bytes

package
v0.54.0 Latest Latest
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 Go to latest Published: Apr 4, 2024 License: BSD-3-Clause Imports: 7 Imported by: 1

Documentation

Overview

Package bytes provide a library for working with byte or slice of bytes.

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

func AppendInt16 

func AppendInt16(data []byte, v int16) []byte

AppendInt16 append an int16 value into slice of byte.

Example 
package main

import (
	"fmt"
	"math"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	for _, v := range []int16{math.MinInt16, 0xab, 0xabc, math.MaxInt16} {
		out := libbytes.AppendInt16([]byte{}, v)
		fmt.Printf("%6d => %#04x => %#02v\n", v, v, out)
	}
}

Output:

-32768 => -0x8000 => []byte{0x80, 0x00}
   171 => 0x00ab => []byte{0x00, 0xab}
  2748 => 0x0abc => []byte{0x0a, 0xbc}
 32767 => 0x7fff => []byte{0x7f, 0xff}

func AppendInt32 

func AppendInt32(data []byte, v int32) []byte

AppendInt32 append an int32 value into slice of byte.

Example 
package main

import (
	"fmt"
	"math"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	for _, v := range []int32{math.MinInt32, 0xab, 0xabc, math.MaxInt32} {
		out := libbytes.AppendInt32([]byte{}, v)
		fmt.Printf("%11d => %#x => %#v\n", v, v, out)
	}
}

Output:

-2147483648 => -0x80000000 => []byte{0x80, 0x0, 0x0, 0x0}
        171 => 0xab => []byte{0x0, 0x0, 0x0, 0xab}
       2748 => 0xabc => []byte{0x0, 0x0, 0xa, 0xbc}
 2147483647 => 0x7fffffff => []byte{0x7f, 0xff, 0xff, 0xff}

func AppendUint16 

func AppendUint16(data []byte, v uint16) []byte

AppendUint16 append an uint16 value into slice of byte.

Example 
package main

import (
	"fmt"
	"math"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	inputs := []uint16{0, 0xab, 0xabc, math.MaxInt16, math.MaxUint16}
	for _, v := range inputs {
		out := libbytes.AppendUint16([]byte{}, v)
		fmt.Printf("%5d => %#04x => %#02v\n", v, v, out)
	}

	v := inputs[4] + 1 // MaxUint16 + 1
	out := libbytes.AppendUint16([]byte{}, v)
	fmt.Printf("%5d => %#04x => %#02v\n", v, v, out)

}

Output:

0 => 0x0000 => []byte{0x00, 0x00}
  171 => 0x00ab => []byte{0x00, 0xab}
 2748 => 0x0abc => []byte{0x0a, 0xbc}
32767 => 0x7fff => []byte{0x7f, 0xff}
65535 => 0xffff => []byte{0xff, 0xff}
    0 => 0x0000 => []byte{0x00, 0x00}

func AppendUint32 

func AppendUint32(data []byte, v uint32) []byte

AppendUint32 append an uint32 value into slice of byte.

Example 
package main

import (
	"fmt"
	"math"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	inputs := []uint32{0, 0xab, 0xabc, math.MaxInt32, math.MaxUint32}
	for _, v := range inputs {
		out := libbytes.AppendUint32([]byte{}, v)
		fmt.Printf("%11d => %#x => %#v\n", v, v, out)
	}

	v := inputs[4] + 2 // MaxUint32 + 2
	out := libbytes.AppendUint32([]byte{}, v)
	fmt.Printf("%11d => %#x => %#v\n", v, v, out)

}

Output:

0 => 0x0 => []byte{0x0, 0x0, 0x0, 0x0}
        171 => 0xab => []byte{0x0, 0x0, 0x0, 0xab}
       2748 => 0xabc => []byte{0x0, 0x0, 0xa, 0xbc}
 2147483647 => 0x7fffffff => []byte{0x7f, 0xff, 0xff, 0xff}
 4294967295 => 0xffffffff => []byte{0xff, 0xff, 0xff, 0xff}
          1 => 0x1 => []byte{0x0, 0x0, 0x0, 0x1}

func Concat 

func Concat(args ...interface{}) (out []byte)

Concat merge one or more []byte or string in args into slice of byte. Any type that is not []byte or string in args will be ignored.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	fmt.Printf("%s\n", libbytes.Concat())
	fmt.Printf("%s\n", libbytes.Concat([]byte{}))
	fmt.Printf("%s\n", libbytes.Concat([]byte{}, []byte("B")))
	fmt.Printf("%s\n", libbytes.Concat("with []int:", []int{1, 2}))
	fmt.Printf("%s\n", libbytes.Concat([]byte("bytes"), " and ", []byte("string")))
	fmt.Printf("%s\n", libbytes.Concat([]byte("A"), 1, []int{2}, []byte{}, []byte("C")))
}

