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buffers.Writer

master
Charles Iliya Krempeaux 2019-09-05 18:32:21 -07:00
parent df322d81e8
commit 711b415c61
2 changed files with 961 additions and 0 deletions
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33
writer.go 100644
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@ -0,0 +1,33 @@
package buffers
type Writer struct {
dst []byte
index int
}
func NewWriter(dst []byte) Writer {
return Writer{
dst:dst,
}
}
func (receiver *Writer) Write(src []byte) (n int, err error) {
if nil == receiver {
return 0, errNilReceiver
}
dst := receiver.dst
if nil == dst {
return 0, errNilDestination
}
dst = dst[receiver.index:]
if expectedAtLeast, actual := len(src), len(dst); actual < expectedAtLeast {
return 0, errTooShort(uint64(expectedAtLeast), uint64(actual))
}
n = copy(dst, src)
receiver.index += n
return n, err
}

928
writer_test.go 100644
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package buffers_test
import (
"github.com/reiver/go-buffers"
"reflect"
"testing"
)
func TestWriterSingleWrite(t *testing.T) {
tests := []struct {
BufferLength int
Src []byte
Expected []byte
}{
{
BufferLength: 0,
Src: []byte("apple"),
Expected: []byte{},
},
{
BufferLength: 1,
Src: []byte("apple"),
Expected: []byte{},
},
{
BufferLength: 2,
Src: []byte("apple"),
Expected: []byte{},
},
{
BufferLength: 3,
Src: []byte("apple"),
Expected: []byte{},
},
{
BufferLength: 4,
Src: []byte("apple"),
Expected: []byte{},
},
{
BufferLength: 5,
Src: []byte("apple"),
Expected: []byte("apple"),
},
{
BufferLength: 6,
Src: []byte("apple"),
Expected: []byte("apple"),
},
{
BufferLength: 7,
Src: []byte("apple"),
Expected: []byte("apple"),
},
{
BufferLength: 8,
Src: []byte("apple"),
Expected: []byte("apple"),
},
{
BufferLength: 9,
Src: []byte("apple"),
Expected: []byte("apple"),
},
{
BufferLength: 10,
Src: []byte("apple"),
Expected: []byte("apple"),
},
{
BufferLength: 0,
Src: []byte("apple BANANA"),
Expected: []byte{},
},
{
BufferLength: 1,
Src: []byte("apple BANANA"),
Expected: []byte{},
},
{
BufferLength: 2,
Src: []byte("apple BANANA"),
Expected: []byte{},
},
{
BufferLength: 3,
Src: []byte("apple BANANA"),
Expected: []byte{},
},
{
BufferLength: 4,
Src: []byte("apple BANANA"),
Expected: []byte{},
},
{
BufferLength: 5,
Src: []byte("apple BANANA"),
Expected: []byte{},
},
{
BufferLength: 6,
Src: []byte("apple BANANA"),
Expected: []byte{},
},
{
BufferLength: 7,
Src: []byte("apple BANANA"),
Expected: []byte{},
},
{
BufferLength: 8,
Src: []byte("apple BANANA"),
Expected: []byte{},
},
{
BufferLength: 9,
Src: []byte("apple BANANA"),
Expected: []byte{},
},
{
BufferLength: 10,
Src: []byte("apple BANANA"),
Expected: []byte{},
},
{
BufferLength: 11,
Src: []byte("apple BANANA"),
Expected: []byte{},
},
{
BufferLength: 12,
Src: []byte("apple BANANA"),
Expected: []byte("apple BANANA"),
},
{
BufferLength: 13,
Src: []byte("apple BANANA"),
Expected: []byte("apple BANANA"),
},
{
BufferLength: 14,
Src: []byte("apple BANANA"),
Expected: []byte("apple BANANA"),
},
{
BufferLength: 15,
Src: []byte("apple BANANA"),
Expected: []byte("apple BANANA"),
},
{
BufferLength: 16,
Src: []byte("apple BANANA"),
Expected: []byte("apple BANANA"),
},
{
BufferLength: 17,
Src: []byte("apple BANANA"),
Expected: []byte("apple BANANA"),
},
{
BufferLength: 18,
Src: []byte("apple BANANA"),
Expected: []byte("apple BANANA"),
