prometheus-adapter/vendor/golang.org/x/text/internal/triegen/compact.go
Solly Ross a293b2bf94 Check in the vendor directory
Travis seems to be having issues pulling deps, so we'll have to check in
the vendor directory and prevent the makefile from trying to regenerate
it normally.
2018-07-13 17:32:49 -04:00

58 lines
2 KiB
Go

// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package triegen
// This file defines Compacter and its implementations.
import "io"
// A Compacter generates an alternative, more space-efficient way to store a
// trie value block. A trie value block holds all possible values for the last
// byte of a UTF-8 encoded rune. Excluding ASCII characters, a trie value block
// always has 64 values, as a UTF-8 encoding ends with a byte in [0x80, 0xC0).
type Compacter interface {
// Size returns whether the Compacter could encode the given block as well
// as its size in case it can. len(v) is always 64.
Size(v []uint64) (sz int, ok bool)
// Store stores the block using the Compacter's compression method.
// It returns a handle with which the block can be retrieved.
// len(v) is always 64.
Store(v []uint64) uint32
// Print writes the data structures associated to the given store to w.
Print(w io.Writer) error
// Handler returns the name of a function that gets called during trie
// lookup for blocks generated by the Compacter. The function should be of
// the form func (n uint32, b byte) uint64, where n is the index returned by
// the Compacter's Store method and b is the last byte of the UTF-8
// encoding, where 0x80 <= b < 0xC0, for which to do the lookup in the
// block.
Handler() string
}
// simpleCompacter is the default Compacter used by builder. It implements a
// normal trie block.
type simpleCompacter builder
func (b *simpleCompacter) Size([]uint64) (sz int, ok bool) {
return blockSize * b.ValueSize, true
}
func (b *simpleCompacter) Store(v []uint64) uint32 {
h := uint32(len(b.ValueBlocks) - blockOffset)
b.ValueBlocks = append(b.ValueBlocks, v)
return h
}
func (b *simpleCompacter) Print(io.Writer) error {
// Structures are printed in print.go.
return nil
}
func (b *simpleCompacter) Handler() string {
panic("Handler should be special-cased for this Compacter")
}