mirror of
https://github.com/emsesp/EMS-ESP32.git
synced 2025-12-13 03:09:51 +03:00
58 lines
1.4 KiB
C++
58 lines
1.4 KiB
C++
/*
|
|
Copyright (c) 2022 Bert Melis. All rights reserved.
|
|
|
|
This work is licensed under the terms of the MIT license.
|
|
For a copy, see <https://opensource.org/licenses/MIT> or
|
|
the LICENSE file.
|
|
*/
|
|
|
|
#include "RemainingLength.h"
|
|
|
|
namespace espMqttClientInternals {
|
|
|
|
int32_t decodeRemainingLength(const uint8_t* stream) {
|
|
uint32_t multiplier = 1;
|
|
int32_t remainingLength = 0;
|
|
uint8_t currentByte = 0;
|
|
uint8_t encodedByte;
|
|
|
|
do {
|
|
encodedByte = stream[currentByte++];
|
|
remainingLength += (encodedByte & 127) * multiplier;
|
|
if (multiplier > 128 * 128 * 128) {
|
|
emc_log_e("Malformed Remaining Length");
|
|
return -1;
|
|
}
|
|
multiplier *= 128;
|
|
} while ((encodedByte & 128) != 0);
|
|
|
|
return remainingLength;
|
|
}
|
|
|
|
uint8_t remainingLengthLength(uint32_t remainingLength) {
|
|
if (remainingLength < 128) return 1;
|
|
if (remainingLength < 16384) return 2;
|
|
if (remainingLength < 2097152) return 3;
|
|
if (remainingLength > 268435455) return 0;
|
|
return 4;
|
|
}
|
|
|
|
uint8_t encodeRemainingLength(uint32_t remainingLength, uint8_t* destination) {
|
|
uint8_t currentByte = 0;
|
|
uint8_t bytesNeeded = 0;
|
|
|
|
do {
|
|
uint8_t encodedByte = remainingLength % 128;
|
|
remainingLength /= 128;
|
|
if (remainingLength > 0) {
|
|
encodedByte = encodedByte | 128;
|
|
}
|
|
destination[currentByte++] = encodedByte;
|
|
bytesNeeded++;
|
|
} while (remainingLength > 0);
|
|
|
|
return bytesNeeded;
|
|
}
|
|
|
|
} // namespace espMqttClientInternals
|