From a5b93847ba6f8c6bdda877e0853b3e295c3241ca Mon Sep 17 00:00:00 2001
From: kongr45gpen <electrovesta@gmail.com>
Date: Thu, 15 Nov 2018 01:48:35 +0200
Subject: [PATCH] Add functions to fetch data from Messages
Implements #2
---
ci/.clang-tidy | 2 +-
inc/ECSS_Definitions.hpp | 2 +
inc/Message.hpp | 154 ++++++++++++++++++++++++++++++++++++++-
src/Message.cpp | 62 ++++++++++++++++
src/main.cpp | 5 ++
5 files changed, 223 insertions(+), 2 deletions(-)
diff --git a/ci/.clang-tidy b/ci/.clang-tidy
index f7f41f2c..4ce5a961 100644
--- a/ci/.clang-tidy
+++ b/ci/.clang-tidy
@@ -17,7 +17,7 @@ Checks: >
-misc-non-private-member-variables-in-classes,
performance-*,
readability-*,
-WarningsAsErrors: '*,-misc-unused-parameters,-llvm-header-guard,-cppcoreguidelines-pro-type-member-init,-google-runtime-references'
+WarningsAsErrors: '*,-misc-unused-parameters,-llvm-header-guard,-cppcoreguidelines-pro-type-member-init,-google-runtime-references,-clang-diagnostic-tautological-constant-out-of-range-compare'
HeaderFilterRegex: '.*'
AnalyzeTemporaryDtors: false
...
diff --git a/inc/ECSS_Definitions.hpp b/inc/ECSS_Definitions.hpp
index ffa70775..1db5923d 100644
--- a/inc/ECSS_Definitions.hpp
+++ b/inc/ECSS_Definitions.hpp
@@ -4,6 +4,8 @@
// Todo: Specify maximum size for regular messages
#define ECSS_MAX_MESSAGE_SIZE 1024
+#define ECSS_MAX_STRING_SIZE 256
+
// 7.4.4.1c
#define ECSS_PUS_VERSION 2
diff --git a/inc/Message.hpp b/inc/Message.hpp
index d32e6ba9..268af02f 100644
--- a/inc/Message.hpp
+++ b/inc/Message.hpp
@@ -7,6 +7,9 @@
/**
* A telemetry (TM) or telecommand (TC) message (request/report), as specified in ECSS-E-ST-70-41C
+ *
+ * @todo Make sure that a message can't be written to or read from at the same time, or make
+ * readable and writable message different classes
*/
class Message {
public:
@@ -40,6 +43,9 @@ public:
//private:
uint8_t currentBit = 0;
+ // Next byte to read for read...() functions
+ uint16_t readPosition = 0;
+
/**
* Appends the least significant \p numBits from \p data to the message
*
@@ -72,6 +78,36 @@ public:
*/
void appendString(uint8_t size, const char *value);
+ /**
+ * Reads the next \p numBits bits from the the message in a big-endian format
+ * @param numBits
+ * @return A maximum number of 16 bits is returned (in big-endian format)
+ */
+ uint16_t readBits(uint8_t numBits);
+
+ /**
+ * Reads the next 1 byte from the message
+ */
+ uint8_t readByte();
+
+ /**
+ * Reads the next 2 bytes from the message
+ */
+ uint16_t readHalfword();
+
+ /**
+ * Reads the next 4 bytes from the message
+ */
+ uint32_t readWord();
+
+ /**
+ * Reads the next \p size bytes from the message, and stores them into the allocated \p string
+ *
+ * NOTE: We assume that \p string is already allocated, and its size is at least
+ * ECSS_MAX_STRING_SIZE. This function does placs a \0 at the end of the created string.
+ */
+ void readString(char *string, uint8_t size);
+
public:
Message(uint8_t serviceType, uint8_t messageType, PacketType packetType,
uint16_t applicationId);
@@ -190,7 +226,123 @@ public:
return appendWord(reinterpret_cast<uint32_t &>(value));
}
- return appendWord(reinterpret_cast<uint32_t&>(value));
+ /**
+ * Fetches a single-byte boolean value from the current position in the message
+ *
+ * PTC = 1, PFC = 0
+ */
+ bool readBoolean() {
+ return static_cast<bool>(readByte());
+ }
+
+ /**
+ * Fetches an enumerated parameter consisting of an arbitrary number of bits from the current
+ * position in the message
+ *
+ * PTC = 2, PFC = \p bits
+ */
+ uint32_t readEnumerated(uint8_t bits) {
+ return readBits(bits);
+ }
+
+ /**
+ * Fetches an enumerated parameter consisting of 1 byte from the current position in the message
+ *
+ * PTC = 2, PFC = 8
+ */
+ uint8_t readEnum8() {
+ return readByte();
+ }
+
+ /**
+ * Fetches an enumerated parameter consisting of 2 bytes from the current position in the
+ * message
+ *
+ * PTC = 2, PFC = 16
+ */
+ uint16_t readEnum16() {
+ return readHalfword();
+ }
+
+ /**
+ * Fetches an enumerated parameter consisting of 4 bytes from the current position in the
+ * message
+ *
+ * PTC = 2, PFC = 32
+ */
+ uint32_t readEnum32() {
+ return readWord();
+ }
+
+ /**