},
{
BufferLength: 19,
Src: []byte("apple BANANA"),
Expected: []byte("apple BANANA"),
},
{
BufferLength: 20,
Src: []byte("apple BANANA"),
Expected: []byte("apple BANANA"),
},
{
BufferLength: 0,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 1,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 2,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 3,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 4,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 5,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 6,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 7,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 8,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 9,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 10,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 11,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 12,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 13,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 14,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 15,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 16,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 17,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 18,
Src: []byte("apple BANANA Cherry"),
Expected: []byte{},
},
{
BufferLength: 19,
Src: []byte("apple BANANA Cherry"),
Expected: []byte("apple BANANA Cherry"),
},
{
BufferLength: 20,
Src: []byte("apple BANANA Cherry"),
Expected: []byte("apple BANANA Cherry"),
},
}
for testNumber, test := range tests {
var buffer []byte = make([]byte, test.BufferLength)
var dst buffers.Writer = buffers.NewWriter(buffer)
n, err := dst.Write(test.Src)
if _, casted := err.(buffers.TooShort); !casted {
if nil != err {
t.Errorf("For test #%d, did not expect an error, but actually got one.", testNumber)
t.Logf("SRC: %q", test.Src)
t.Logf("DST: %q (full)", buffer)
t.Logf("DST EXPECTED: %q", test.Expected)
t.Logf("ERROR TYPE: %T", err)
t.Logf("ERROR: %q", err)
continue
}
}
var expectedWritten int
{
lenBuffer := len(buffer)
lenSrc := len(test.Src)
if lenBuffer < lenSrc {
expectedWritten = lenBuffer
} else {
expectedWritten = lenSrc
}
if _, casted := err.(buffers.TooShort); casted {
expectedWritten = 0
}
}
if expected, actual := expectedWritten, n; expected != actual {
t.Errorf("For test #%d, the actual number of bytes written was not what was expected.", testNumber)
t.Logf("SRC: %q", test.Src)
t.Logf("DST: %q (full)", buffer)
t.Logf("DST: %q", buffer[n:])
t.Logf("DST EXPECTED: %q", test.Expected)
t.Logf("EXPECTED: %d", expected)
t.Logf("ACTUAL: %d", actual)
continue
}
if expected, actual := test.Expected, buffer[:n]; !reflect.DeepEqual(expected, actual) {
t.Errorf("For test #%d, what was written is not what was expected.", testNumber)
t.Logf("SRC: %q", test.Src)
t.Logf("DST: %q (full)", buffer)
t.Logf("DST: %q", buffer[n:])
t.Logf("DST EXPECTED: %q", test.Expected)
t.Logf("EXPECTED: %q", expected,)
t.Logf("ACTUAL: %q", actual)
continue
}
}
}
func TestWriterMultipleWrites(t *testing.T) {
tests := []struct {
BufferLength int
Srces [][]byte
Expected []byte
}{
{
BufferLength: 0,
Srces: [][]byte{
[]byte("a"),
[]byte("p"),
[]byte("p"),
[]byte("l"),
[]byte("e"),
},
Expected: []byte{},
},
{
BufferLength: 1,
Srces: [][]byte{
[]byte("a"),
[]byte("p"),
[]byte("p"),
[]byte("l"),
[]byte("e"),
},
Expected: []byte("a"),
},
{
BufferLength: 2,
Srces: [][]byte{
