Function writeInt [src]

Writes an integer to memory, storing it in twos-complement. This function always succeeds, has defined behavior for all inputs, but the integer bit width must be divisible by 8.

Prototype

 pub inline fn writeInt(comptime T: type, buffer: *[@divExact(@typeInfo(T).int.bits, 8)]u8, value: T, endian: Endian) void

Parameters

T: typebuffer: *[@divExact(@typeInfo(T).int.bits, 8)]u8value: Tendian: Endian

Example

 test writeInt {
    var buf0: [0]u8 = undefined;
    var buf1: [1]u8 = undefined;
    var buf2: [2]u8 = undefined;
    var buf9: [9]u8 = undefined;

    writeInt(u0, &buf0, 0x0, .big);
    try testing.expect(eql(u8, buf0[0..], &[_]u8{}));
    writeInt(u0, &buf0, 0x0, .little);
    try testing.expect(eql(u8, buf0[0..], &[_]u8{}));

    writeInt(u8, &buf1, 0x12, .big);
    try testing.expect(eql(u8, buf1[0..], &[_]u8{0x12}));
    writeInt(u8, &buf1, 0x34, .little);
    try testing.expect(eql(u8, buf1[0..], &[_]u8{0x34}));

    writeInt(u16, &buf2, 0x1234, .big);
    try testing.expect(eql(u8, buf2[0..], &[_]u8{ 0x12, 0x34 }));
    writeInt(u16, &buf2, 0x5678, .little);
    try testing.expect(eql(u8, buf2[0..], &[_]u8{ 0x78, 0x56 }));

    writeInt(u72, &buf9, 0x123456789abcdef024, .big);
    try testing.expect(eql(u8, buf9[0..], &[_]u8{ 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x24 }));
    writeInt(u72, &buf9, 0xfedcba9876543210ec, .little);
    try testing.expect(eql(u8, buf9[0..], &[_]u8{ 0xec, 0x10, 0x32, 0x54, 0x76, 0x98, 0xba, 0xdc, 0xfe }));

    writeInt(i8, &buf1, -1, .big);
    try testing.expect(eql(u8, buf1[0..], &[_]u8{0xff}));
    writeInt(i8, &buf1, -2, .little);
    try testing.expect(eql(u8, buf1[0..], &[_]u8{0xfe}));

    writeInt(i16, &buf2, -3, .big);
    try testing.expect(eql(u8, buf2[0..], &[_]u8{ 0xff, 0xfd }));
    writeInt(i16, &buf2, -4, .little);
    try testing.expect(eql(u8, buf2[0..], &[_]u8{ 0xfc, 0xff }));
}

Source

  pub inline fn writeInt(comptime T: type, buffer: *[@divExact(@typeInfo(T).int.bits, 8)]u8, value: T, endian: Endian) void {
    buffer.* = @bitCast(if (endian == native_endian) value else @byteSwap(value));
}  