+ * Fetches an 1-byte unsigned integer from the current position in the message
+ *
+ * PTC = 3, PFC = 4
+ */
+ uint8_t readUint8() {
+ return readByte();
+ }
+
+ /**
+ * Fetches a 2-byte unsigned integer from the current position in the message
+ *
+ * PTC = 3, PFC = 8
+ */
+ uint16_t readUint16() {
+ return readHalfword();
+ }
+
+ /**
+ * Fetches a 4-byte unsigned integer from the current position in the message
+ *
+ * PTC = 3, PFC = 14
+ */
+ uint32_t readUint32() {
+ return readWord();
+ }
+
+ /**
+ * Fetches an 1-byte signed integer from the current position in the message
+ *
+ * PTC = 4, PFC = 4
+ */
+ int8_t readSint8() {
+ uint8_t value = readByte();
+ return reinterpret_cast<int8_t &>(value);
+ }
+
+ /**
+ * Fetches a 2-byte unsigned integer from the current position in the message
+ *
+ * PTC = 4, PFC = 8
+ */
+ int16_t readSint16() {
+ uint16_t value = readHalfword();
+ return reinterpret_cast<int16_t &>(value);
+ }
+
+ /**
+ * Fetches a 4-byte unsigned integer from the current position in the message
+ *
+ * PTC = 4, PFC = 14
+ */
+ int32_t readSint32() {
+ uint32_t value = readWord();
+ return reinterpret_cast<int32_t &>(value);
+ }
+
+ /**
+ * Fetches an 4-byte single-precision floating point number from the current position in the
+ * message
+ *
+ * PTC = 5, PFC = 1
+ */
+ float readFloat() {
+ static_assert(sizeof(uint32_t) == sizeof(float),
+ "Floating point numbers must be 32 bits long");
+
+ uint32_t value = readWord();
+ return reinterpret_cast<float &>(value);
}
};
diff --git a/src/Message.cpp b/src/Message.cpp
index 47ac5575..d17eb0f5 100644
--- a/src/Message.cpp
+++ b/src/Message.cpp
@@ -67,13 +67,75 @@ void Message::appendWord(uint32_t value) {
void Message::appendString(uint8_t size, const char *value) {
assert(dataSize + size <= ECSS_MAX_MESSAGE_SIZE);
+ assert(size < ECSS_MAX_STRING_SIZE);
memcpy(data + dataSize, value, size);
dataSize += size;
}
+uint16_t Message::readBits(uint8_t numBits) {
+ assert(numBits <= 16);
+ // TODO: Add assert
+
+ uint16_t value = 0x0;
+
+ while (numBits > 0) {
+ assert(readPosition < ECSS_MAX_MESSAGE_SIZE);
+
+ if (currentBit + numBits >= 8) {
+ auto bitsToAddNow = static_cast<uint8_t>(8 - currentBit);
+
+ auto maskedData = static_cast<uint8_t>(data[readPosition] & ((1 << bitsToAddNow) - 1));
+ value |= maskedData << (numBits - bitsToAddNow);
+
+ numBits -= bitsToAddNow;
+ currentBit = 0;
+ readPosition++;
+ } else {
+ value |= (data[readPosition] >> (8 - currentBit - numBits)) & ((1 << numBits) - 1);
+ currentBit = currentBit + numBits;
+ numBits = 0;
+ }
+ }
+
+ return value;
+}
+
+uint8_t Message::readByte() {
+ assert(readPosition < ECSS_MAX_MESSAGE_SIZE);
+
+ uint8_t value = data[readPosition];
+ readPosition++;
+
+ return value;
+}
+
+uint16_t Message::readHalfword() {
+ assert(readPosition + 2 < ECSS_MAX_MESSAGE_SIZE);
+
+ uint16_t value = (data[readPosition] << 8) | data[readPosition + 1];
+ readPosition += 2;
return value;
}
+uint32_t Message::readWord() {
+ assert(readPosition + 4 < ECSS_MAX_MESSAGE_SIZE);
+
+ uint32_t value = (data[readPosition] << 24) | (data[readPosition + 1] << 16) |
+ (data[readPosition + 2] << 8) | data[readPosition + 3];
+ readPosition += 4;
+
+ return value;
+}
+
+void Message::readString(char *string, uint8_t size) {
+ assert(readPosition + size <= ECSS_MAX_MESSAGE_SIZE);
+ assert(size < ECSS_MAX_STRING_SIZE);
+
+ memcpy(string, data + readPosition, size);
+ string[size] = '\0';
+
+ readPosition += size;
+}
diff --git a/src/main.cpp b/src/main.cpp
index 5d941648..cc24193a 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -9,10 +9,15 @@ int main() {
packet.appendBits(15, 0x28a8);
packet.appendBits(1, 1);
packet.appendFloat(5.7);
+ packet.appendSint32(-123456789);
std::cout << "Hello, World!" << std::endl;
std::cout << std::hex << packet.data << std::endl; // packet data must be 'helloQQ'
+ char string[6];
+ packet.readString(string, 5);
+ std::cout << "Word: " << string << " " << packet.readBits(15) << packet.readBits(1) << std::endl;
+ std::cout << packet.readFloat() << " " << std::dec << packet.readSint32() << std::endl;
// ST[17] test
TestService testService;
--
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