Output:


B
with []int:
bytes and string
AC

func Copy 

func Copy(src []byte) (dst []byte)

Copy slice of bytes from parameter.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	// Copying empty slice.
	org := []byte{}
	cp := libbytes.Copy(org)
	fmt.Printf("%d %q\n", len(cp), cp)

	org = []byte("slice of life")
	tmp := org
	cp = libbytes.Copy(org)
	fmt.Printf("%d %q\n", len(cp), cp)
	fmt.Printf("Original address == tmp address: %v\n", &org[0] == &tmp[0])
	fmt.Printf("Original address == copy address: %v\n", &org[0] == &cp[0])

}

Output:

0 ""
13 "slice of life"
Original address == tmp address: true
Original address == copy address: false

func CutUntilToken 

func CutUntilToken(text, token []byte, startAt int, checkEsc bool) (cut []byte, pos int, found bool)

CutUntilToken cut text until we found token.

If token found, it will return all bytes before token, position of byte after token, and true.

If no token found, it will return false.

If checkEsc is true, token that is prefixed with escaped character ('\') will be skipped, the escape character will be removed.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	text := []byte(`\\abc \def \deg`)

	cut, pos, found := libbytes.CutUntilToken(text, nil, 0, false)
	fmt.Printf("'%s' %d %t\n", cut, pos, found)

	cut, pos, found = libbytes.CutUntilToken(text, []byte("def"), 0, false)
	fmt.Printf("'%s' %d %t\n", cut, pos, found)

	cut, pos, found = libbytes.CutUntilToken(text, []byte("def"), 0, true)
	fmt.Printf("'%s' %d %t\n", cut, pos, found)

	cut, pos, found = libbytes.CutUntilToken(text, []byte("ef"), -1, true)
	fmt.Printf("'%s' %d %t\n", cut, pos, found)

	cut, pos, found = libbytes.CutUntilToken(text, []byte("hi"), 0, true)
	fmt.Printf("'%s' %d %t\n", cut, pos, found)

}

Output:

'\\abc \def \deg' -1 false
'\\abc \' 10 true
'\abc def \deg' 15 false
'\abc \d' 10 true
'\abc \def \deg' 15 false

func DumpPrettyTable 

func DumpPrettyTable(w io.Writer, title string, data []byte)

DumpPrettyTable write each byte in slice data as hexadecimal, ASCII character, and integer with 8 columns width.

Example 
package main

import (
	"bytes"
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		data = []byte{1, 2, 3, 'H', 'e', 'l', 'l', 'o', 254, 255}
		bb   bytes.Buffer
	)

	libbytes.DumpPrettyTable(&bb, `DumpPrettyTable`, data)
	fmt.Println(bb.String())
}

Output:

DumpPrettyTable
          |  0  1  2  3  4  5  6  7 | 01234567 |   0   1   2   3   4   5   6   7 |
          |  8  9  A  B  C  D  E  F | 89ABCDEF |   8   9   A   B   C   D   E   F |
0x00000000| 01 02 03 48 65 6c 6c 6f | ...Hello |   1   2   3  72 101 108 108 111 |0
0x00000008| fe ff                   | ..       | 254 255                         |8

func EncloseRemove 

func EncloseRemove(text, leftToken, rightToken []byte) (cut []byte, found bool)

EncloseRemove given a text, find the leftToken and rightToken and cut the content in between them and return it with status true. Keep doing it until no more leftToken and rightToken found.

If no leftToken or rightToken is found, it will return text as is and false.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	text := []byte(`[[ A ]]-[[ B ]] C`)

	got, isCut := libbytes.EncloseRemove(text, []byte("[["), []byte("]]"))
	fmt.Printf("'%s' %t\n", got, isCut)

	got, isCut = libbytes.EncloseRemove(text, []byte("[["), []byte("}}"))
	fmt.Printf("'%s' %t\n", got, isCut)

	text = []byte(`// Copyright 2016-2018 "Shulhan <ms@kilabit.info>". All rights reserved.`)

	got, isCut = libbytes.EncloseRemove(text, []byte("<"), []byte(">"))
	fmt.Printf("'%s' %t\n", got, isCut)

	got, isCut = libbytes.EncloseRemove(text, []byte(`"`), []byte(`"`))
	fmt.Printf("'%s' %t\n", got, isCut)

	got, isCut = libbytes.EncloseRemove(text, []byte(`/`), []byte(`/`))
	fmt.Printf("'%s' %t\n", got, isCut)

	text = []byte(`/* TEST */`)

	got, isCut = libbytes.EncloseRemove(text, []byte(`/*`), []byte(`*/`))
	fmt.Printf("'%s' %t\n", got, isCut)

