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authorMatthias P. Braendli <matthias.braendli@mpb.li>2018-02-09 11:42:51 +0100
committerMatthias P. Braendli <matthias.braendli@mpb.li>2018-02-09 11:42:51 +0100
commitf4ef1284d754ecd907dd4ed3072f8be65b26f2de (patch)
tree8226900d44c2c0708188fc4a3dd07dea263bd115 /lib/charset/utf8/core.h
parentd10839ab23b4ac4dea5ba183c451b650dd07331a (diff)
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Add charset conversion library
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diff --git a/lib/charset/utf8/core.h b/lib/charset/utf8/core.h
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+// Copyright 2006 Nemanja Trifunovic
+
+/*
+Permission is hereby granted, free of charge, to any person or organization
+obtaining a copy of the software and accompanying documentation covered by
+this license (the "Software") to use, reproduce, display, distribute,
+execute, and transmit the Software, and to prepare derivative works of the
+Software, and to permit third-parties to whom the Software is furnished to
+do so, all subject to the following:
+
+The copyright notices in the Software and this entire statement, including
+the above license grant, this restriction and the following disclaimer,
+must be included in all copies of the Software, in whole or in part, and
+all derivative works of the Software, unless such copies or derivative
+works are solely in the form of machine-executable object code generated by
+a source language processor.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+*/
+
+
+#ifndef UTF8_FOR_CPP_CORE_H_2675DCD0_9480_4c0c_B92A_CC14C027B731
+#define UTF8_FOR_CPP_CORE_H_2675DCD0_9480_4c0c_B92A_CC14C027B731
+
+#include <iterator>
+
+namespace utf8
+{
+ // The typedefs for 8-bit, 16-bit and 32-bit unsigned integers
+ // You may need to change them to match your system.
+ // These typedefs have the same names as ones from cstdint, or boost/cstdint
+ typedef unsigned char uint8_t;
+ typedef unsigned short uint16_t;
+ typedef unsigned int uint32_t;
+
+// Helper code - not intended to be directly called by the library users. May be changed at any time
+namespace internal
+{
+ // Unicode constants
+ // Leading (high) surrogates: 0xd800 - 0xdbff
+ // Trailing (low) surrogates: 0xdc00 - 0xdfff
+ const uint16_t LEAD_SURROGATE_MIN = 0xd800u;
+ const uint16_t LEAD_SURROGATE_MAX = 0xdbffu;
+ const uint16_t TRAIL_SURROGATE_MIN = 0xdc00u;
+ const uint16_t TRAIL_SURROGATE_MAX = 0xdfffu;
+ const uint16_t LEAD_OFFSET = LEAD_SURROGATE_MIN - (0x10000 >> 10);
+ const uint32_t SURROGATE_OFFSET = 0x10000u - (LEAD_SURROGATE_MIN << 10) - TRAIL_SURROGATE_MIN;
+
+ // Maximum valid value for a Unicode code point
+ const uint32_t CODE_POINT_MAX = 0x0010ffffu;
+
+ template<typename octet_type>
+ inline uint8_t mask8(octet_type oc)
+ {
+ return static_cast<uint8_t>(0xff & oc);
+ }
+ template<typename u16_type>
+ inline uint16_t mask16(u16_type oc)
+ {
+ return static_cast<uint16_t>(0xffff & oc);
+ }
+ template<typename octet_type>
+ inline bool is_trail(octet_type oc)
+ {
+ return ((utf8::internal::mask8(oc) >> 6) == 0x2);
+ }
+
+ template <typename u16>
+ inline bool is_lead_surrogate(u16 cp)
+ {
+ return (cp >= LEAD_SURROGATE_MIN && cp <= LEAD_SURROGATE_MAX);