[]byte("a"),
[]byte("p"),
[]byte("p"),
[]byte("l"),
[]byte("e"),
},
Expected: []byte("ap"),
},
{
BufferLength: 3,
Srces: [][]byte{
[]byte("a"),
[]byte("p"),
[]byte("p"),
[]byte("l"),
[]byte("e"),
},
Expected: []byte("app"),
},
{
BufferLength: 4,
Srces: [][]byte{
[]byte("a"),
[]byte("p"),
[]byte("p"),
[]byte("l"),
[]byte("e"),
},
Expected: []byte("appl"),
},
{
BufferLength: 5,
Srces: [][]byte{
[]byte("a"),
[]byte("p"),
[]byte("p"),
[]byte("l"),
[]byte("e"),
},
Expected: []byte("apple"),
},
{
BufferLength: 6,
Srces: [][]byte{
[]byte("a"),
[]byte("p"),
[]byte("p"),
[]byte("l"),
[]byte("e"),
},
Expected: []byte("apple"),
},
{
BufferLength: 7,
Srces: [][]byte{
[]byte("a"),
[]byte("p"),
[]byte("p"),
[]byte("l"),
[]byte("e"),
},
Expected: []byte("apple"),
},
{
BufferLength: 8,
Srces: [][]byte{
[]byte("a"),
[]byte("p"),
[]byte("p"),
[]byte("l"),
[]byte("e"),
},
Expected: []byte("apple"),
},
{
BufferLength: 9,
Srces: [][]byte{
[]byte("a"),
[]byte("p"),
[]byte("p"),
[]byte("l"),
[]byte("e"),
},
Expected: []byte("apple"),
},
{
BufferLength: 10,
Srces: [][]byte{
[]byte("a"),
[]byte("p"),
[]byte("p"),
[]byte("l"),
[]byte("e"),
},
Expected: []byte("apple"),
},
{
BufferLength: 0,
Srces: [][]byte{
[]byte("BA"),
[]byte("NA"),
[]byte("N"),
[]byte("A"),
},
Expected: []byte{},
},
{
BufferLength: 1,
Srces: [][]byte{
[]byte("BA"),
[]byte("NA"),
[]byte("N"),
[]byte("A"),
},
Expected: []byte{},
},
{
BufferLength: 2,
Srces: [][]byte{
[]byte("BA"),
[]byte("NA"),
[]byte("N"),
[]byte("A"),
},
Expected: []byte("BA"),
},
{
BufferLength: 3,
Srces: [][]byte{
[]byte("BA"),
[]byte("NA"),
[]byte("N"),
[]byte("A"),
},
Expected: []byte("BA"),
},
{
BufferLength: 4,
Srces: [][]byte{
[]byte("BA"),
[]byte("NA"),
[]byte("N"),
[]byte("A"),
},
Expected: []byte("BANA"),
},
{
BufferLength: 5,
Srces: [][]byte{
[]byte("BA"),
[]byte("NA"),
[]byte("N"),
[]byte("A"),
},
Expected: []byte("BANAN"),
},
{
BufferLength: 6,
Srces: [][]byte{
[]byte("BA"),
[]byte("NA"),
[]byte("N"),
[]byte("A"),
},
Expected: []byte("BANANA"),
},
{
BufferLength: 7,
Srces: [][]byte{
[]byte("BA"),
[]byte("NA"),
[]byte("N"),
[]byte("A"),
},
Expected: []byte("BANANA"),
},
{
BufferLength: 8,
Srces: [][]byte{
[]byte("BA"),
[]byte("NA"),
[]byte("N"),
[]byte("A"),
},
Expected: []byte("BANANA"),
},
{
BufferLength: 9,
Srces: [][]byte{
[]byte("BA"),
[]byte("NA"),
[]byte("N"),
[]byte("A"),
},
Expected: []byte("BANANA"),
},
{
BufferLength: 10,
Srces: [][]byte{
[]byte("BA"),
[]byte("NA"),
[]byte("N"),
[]byte("A"),
},
Expected: []byte("BANANA"),
},
{
BufferLength: 0,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte{},
},
{
BufferLength: 1,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte{},
},
{
BufferLength: 2,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte{},
},
{
BufferLength: 3,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte{},
},
{
BufferLength: 4,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte{},
},
{
BufferLength: 5,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte{},
},
{
BufferLength: 6,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple "),
},
{
BufferLength: 7,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple "),
},
{
BufferLength: 8,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple "),
},
{
BufferLength: 9,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple "),
},
{
