Examples to pack "bin 8" byte sequences (0xC4 coding)?

[FerGT50]

Hello,

let's say I have a byte buffer, like

uint8_t buffer[64] = {25, 108, ... etc};

I do not want to encode it as "Array", but as a "Bin 8".
How to I use your MsgPack::bin_t type in practice?
Is there an example you may have (I did not find one in the library package)?

Thanks

[Hideaki Tai]

As mentioned in README, the following types are encoded to "bin". So uint8_t buffer[64] will be encoded to "bin" as is. Msgpack::bin_t<uint8_t> is also available (alias for std::vector<uint8_t>)

• unsigned char* (need to serialize(ptr, size) or pack(ptr, size))
• unsigned char[] (need to serialize(ptr, size) or pack(ptr, size))
• std::vector<char> (MsgPack::bin_t<char>)
• std::vector<unsigned char> (MsgPack::bin_t<unsigned char>)
• std::array<char>
• std::array<unsigned char>

[FerGT50]

As mentioned in README, the following types are encoded to "bin". So uint8_t buffer[64] will be encoded to "bin" as is.

That's what I thought, so I tried this simple test:

#include <MsgPack.h>
#include <base64.hpp> // For debug

#define DEBUG_SERIAL Serial

#define MSGPACK_DEBUGLOG_ENABLE

#define SERIAL_DEBUGMODE



/////////////////////////
// Forward Declarations
/////////////////////////

void prepareMessagePack();


//////////
// SETUP
//////////

void setup() 
{  
  #ifdef SERIAL_DEBUGMODE
  DEBUG_SERIAL.begin(115200);
  while (!DEBUG_SERIAL)
  {    
  }
  delay(2000);
  DEBUG_SERIAL.println();
  #endif
  
  delay(2000);

  prepareMessagePack();
}


/////////
// LOOP
/////////

void loop() 
{
}


void prepareMessagePack()
{ 
  uint32_t u32_1 = 10000UL;
  uint16_t u16_1 = 1000U;
  uint32_t u32_2 = 20000UL;
  String s_1 = "Test1";
  uint8_t buffer_1[32] = {100, 247, 101, 203, 134, 82, 87, 156, 248, 88, 46, 95, 26, 26, 58, 124, 165, 123, 139, 160, 11, 191, 161, 7, 157, 2, 154, 35, 74, 130, 144, 170}; 
  MsgPack::Packer msgPacker;

  msgPacker.serialize (u32_1, u16_1, u32_2, s_1, buffer_1);

  const uint8_t* packData = msgPacker.data();
  uint32_t packLen = msgPacker.size();

  char debugB64[1024] = "";
  DEBUG_SERIAL.println("\nMessagePack B64:");
  encode_base64((unsigned char*)(packData), packLen, (unsigned char*)debugB64);
  DEBUG_SERIAL.println((char *)debugB64);
}

Unfortunately, it does not compile (ESP-32), throwing loads of errors.
I cannot copy all the compilation log here (too long), here are the first rows:

