82 lines
1.8 KiB
Go
82 lines
1.8 KiB
Go
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package format
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import (
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"io"
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"unicode/utf8"
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"unsafe"
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)
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// ensure we conform to io.Writer.
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var _ io.Writer = (*Buffer)(nil)
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// Buffer is a simple wrapper around a byte slice.
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type Buffer struct {
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B []byte
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}
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// Write will append given byte slice to buffer, fulfilling io.Writer.
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func (buf *Buffer) Write(b []byte) (int, error) {
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buf.B = append(buf.B, b...)
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return len(b), nil
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}
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// AppendByte appends given byte to the buffer.
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func (buf *Buffer) AppendByte(b byte) {
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buf.B = append(buf.B, b)
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}
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// AppendRune appends given rune to the buffer.
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func (buf *Buffer) AppendRune(r rune) {
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if r < utf8.RuneSelf {
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buf.B = append(buf.B, byte(r))
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return
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}
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l := buf.Len()
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for i := 0; i < utf8.UTFMax; i++ {
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buf.B = append(buf.B, 0)
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}
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n := utf8.EncodeRune(buf.B[l:buf.Len()], r)
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buf.B = buf.B[:l+n]
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}
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// Append will append given byte slice to the buffer.
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func (buf *Buffer) Append(b []byte) {
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buf.B = append(buf.B, b...)
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}
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// AppendString appends given string to the buffer.
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func (buf *Buffer) AppendString(s string) {
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buf.B = append(buf.B, s...)
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}
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// Len returns the length of the buffer's underlying byte slice.
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func (buf *Buffer) Len() int {
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return len(buf.B)
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}
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// Cap returns the capacity of the buffer's underlying byte slice.
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func (buf *Buffer) Cap() int {
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return cap(buf.B)
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}
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// Truncate will reduce the length of the buffer by 'n'.
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func (buf *Buffer) Truncate(n int) {
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if n > len(buf.B) {
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n = len(buf.B)
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}
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buf.B = buf.B[:buf.Len()-n]
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}
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// Reset will reset the buffer length to 0 (retains capacity).
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func (buf *Buffer) Reset() {
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buf.B = buf.B[:0]
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}
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// String returns the underlying byte slice as a string. Please note
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// this value is tied directly to the underlying byte slice, if you
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// write to the buffer then returned string values will also change.
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func (buf *Buffer) String() string {
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return *(*string)(unsafe.Pointer(&buf.B))
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}
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