BufferLength: 10,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple "),
},
{
BufferLength: 11,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple "),
},
{
BufferLength: 12,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple BANANA"),
},
{
BufferLength: 13,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple BANANA "),
},
{
BufferLength: 14,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple BANANA "),
},
{
BufferLength: 15,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple BANANA "),
},
{
BufferLength: 16,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple BANANA "),
},
{
BufferLength: 17,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple BANANA "),
},
{
BufferLength: 18,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple BANANA "),
},
{
BufferLength: 19,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple BANANA Cherry"),
},
{
BufferLength: 20,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple BANANA Cherry"),
},
{
BufferLength: 21,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple BANANA Cherry"),
},
{
BufferLength: 22,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple BANANA Cherry"),
},
{
BufferLength: 23,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple BANANA Cherry"),
},
{
BufferLength: 24,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple BANANA Cherry"),
},
{
BufferLength: 25,
Srces: [][]byte{
[]byte("apple "),
[]byte("BANANA"),
[]byte(" "),
[]byte("Cherry"),
},
Expected: []byte("apple BANANA Cherry"),
},
}
TestLoop: for testNumber, test := range tests {
var buffer []byte = make([]byte, test.BufferLength)
var dst buffers.Writer = buffers.NewWriter(buffer)
var sum int
InnerLoop: for srcNumber, src := range test.Srces {
n, err := dst.Write(src)
if _, casted := err.(buffers.TooShort); casted {
break InnerLoop
}
if nil != err {
t.Errorf("For test #%d and src #%d, did not expect an error, but actually got one.", testNumber, srcNumber)
t.Logf("BUFFER LENGTH: %d", test.BufferLength)
for i, s := range test.Srces {
t.Logf("SRC[%d]: %q", i, s)
}
t.Logf("SRC: %q", src)
t.Logf("DST: %q (full)", buffer)
t.Logf("DST EXPECTED: %q", test.Expected)
t.Logf("ERROR TYPE: %T", err)
t.Logf("ERROR: %q", err)
continue TestLoop
}
var expectedWritten int
{
lenBuffer := len(buffer)
lenSrc := len(src)
if lenBuffer-sum < lenSrc {
expectedWritten = lenBuffer-sum
} else {
expectedWritten = lenSrc
}
}
if expected, actual := expectedWritten, n; expected != actual {
t.Errorf("For test #%d and src #%d, the actual number of bytes written was not what was expected.", testNumber, srcNumber)
t.Logf("BUFFER LENGTH: %d", test.BufferLength)
for i, s := range test.Srces {
t.Logf("SRC[%d]: %q", i, s)
}
t.Logf("SRC: %q", src)
t.Logf("DST: %q (full)", buffer)
t.Logf("DST: %q", buffer[n:])
t.Logf("DST EXPECTED: %q", test.Expected)
t.Logf("EXPECTED: %d", expected)
t.Logf("ACTUAL: %d", actual)
continue TestLoop
}
sum += n
}
if expected, actual := test.Expected, buffer[:sum]; !reflect.DeepEqual(expected, actual) {
t.Errorf("For test #%d, what was written is not what was expected.", testNumber)
t.Logf("BUFFER LENGTH: %d", test.BufferLength)
for i, s := range test.Srces {
t.Logf("SRC[%d]: %q", i, s)
}
t.Logf("DST: %q (full)", buffer)
t.Logf("DST: %q", buffer[sum:])
t.Logf("DST EXPECTED: %q", test.Expected)
t.Logf("EXPECTED: %q", expected,)
t.Logf("ACTUAL: %q", actual)
continue TestLoop
}
}
}