In file included from L:\Progetti\Arduino\libraries\MsgPack/MsgPack.h:13,
                 from L:\Progetti\Arduino\ESP32_MessagePackTest1\ESP32_MessagePackTest1.ino:1:
L:\Progetti\Arduino\libraries\MsgPack/MsgPack/Packer.h: In instantiation of 'typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type arduino::msgpack::Packer::serialize(const First&, Rest&& ...) [with First = unsigned char [32]; Rest = {}; typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type = void]':
L:\Progetti\Arduino\libraries\MsgPack/MsgPack/Packer.h:51:13:   recursively required from 'typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type arduino::msgpack::Packer::serialize(const First&, Rest&& ...) [with First = short unsigned int; Rest = {unsigned int&, String&, unsigned char (&)[32]}; typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type = void]'
L:\Progetti\Arduino\libraries\MsgPack/MsgPack/Packer.h:51:13:   required from 'typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type arduino::msgpack::Packer::serialize(const First&, Rest&& ...) [with First = unsigned int; Rest = {short unsigned int&, unsigned int&, String&, unsigned char (&)[32]}; typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type = void]'
L:\Progetti\Arduino\ESP32_MessagePackTest1\ESP32_MessagePackTest1.ino:58:58:   required from here
L:\Progetti\Arduino\libraries\MsgPack/MsgPack/Packer.h:50:13: error: no matching function for call to 'arduino::msgpack::Packer::pack(const unsigned char [32])'
             pack(first);
             ^~~~
L:\Progetti\Arduino\libraries\MsgPack/MsgPack/Packer.h:136:14: note: candidate: 'template<class T> typename std::enable_if<(std::is_same<T, arduino::msgpack::object::nil_t>::value || std::is_same<T, std::nullptr_t>::value)>::type arduino::msgpack::Packer::pack(const T&)'
         auto pack(const T& n) -> typename std::enable_if<
              ^~~~
L:\Progetti\Arduino\libraries\MsgPack/MsgPack/Packer.h:136:14: note:   template argument deduction/substitution failed:
L:\Progetti\Arduino\libraries\MsgPack/MsgPack/Packer.h: In substitution of 'template<class T> typename std::enable_if<(std::is_same<T, arduino::msgpack::object::nil_t>::value || std::is_same<T, std::nullptr_t>::value)>::type arduino::msgpack::Packer::pack(const T&) [with T = unsigned char [32]]':
L:\Progetti\Arduino\libraries\MsgPack/MsgPack/Packer.h:51:13:   recursively required from 'typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type arduino::msgpack::Packer::serialize(const First&, Rest&& ...) [with First = short unsigned int; Rest = {unsigned int&, String&, unsigned char (&)[32]}; typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type = void]'
L:\Progetti\Arduino\libraries\MsgPack/MsgPack/Packer.h:51:13:   required from 'typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type arduino::msgpack::Packer::serialize(const First&, Rest&& ...) [with First = unsigned int; Rest = {short unsigned int&, unsigned int&, String&, unsigned char (&)[32]}; typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type = void]'
L:\Progetti\Arduino\ESP32_MessagePackTest1\ESP32_MessagePackTest1.ino:58:58:   required from here
L:\Progetti\Arduino\libraries\MsgPack/MsgPack/Packer.h:136:14: error: no type named 'type' in 'struct std::enable_if<false, void>'
L:\Progetti\Arduino\libraries\MsgPack/MsgPack/Packer.h: In instantiation of 'typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type arduino::msgpack::Packer::serialize(const First&, Rest&& ...) [with First = unsigned char [32]; Rest = {}; typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type = void]':
L:\Progetti\Arduino\libraries\MsgPack/MsgPack/Packer.h:51:13:   recursively required from 'typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type arduino::msgpack::Packer::serialize(const First&, Rest&& ...) [with First = short unsigned int; Rest = {unsigned int&, String&, unsigned char (&)[32]}; typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type = void]'
L:\Progetti\Arduino\libraries\MsgPack/MsgPack/Packer.h:51:13:   required from 'typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type arduino::msgpack::Packer::serialize(const First&, Rest&& ...) [with First = unsigned int; Rest = {short unsigned int&, unsigned int&, String&, unsigned char (&)[32]}; typename std::enable_if<(((! std::is_pointer<_Tp>::value) || std::is_same<First, const char*>::value) || std::is_same<First, const __FlashStringHelper*>::value)>::type = void]'
L:\Progetti\Arduino\ESP32_MessagePackTest1\ESP32_MessagePackTest1.ino:58:58:   required from here
L:\Progetti\Arduino\libraries\MsgPack/MsgPack/Packer.h:146:14: note: candidate: 'template<class T> typename std::enable_if<std::is_same<T, bool>::value>::type arduino::msgpack::Packer::pack(const T&)'
         auto pack(const T& b) -> typename std::enable_if<std::is_same<T, bool>::value>::type {
              ^~~~

What am I doing wrong?

Thanks for your support

[Hideaki Tai]

You should use packer.pack(buffer_1, sizeof(buffer_1)) manually because the pointer itself doesn’t have the information of its size. You can serialize() it by using std::vector or std::array.