circuitpython/shared-module/usb/utf16le.c

86 lines
3.4 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2022 Scott Shawcroft for Adafruit Industries
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* 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 AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "shared-module/usb/utf16le.h"
STATIC void _convert_utf16le_to_utf8(const uint16_t *utf16, size_t utf16_len, uint8_t *utf8, size_t utf8_len) {
// TODO: Check for runover.
(void)utf8_len;
for (size_t i = 0; i < utf16_len; i++) {
uint16_t chr = utf16[i];
if (chr < 0x80) {
*utf8++ = chr & 0xff;
} else if (chr < 0x800) {
*utf8++ = (uint8_t)(0xC0 | (chr >> 6 & 0x1F));
*utf8++ = (uint8_t)(0x80 | (chr >> 0 & 0x3F));
} else if (chr < 0x10000) {
// TODO: Verify surrogate.
*utf8++ = (uint8_t)(0xE0 | (chr >> 12 & 0x0F));
*utf8++ = (uint8_t)(0x80 | (chr >> 6 & 0x3F));
*utf8++ = (uint8_t)(0x80 | (chr >> 0 & 0x3F));
} else {
// TODO: Handle UTF-16 code points that take two entries.
uint32_t hc = ((chr & 0xFFFF0000) - 0xD8000000) >> 6; /* Get high 10 bits */
chr = (chr & 0xFFFF) - 0xDC00; /* Get low 10 bits */
chr = (hc | chr) + 0x10000;
*utf8++ = (uint8_t)(0xF0 | (chr >> 18 & 0x07));
*utf8++ = (uint8_t)(0x80 | (chr >> 12 & 0x3F));
*utf8++ = (uint8_t)(0x80 | (chr >> 6 & 0x3F));
*utf8++ = (uint8_t)(0x80 | (chr >> 0 & 0x3F));
}
}
}
// Count how many bytes a utf-16-le encoded string will take in utf-8.
STATIC mp_int_t _count_utf8_bytes(const uint16_t *buf, size_t len) {
size_t total_bytes = 0;
for (size_t i = 0; i < len; i++) {
uint16_t chr = buf[i];
if (chr < 0x80) {
total_bytes += 1;
} else if (chr < 0x800) {
total_bytes += 2;
} else if (chr < 0x10000) {
total_bytes += 3;
} else {
total_bytes += 4;
}
}
return total_bytes;
}
mp_obj_t utf16le_to_string(const uint16_t *buf, size_t utf16_len) {
size_t size = _count_utf8_bytes(buf, utf16_len);
vstr_t vstr;
vstr_init_len(&vstr, size + 1);
byte *p = (byte *)vstr.buf;
// Null terminate.
p[size] = '\0';
_convert_utf16le_to_utf8(buf, utf16_len, p, size);
return mp_obj_new_str_from_vstr(&mp_type_str, &vstr);
}