zstd- Модуль
- std.
bytes → - Получатель
- Bytes
- Минимальное число аргументов
- 0
- Максимальное число аргументов
- 0
Declaration and parameters
СсылкаДоступность
Включено по умолчанию · Не определено
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.
Получатель
Bytes
Ограничения параметров
Bytes.zstdCompress accepts an int level from 1 through 22. The default is 3 and other values return Err with a string.
The level is a compression effort hint. The API does not promise a size ratio, execution time, or different bytes for every pair of levels.
A successful call returns Ok with one RFC 8878 frame requiring no external dictionary. Empty input is valid.
Bytes.zstdDecompress accepts one standard frame containing raw, RLE, or compressed blocks, with valid frame parameters and an optional content checksum.
A frame requiring an unavailable dictionary, a malformed header or block, a size or checksum mismatch, and truncation return Err with a string.
Skippable frames, additional frames, and other trailing bytes return Err. The entire input must represent one data frame.
Decompression returns all uncompressed bytes in Ok or an error without a partial output. Compressing then decompressing preserves the input bytes.
The receiver and explicit level expression evaluate once in that order. The input remains unchanged and the operation performs no I/O.
Связанное правило · Use Zstandard frames and explicit effort levels →Результат
The declared result type is Result<Bytes, string>.
Эффекты
Ошибки
Result and effects
СсылкаDecode one complete Zstandard data frame. Invalid framing, unavailable dictionaries, and trailing data return Err.
Resolved contracts
СсылкаRelated entries
СсылкаUse Zstandard frames and explicit effort levels
СсылкаUse Zstandard frames and explicit effort levels
Bytes.zstdCompress accepts an int level from 1 through 22. The default is 3 and other values return Err with a string.
The level is a compression effort hint. The API does not promise a size ratio, execution time, or different bytes for every pair of levels.
A successful call returns Ok with one RFC 8878 frame requiring no external dictionary. Empty input is valid.
Bytes.zstdDecompress accepts one standard frame containing raw, RLE, or compressed blocks, with valid frame parameters and an optional content checksum.
A frame requiring an unavailable dictionary, a malformed header or block, a size or checksum mismatch, and truncation return Err with a string.
Skippable frames, additional frames, and other trailing bytes return Err. The entire input must represent one data frame.
Decompression returns all uncompressed bytes in Ok or an error without a partial output. Compressing then decompressing preserves the input bytes.
The receiver and explicit level expression evaluate once in that order. The input remains unchanged and the operation performs no I/O.
Причина
A bounded level range keeps calls portable. A complete frame boundary and explicit dictionary failure make the returned bytes independent of hidden decoder state.
Use the default and both supported level boundaries
Ссылкаimport std.ioimport std.testlet source = "hello".encodeUtf8()io.writeLine(test.assertOk(test.assertOk(source.zstdCompress()).zstdDecompress()).toHex())for level in ([1, 22]) {io.writeLine(test.assertOk(test.assertOk(source.zstdCompress(level)).zstdDecompress()).toHex())}for level in ([0, 23]) {match (source.zstdCompress(level)) {case Err(_) => io.writeLine("invalid level")case Ok(_) => io.writeLine("accepted")}}
68656c6c6f
68656c6c6f
68656c6c6f
invalid level
invalid level
Ожидаемый результат
Ожидаемый результат
Выполнение завершается. Код завершения 0.
68656c6c6f68656c6c6f68656c6c6finvalid levelinvalid level
Decode a valid Zstandard RLE block
Ссылкаimport std.bytes { Bytes }import std.ioimport std.testlet encoded = test.assertOk(Bytes.fromHex("28b52ffd20052b000041"))match (encoded.zstdDecompress()) {case Ok(bytes) => io.writeLine(bytes.toHex())case Err(_) => io.writeLine("rejected")}
4141414141
Ожидаемый результат
Ожидаемый результат
Выполнение завершается. Код завершения 0.
4141414141
Decode short nonfinal Zstandard raw blocks
Ссылкаimport std.bytes { Bytes }import std.ioimport std.testlet encoded = test.assertOk(Bytes.fromHex("28b52ffd20020800004109000042"))match (encoded.zstdDecompress()) {case Ok(bytes) => io.writeLine(bytes.toHex())case Err(_) => io.writeLine("rejected")}
4142
Ожидаемый результат
Ожидаемый результат
Выполнение завершается. Код завершения 0.
4142
Reject missing block data and trailing bytes
Ссылкаimport std.bytes { Bytes }import std.ioimport std.testfor hex in (["", "28b52ffd20052900006869", "28b52ffd200001000000"]) {match (test.assertOk(Bytes.fromHex(hex)).zstdDecompress()) {case Err(_) => io.writeLine("invalid Zstandard")case Ok(_) => io.writeLine("accepted")}}
invalid Zstandard
invalid Zstandard
invalid Zstandard
Ожидаемый результат
Ожидаемый результат
Выполнение завершается. Код завершения 0.
invalid Zstandardinvalid Zstandardinvalid Zstandard