mirror of https://github.com/ARMmbed/mbed-os.git
88 lines
2.2 KiB
C
88 lines
2.2 KiB
C
/*
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* Copyright (c) 2014-2015, 2018, Pelion and affiliates.
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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* Most functions can be inlined, and definitions are in common_functions.h.
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* Define COMMON_FUNCTIONS_FN before including it to generate external definitions.
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*/
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#define COMMON_FUNCTIONS_FN extern
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#include "common_functions.h"
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#include <string.h>
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/* Returns mask for <split_value> (0-8) most-significant bits of a byte */
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static inline uint8_t context_split_mask(uint_fast8_t split_value)
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{
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return (uint8_t) - (0x100u >> split_value);
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}
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bool bitsequal(const uint8_t *a, const uint8_t *b, uint_fast8_t bits)
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{
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uint_fast8_t bytes = bits / 8;
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bits %= 8;
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if (bytes && memcmp(a, b, bytes)) {
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return false;
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}
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if (bits) {
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uint_fast8_t split_bit = context_split_mask(bits);
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if ((a[bytes] & split_bit) != (b[bytes] & split_bit)) {
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return false;
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}
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}
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return true;
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}
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uint8_t *bitcopy(uint8_t *restrict dst, const uint8_t *restrict src, uint_fast8_t bits)
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{
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uint_fast8_t bytes = bits / 8;
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bits %= 8;
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if (bytes) {
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dst = (uint8_t *) memcpy(dst, src, bytes) + bytes;
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src += bytes;
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}
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if (bits) {
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uint_fast8_t split_bit = context_split_mask(bits);
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*dst = (*src & split_bit) | (*dst & ~ split_bit);
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}
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return dst;
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}
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uint8_t *bitcopy0(uint8_t *restrict dst, const uint8_t *restrict src, uint_fast8_t bits)
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{
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uint_fast8_t bytes = bits / 8;
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bits %= 8;
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if (bytes) {
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dst = (uint8_t *) memcpy(dst, src, bytes) + bytes;
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src += bytes;
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}
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if (bits) {
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uint_fast8_t split_bit = context_split_mask(bits);
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*dst = (*src & split_bit);
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}
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return dst;
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}
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