+ }
+
+ template <typename u16>
+ inline bool is_trail_surrogate(u16 cp)
+ {
+ return (cp >= TRAIL_SURROGATE_MIN && cp <= TRAIL_SURROGATE_MAX);
+ }
+
+ template <typename u16>
+ inline bool is_surrogate(u16 cp)
+ {
+ return (cp >= LEAD_SURROGATE_MIN && cp <= TRAIL_SURROGATE_MAX);
+ }
+
+ template <typename u32>
+ inline bool is_code_point_valid(u32 cp)
+ {
+ return (cp <= CODE_POINT_MAX && !utf8::internal::is_surrogate(cp));
+ }
+
+ template <typename octet_iterator>
+ inline typename std::iterator_traits<octet_iterator>::difference_type
+ sequence_length(octet_iterator lead_it)
+ {
+ uint8_t lead = utf8::internal::mask8(*lead_it);
+ if (lead < 0x80)
+ return 1;
+ else if ((lead >> 5) == 0x6)
+ return 2;
+ else if ((lead >> 4) == 0xe)
+ return 3;
+ else if ((lead >> 3) == 0x1e)
+ return 4;
+ else
+ return 0;
+ }
+
+ template <typename octet_difference_type>
+ inline bool is_overlong_sequence(uint32_t cp, octet_difference_type length)
+ {
+ if (cp < 0x80) {
+ if (length != 1)
+ return true;
+ }
+ else if (cp < 0x800) {
+ if (length != 2)
+ return true;
+ }
+ else if (cp < 0x10000) {
+ if (length != 3)
+ return true;
+ }
+
+ return false;
+ }
+
+ enum utf_error {UTF8_OK, NOT_ENOUGH_ROOM, INVALID_LEAD, INCOMPLETE_SEQUENCE, OVERLONG_SEQUENCE, INVALID_CODE_POINT};
+
+ /// Helper for get_sequence_x
+ template <typename octet_iterator>
+ utf_error increase_safely(octet_iterator& it, octet_iterator end)
+ {
+ if (++it == end)
+ return NOT_ENOUGH_ROOM;
+
+ if (!utf8::internal::is_trail(*it))
+ return INCOMPLETE_SEQUENCE;
+
+ return UTF8_OK;
+ }
+
+ #define UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(IT, END) {utf_error ret = increase_safely(IT, END); if (ret != UTF8_OK) return ret;}
+
+ /// get_sequence_x functions decode utf-8 sequences of the length x
+ template <typename octet_iterator>
+ utf_error get_sequence_1(octet_iterator& it, octet_iterator end, uint32_t& code_point)
+ {
+ if (it == end)
+ return NOT_ENOUGH_ROOM;
+
+ code_point = utf8::internal::mask8(*it);
+
+ return UTF8_OK;
+ }
+
+ template <typename octet_iterator>
+ utf_error get_sequence_2(octet_iterator& it, octet_iterator end, uint32_t& code_point)
+ {
+ if (it == end)
+ return NOT_ENOUGH_ROOM;
+
+ code_point = utf8::internal::mask8(*it);
+
+ UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end)
+
+ code_point = ((code_point << 6) & 0x7ff) + ((*it) & 0x3f);
+
+ return UTF8_OK;
+ }
+
+ template <typename octet_iterator>
+ utf_error get_sequence_3(octet_iterator& it, octet_iterator end, uint32_t& code_point)
+ {
+ if (it == end)
+ return NOT_ENOUGH_ROOM;
+
+ code_point = utf8::internal::mask8(*it);
+
+ UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end)
+
+ code_point = ((code_point << 12) & 0xffff) + ((utf8::internal::mask8(*it) << 6) & 0xfff);
+
+ UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end)
+
+ code_point += (*it) & 0x3f;
+
+ return UTF8_OK;
+ }
+
+ template <typename octet_iterator>
+ utf_error get_sequence_4(octet_iterator& it, octet_iterator end, uint32_t& code_point)
+ {
+ if (it == end)
+ return NOT_ENOUGH_ROOM;
+
+ code_point = utf8::internal::mask8(*it);
+
+ UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end)
+
+ code_point = ((code_point << 18) & 0x1fffff) + ((utf8::internal::mask8(*it) << 12) & 0x3ffff);
