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Function std.bitmanip.peek

Takes a range of ubytes and converts the first T.sizeof bytes to T. The value returned is converted from the given endianness to the native endianness. The range is not consumed.

T peek(T, Endian endianness = Endian.bigEndian, R) (
  R range
)
if (canSwapEndianness!T && isForwardRange!R && is(ElementType!R : const(ubyte)));

T peek(T, Endian endianness = Endian.bigEndian, R) (
  R range,
  size_t index
)
if (canSwapEndianness!T && isForwardRange!R && hasSlicing!R && is(ElementType!R : const(ubyte)));

T peek(T, Endian endianness = Endian.bigEndian, R) (
  R range,
  size_t* index
)
if (canSwapEndianness!T && isForwardRange!R && hasSlicing!R && is(ElementType!R : const(ubyte)));

Parameters

NameDescription
T The integral type to convert the first T.sizeof bytes to.
endianness The endianness that the bytes are assumed to be in.
range The range to read from.
index The index to start reading from (instead of starting at the front). If index is a pointer, then it is updated to the index after the bytes read. The overloads with index are only available if hasSlicing!R is true.

Example

ubyte[] buffer = [1, 5, 22, 9, 44, 255, 8];
writeln(buffer.peek!uint()); // 17110537
writeln(buffer.peek!ushort()); // 261
writeln(buffer.peek!ubyte()); // 1

writeln(buffer.peek!uint(2)); // 369700095
writeln(buffer.peek!ushort(2)); // 5641
writeln(buffer.peek!ubyte(2)); // 22

size_t index = 0;
writeln(buffer.peek!ushort(&index)); // 261
writeln(index); // 2

writeln(buffer.peek!uint(&index)); // 369700095
writeln(index); // 6

writeln(buffer.peek!ubyte(&index)); // 8
writeln(index); // 7

Example

import std.algorithm.iteration : filter;
ubyte[] buffer = [1, 5, 22, 9, 44, 255, 7];
auto range = filter!"true"(buffer);
writeln(range.peek!uint()); // 17110537
writeln(range.peek!ushort()); // 261
writeln(range.peek!ubyte()); // 1

Authors

Walter Bright, Andrei Alexandrescu, Jonathan M Davis, Alex Rønne Petersen, Damian Ziemba, Amaury SECHET

License

Boost License 1.0.