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52 lines
1.7 KiB
C
52 lines
1.7 KiB
C
/*
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* Copyright 2024 Google LLC
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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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#include "util/ihex.h"
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typedef struct IHEXRecord {
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char start;
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char data_count[2];
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char address[4];
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char type[2];
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char data[]; // Variable data and checksum
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} IHEXRecord;
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static void prv_hexlify(char *str, uint32_t value, uint8_t num_bytes) {
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for (int i = num_bytes * 2 - 1; i >= 0; --i) {
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uint8_t nibble = (value >> (4 * i)) & 0xF;
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if (nibble >= 0xA) {
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*str++ = 'A' + (nibble - 0xA);
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} else {
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*str++ = '0' + nibble;
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}
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}
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}
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void ihex_encode(uint8_t *out, uint8_t type, uint16_t address,
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const void *data, uint8_t data_len) {
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IHEXRecord *record = (IHEXRecord *)out;
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uint8_t checksum = data_len + (address >> 8) + (address & 0xff) + type;
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record->start = ':';
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prv_hexlify(record->data_count, data_len, sizeof(data_len));
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prv_hexlify(record->address, address, sizeof(address));
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prv_hexlify(record->type, type, sizeof(type));
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for (uint16_t i = 0; i < data_len; ++i) {
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uint8_t data_byte = ((uint8_t *)data)[i];
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checksum += data_byte;
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prv_hexlify(&record->data[i*2], data_byte, sizeof(data_byte));
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}
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prv_hexlify(&record->data[data_len*2], ~checksum + 1, sizeof(checksum));
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}
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