}

Output:

'- C' true
'[[ A ]]-[[ B ]] C' false
'// Copyright 2016-2018 "Shulhan ". All rights reserved.' true
'// Copyright 2016-2018 . All rights reserved.' true
' Copyright 2016-2018 "Shulhan <ms@kilabit.info>". All rights reserved.' true
'' true

func EncloseToken 

func EncloseToken(text, token, leftcap, rightcap []byte) (
	newtext []byte,
	found bool,
)

EncloseToken find "token" in "text" and enclose it with bytes from "leftcap" and "rightcap". If at least one token found, it will return modified text with true status. If no token is found, it will return the same text with false status.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	text := []byte(`// Copyright 2016-2018 "Shulhan <ms@kilabit.info>". All rights reserved.`)

	got, isChanged := libbytes.EncloseToken(text, []byte(`"`), []byte(`\`), []byte(`_`))
	fmt.Printf("%t '%s'\n", isChanged, got)

	got, isChanged = libbytes.EncloseToken(text, []byte(`_`), []byte(`-`), []byte(`-`))
	fmt.Printf("%t '%s'\n", isChanged, got)

	got, isChanged = libbytes.EncloseToken(text, []byte(`/`), []byte(`\`), nil)
	fmt.Printf("%t '%s'\n", isChanged, got)

	got, isChanged = libbytes.EncloseToken(text, []byte(`<`), []byte(`<`), []byte(` `))
	fmt.Printf("%t '%s'\n", isChanged, got)

}

Output:

true '// Copyright 2016-2018 \"_Shulhan <ms@kilabit.info>\"_. All rights reserved.'
false '// Copyright 2016-2018 "Shulhan <ms@kilabit.info>". All rights reserved.'
true '\/\/ Copyright 2016-2018 "Shulhan <ms@kilabit.info>". All rights reserved.'
true '// Copyright 2016-2018 "Shulhan << ms@kilabit.info>". All rights reserved.'

func InReplace 

func InReplace(text, allowed []byte, c byte) []byte

InReplace replace any characters in "text" that is not in "allowed" with character "c". The replacement occur inside the "text" backing storage, which means the passed "text" will changes and returned.

Example 
package main

import (
	"fmt"

	"git.sr.ht/~shulhan/pakakeh.go/lib/ascii"
	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	text := libbytes.InReplace([]byte{}, []byte(ascii.LettersNumber), '_')
	fmt.Printf("%q\n", text)

	text = libbytes.InReplace([]byte("/a/b/c"), []byte(ascii.LettersNumber), '_')
	fmt.Printf("%q\n", text)

	_ = libbytes.InReplace(text, []byte(ascii.LettersNumber), '/')
	fmt.Printf("%q\n", text)

}

Output:

""
"_a_b_c"
"/a/b/c"

func Indexes 

func Indexes(text, token []byte) (idxs []int)

Indexes returns the index of the all instance of "token" in "text", or nil if no "token" found.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	fmt.Println(libbytes.Indexes([]byte(""), []byte("moo")))
	fmt.Println(libbytes.Indexes([]byte("moo moomoo"), []byte{}))
	fmt.Println(libbytes.Indexes([]byte("moo moomoo"), []byte("moo")))
}

Output:

[]
[]
[0 4 7]

func IsTokenAt 

func IsTokenAt(text, token []byte, p int) bool

IsTokenAt return true if `text` at index `p` match with `token`, otherwise it will return false. Empty token always return false.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	text := []byte("Hello, world")
	tokenWorld := []byte("world")
	tokenWorlds := []byte("worlds")
	tokenEmpty := []byte{}

	fmt.Printf("%t\n", libbytes.IsTokenAt(text, tokenEmpty, 6))
	fmt.Printf("%t\n", libbytes.IsTokenAt(text, tokenWorld, -1))
	fmt.Printf("%t\n", libbytes.IsTokenAt(text, tokenWorld, 6))
	fmt.Printf("%t\n", libbytes.IsTokenAt(text, tokenWorld, 7))
	fmt.Printf("%t\n", libbytes.IsTokenAt(text, tokenWorld, 8))
	fmt.Printf("%t\n", libbytes.IsTokenAt(text, tokenWorlds, 8))
}

Output:

false
false
false
true
false
false

func MergeSpaces 

func MergeSpaces(in []byte) (out []byte)

MergeSpaces convert sequences of white spaces into single space ' '.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	fmt.Printf("%s\n", libbytes.MergeSpaces([]byte("")))
	fmt.Printf("%s\n", libbytes.MergeSpaces([]byte(" \t\v\r\n\r\n\fa \t\v\r\n\r\n\f")))
}

Output:


 a

func ParseHexDump 

func ParseHexDump(in []byte, networkByteOrder bool) (out []byte, err error)

ParseHexDump parse the default output of hexdump(1) utility from parameter in back into stream of byte.

