1// Copyright (c) 2016 Uber Technologies, Inc. 2// 3// Permission is hereby granted, free of charge, to any person obtaining a copy 4// of this software and associated documentation files (the "Software"), to deal 5// in the Software without restriction, including without limitation the rights 6// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 7// copies of the Software, and to permit persons to whom the Software is 8// furnished to do so, subject to the following conditions: 9// 10// The above copyright notice and this permission notice shall be included in 11// all copies or substantial portions of the Software. 12// 13// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 14// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 15// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 16// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 17// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 18// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 19// THE SOFTWARE. 20 21// Package buffer provides a thin wrapper around a byte slice. Unlike the 22// standard library's bytes.Buffer, it supports a portion of the strconv 23// package's zero-allocation formatters. 24package buffer // import "go.uber.org/zap/buffer" 25 26import "strconv" 27 28const _size = 1024 // by default, create 1 KiB buffers 29 30// Buffer is a thin wrapper around a byte slice. It's intended to be pooled, so 31// the only way to construct one is via a Pool. 32type Buffer struct { 33 bs []byte 34 pool Pool 35} 36 37// AppendByte writes a single byte to the Buffer. 38func (b *Buffer) AppendByte(v byte) { 39 b.bs = append(b.bs, v) 40} 41 42// AppendString writes a string to the Buffer. 43func (b *Buffer) AppendString(s string) { 44 b.bs = append(b.bs, s...) 45} 46 47// AppendInt appends an integer to the underlying buffer (assuming base 10). 48func (b *Buffer) AppendInt(i int64) { 49 b.bs = strconv.AppendInt(b.bs, i, 10) 50} 51 52// AppendUint appends an unsigned integer to the underlying buffer (assuming 53// base 10). 54func (b *Buffer) AppendUint(i uint64) { 55 b.bs = strconv.AppendUint(b.bs, i, 10) 56} 57 58// AppendBool appends a bool to the underlying buffer. 59func (b *Buffer) AppendBool(v bool) { 60 b.bs = strconv.AppendBool(b.bs, v) 61} 62 63// AppendFloat appends a float to the underlying buffer. It doesn't quote NaN 64// or +/- Inf. 65func (b *Buffer) AppendFloat(f float64, bitSize int) { 66 b.bs = strconv.AppendFloat(b.bs, f, 'f', -1, bitSize) 67} 68 69// Len returns the length of the underlying byte slice. 70func (b *Buffer) Len() int { 71 return len(b.bs) 72} 73 74// Cap returns the capacity of the underlying byte slice. 75func (b *Buffer) Cap() int { 76 return cap(b.bs) 77} 78 79// Bytes returns a mutable reference to the underlying byte slice. 80func (b *Buffer) Bytes() []byte { 81 return b.bs 82} 83 84// String returns a string copy of the underlying byte slice. 85func (b *Buffer) String() string { 86 return string(b.bs) 87} 88 89// Reset resets the underlying byte slice. Subsequent writes re-use the slice's 90// backing array. 91func (b *Buffer) Reset() { 92 b.bs = b.bs[:0] 93} 94 95// Write implements io.Writer. 96func (b *Buffer) Write(bs []byte) (int, error) { 97 b.bs = append(b.bs, bs...) 98 return len(bs), nil 99} 100 101// TrimNewline trims any final "\n" byte from the end of the buffer. 102func (b *Buffer) TrimNewline() { 103 if i := len(b.bs) - 1; i >= 0 { 104 if b.bs[i] == '\n' { 105 b.bs = b.bs[:i] 106 } 107 } 108} 109 110// Free returns the Buffer to its Pool. 111// 112// Callers must not retain references to the Buffer after calling Free. 113func (b *Buffer) Free() { 114 b.pool.put(b) 115} 116