7base64 Module

7.1Overview

The base64 module provides measures to decode/encode data formatted in base64 format.

To decode a stream that is formatted in base64, use one of the following functions:

base64.decode() .. Reads base64 sequence from the given stream and returns a decoded data as binary. This is convenient when the data size is expected to be small.
base64.reader() .. Creates a stream that decodes base64 sequence from the given stream. stream#reader@base64() method is another form of this function. You should use this way if the data size is expected to be large.

To encode a data into base64 format, use one of the following functions:

base64.encode() .. Encodes the stream from the given stream and returns a encoded data as binary. This is convenient when the data size is expected to be small.
base64.writer() .. Creates a stream that encodes data from write() method into the given stream. stream#writer@base64() method is another form of this function. You should use this way if the data size is expected to be large.

7.2Module Function

The base64 module provides following functions:

base64.decode(stream:stream:r) {block?}

Reads text stream that is formatted in base64 and returns the decoded result in binary.

If block is specified, it would be evaluated with a block parameter |data:binary|, where data is the created instance. In this case, the block's result would become the function's returned value.

base64.encode(stream:stream:r, linelen:number:nil => 76) {block?}

Encodes content of the stream into base64 format and returns the result in binary.

base64.reader(stream:stream:r) {block?}

Creates a stream instance that reads data formatted in base64 from stream.

If block is specified, it would be evaluated with a block parameter |s:stream|, where s is the created instance. In this case, the block's result would become the function's returned value.

base64.writer(stream:stream:w, linelen:number:nil => 76) {block?}

Creates a stream instance that encodes data to base64 format and writes it to the stream.

The number of characters per line is specified by an argument linelen. If omitted, that is 76.

If block is specified, it would be evaluated with a block parameter |s:stream|, where s is the created instance. In this case, the block's result would become the function's returned value.

7.3Extension to stream Class

The base64 module extends the stream class with following methods:

stream#reader@base64() {block?}

Creates a stream instance that reads data formatted in base64 from the target stream instance.

If block is specified, it would be evaluated with a block parameter |s:stream|, where s is the created instance. In this case, the block's result would become the function's returned value.

stream#writer@base64(linelen:number:nil => 76) {block?}

Creates a stream instance that encodes data to base64 format and writes it to the target stream instance.

The number of characters per line is specified by an argument linelen. If omitted, that is 76.

If block is specified, it would be evaluated with a block parameter |s:stream|, where s is the created instance. In this case, the block's result would become the function's returned value.