version: 1.10

package suffixarray

import "index/suffixarray"

Overview

Package suffixarray implements substring search in logarithmic time using an
in-memory suffix array.

Example use:

// create index for some data
index := suffixarray.New(data)
// lookup byte slice s
offsets1 := index.Lookup(s, -1) // the list of all indices where s occurs in data
offsets2 := index.Lookup(s, 3)  // the list of at most 3 indices where s occurs in data

Index

• type Index
  • func New(data []byte) *Index
  • func (x *Index) Bytes() []byte
  • func (x Index) FindAllIndex(r regexp.Regexp, n int) (result [][]int)
  • func (x *Index) Lookup(s []byte, n int) (result []int)
  • func (x *Index) Read(r io.Reader) error
  • func (x *Index) Write(w io.Writer) error

Examples

• Index.Lookup

Package files

qsufsort.go suffixarray.go

type Index
¶

type Index struct {
    // contains filtered or unexported fields
}

Index implements a suffix array for fast substring search.

func New
¶

func New(data []byte) *Index

New creates a new Index for data. Index creation time is O(N*log(N)) for N =
len(data).

func (*Index) Bytes
¶

func (x *Index) Bytes() []byte

Bytes returns the data over which the index was created. It must not be
modified.

func (*Index) FindAllIndex
¶

func (x *Index) FindAllIndex(r *regexp.Regexp, n int) (result [][]int)

FindAllIndex returns a sorted list of non-overlapping matches of the regular
expression r, where a match is a pair of indices specifying the matched slice of
x.Bytes(). If n < 0, all matches are returned in successive order. Otherwise, at
most n matches are returned and they may not be successive. The result is nil if
there are no matches, or if n == 0.

func (*Index) Lookup
¶

func (x *Index) Lookup(s []byte, n int) (result []int)

Lookup returns an unsorted list of at most n indices where the byte string s
occurs in the indexed data. If n < 0, all occurrences are returned. The result
is nil if s is empty, s is not found, or n == 0. Lookup time is O(log(N)*len(s)

• len(result)) where N is the size of the indexed data.

Example:

index := suffixarray.New([]byte("banana"))
offsets := index.Lookup([]byte("ana"), -1)
for _, off := range offsets {
    fmt.Println(off)
}
// Unordered output:
// 1
// 3

func (*Index) Read
¶

func (x *Index) Read(r io.Reader) error

Read reads the index from r into x; x must not be nil.

func (*Index) Write
¶

func (x *Index) Write(w io.Writer) error

Write writes the index x to w.