16> |
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inline bool is_surrogate(u16 cp) |
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{ |
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return (cp >= LEAD_SURROGATE_MIN && cp <= TRAIL_SURROGATE_MAX); |
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} |
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template <typename u32> |
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inline bool is_code_point_valid(u32 cp) |
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{ |
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return (cp <= CODE_POINT_MAX && !utf8::internal::is_surrogate(cp)); |
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} |
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template <typename octet_iterator> |
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inline typename std::iterator_traits<octet_iterator>::difference_type |
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sequence_length(octet_iterator lead_it) |
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{ |
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uint8_t lead = utf8::internal::mask8(*lead_it); |
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if (lead < 0x80) |
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return 1; |
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else if ((lead >> 5) == 0x6) |
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return 2; |
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else if ((lead >> 4) == 0xe) |
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return 3; |
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else if ((lead >> 3) == 0x1e) |
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return 4; |
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else |
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return 0; |
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} |
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template <typename octet_difference_type> |
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inline bool is_overlong_sequence(uint32_t cp, octet_difference_type length) |
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{ |
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if (cp < 0x80) { |
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if (length != 1) |
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return true; |
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} |
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else if (cp < 0x800) { |
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if (length != 2) |
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return true; |
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} |
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else if (cp < 0x10000) { |
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if (length != 3) |
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return true; |
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} |
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return false; |
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} |
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enum utf_error {UTF8_OK, NOT_ENOUGH_ROOM, INVALID_LEAD, INCOMPLETE_SEQUENCE, OVERLONG_SEQUENCE, INVALID_CODE_POINT}; |
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/// Helper for get_sequence_x
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template <typename octet_iterator> |
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utf_error increase_safely(octet_iterator& it, octet_iterator end) |
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{ |
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if (++it == end) |
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return NOT_ENOUGH_ROOM; |
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if (!utf8::internal::is_trail(*it)) |
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return INCOMPLETE_SEQUENCE; |
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return UTF8_OK; |
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} |
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#define UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(IT, END) {utf_error ret = increase_safely(IT, END); if (ret != UTF8_OK) return ret;} |
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/// get_sequence_x functions decode utf-8 sequences of the length x
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template <typename octet_iterator> |
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utf_error get_sequence_1(octet_iterator& it, octet_iterator end, uint32_t& code_point) |
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{ |
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if (it == end) |
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return NOT_ENOUGH_ROOM; |
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code_point = utf8::internal::mask8(*it); |
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return UTF8_OK; |
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} |
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template <typename octet_iterator> |
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utf_error get_sequence_2(octet_iterator& it, octet_iterator end, uint32_t& code_point) |
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{ |
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if (it == end) |
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return NOT_ENOUGH_ROOM; |
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code_point = utf8::internal::mask8(*it); |
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UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end) |
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code_point = ((code_point << 6) & 0x7ff) + ((*it) & 0x3f); |
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return UTF8_OK; |
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} |
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template <typename octet_iterator> |
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utf_error get_sequence_3(octet_iterator& it, octet_iterator end, uint32_t& code_point) |
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{ |
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if (it == end) |
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return NOT_ENOUGH_ROOM; |
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code_point = utf8::internal::mask8(*it); |
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UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end) |
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code_point = ((code_point << 12) & 0xffff) + ((utf8::internal::mask8(*it) << 6) & 0xfff); |
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UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end) |
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code_point += (*it) & 0x3f; |
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return UTF8_OK; |
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} |
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template <typename octet_iterator> |
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utf_error get_sequence_4(octet_iterator& it, octet_iterator end, uint32_t& code_point) |
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{ |
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if (it == end) |
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return NOT_ENOUGH_ROOM; |
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code_point = utf8::internal::mask8(*it); |
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UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end) |
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code_point = ((code_point << 18) & 0x1fffff) + ((utf8::internal::mask8(*it) << 12) & 0x3ffff); |
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UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end) |
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code_point += (utf8::internal::mask8(*it) << 6) & 0xfff; |
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UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end) |
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code_point += (*it) & 0x3f; |
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return UTF8_OK; |
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} |
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#undef UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR |
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template <typename octet_iterator> |
