// Copyright 2022 The Gitea Authors. All rights reserved.// SPDX-License-Identifier: MIT package util import "unsafe" func isSnakeCaseUpper(c byte) bool {	return 'A' <= c && c <= 'Z'} func isSnakeCaseLowerOrNumber(c byte) bool {	return 'a' <= c && c <= 'z' || '0' <= c && c <= '9'} // ToSnakeCase convert the input string to snake_case format.//// Some samples.////	"FirstName"  => "first_name"//	"HTTPServer" => "http_server"//	"NoHTTPS"    => "no_https"//	"GO_PATH"    => "go_path"//	"GO PATH"    => "go_path"      // space is converted to underscore.//	"GO-PATH"    => "go_path"      // hyphen is converted to underscore.func ToSnakeCase(input string) string {	if len(input) == 0 {		return ""	} 	var res []byte	if len(input) == 1 {		c := input[0]		if isSnakeCaseUpper(c) {			res = []byte{c + 'a' - 'A'}		} else if isSnakeCaseLowerOrNumber(c) {			res = []byte{c}		} else {			res = []byte{'_'}		}	} else {		res = make([]byte, 0, len(input)*4/3)		pos := 0		needSep := false		for pos < len(input) {			c := input[pos]			if c >= 0x80 {				res = append(res, c)				pos++				continue			}			isUpper := isSnakeCaseUpper(c)			if isUpper || isSnakeCaseLowerOrNumber(c) {				end := pos + 1				if isUpper {					// skip the following upper letters					for end < len(input) && isSnakeCaseUpper(input[end]) {						end++					}					if end-pos > 1 && end < len(input) && isSnakeCaseLowerOrNumber(input[end]) {						end--					}				}				// skip the following lower or number letters				for end < len(input) && (isSnakeCaseLowerOrNumber(input[end]) || input[end] >= 0x80) {					end++				}				if needSep {					res = append(res, '_')				}				res = append(res, input[pos:end]...)				pos = end				needSep = true			} else {				res = append(res, '_')				pos++				needSep = false			}		}		for i := 0; i < len(res); i++ {			if isSnakeCaseUpper(res[i]) {				res[i] += 'a' - 'A'			}		}	}	return UnsafeBytesToString(res)} // UnsafeBytesToString uses Go's unsafe package to convert a byte slice to a string.func UnsafeBytesToString(b []byte) string {	return unsafe.String(unsafe.SliceData(b), len(b))} // UnsafeStringToBytes uses Go's unsafe package to convert a string to a byte slice.func UnsafeStringToBytes(s string) []byte {	return unsafe.Slice(unsafe.StringData(s), len(s))} // AsciiEqualFold is taken from Golang, but reimplemented here, since the original is not exposed to public// Taken from: https://cs.opensource.google/go/go/+/refs/tags/go1.24.4:src/net/http/internal/ascii/print.gofunc ASCIIEqualFold(s, t string) bool {	if len(s) != len(t) {		return false	}	for i := 0; i < len(s); i++ {		if ASCIILower(s[i]) != ASCIILower(t[i]) {			return false		}	}	return true} // AsciiLower returns the ASCII lowercase version of b.func ASCIILower(b byte) byte {	if 'A' <= b && b <= 'Z' {		return b + ('a' - 'A')	}	return b}