+
+ UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end)
+
+ code_point += (utf8::internal::mask8(*it) << 6) & 0xfff;
+
+ UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end)
+
+ code_point += (*it) & 0x3f;
+
+ return UTF8_OK;
+ }
+
+ #undef UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR
+
+ template <typename octet_iterator>
+ utf_error validate_next(octet_iterator& it, octet_iterator end, uint32_t& code_point)
+ {
+ // Save the original value of it so we can go back in case of failure
+ // Of course, it does not make much sense with i.e. stream iterators
+ octet_iterator original_it = it;
+
+ uint32_t cp = 0;
+ // Determine the sequence length based on the lead octet
+ typedef typename std::iterator_traits<octet_iterator>::difference_type octet_difference_type;
+ const octet_difference_type length = utf8::internal::sequence_length(it);
+
+ // Get trail octets and calculate the code point
+ utf_error err = UTF8_OK;
+ switch (length) {
+ case 0:
+ return INVALID_LEAD;
+ case 1:
+ err = utf8::internal::get_sequence_1(it, end, cp);
+ break;
+ case 2:
+ err = utf8::internal::get_sequence_2(it, end, cp);
+ break;
+ case 3:
+ err = utf8::internal::get_sequence_3(it, end, cp);
+ break;
+ case 4:
+ err = utf8::internal::get_sequence_4(it, end, cp);
+ break;
+ }
+
+ if (err == UTF8_OK) {
+ // Decoding succeeded. Now, security checks...
+ if (utf8::internal::is_code_point_valid(cp)) {
+ if (!utf8::internal::is_overlong_sequence(cp, length)){
+ // Passed! Return here.
+ code_point = cp;
+ ++it;
+ return UTF8_OK;
+ }
+ else
+ err = OVERLONG_SEQUENCE;
+ }
+ else
+ err = INVALID_CODE_POINT;
+ }
+
+ // Failure branch - restore the original value of the iterator
+ it = original_it;
+ return err;
+ }
+
+ template <typename octet_iterator>
+ inline utf_error validate_next(octet_iterator& it, octet_iterator end) {
+ uint32_t ignored;
+ return utf8::internal::validate_next(it, end, ignored);
+ }
+
+} // namespace internal
+
+ /// The library API - functions intended to be called by the users
+
+ // Byte order mark
+ const uint8_t bom[] = {0xef, 0xbb, 0xbf};
+
+ template <typename octet_iterator>
+ octet_iterator find_invalid(octet_iterator start, octet_iterator end)
+ {
+ octet_iterator result = start;
+ while (result != end) {
+ utf8::internal::utf_error err_code = utf8::internal::validate_next(result, end);
+ if (err_code != internal::UTF8_OK)
+ return result;
+ }
+ return result;
+ }
+
+ template <typename octet_iterator>
+ inline bool is_valid(octet_iterator start, octet_iterator end)
+ {
+ return (utf8::find_invalid(start, end) == end);
+ }
+
+ template <typename octet_iterator>
+ inline bool starts_with_bom (octet_iterator it, octet_iterator end)
+ {
+ return (
+ ((it != end) && (utf8::internal::mask8(*it++)) == bom[0]) &&
+ ((it != end) && (utf8::internal::mask8(*it++)) == bom[1]) &&
+ ((it != end) && (utf8::internal::mask8(*it)) == bom[2])
+ );
+ }
+
+ //Deprecated in release 2.3
+ template <typename octet_iterator>
+ inline bool is_bom (octet_iterator it)
+ {
+ return (
+ (utf8::internal::mask8(*it++)) == bom[0] &&
+ (utf8::internal::mask8(*it++)) == bom[1] &&
+ (utf8::internal::mask8(*it)) == bom[2]
+ );
+ }
+} // namespace utf8
+
+#endif // header guard
+
+