The implementation of the important function "SEARCHB" is missing from this project.

[godsmell]

Description
The implementation of the important function "SEARCHB" is missing from this project.

Describe the results you expected:
获取到螺钉编号为: 1020

func Test2MyTest(t *testing.T) {
	f, err := excelize.OpenFile("../test.xlsx")
	if err != nil {
		fmt.Println(err)
		return
	}
	defer f.Close()

	f.SetCellValue("Sheet1", "A1", "螺钉1020")
	f.SetCellFormula("Sheet1", "B1", `MIDB(A1,SEARCHB("?",A1),2*LEN(A1)-LENB(A1))`)
	if foo, err := f.CalcCellValue("Sheet1", "B1"); err == nil {
		fmt.Println("获取到螺钉编号为:", foo)
	} else {
		fmt.Println("ERROR:", err)
	}
}

Describe the results you received:

Running tool: C:\golang\go\bin\go.exe test -timeout 30s -run ^Test2MyTest$ excelizer/testing -v

=== RUN   Test2MyTest
--- FAIL: Test2MyTest (0.00s)
panic: runtime error: slice bounds out of range [-1:] [recovered]
	panic: runtime error: slice bounds out of range [-1:]

goroutine 21 [running]:
testing.tRunner.func1.2({0x7a6800, 0xc0000140d8})
	C:/golang/go/src/testing/testing.go:1389 +0x24e
testing.tRunner.func1()
	C:/golang/go/src/testing/testing.go:1392 +0x39f
panic({0x7a6800, 0xc0000140d8})
	C:/golang/go/src/runtime/panic.go:838 +0x207
github.com/xuri/excelize/v2.(*formulaFuncs).mid(0xc000020410?, {0x7cf338, 0x4}, 0xc0004423a8?)
	C:/golang/gopath/pkg/mod/github.com/xuri/excelize/[email protected]/calc.go:13796 +0xa18
github.com/xuri/excelize/v2.(*formulaFuncs).MIDB(0xc0000981e0?, 0x2?)
	C:/golang/gopath/pkg/mod/github.com/xuri/excelize/[email protected]/calc.go:13766 +0x67
reflect.Value.call({0x7cb7c0?, 0xc00001ec90?, 0x106?}, {0x7cf124, 0x4}, {0xc000442e20, 0x1, 0x895040?})
	C:/golang/go/src/reflect/value.go:556 +0x845
reflect.Value.Call({0x7cb7c0?, 0xc00001ec90?, 0x0?}, {0xc000442e20, 0x1, 0x1})
	C:/golang/go/src/reflect/value.go:339 +0xbf
github.com/xuri/excelize/v2.callFuncByName({0x7cb7c0?, 0xc00001ec90?}, {0xc00001216c, 0x0?}, {0xc000442e20, 0x1, 0x1})
	C:/golang/gopath/pkg/mod/github.com/xuri/excelize/[email protected]/calc.go:1685 +0x150
github.com/xuri/excelize/v2.(*File).evalInfixExpFunc(_, _, {_, _}, {_, _}, {{0x0, 0x0}, {0x7d5e6a, 0x8}, ...}, ...)
	C:/golang/gopath/pkg/mod/github.com/xuri/excelize/[email protected]/calc.go:1053 +0x4dd
github.com/xuri/excelize/v2.(*File).evalInfixExp(0xc000085d40?, 0xc00040e990?, {0x7d23b2, 0x6}, {0x7cd9ce, 0x2}, {0xc0003af000, 0x13, 0x13?})
	C:/golang/gopath/pkg/mod/github.com/xuri/excelize/[email protected]/calc.go:1028 +0x1a39
github.com/xuri/excelize/v2.(*File).calcCellValue(0x0?, 0x0?, {0x7d23b2, 0x6}, {0x7cd9ce, 0x2})
	C:/golang/gopath/pkg/mod/github.com/xuri/excelize/[email protected]/calc.go:844 +0x1b1
github.com/xuri/excelize/v2.(*File).CalcCellValue(0xc000085d40?, {0x7d23b2, 0x6}, {0x7cd9ce, 0x2}, {0x0, 0x0, 0x0?})
	C:/golang/gopath/pkg/mod/github.com/xuri/excelize/[email protected]/calc.go:807 +0x2f7
excelizer/testing.Test2MyTest(0x0?)
	d:/DEV/go-dev/excelizer/testing/excel_test.go:189 +0x15e
testing.tRunner(0xc000085a00, 0x801cc0)
	C:/golang/go/src/testing/testing.go:1439 +0x102
created by testing.(*T).Run
	C:/golang/go/src/testing/testing.go:1486 +0x35f
FAIL	excelizer/testing	0.331s

Can you provide the implementation of the function SEARCHB?

Environment details (OS, Microsoft Excel™ version, physical, etc.):

[godsmell]

Thanks a lot !

[xuri]

Thanks for your issue. I have fixed this issue, please try to upgrade the master branch code, and this patch will be released in the next version.