An example of default output of hexdump is 

0000000 7865 5f70 6964 2f72 0000 0000 0000 0000
0000010 0000 0000 0000 0000 0000 0000 0000 0000
*
0000060 0000 0000 3030 3030 3537 0035 3030 3130

The first column is the address and the rest of the column is the data.

Each data column is 16-bit words in big-endian order, so in the above example, the first byte would be 65, second byte is 78 and so on. If parameter networkByteOrder is true, the first byte would be 78, second by is 65, and so on.

The asterisk "*" means that the address from 0000020 to 0000050 is equal to the previous line, 0000010.

Example 
package main

import (
	"fmt"
	"log"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		in = []byte("0000000 6548 6c6c 2c6f 7720 726f 646c 0021")

		out []byte
		err error
	)

	out, err = libbytes.ParseHexDump(in, false)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Printf(`%s`, libbytes.TrimNull(out))
}

Output:

Hello, world!

func PrintHex 

func PrintHex(title string, data []byte, col int)

PrintHex will print each byte in slice as hexadecimal value into N column length.

Example 
package main

import (
	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	title := "PrintHex"
	data := []byte("Hello, world !")
	libbytes.PrintHex(title, data, 5)
}

Output:

PrintHex
   0 - 48 65 6C 6C 6F || H e l l o
   5 - 2C 20 77 6F 72 || , . w o r
  10 - 6C 64 20 21    || l d . !

func ReadHexByte 

func ReadHexByte(data []byte, x int) (b byte, ok bool)

ReadHexByte read two hexadecimal characters from "data" start from index "x" and convert them to byte. It will return the byte and true if its read exactly two hexadecimal characters, otherwise it will return 0 and false.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	fmt.Println(libbytes.ReadHexByte([]byte{}, 0))
	fmt.Println(libbytes.ReadHexByte([]byte("x0"), 0))
	fmt.Println(libbytes.ReadHexByte([]byte("00"), 0))
	fmt.Println(libbytes.ReadHexByte([]byte("01"), 0))
	fmt.Println(libbytes.ReadHexByte([]byte("10"), 0))
	fmt.Println(libbytes.ReadHexByte([]byte("1A"), 0))
	fmt.Println(libbytes.ReadHexByte([]byte("1a"), 0))
	fmt.Println(libbytes.ReadHexByte([]byte("1a"), -1))
}

Output:

0 false
0 false
0 true
1 true
16 true
26 true
26 true
0 false

func ReadInt16 

func ReadInt16(data []byte, x uint) (v int16)

ReadInt16 read int16 value from "data" start at index "x". It will return 0 if "x" is out of range.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	fmt.Println(libbytes.ReadInt16([]byte{0x01, 0x02, 0x03, 0x04}, 3)) // x is out of range.
	fmt.Println(libbytes.ReadInt16([]byte{0x01, 0x02, 0x03, 0x04}, 0)) // 0x0102
	fmt.Println(libbytes.ReadInt16([]byte{0x01, 0x02, 0xf0, 0x04}, 2)) // 0xf004
}

Output:

0
258
-4092

func ReadInt32 

func ReadInt32(data []byte, x uint) (v int32)

ReadInt32 read int32 value from "data" start at index "x". It will return 0 if "x" is out of range.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	fmt.Println(libbytes.ReadInt32([]byte{0x01, 0x02, 0x03, 0x04}, 1)) // x is out of range.
	fmt.Println(libbytes.ReadInt32([]byte{0x01, 0x02, 0x03, 0x04}, 0)) // 0x01020304
	fmt.Println(libbytes.ReadInt32([]byte{0xf1, 0x02, 0x03, 0x04}, 0)) // 0xf1020304
}

Output:

0
16909060
-251526396

func ReadUint16 

func ReadUint16(data []byte, x uint) (v uint16)

ReadUint16 read uint16 value from "data" start at index "x". If x is out of range, it will return 0.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	fmt.Println(libbytes.ReadUint16([]byte{0x01, 0x02, 0xf0, 0x04}, 3)) // x is out of range.
	fmt.Println(libbytes.ReadUint16([]byte{0x01, 0x02, 0xf0, 0x04}, 0)) // 0x0102
	fmt.Println(libbytes.ReadUint16([]byte{0x01, 0x02, 0xf0, 0x04}, 2)) // 0xf004
}

