zap/src/mem/utf8declen.c


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/*
	Copyright 2022 Gabriel Jensen.
	This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
	If a copy of the MPL was not distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/.
*/

#include <zap/priv.h>

#include <zap/mem.h>

#include <stddef.h>

zap_sz zap_utf8declen(zap_chr8 const * const _in) {
	zap_sz len = 0x0u;
	zap_chr8 const * in;
	for (in = _in;;++len) {
		zap_chr8 const oct = *in;
		sus_unlikely (oct == 0x0u) {break;}
		if (oct >= 0xF0u) {
			in += 0x4u;
			continue;
		}
		if (oct >= 0xE0u) {
			in += 0x3u;
			continue;
		}
		if (oct >= 0xC0u) {
			in += 0x2u;
			continue;
		}
		++in;
		continue;
	}
	return len;
}