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54 lines
1.3 KiB
C++
54 lines
1.3 KiB
C++
#include "internal/utf_converter.h"
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ssize_t utf8_to_utf16(const uint8_t *in, uint64_t in_len, uint16_t *out, uint64_t max_out) {
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uint64_t num_out = 0;
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uint64_t num_in = 0;
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while (num_in < in_len) {
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uint32_t uni;
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uint64_t todo;
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uint8_t ch = in[num_in];
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num_in++;
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if (ch <= 0x7F) {
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uni = ch;
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todo = 0;
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} else if (ch <= 0xBF) {
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return -1;
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} else if (ch <= 0xDF) {
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uni = ch & 0x1F;
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todo = 1;
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} else if (ch <= 0xEF) {
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uni = ch & 0x0F;
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todo = 2;
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} else if (ch <= 0xF7) {
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uni = ch & 0x07;
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todo = 3;
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} else {
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return -1;
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}
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for (uint64_t j = 0; j < todo; ++j) {
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if (num_in == in_len) return -1;
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uint8_t ch = in[num_in];
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num_in++;
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if (ch < 0x80 || ch > 0xBF) return -1;
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uni <<= 6;
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uni += ch & 0x3F;
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}
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if (uni >= 0xD800 && uni <= 0xDFFF) return -1;
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if (uni > 0x10FFFF) return -1;
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if (uni <= 0xFFFF) {
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if (num_out == max_out) return -1;
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out[num_out] = uni;
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num_out++;
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} else {
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uni -= 0x10000;
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if (num_out + 1 >= max_out) return -1;
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out[num_out] = (uni >> 10) + 0xD800;
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out[num_out + 1] = (uni & 0x3FF) + 0xDC00;
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num_out += 2;
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}
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}
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if (num_out == max_out) return -1;
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out[num_out] = 0;
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return num_out;
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}
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