Output:

0
258
61444

func ReadUint32 

func ReadUint32(data []byte, x uint) (v uint32)

ReadUint32 read uint32 value from "data" start at index "x". If x is out of range, it will return 0.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	fmt.Println(libbytes.ReadUint32([]byte{0x01, 0x02, 0x03, 0x04}, 1)) // x is out of range.
	fmt.Println(libbytes.ReadUint32([]byte{0x01, 0x02, 0x03, 0x04}, 0)) // 0x01020304
	fmt.Println(libbytes.ReadUint32([]byte{0xf1, 0x02, 0x03, 0x04}, 0)) // 0xf1020304
}

Output:

0
16909060
4043440900

func RemoveSpaces 

func RemoveSpaces(in []byte) (out []byte)

RemoveSpaces remove all spaces from input in.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		in  = []byte(" a\nb\tc d\r")
		out = libbytes.RemoveSpaces(in)
	)

	fmt.Printf("%s\n", out)

}

Output:

abcd

func SkipAfterToken 

func SkipAfterToken(text, token []byte, startAt int, checkEsc bool) (int, bool)

SkipAfterToken skip all bytes until matched "token" is found and return the index after the token and boolean true.

If "checkEsc" is true, token that is prefixed with escaped character '\' will be considered as non-match token.

If no token found it will return -1 and boolean false.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	text := []byte(`abc \def ghi`)

	fmt.Println(libbytes.SkipAfterToken(text, []byte("def"), -1, false))
	fmt.Println(libbytes.SkipAfterToken(text, []byte("def"), 0, true))
	fmt.Println(libbytes.SkipAfterToken(text, []byte("deg"), 0, false))
	fmt.Println(libbytes.SkipAfterToken(text, []byte("deg"), 0, true))
	fmt.Println(libbytes.SkipAfterToken(text, []byte("ef"), 0, true))
	fmt.Println(libbytes.SkipAfterToken(text, []byte("hi"), 0, true))
}

Output:

8 true
-1 false
-1 false
-1 false
8 true
12 true

func SnippetByIndexes 

func SnippetByIndexes(s []byte, indexes []int, sniplen int) (snippets [][]byte)

SnippetByIndexes take snippet in between of each index with minimum snippet length. The sniplen is the length before and after index, not the length of all snippet.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	s := []byte("// Copyright 2018, Shulhan <ms@kilabit.info>. All rights reserved.")
	indexes := []int{3, 20, len(s) - 4}

	snippets := libbytes.SnippetByIndexes(s, indexes, 5)
	for _, snip := range snippets {
		fmt.Printf("%s\n", snip)
	}
}

Output:

// Copyr
18, Shulha
reserved.

func SplitEach 

func SplitEach(data []byte, n int) (chunks [][]byte)

SplitEach split the data into n number of bytes. If n is less or equal than zero, it will return the data as chunks.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var data = []byte(`Hello`)

	fmt.Printf("%s\n", libbytes.SplitEach(data, 0))
	fmt.Printf("%s\n", libbytes.SplitEach(data, 1))
	fmt.Printf("%s\n", libbytes.SplitEach(data, 2))
	fmt.Printf("%s\n", libbytes.SplitEach(data, 5))
	fmt.Printf("%s\n", libbytes.SplitEach(data, 10))
}

Output:

[Hello]
[H e l l o]
[He ll o]
[Hello]
[Hello]

func TokenFind 

func TokenFind(text, token []byte, startat int) (at int)

TokenFind return the first index of matched token in text, start at custom index. If "startat" parameter is less than 0, then it will be set to 0. If token is empty or no token found it will return -1.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	text := []byte("// Copyright 2018, Shulhan <ms@kilabit.info>. All rights reserved.")

	fmt.Println(libbytes.TokenFind(text, []byte{}, 0))
	fmt.Println(libbytes.TokenFind(text, []byte("right"), -1))
	fmt.Println(libbytes.TokenFind(text, []byte("."), 0))
	fmt.Println(libbytes.TokenFind(text, []byte("."), 42))
	fmt.Println(libbytes.TokenFind(text, []byte("."), 48))
	fmt.Println(libbytes.TokenFind(text, []byte("d."), 0))
}

Output:

-1
7
38
44
65
64

func TrimNull 

func TrimNull(in []byte) (out []byte)

TrimNull remove 0 value ("\0" or NULL in C) at leading and trailing of in.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var in = []byte{0, 'H', 'e', 'l', 'l', 'o', 0, 0}

	in = libbytes.TrimNull(in)
	fmt.Printf(`%s`, in)
}

Output:

