141 lines
3.8 KiB
C
141 lines
3.8 KiB
C
/*
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* Copyright © 2012 Intel Corporation
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* Copyright © 2014 Ran Benita <ran234@gmail.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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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 AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* 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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* Author: Rob Bradford <rob@linux.intel.com>
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*/
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#include "config.h"
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#include <stddef.h>
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#include <stdbool.h>
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#include <inttypes.h>
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#include "utf8.h"
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int
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utf32_to_utf8(uint32_t unichar, char *buffer)
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{
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int count, shift, length;
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uint8_t head;
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if (unichar <= 0x007f) {
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buffer[0] = unichar;
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buffer[1] = '\0';
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return 2;
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}
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else if (unichar <= 0x07FF) {
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length = 2;
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head = 0xc0;
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}
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else if (unichar <= 0xffff) {
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length = 3;
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head = 0xe0;
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}
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else if (unichar <= 0x10ffff) {
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length = 4;
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head = 0xf0;
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}
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else {
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buffer[0] = '\0';
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return 0;
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}
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for (count = length - 1, shift = 0; count > 0; count--, shift += 6)
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buffer[count] = 0x80 | ((unichar >> shift) & 0x3f);
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buffer[0] = head | ((unichar >> shift) & 0x3f);
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buffer[length] = '\0';
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return length + 1;
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}
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bool
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is_valid_utf8(const char *ss, size_t len)
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{
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size_t i = 0;
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size_t tail_bytes = 0;
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const uint8_t *s = (const uint8_t *) ss;
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/* This beauty is from:
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* The Unicode Standard Version 6.2 - Core Specification, Table 3.7
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* https://www.unicode.org/versions/Unicode6.2.0/ch03.pdf#G7404
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* We can optimize if needed. */
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while (i < len)
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{
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if (s[i] <= 0x7F) {
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tail_bytes = 0;
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}
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else if (s[i] >= 0xC2 && s[i] <= 0xDF) {
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tail_bytes = 1;
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}
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else if (s[i] == 0xE0) {
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i++;
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if (i >= len || !(s[i] >= 0xA0 && s[i] <= 0xBF))
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return false;
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tail_bytes = 1;
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}
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else if (s[i] >= 0xE1 && s[i] <= 0xEC) {
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tail_bytes = 2;
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}
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else if (s[i] == 0xED) {
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i++;
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if (i >= len || !(s[i] >= 0x80 && s[i] <= 0x9F))
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return false;
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tail_bytes = 1;
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}
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else if (s[i] >= 0xEE && s[i] <= 0xEF) {
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tail_bytes = 2;
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}
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else if (s[i] == 0xF0) {
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i++;
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if (i >= len || !(s[i] >= 0x90 && s[i] <= 0xBF))
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return false;
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tail_bytes = 2;
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}
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else if (s[i] >= 0xF1 && s[i] <= 0xF3) {
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tail_bytes = 3;
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}
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else if (s[i] == 0xF4) {
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i++;
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if (i >= len || !(s[i] >= 0x80 && s[i] <= 0x8F))
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return false;
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tail_bytes = 2;
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}
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else {
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return false;
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}
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i++;
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while (i < len && tail_bytes > 0 && s[i] >= 0x80 && s[i] <= 0xBF) {
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i++;
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tail_bytes--;
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}
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if (tail_bytes != 0)
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return false;
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}
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return true;
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}
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