49 lines
1.3 KiB
Go
49 lines
1.3 KiB
Go
// Package buffer implements a series of Buffers which can be composed to implement complicated buffering strategies
|
|
package buffer
|
|
|
|
import (
|
|
"io"
|
|
"os"
|
|
)
|
|
|
|
// Buffer is used to Write() data which will be Read() later.
|
|
type Buffer interface {
|
|
Len() int64 // How much data is Buffered in bytes
|
|
Cap() int64 // How much data can be Buffered at once in bytes.
|
|
io.Reader // Read() will read from the top of the buffer [io.EOF if empty]
|
|
io.Writer // Write() will write to the end of the buffer [io.ErrShortWrite if not enough space]
|
|
Reset() // Truncates the buffer, Len() == 0.
|
|
}
|
|
|
|
// BufferAt is a buffer which supports io.ReaderAt and io.WriterAt
|
|
type BufferAt interface {
|
|
Buffer
|
|
io.ReaderAt
|
|
io.WriterAt
|
|
}
|
|
|
|
func len64(p []byte) int64 {
|
|
return int64(len(p))
|
|
}
|
|
|
|
// Gap returns buf.Cap() - buf.Len()
|
|
func Gap(buf Buffer) int64 {
|
|
return buf.Cap() - buf.Len()
|
|
}
|
|
|
|
// Full returns true iff buf.Len() == buf.Cap()
|
|
func Full(buf Buffer) bool {
|
|
return buf.Len() == buf.Cap()
|
|
}
|
|
|
|
// Empty returns false iff buf.Len() == 0
|
|
func Empty(buf Buffer) bool {
|
|
return buf.Len() == 0
|
|
}
|
|
|
|
// NewUnboundedBuffer returns a Buffer which buffers "mem" bytes to memory
|
|
// and then creates file's of size "file" to buffer above "mem" bytes.
|
|
func NewUnboundedBuffer(mem, file int64) Buffer {
|
|
return NewMulti(New(mem), NewPartition(NewFilePool(file, os.TempDir())))
|
|
}
|