Hello

func WordIndexes 

func WordIndexes(s []byte, word []byte) (idxs []int)

WordIndexes returns the index of the all instance of word in s as long as word is separated by space or at the beginning or end of s.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	text := []byte("moo moomoo moo")

	fmt.Println(libbytes.WordIndexes(text, []byte("mo")))
	fmt.Println(libbytes.WordIndexes(text, []byte("moo")))
	fmt.Println(libbytes.WordIndexes(text, []byte("mooo")))
}

Output:

[]
[0 11]
[]

func WriteUint16 

func WriteUint16(data []byte, x uint, v uint16)

WriteUint16 write uint16 value "v" into "data" start at position "x". If x is out range, the data will not change.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	data := []byte("Hello, world!")

	var v uint16

	v = 'h' << 8
	v |= 'E'

	libbytes.WriteUint16(data, uint(len(data)-1), v) // Index out of range
	fmt.Println(string(data))

	libbytes.WriteUint16(data, 0, v)
	fmt.Println(string(data))
}

Output:

Hello, world!
hEllo, world!

func WriteUint32 

func WriteUint32(data []byte, x uint, v uint32)

WriteUint32 write uint32 value into "data" start at position "x". If x is out range, the data will not change.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	data := []byte("Hello, world!")

	var v uint32

	v = 'h' << 24
	v |= 'E' << 16
	v |= 'L' << 8
	v |= 'L'

	libbytes.WriteUint32(data, uint(len(data)-1), v) // Index out of range
	fmt.Println(string(data))

	libbytes.WriteUint32(data, 0, v)
	fmt.Println(string(data))

	libbytes.WriteUint32(data, 7, v)
	fmt.Println(string(data))
}

Output:

Hello, world!
hELLo, world!
hELLo, hELLd!

Types

type Parser 

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

Parser implement tokenize parser for stream of byte using one or more delimiters as separator between token.

func NewParser 

func NewParser(content, delims []byte) (bp *Parser)

NewParser create new Parser to parse content using delims as initial delimiters.

func (*Parser) AddDelimiters 

func (bp *Parser) AddDelimiters(delims []byte)

AddDelimiters add another delimiters to the current parser.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte(` a = b ; c = d `)
		delims  = []byte(`=`)
		parser  = libbytes.NewParser(content, delims)
	)

	token, d := parser.ReadNoSpace()
	fmt.Printf("%s:%c\n", token, d)

	parser.AddDelimiters([]byte{';'})
	token, d = parser.ReadNoSpace()
	fmt.Printf("%s:%c\n", token, d)

}

Output:

a:=
b:;

func (*Parser) Delimiters 

func (bp *Parser) Delimiters() []byte

Delimiters return the copy of current delimiters.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte(`a=b;c=d;`)
		delims  = []byte{'=', ';'}
		parser  = libbytes.NewParser(content, delims)
	)

	fmt.Printf("%s\n", parser.Delimiters())
}

Output:

=;

func (*Parser) Read 

func (bp *Parser) Read() (token []byte, d byte)

Read read a token until one of the delimiters found. If one of delimiter match, it will return it as d. When end of content encountered, the returned token may be not empty but the d will be zero.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte("a = b; ")
		delims  = []byte{'=', ';'}
		parser  = libbytes.NewParser(content, delims)
	)

	token, c := parser.Read()
	fmt.Printf("token:'%s' c:%q\n", token, c)
	token, c = parser.Read()
	fmt.Printf("token:'%s' c:%q\n", token, c)
	token, c = parser.Read()
	fmt.Printf("token:'%s' c:%q\n", token, c)

}

Output:

token:'a ' c:'='
token:' b' c:';'
token:' ' c:'\x00'

func (*Parser) ReadLine 

func (bp *Parser) ReadLine() (line []byte, c byte)

ReadLine read until it found new line ('\n') or end of content, ignoring all delimiters. The returned line will not contain '\n'.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte("a=b;\nc=d;")
		delims  = []byte{'=', ';'}
		parser  = libbytes.NewParser(content, delims)
	)

	token, c := parser.ReadLine()
	fmt.Printf("token:%s c:%q\n", token, c)

	token, c = parser.ReadLine()
	fmt.Printf("token:%s c:%q\n", token, c)

}

Output:

token:a=b; c:'\n'
token:c=d; c:'\x00'

func (*Parser) ReadN 

func (bp *Parser) ReadN(n int) (token []byte, d byte)

