fsfw/globalfunctions/DleEncoder.cpp

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2020-08-13 20:53:35 +02:00
#include "DleEncoder.h"
DleEncoder::DleEncoder() {
}
DleEncoder::~DleEncoder() {
}
ReturnValue_t DleEncoder::decode(const uint8_t *sourceStream,
uint32_t sourceStreamLen, uint32_t *readLen, uint8_t *destStream,
uint32_t maxDestStreamlen, uint32_t *decodedLen) {
uint32_t encodedIndex = 0, decodedIndex = 0;
uint8_t nextByte;
if (*sourceStream != STX) {
return RETURN_FAILED;
}
++encodedIndex;
while ((encodedIndex < sourceStreamLen) && (decodedIndex < maxDestStreamlen)
&& (sourceStream[encodedIndex] != ETX)
&& (sourceStream[encodedIndex] != STX)) {
if (sourceStream[encodedIndex] == DLE) {
nextByte = sourceStream[encodedIndex + 1];
if (nextByte == 0x10) {
destStream[decodedIndex] = nextByte;
} else {
if ((nextByte == 0x42) || (nextByte == 0x43)
|| (nextByte == 0x4D)) {
destStream[decodedIndex] = nextByte - 0x40;
} else {
return RETURN_FAILED;
}
}
++encodedIndex;
} else {
destStream[decodedIndex] = sourceStream[encodedIndex];
}
++encodedIndex;
++decodedIndex;
}
if (sourceStream[encodedIndex] != ETX) {
return RETURN_FAILED;
} else {
*readLen = ++encodedIndex;
*decodedLen = decodedIndex;
return RETURN_OK;
}
}
ReturnValue_t DleEncoder::encode(const uint8_t* sourceStream,
uint32_t sourceLen, uint8_t* destStream, uint32_t maxDestLen,
uint32_t* encodedLen, bool addStxEtx) {
if (maxDestLen < 2) {
return RETURN_FAILED;
}
uint32_t encodedIndex = 0, sourceIndex = 0;
uint8_t nextByte;
if (addStxEtx) {
destStream[0] = STX;
++encodedIndex;
}
while ((encodedIndex < maxDestLen) && (sourceIndex < sourceLen)) {
nextByte = sourceStream[sourceIndex];
if ((nextByte == STX) || (nextByte == ETX) || (nextByte == 0x0D)) {
if (encodedIndex + 1 >= maxDestLen) {
return RETURN_FAILED;
} else {
destStream[encodedIndex] = DLE;
++encodedIndex;
destStream[encodedIndex] = nextByte + 0x40;
}
} else if (nextByte == DLE) {
if (encodedIndex + 1 >= maxDestLen) {
return RETURN_FAILED;
} else {
destStream[encodedIndex] = DLE;
++encodedIndex;
destStream[encodedIndex] = DLE;
}
} else {
destStream[encodedIndex] = nextByte;
}
++encodedIndex;
++sourceIndex;
}
if ((sourceIndex == sourceLen) && (encodedIndex < maxDestLen)) {
if (addStxEtx) {
destStream[encodedIndex] = ETX;
++encodedIndex;
}
*encodedLen = encodedIndex;
return RETURN_OK;
} else {
return RETURN_FAILED;
}
}