sg3des / stob

marshal/unmarshal struct to raw bytes

stob - convert struct to bytes and back

stob is package for convert structs to bytes or fill structs from bytes, as it does on C, i.e convert raw bytes to struct, and restore struct from raw bytes.

Unfortunately go does not allow do it also as simple as it can be done on C. There are 3 solutions:

1. use unsafe package - this is very fast, but not flexibly.

2. generatable code - it`s also fast, but it is not convenient.

3. reflection - it`s relatively slow...

stob use reflection for read and write struct to bytes.

Install

go get github.com/sg3des/stob

Example

type YourStruct struct {
	Str      string 
	Int      int `bo:"le"`
	Byte     byte
	Bytes    []byte `num:"8"`
	Bytes4   [4]byte
	Bool     bool
	Float    float32 `bo:"be"`
}

a := YourStruct{
	Str:      "string",
	Int:      999,
	Byte:     255,
	Bytes:    []byte{1, 2, 3, 4, 5, 6, 7, 8},
	Bytes4:   [4]byte{10, 11, 12, 13},
	Bool:     rand.Intn(2) == 1,
	Float:    rand.Float32(),
}

stob.Write(w, a)

it will be write how:

73 74 72 69 6e 67 00 e7  03 00 00 00 00 00 00 ff  |string..........|
01 02 03 04 05 06 07 08  0a 0b 0c 0d 01 3f 70 c5  |.............?p.|
34                                                |4|

to restore struct from bytes:

stob.Read(r, &a)

Tags

stob knows 3 tags:

• bo:"le" or bo:"be" - it`s byte order little or big endian
• num:"8" - count of elements in slice
• size:"4" - size of element, example size of string, but it also allows read\write big integers to small number of bytes.

WARNING: if []byte slice does not have num tag, then all next bytes will be writed to this field!

Benchmark

BenchmarkRead-8    2000000    762 ns/op    10 B/op    10 allocs/op
BenchmarkWrite-8   2000000    750 ns/op    24 B/op    6 allocs/op

unsafe:
BenchmarkRead-8    10000000   205 ns/op    0 B/op     0 allocs/op
BenchmarkWrite-8   5000000    257 ns/op    16 B/op    1 allocs/op

TODO

• types
• tests
• reader and writer for custom types