lang: core: strings, util: Add left and right padding functions

Golang didn't want these in the standard library, but they are useful.

util/pad_test.go

@@ -0,0 +1,86 @@
+// Mgmt
+// Copyright (C) 2013-2024+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+// Additional permission under GNU GPL version 3 section 7
+//
+// If you modify this program, or any covered work, by linking or combining it
+// with embedded mcl code and modules (and that the embedded mcl code and
+// modules which link with this program, contain a copy of their source code in
+// the authoritative form) containing parts covered by the terms of any other
+// license, the licensors of this program grant you additional permission to
+// convey the resulting work. Furthermore, the licensors of this program grant
+// the original author, James Shubin, additional permission to update this
+// additional permission if he deems it necessary to achieve the goals of this
+// additional permission.
+
+//go:build !root
+
+package util
+
+import (
+	"testing"
+)
+
+func TestLeftPad(t *testing.T) {
+	tests := []struct {
+		s      string
+		pad    string
+		length int
+		result string
+	}{
+		{"", "", 0, ""},
+		{"", "x", 0, ""},
+		{"", "x", 2, "xx"},
+		{"", "ab", 3, "abab"},
+		{"hello", " ", 7, "  hello"},
+		{"hello", "ab", 5, "hello"},
+		{"hello", "ab", 6, "abhello"},
+		{"hello", "ab", 8, "ababhello"},
+	}
+
+	for i, test := range tests {
+		actual := LeftPad(test.s, test.pad, test.length)
+		if actual != test.result {
+			t.Errorf("index: %d, expected: %s, actual: %s", i, test.result, actual)
+		}
+	}
+}
+
+func TestRightPad(t *testing.T) {
+	tests := []struct {
+		s      string
+		pad    string
+		length int
+		result string
+	}{
+		{"", "", 0, ""},
+		{"", "x", 0, ""},
+		{"", "x", 2, "xx"},
+		{"", "ab", 3, "abab"},
+		{"hello", " ", 7, "hello  "},
+		{"hello", "ab", 5, "hello"},
+		{"hello", "ab", 6, "helloab"},
+		{"hello", "ab", 8, "helloabab"},
+	}
+
+	for i, test := range tests {
+		actual := RightPad(test.s, test.pad, test.length)
+		if actual != test.result {
+			t.Errorf("index: %d, expected: %s, actual: %s", i, test.result, actual)
+		}
+	}
+}