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added CountVarUint64, CountVarUint32, CountVarSize

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This commit is contained in:
dima
2025-11-01 16:16:20 +00:00
parent 142699e328
commit 7fa2d0f292
2 changed files with 151 additions and 15 deletions
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74
little/little.go
View File

@@ -996,6 +996,24 @@ func ReadVarUint64(src io.Reader) (num uint64, err error) {
return
}
func WriteBool(w io.Writer, flag bool) (err error) {
var b byte
if flag {
b = 1
}
_, err = w.Write([]byte{b})
return
}
func ReadBool(src io.Reader) (bool, error) {
b, err := ReadByte(src)
if err != nil {
return false, err
}
return b == 1, nil
}
// uint64
func WriteVarSize(w io.Writer, n int) (int, error) {
num := uint64(n)
a := make([]byte, 9)
@@ -1013,15 +1031,6 @@ func WriteVarSize(w io.Writer, n int) (int, error) {
return w.Write(a)
}
func WriteBool(w io.Writer, flag bool) (err error) {
var b byte
if flag {
b = 1
}
_, err = w.Write([]byte{b})
return
}
func ReadVarSize(src io.Reader) (_ int, err error) {
var (
b byte
@@ -1047,10 +1056,47 @@ func ReadVarSize(src io.Reader) (_ int, err error) {
return int(num), nil
}
func ReadBool(src io.Reader) (bool, error) {
b, err := ReadByte(src)
if err != nil {
return false, err
var varUint32Cutoffs = []uint32{
1 << 7,
1 << 14,
1 << 21,
1 << 28,
}
return b == 1, nil
func CountVarUint32(n uint32) int {
for i, cutoff := range varUint32Cutoffs {
if n < cutoff {
return i + 1
}
}
return 5
}
var varUint64Cutoffs = []uint64{
1 << 7,
1 << 14,
1 << 21,
1 << 28,
1 << 35,
1 << 42,
1 << 49,
1 << 56,
}
func CountVarUint64(n uint64) int {
for i, cutoff := range varUint64Cutoffs {
if n < cutoff {
return i + 1
}
}
return 9
}
func CountVarSize(n int) int {
u64 := uint64(n)
for i, cutoff := range varUint64Cutoffs {
if u64 < cutoff {
return i + 1
}
}
return 9
}

90
little/little_test.go
View File

@@ -703,6 +703,96 @@ func TestWriteReadBool(t *testing.T) {
}
}
// VAR SIZE COUNT
func TestCountVarUint32(t *testing.T) {
var testCases = []struct {
Num uint32
Count int
}{
{Num: (1 << 7) - 1, Count: 1},
{Num: (1 << 7), Count: 2},
{Num: (1 << 14) - 1, Count: 2},
{Num: (1 << 14), Count: 3},
{Num: (1 << 21) - 1, Count: 3},
{Num: (1 << 21), Count: 4},
{Num: (1 << 28) - 1, Count: 4},
{Num: (1 << 28), Count: 5},
{Num: (1 << 32) - 1, Count: 5},
}
for _, testCase := range testCases {
count := CountVarUint32(testCase.Num)
if count != testCase.Count {
t.Fatalf("calculated count %d is not equal %d for num %d\n",
count, testCase.Count, testCase.Num)
}
}
}
func TestCountVarUint64(t *testing.T) {
var testCases = []struct {
Num uint64
Count int
}{
{Num: (1 << 7) - 1, Count: 1},
{Num: (1 << 7), Count: 2},
{Num: (1 << 14) - 1, Count: 2},
{Num: (1 << 14), Count: 3},
{Num: (1 << 21) - 1, Count: 3},
{Num: (1 << 21), Count: 4},
{Num: (1 << 28) - 1, Count: 4},
{Num: (1 << 28), Count: 5},
{Num: (1 << 35) - 1, Count: 5},
{Num: (1 << 35), Count: 6},
{Num: (1 << 42) - 1, Count: 6},
{Num: (1 << 42), Count: 7},
{Num: (1 << 49) - 1, Count: 7},
{Num: (1 << 49), Count: 8},
{Num: (1 << 56) - 1, Count: 8},
{Num: (1 << 56), Count: 9},
{Num: (1 << 64) - 1, Count: 9},
}
for _, testCase := range testCases {
count := CountVarUint64(testCase.Num)
if count != testCase.Count {
t.Fatalf("calculated count %d is not equal %d for num %d\n",
count, testCase.Count, testCase.Num)
}
}
}
func TestCountVarSize(t *testing.T) {
var testCases = []struct {
Num int
Count int
}{
{Num: (1 << 7) - 1, Count: 1},
{Num: (1 << 7), Count: 2},
{Num: (1 << 14) - 1, Count: 2},
{Num: (1 << 14), Count: 3},
{Num: (1 << 21) - 1, Count: 3},
{Num: (1 << 21), Count: 4},
{Num: (1 << 28) - 1, Count: 4},
{Num: (1 << 28), Count: 5},
{Num: (1 << 35) - 1, Count: 5},
{Num: (1 << 35), Count: 6},
{Num: (1 << 42) - 1, Count: 6},
{Num: (1 << 42), Count: 7},
{Num: (1 << 49) - 1, Count: 7},
{Num: (1 << 49), Count: 8},
{Num: (1 << 56) - 1, Count: 8},
{Num: (1 << 56), Count: 9},
{Num: (1 << 63) - 1, Count: 9},
}
for _, testCase := range testCases {
count := CountVarSize(testCase.Num)
if count != testCase.Count {
t.Fatalf("calculated count %d is not equal %d for num %d\n",
count, testCase.Count, testCase.Num)
}
}
}
// HELPERS
const letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"