stream_helper

Below, a helper object bs is generated from the array b of smplbuf, and data input is performed using the mwx::stream::operator <<() operator.

smplbuf_u8<32> b;
auto&& bs = b.get_stream_helper(); // Helper object

// Generate data sequence
uint8_t FOURCHARS[]={'A', 'B', 'C', 'D'};
bs << FOURCHARS;
bs << ';';
bs << uint32_t(0x30313233); // "0123"
bs << format(";%d", 99);

Serial << b << crlf; // Output to Serial is via smplbuf_u8<32> class

// Result: ABCD;0123;99

Overview

stream_helper behaves as if the data array is a stream.

Internally, it keeps track of the read/write position within the data array. It behaves as follows:

• When reading or writing, the read/write position moves to the next position.
• After reading the last data or appending data to the end, the read/write position becomes the end position.
• When the read/write position is at the end,
  • available() returns false.
  • Reading is not possible.
  • Writing appends data if within writable range.

Creating stream_helper

stream_helper is created from member functions of data classes (smplbuf, EEPROM).

auto&& obj_helper = obj.get_stream_helper()
// obj is an object of a data class, and obj_helper's type is long, so it is received with auto&&.

Methods

rewind()

void rewind()

Moves the read/write position to the beginning.

seek()

int seek(int offset, int whence = MWX_SEEK_SET)

Sets the read/write position.

tell()

int tell()

Returns the read/write position. Returns -1 if at the end position.

available()

int available()

Returns 0 if the read/write position is at the end. Otherwise, returns a non-zero value.