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utf_error validate_next(octet_iterator& it, octet_iterator end, uint32_t& code_point) |
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{ |
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// Save the original value of it so we can go back in case of failure
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// Of course, it does not make much sense with i.e. stream iterators
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octet_iterator original_it = it; |
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uint32_t cp = 0; |
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// Determine the sequence length based on the lead octet
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typedef typename std::iterator_traits<octet_iterator>::difference_type octet_difference_type; |
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const octet_difference_type length = utf8::internal::sequence_length(it); |
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// Get trail octets and calculate the code point
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utf_error err = UTF8_OK; |
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switch (length) { |
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case 0: |
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return INVALID_LEAD; |
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case 1: |
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err = utf8::internal::get_sequence_1(it, end, cp); |
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break; |
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case 2: |
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err = utf8::internal::get_sequence_2(it, end, cp); |
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break; |
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case 3: |
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err = utf8::internal::get_sequence_3(it, end, cp); |
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break; |
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case 4: |
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err = utf8::internal::get_sequence_4(it, end, cp); |
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break; |
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} |
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if (err == UTF8_OK) { |
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// Decoding succeeded. Now, security checks...
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if (utf8::internal::is_code_point_valid(cp)) { |
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if (!utf8::internal::is_overlong_sequence(cp, length)){ |
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// Passed! Return here.
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code_point = cp; |
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++it; |
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return UTF8_OK; |
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} |
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else |
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err = OVERLONG_SEQUENCE; |
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} |
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else |
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err = INVALID_CODE_POINT; |
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} |
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// Failure branch - restore the original value of the iterator
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it = original_it; |
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return err; |
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} |
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template <typename octet_iterator> |
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inline utf_error validate_next(octet_iterator& it, octet_iterator end) { |
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uint32_t ignored; |
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return utf8::internal::validate_next(it, end, ignored); |
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} |
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} // namespace internal
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/// The library API - functions intended to be called by the users
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// Byte order mark
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const uint8_t bom[] = {0xef, 0xbb, 0xbf}; |
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template <typename octet_iterator> |
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octet_iterator find_invalid(octet_iterator start, octet_iterator end) |
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{ |
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octet_iterator result = start; |
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while (result != end) { |
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utf8::internal::utf_error err_code = utf8::internal::validate_next(result, end); |
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if (err_code != internal::UTF8_OK) |
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return result; |
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} |
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return result; |
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} |
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template <typename octet_iterator> |
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int num_characters(octet_iterator start, octet_iterator end) |
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{ |
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int count = 0; |
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octet_iterator it = start; |
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while (it != end) { |
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utf8::internal::utf_error err_code = utf8::internal::validate_next(it, end); |
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if (err_code != internal::UTF8_OK) |
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return -1; |
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count++; |
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} |
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return count; |
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} |
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template <typename octet_iterator> |
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inline bool is_valid(octet_iterator start, octet_iterator end) |
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{ |
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return (utf8::find_invalid(start, end) == end); |
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} |
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template <typename octet_iterator> |
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inline bool starts_with_bom (octet_iterator it, octet_iterator end) |
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{ |
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return ( |
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((it != end) && (utf8::internal::mask8(*it++)) == bom[0]) && |
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((it != end) && (utf8::internal::mask8(*it++)) == bom[1]) && |
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((it != end) && (utf8::internal::mask8(*it)) == bom[2]) |
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); |
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} |
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//Deprecated in release 2.3
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template <typename octet_iterator> |
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inline bool is_bom (octet_iterator it) |
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{ |
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return ( |
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(utf8::internal::mask8(*it++)) == bom[0] && |
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(utf8::internal::mask8(*it++)) == bom[1] && |
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(utf8::internal::mask8(*it)) == bom[2] |
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); |
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} |
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} // namespace utf8
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#endif // header guard
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