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Declaration and parameters
링크사용 조건
기본 포함 · 미정
Import std.bytes in language mode 5.21.
The current compiler selects std/bytes.tpz for this language mode. Availability in other released editions and inclusion in each installed distribution are Pending.
수신자
매개변수 제약
A Bytes value is an immutable ordered sequence of octets. Each octet is an int from 0 through 255.
Bytes.empty returns the empty sequence. Bytes.fromArray accepts an Array<int> and returns an independent snapshot in Ok.
Bytes.fromArray returns Err with a string identifying the first element outside 0 through 255. It does not wrap, clamp, or return a partial sequence.
Bytes.toArray returns a new Array<int> in byte order. Mutating that array or the original input array does not change an existing Bytes value.
Bytes.concat returns the receiver bytes followed by the argument bytes. Either input may be empty and both inputs retain their contents.
Bytes.get uses a zero-based byte index. It returns Some(byte) within the sequence and None() for every negative or past-end index.
Bytes.length is the number of bytes and is read as a property. Compare it with zero to test emptiness.
Receivers and supplied arguments evaluate once from left to right before the operation begins. These operations perform no I/O or text normalization.
A correctly typed lookup or concatenation has no data-dependent Result failure. Allocation exhaustion is an operational failure and is not a decoded data error.
관련 규칙 · Construct and inspect immutable byte sequences →결과
The declared result type is Bytes.
효과
실패
Result and effects
링크Return an immutable sequence containing zero bytes.
Resolved contracts
링크Related entries
링크Construct and inspect immutable byte sequences
링크Construct and inspect immutable byte sequences
A Bytes value is an immutable ordered sequence of octets. Each octet is an int from 0 through 255.
Bytes.empty returns the empty sequence. Bytes.fromArray accepts an Array<int> and returns an independent snapshot in Ok.
Bytes.fromArray returns Err with a string identifying the first element outside 0 through 255. It does not wrap, clamp, or return a partial sequence.
Bytes.toArray returns a new Array<int> in byte order. Mutating that array or the original input array does not change an existing Bytes value.
Bytes.concat returns the receiver bytes followed by the argument bytes. Either input may be empty and both inputs retain their contents.
Bytes.get uses a zero-based byte index. It returns Some(byte) within the sequence and None() for every negative or past-end index.
Bytes.length is the number of bytes and is read as a property. Compare it with zero to test emptiness.
Receivers and supplied arguments evaluate once from left to right before the operation begins. These operations perform no I/O or text normalization.
A correctly typed lookup or concatenation has no data-dependent Result failure. Allocation exhaustion is an operational failure and is not a decoded data error.
이유
Exact octets keep binary payloads independent of text encoding. Snapshot conversion prevents later array edits from silently changing a payload.
Preserve empty values and byte order
링크import std.bytes { Bytes }import std.ioimport std.testlet empty = test.assertOk(Bytes.fromArray([]))let value = test.assertOk(Bytes.fromArray([0, 128, 255]))io.writeLine(Bytes.empty().toHex())io.writeLine(empty.concat(value).toHex())io.writeLine(value.concat(test.assertOk(Bytes.fromArray([1]))).toHex())
0080ff
0080ff01
기대 결과
기대 결과
실행을 마칩니다. 종료 코드 0.
0080ff0080ff01
Reject out-of-range array elements
링크import std.bytes { Bytes }import std.iofor values in ([[0, -1, 255], [0, 256, 255]]) {match (Bytes.fromArray(values)) {case Err(_) => io.writeLine("invalid byte")case Ok(_) => io.writeLine("accepted")}}
invalid byte
invalid byte
기대 결과
기대 결과
실행을 마칩니다. 종료 코드 0.
invalid byteinvalid byte
Read optional bytes at both boundaries
링크import std.bytes { Bytes }import std.ioimport std.testlet value = test.assertOk(Bytes.fromArray([0, 128, 255]))for index in ([-1, 0, 2, 3]) {match (value.get(index)) {case Some(byte) => io.writeLine("{byte}")case None() => io.writeLine("absent")}}
absent
0
255
absent
기대 결과
기대 결과
실행을 마칩니다. 종료 코드 0.
absent0255absent
Keep array edits independent from bytes
링크import std.bytes { Bytes }import std.ioimport std.testlet mut input = [0, 255]let value = test.assertOk(Bytes.fromArray(input))let mut output = value.toArray()input[0] = 7output[1] = 8io.writeLine(value.toHex())io.writeLine("{input[0]},{output[1]}")
00ff
7,8
기대 결과
기대 결과
실행을 마칩니다. 종료 코드 0.
00ff7,8
Evaluate the receiver before its argument
링크import std.bytes { Bytes }import std.iofunction receiver() -> Bytes {io.writeLine("receiver")return "a".encodeUtf8()}function argument() -> Bytes {io.writeLine("argument")return "b".encodeUtf8()}io.writeLine(receiver().concat(argument()).toHex())
receiver
argument
6162
기대 결과
기대 결과
실행을 마칩니다. 종료 코드 0.
receiverargument6162