Created

spreedsheetx/column.go

@@ -0,0 +1,192 @@
+package spreedsheetx
+
+import (
+	"errors"
+	"fmt"
+	"math"
+	"regexp"
+	"strings"
+)
+
+// https://support.microsoft.com/en-us/office/excel-specifications-and-limits-1672b34d-7043-467e-8e27-269d656771c3?ui=en-us&rs=en-us&ad=us
+// Max index is 16384 XFD
+
+var (
+	rxColumnName = regexp.MustCompile("^[A-Za-z]{1,3}$")
+)
+
+const (
+	minNumber = 1
+	maxNumber = 16384
+	a         = 64
+)
+
+type Column struct {
+	startName string // 最开始操作的列
+	endName   string // 最远到达的列
+	current   string // 当前列
+}
+
+func isValidName(name string) bool {
+	return rxColumnName.MatchString(name) && toNumber(name) <= maxNumber
+}
+
+func reverse(name string) []rune {
+	d := []rune(name)
+	for i, j := 0, len(d)-1; i < j; i, j = i+1, j-1 {
+		d[i], d[j] = d[j], d[i]
+	}
+	return d
+}
+
+func toNumber(name string) int {
+	name = strings.ToUpper(name)
+	switch len(name) {
+	case 0:
+		return 0
+	case 1:
+		return int(rune(name[0])) - a
+	default:
+		number := 0
+		for i, r := range reverse(name) {
+			if i == 0 {
+				number += int(r) - a
+			} else {
+				number += (int(r) - a) * int(math.Pow(26, float64(i)))
+			}
+		}
+		return number
+	}
+}
+
+func NewColumn(name string) *Column {
+	name = strings.ToUpper(name)
+	if !isValidName(name) {
+		panic("invalid column name")
+	}
+
+	return &Column{
+		startName: name,
+		endName:   name,
+		current:   name,
+	}
+}
+
+// ToFirst 到第一列，总是返回 A 列
+func (c *Column) ToFirst() *Column {
+	c.current = "A"
+	return c
+}
+
+// Next 当前列的下一列
+func (c *Column) Next() (*Column, error) {
+	return c.RightShift(1)
+}
+
+func (c *Column) Prev() (*Column, error) {
+	return c.LeftShift(1)
+}
+
+// StartName 返回最开始的列名
+func (c Column) StartName() string {
+	return c.startName
+}
+
+func (c *Column) setEndName(name string) *Column {
+	if c.endName < name || len(c.endName) < len(name) {
+		c.endName = name
+	}
+	return c
+}
+
+// EndName 返回最远到达的列名
+func (c Column) EndName() string {
+	return c.endName
+}
+
+// Name 当前列名
+func (c Column) Name() string {
+	return c.current
+}
+
+// NameWithRow 带行号的列名，比如：A1
+func (c Column) NameWithRow(row int) string {
+	return fmt.Sprintf("%s%d", c.current, row)
+}
+
+// Reset 重置到最开始的列（NewColumn 创建时的列）
+func (c *Column) Reset() *Column {
+	c.current = c.startName
+	c.endName = c.startName
+	return c
+}
+
+// To 跳转到指定的列
+func (c *Column) To(name string) (*Column, error) {
+	name = strings.ToUpper(name)
+	if !isValidName(name) {
+		return c, fmt.Errorf("invalid column name %s", name)
+	}
+	c.current = name
+	c.setEndName(name)
+	return c, nil
+}
+
+func (c *Column) RightShift(steps int) (*Column, error) {
+	if steps <= 0 {
+		return c, nil
+	}
+	return c.shift(steps)
+}
+
+func (c *Column) LeftShift(steps int) (*Column, error) {
+	if steps <= 0 {
+		return c, nil
+	}
+	return c.shift(-steps)
+}
+
+// RightShift 基于当前位置右移多少列
+func (c *Column) shift(steps int) (*Column, error) {
+	if steps == 0 {
+		return c, nil
+	}
+
+	number := toNumber(c.current)
+	number += steps
+	if number > maxNumber {
+		return c, errors.New("out of max columns")
+	} else if number < minNumber {
+		return c, errors.New("out of min columns")
+	}
+
+	sb := strings.Builder{}
+	sb.Grow(3) // Max 3 letters
+	times := 0
+	for {
+		times++
+		quotient := number / 26
+		remainder := number % 26
+		if remainder == 0 {
+			sb.WriteRune('Z')
+		} else {
+			sb.WriteRune(rune(a + remainder))
+		}
+		if quotient == 0 {
+			break
+		} else if quotient <= 26 {
+			if quotient != 1 || (times >= 1 && remainder != 0) {
+				sb.WriteRune(rune(a + quotient))
+			}
+			break
+		}
+		number = quotient
+	}
+
+	c.current = string(reverse(sb.String()))
+	if steps > 0 {
+		// Is right shift
+		c.setEndName(c.current)
+	}
+	return c, nil
+}

