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doc and improvements for DLE encoder

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This commit is contained in:
Robin Müller
2020-07-07 16:36:41 +02:00
parent cb691db807
commit 4f1f610ae0
3 changed files with 78 additions and 28 deletions
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39
globalfunctions/DleEncoder.cpp
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@ -1,18 +1,16 @@
#include <framework/globalfunctions/DleEncoder.h>
DleEncoder::DleEncoder() {
}
DleEncoder::DleEncoder() {}
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;
size_t sourceStreamLen, size_t *readLen, uint8_t *destStream,
size_t maxDestStreamlen, size_t *decodedLen) {
size_t encodedIndex = 0, decodedIndex = 0;
uint8_t nextByte;
if (*sourceStream != STX) {
return RETURN_FAILED;
return DECODING_ERROR;
}
++encodedIndex;
while ((encodedIndex < sourceStreamLen) && (decodedIndex < maxDestStreamlen)
@ -20,14 +18,18 @@ ReturnValue_t DleEncoder::decode(const uint8_t *sourceStream,
&& (sourceStream[encodedIndex] != STX)) {
if (sourceStream[encodedIndex] == DLE) {
nextByte = sourceStream[encodedIndex + 1];
if (nextByte == 0x10) {
// The next byte is a DLE character that was escaped by another
// DLE character, so we can write it to the destination stream.
if (nextByte == DLE) {
destStream[decodedIndex] = nextByte;
} else {
// The next byte is a STX, DTX or 0x0D character which
// was escaped by a DLE character
if ((nextByte == 0x42) || (nextByte == 0x43)
|| (nextByte == 0x4D)) {
destStream[decodedIndex] = nextByte - 0x40;
} else {
return RETURN_FAILED;
return DECODING_ERROR;
}
}
++encodedIndex;
@ -38,7 +40,7 @@ ReturnValue_t DleEncoder::decode(const uint8_t *sourceStream,
++decodedIndex;
}
if (sourceStream[encodedIndex] != ETX) {
return RETURN_FAILED;
return DECODING_ERROR;
} else {
*readLen = ++encodedIndex;
*decodedLen = decodedIndex;
@ -47,12 +49,12 @@ ReturnValue_t DleEncoder::decode(const uint8_t *sourceStream,
}
ReturnValue_t DleEncoder::encode(const uint8_t* sourceStream,
uint32_t sourceLen, uint8_t* destStream, uint32_t maxDestLen,
uint32_t* encodedLen, bool addStxEtx) {
size_t sourceLen, uint8_t* destStream, size_t maxDestLen,
size_t* encodedLen, bool addStxEtx) {
if (maxDestLen < 2) {
return RETURN_FAILED;
return STREAM_TOO_SHORT;
}
uint32_t encodedIndex = 0, sourceIndex = 0;
size_t encodedIndex = 0, sourceIndex = 0;
uint8_t nextByte;
if (addStxEtx) {
destStream[0] = STX;
@ -62,15 +64,16 @@ ReturnValue_t DleEncoder::encode(const uint8_t* sourceStream,
nextByte = sourceStream[sourceIndex];
if ((nextByte == STX) || (nextByte == ETX) || (nextByte == 0x0D)) {
if (encodedIndex + 1 >= maxDestLen) {
return RETURN_FAILED;
return STREAM_TOO_SHORT;
} else {
destStream[encodedIndex] = DLE;
++encodedIndex;
// Escaped byte will be actual byte + 0x40.
destStream[encodedIndex] = nextByte + 0x40;
}
} else if (nextByte == DLE) {
if (encodedIndex + 1 >= maxDestLen) {
return RETURN_FAILED;
return STREAM_TOO_SHORT;
} else {
destStream[encodedIndex] = DLE;
++encodedIndex;
@ -90,6 +93,6 @@ ReturnValue_t DleEncoder::encode(const uint8_t* sourceStream,
*encodedLen = encodedIndex;
return RETURN_OK;
} else {
return RETURN_FAILED;
return STREAM_TOO_SHORT;
}
}