ReadN read exactly n characters ignoring the delimiters. It will return the token and the character after n or 0 if end-of-content.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte(`a=b;c=d;`)
		delims  = []byte{'=', ';'}
		parser  = libbytes.NewParser(content, delims)
	)

	token, c := parser.ReadN(2)
	fmt.Printf("token:%s c:%q\n", token, c)

	token, c = parser.ReadN(0)
	fmt.Printf("token:%s c:%q\n", token, c)

	token, c = parser.ReadN(10)
	fmt.Printf("token:%s c:%q\n", token, c)
}

Output:

token:a= c:'b'
token: c:'b'
token:b;c=d; c:'\x00'

func (*Parser) ReadNoSpace 

func (bp *Parser) ReadNoSpace() (token []byte, d byte)

ReadNoSpace read the next token by ignoring the leading spaces, even if its one of the delimiter. The returned token will have no trailing spaces.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte(` a = b ;`)
		delims  = []byte(`=;`)
		parser  = libbytes.NewParser(content, delims)
	)

	for {
		token, d := parser.ReadNoSpace()
		fmt.Printf("%s:%q\n", token, d)
		if d == 0 {
			break
		}
	}
}

Output:

a:'='
b:';'
:'\x00'

func (*Parser) Remaining 

func (bp *Parser) Remaining() []byte

Remaining return the copy of un-parsed content.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte(` a = b ;`)
		delims  = []byte(`=;`)
		parser  = libbytes.NewParser(content, delims)
	)

	token, d := parser.ReadNoSpace()
	remain := parser.Remaining()
	fmt.Printf("token:%s d:%c remain:%s\n", token, d, remain)
}

Output:

token:a d:= remain: b ;

func (*Parser) RemoveDelimiters 

func (bp *Parser) RemoveDelimiters(delims []byte)

RemoveDelimiters remove delimiters delims from current delimiters.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte(` a = b ; c = d `)
		delims  = []byte(`=;`)
		parser  = libbytes.NewParser(content, delims)
	)

	token, _ := parser.ReadNoSpace()
	fmt.Printf("%s\n", token)

	parser.RemoveDelimiters([]byte{';'})
	token, _ = parser.ReadNoSpace()
	fmt.Printf("%s\n", token)

}

Output:

a
b ; c

func (*Parser) Reset 

func (bp *Parser) Reset(content, delims []byte)

Reset the Parser by setting all internal state to new content and delimiters.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte(`a.b.c;`)
		delims  = []byte(`.`)
		parser  = libbytes.NewParser(content, delims)
	)

	parser.Read()
	parser.Reset(content, delims)
	remain, pos := parser.Stop()
	fmt.Printf("remain:%s pos:%d\n", remain, pos)
}

Output:

remain:a.b.c; pos:0

func (*Parser) SetDelimiters 

func (bp *Parser) SetDelimiters(delims []byte)

SetDelimiters replace the current delimiters with delims.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte(`a.b.c;`)
		delims  = []byte(`.`)
		parser  = libbytes.NewParser(content, delims)
		token   []byte
	)

	token, _ = parser.Read()
	fmt.Println(string(token))

	parser.SetDelimiters([]byte(`;`))

	token, _ = parser.Read()
	fmt.Println(string(token))

}

Output:

a
b.c

func (*Parser) Skip 

func (bp *Parser) Skip() (c byte)

Skip skip parsing token until one of the delimiters found or end-of-content.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte(`a = b; c = d;`)
		delims  = []byte{'=', ';'}
		parser  = libbytes.NewParser(content, delims)
		token   []byte
	)

	parser.Skip()
	token, _ = parser.ReadNoSpace()
	fmt.Println(string(token))

	parser.Skip()
	token, _ = parser.ReadNoSpace()
	fmt.Println(string(token))

	parser.Skip()
	token, _ = parser.ReadNoSpace()
	fmt.Println(string(token))

}

Output:

b
d

func (*Parser) SkipHorizontalSpaces 

func (bp *Parser) SkipHorizontalSpaces() (n int, c byte)

SkipHorizontalSpaces skip space (" "), tab ("\t"), carriage return ("\r"), and form feed ("\f") characters; and return the number of space skipped and first non-space character or 0 if it reach end-of-content.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte(" \t\r\fA. \nB.")
		delims  = []byte{'.'}
		parser  = libbytes.NewParser(content, delims)
		n       int
	)

	n, _ = parser.SkipHorizontalSpaces()
	token, d := parser.Read()
	fmt.Printf("n:%d token:%s delim:%q\n", n, token, d)

	n, _ = parser.SkipHorizontalSpaces()
	token, d = parser.Read() // The token include \n.
	fmt.Printf("n:%d token:%s delim:%q\n", n, token, d)

	n, _ = parser.SkipHorizontalSpaces()
	token, d = parser.Read() // The token include \n.
	fmt.Printf("n:%d token:%s delim:%q\n", n, token, d)