spreedsheetx/column_test.go

@@ -0,0 +1,88 @@
+package spreedsheetx
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestNewColumn(t *testing.T) {
+	column := NewColumn("A")
+	assert.Equal(t, "A", column.Name())
+	column.Next()
+	assert.Equal(t, "B", column.Name())
+	column.RightShift(2)
+	assert.Equal(t, "D", column.Name())
+	column.To("F")
+	assert.Equal(t, "F", column.Name())
+	column.Next()
+	assert.Equal(t, "G", column.Name())
+	_, err := column.To("ZZZ")
+	assert.Equal(t, true, err != nil, "err")
+}
+
+func TestNewColumn2(t *testing.T) {
+	column := NewColumn("A")
+	column.To("ZZ")
+	assert.Equal(t, "ZZ", column.Name())
+	column.RightShift(2)
+	assert.Equal(t, "AAB", column.Name())
+}
+
+func TestNewColumn3(t *testing.T) {
+	column := NewColumn("ABC")
+	assert.Equal(t, "ABC", column.Name())
+	column.RightShift(2)
+	assert.Equal(t, "ABE", column.Name())
+	column.RightShift(53)
+	assert.Equal(t, "ADF", column.Name())
+	column.To("A")
+	column.Next()
+	assert.Equal(t, "B", column.Name())
+	column.Next()
+	assert.Equal(t, "C", column.Name())
+	column.To("A")
+	column.RightShift(26)
+	assert.Equal(t, "AA", column.Name())
+}
+
+func TestNewColumn4(t *testing.T) {
+	column := NewColumn("A")
+	column.RightShift(1000)
+	assert.Equal(t, "ALM", column.Name())
+	column.To("A")
+	column.RightShift(25)
+	assert.Equal(t, "Z", column.Name())
+	column.RightShift(1)
+	assert.Equal(t, "AA", column.Name())
+	column.To("A")
+	column.RightShift(maxNumber - 1)
+	assert.Equal(t, "XFD", column.Name())
+}
+
+func TestNewColumn5(t *testing.T) {
+	column := NewColumn("A")
+	column.Next()
+	column.RightShift(26)
+	assert.Equal(t, "AB", column.Name())
+	column.Reset()
+	assert.Equal(t, "A", column.Name())
+	assert.Equal(t, "A", column.StartName())
+	assert.Equal(t, "A", column.EndName())
+}
+
+func TestNewLeftShift(t *testing.T) {
+	column := NewColumn("Z")
+	column.Prev()
+	assert.Equal(t, "Y", column.Name())
+	column.LeftShift(23)
+	assert.Equal(t, "B", column.Name())
+	column.LeftShift(1)
+	assert.Equal(t, "A", column.Name())
+	_, err := column.LeftShift(1)
+	assert.Equal(t, err != nil, true, "err")
+	column.Reset()
+	assert.Equal(t, "Z", column.Name())
+	assert.Equal(t, "Z", column.StartName())
+	column.To("AA")
+	assert.Equal(t, "AA", column.EndName())
+}