87 lines
1.8 KiB
Go
87 lines
1.8 KiB
Go
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package helpers
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import (
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"bytes"
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"strings"
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)
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// This provides an efficient way to join lots of big string and byte slices
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// together. It avoids the cost of repeatedly reallocating as the buffer grows
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// by measuring exactly how big the buffer should be and then allocating once.
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// This is a measurable speedup.
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type Joiner struct {
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lastByte byte
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strings []joinerString
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bytes []joinerBytes
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length uint32
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}
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type joinerString struct {
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data string
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offset uint32
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}
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type joinerBytes struct {
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data []byte
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offset uint32
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}
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func (j *Joiner) AddString(data string) {
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if len(data) > 0 {
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j.lastByte = data[len(data)-1]
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}
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j.strings = append(j.strings, joinerString{data, j.length})
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j.length += uint32(len(data))
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}
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func (j *Joiner) AddBytes(data []byte) {
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if len(data) > 0 {
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j.lastByte = data[len(data)-1]
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}
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j.bytes = append(j.bytes, joinerBytes{data, j.length})
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j.length += uint32(len(data))
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}
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func (j *Joiner) LastByte() byte {
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return j.lastByte
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}
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func (j *Joiner) Length() uint32 {
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return j.length
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}
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func (j *Joiner) EnsureNewlineAtEnd() {
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if j.length > 0 && j.lastByte != '\n' {
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j.AddString("\n")
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}
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}
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func (j *Joiner) Done() []byte {
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if len(j.strings) == 0 && len(j.bytes) == 1 && j.bytes[0].offset == 0 {
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// No need to allocate if there was only a single byte array written
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return j.bytes[0].data
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}
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buffer := make([]byte, j.length)
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for _, item := range j.strings {
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copy(buffer[item.offset:], item.data)
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}
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for _, item := range j.bytes {
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copy(buffer[item.offset:], item.data)
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}
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return buffer
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}
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func (j *Joiner) Contains(s string, b []byte) bool {
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for _, item := range j.strings {
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if strings.Contains(item.data, s) {
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return true
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}
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}
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for _, item := range j.bytes {
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if bytes.Contains(item.data, b) {
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return true
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}
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}
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return false
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}
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