58 lines
1.8 KiB
C++
58 lines
1.8 KiB
C++
// -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
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// Copyright (C) 2013 Henner Zeller <h.zeller@acm.org>
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//
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation version 2.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://gnu.org/licenses/gpl-2.0.txt>
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#ifndef RPI_GRAPHICS_UTF8_H
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#define RPI_GRAPHICS_UTF8_H
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#include <stdint.h>
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// Utility function that reads UTF-8 encoded codepoints from byte iterator.
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// No error checking, we assume string is UTF-8 clean.
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template <typename byte_iterator>
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uint32_t utf8_next_codepoint(byte_iterator &it) {
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uint32_t cp = *it++;
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if (cp < 0x80) {
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return cp; // iterator already incremented.
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}
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else if ((cp & 0xE0) == 0xC0) {
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cp = ((cp & 0x1F) << 6) + (*it & 0x3F);
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}
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else if ((cp & 0xF0) == 0xE0) {
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cp = ((cp & 0x0F) << 12) + ((*it & 0x3F) << 6);
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cp += (*++it & 0x3F);
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}
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else if ((cp & 0xF8) == 0xF0) {
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cp = ((cp & 0x07) << 18) + ((*it & 0x3F) << 12);
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cp += (*++it & 0x3F) << 6;
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cp += (*++it & 0x3F);
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}
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else if ((cp & 0xFC) == 0xF8) {
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cp = ((cp & 0x03) << 24) + ((*it & 0x3F) << 18);
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cp += (*++it & 0x3F) << 12;
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cp += (*++it & 0x3F) << 6;
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cp += (*++it & 0x3F);
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}
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else if ((cp & 0xFE) == 0xFC) {
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cp = ((cp & 0x01) << 30) + ((*it & 0x3F) << 24);
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cp += (*++it & 0x3F) << 18;
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cp += (*++it & 0x3F) << 12;
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cp += (*++it & 0x3F) << 6;
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cp += (*++it & 0x3F);
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}
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++it;
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return cp;
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}
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#endif // RPI_GRAPHICS_UTF8_H
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