}

Output:

n:4 token:A delim:'.'
n:1 token:
B delim:'.'
n:0 token: delim:'\x00'

func (*Parser) SkipLine 

func (bp *Parser) SkipLine() (c byte)

SkipLine skip all characters until new line. It will return 0 if EOF.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte("a\nb\nc\nd e\n")
		delims  = []byte("\n")
		parser  = libbytes.NewParser(content, delims)
	)

	parser.SkipLine()
	token, _ := parser.Read()
	fmt.Printf("token:'%s'\n", token)

	parser.SkipLine()
	token, _ = parser.Read()
	fmt.Printf("token:'%s'\n", token)
}

Output:

token:'b'
token:'d e'

func (*Parser) SkipN 

func (bp *Parser) SkipN(n int) (c byte)

SkipN skip exactly N characters ignoring delimiters. It will return the next character after N or 0 if it reach end-of-content.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte(`a=b;c=d;`)
		delims  = []byte{'=', ';'}
		parser  = libbytes.NewParser(content, delims)
		token   []byte
		c       byte
	)

	c = parser.SkipN(2)
	fmt.Printf("Skip: %c\n", c)
	token, _ = parser.ReadNoSpace()
	fmt.Println(string(token))

	c = parser.SkipN(2)
	fmt.Printf("Skip: %c\n", c)
	token, _ = parser.ReadNoSpace()
	fmt.Println(string(token))

	_ = parser.SkipN(2)
	token, _ = parser.ReadNoSpace()
	fmt.Println(string(token))

}

Output:

Skip: b
b
Skip: d
d

func (*Parser) SkipSpaces 

func (bp *Parser) SkipSpaces() (n int, c byte)

SkipSpaces skip all spaces character (' ', '\f', '\n', '\r', '\t') and return the number of spaces skipped and first non-space character or 0 if it reach end-of-content.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte(" \t\r\fA. \nB.")
		delims  = []byte{'.'}
		parser  = libbytes.NewParser(content, delims)
		n       int
	)

	n, _ = parser.SkipSpaces()
	token, d := parser.Read()
	fmt.Printf("n:%d token:%s delim:%q\n", n, token, d)

	n, _ = parser.SkipSpaces()
	token, d = parser.Read() // The token include \n.
	fmt.Printf("n:%d token:%s delim:%q\n", n, token, d)

	n, _ = parser.SkipSpaces()
	token, d = parser.Read() // The token include \n.
	fmt.Printf("n:%d token:%s delim:%q\n", n, token, d)

}

Output:

n:4 token:A delim:'.'
n:2 token:B delim:'.'
n:0 token: delim:'\x00'

func (*Parser) Stop 

func (bp *Parser) Stop() (remain []byte, pos int)

Stop the parser, return the remaining unparsed content and its last position, and then call Reset to reset the internal state back to zero.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		content = []byte(`a.b.c;`)
		delims  = []byte(`.`)
		parser  = libbytes.NewParser(content, delims)

		remain []byte
		pos    int
	)

	parser.Read()
	remain, pos = parser.Stop()
	fmt.Printf("remain:%s pos:%d\n", remain, pos)

	parser.Reset(content, []byte(`;`))
	parser.Read()
	remain, pos = parser.Stop()
	fmt.Printf("remain:%s pos:%d\n", remain, pos)

}

Output:

remain:b.c; pos:2
remain: pos:6

func (*Parser) UnreadN 

func (bp *Parser) UnreadN(n int) byte

UnreadN unread N characters and return the character its pointed to. If N greater than current position index, it will reset the read pointer index back to zero.

Example 
package main

import (
	"fmt"

	libbytes "git.sr.ht/~shulhan/pakakeh.go/lib/bytes"
)

func main() {
	var (
		parser = libbytes.NewParser([]byte(`a,b.c/d`), []byte(`,./`))
		token  []byte
		c      byte
	)

	parser.Read()
	parser.Read()
	parser.Read()
	parser.Read() // All content should be readed now.

	c = parser.UnreadN(2) // Move the index to '/'.
	fmt.Printf("UnreadN(2): %c\n", c)

	token, c = parser.Read()
	fmt.Printf("Read: %s %c\n", token, c)

	// Position 99 greater than current index, this will reset index to 0.
	c = parser.UnreadN(99)
	fmt.Printf("UnreadN(99): %c\n", c)

	token, c = parser.Read()
	fmt.Printf("Read: %s %c\n", token, c)

}

Output:

UnreadN(2): /
Read:  /
UnreadN(99): a
Read: a ,

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