80 lines
1.9 KiB
C
80 lines
1.9 KiB
C
/*
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* Based on code from libblkid,
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*
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* Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
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* Copyright (C) 2009 Karel Zak <kzak@redhat.com>
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* Copyright (C) 2020 Pali Rohár <pali.rohar@gmail.com>
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*
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* This file may be redistributed under the terms of the
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* GNU Lesser General Public License.
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*/
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#include "c.h"
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#include "encode.h"
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size_t ul_encode_to_utf8(int enc, unsigned char *dest, size_t len,
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const unsigned char *src, size_t count)
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{
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size_t i, j;
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uint32_t c;
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uint16_t c2;
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for (j = i = 0; i < count; i++) {
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if (enc == UL_ENCODE_UTF16LE) {
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if (i+2 > count)
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break;
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c = (src[i+1] << 8) | src[i];
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i++;
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} else if (enc == UL_ENCODE_UTF16BE) {
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if (i+2 > count)
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break;
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c = (src[i] << 8) | src[i+1];
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i++;
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} else if (enc == UL_ENCODE_LATIN1) {
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c = src[i];
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} else {
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return 0;
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}
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if ((enc == UL_ENCODE_UTF16LE || enc == UL_ENCODE_UTF16BE) &&
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c >= 0xD800 && c <= 0xDBFF && i+2 < count) {
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if (enc == UL_ENCODE_UTF16LE)
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c2 = (src[i+2] << 8) | src[i+1];
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else
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c2 = (src[i+1] << 8) | src[i+2];
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if (c2 >= 0xDC00 && c2 <= 0xDFFF) {
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c = 0x10000 + ((c - 0xD800) << 10) + (c2 - 0xDC00);
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i += 2;
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}
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}
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if (c == 0) {
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dest[j] = '\0';
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break;
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}
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if (c < 0x80) {
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if (j+1 >= len)
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break;
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dest[j++] = (uint8_t) c;
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} else if (c < 0x800) {
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if (j+2 >= len)
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break;
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dest[j++] = (uint8_t) (0xc0 | (c >> 6));
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dest[j++] = (uint8_t) (0x80 | (c & 0x3f));
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} else if (c < 0x10000) {
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if (j+3 >= len)
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break;
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dest[j++] = (uint8_t) (0xe0 | (c >> 12));
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dest[j++] = (uint8_t) (0x80 | ((c >> 6) & 0x3f));
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dest[j++] = (uint8_t) (0x80 | (c & 0x3f));
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} else {
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if (j+4 >= len)
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break;
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dest[j++] = (uint8_t) (0xf0 | (c >> 18));
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dest[j++] = (uint8_t) (0x80 | ((c >> 12) & 0x3f));
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dest[j++] = (uint8_t) (0x80 | ((c >> 6) & 0x3f));
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dest[j++] = (uint8_t) (0x80 | (c & 0x3f));
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}
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}
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dest[j] = '\0';
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return j;
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}
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