php.go

// php2go functions

package php2go

import (
	"archive/zip"
	"bytes"
	"crypto/md5"
	crand "crypto/rand"
	"crypto/sha1"
	"encoding/base64"
	"encoding/binary"
	"encoding/csv"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"hash/crc32"
	"html"
	"io"
	"io/ioutil"
	"math"
	"math/big"
	"math/rand"
	"net"
	"net/url"
	"os"
	"os/exec"
	"path/filepath"
	"reflect"
	"runtime"
	"strconv"
	"strings"
	"syscall"
	"time"
	"unicode"
	"unicode/utf8"
)

//////////// Date/Time Functions ////////////

// Time time()
func Time() int64 {
	return time.Now().Unix()
}

// Strtotime strtotime()
// Strtotime("02/01/2006 15:04:05", "02/01/2016 15:04:05") == 1451747045
// Strtotime("3 04 PM", "8 41 PM") == -62167144740
func Strtotime(format, strtime string) (int64, error) {
	t, err := time.Parse(format, strtime)
	if err != nil {
		return 0, err
	}
	return t.Unix(), nil
}

// Date date()
// Date("02/01/2006 15:04:05 PM", 1524799394)
// Note: the behavior is inconsistent with php's date function
func Date(format string, timestamp int64) string {
	return time.Unix(timestamp, 0).Format(format)
}

// Checkdate checkdate()
// Validate a Gregorian date
func Checkdate(month, day, year int) bool {
	if month < 1 || month > 12 || day < 1 || day > 31 || year < 1 || year > 32767 {
		return false
	}
	switch month {
	case 4, 6, 9, 11:
		if day > 30 {
			return false
		}
	case 2:
		// leap year
		if year%4 == 0 && (year%100 != 0 || year%400 == 0) {
			if day > 29 {
				return false
			}
		} else if day > 28 {
			return false
		}
	}

	return true
}

// Sleep sleep()
func Sleep(t int64) {
	time.Sleep(time.Duration(t) * time.Second)
}

// Usleep usleep()
func Usleep(t int64) {
	time.Sleep(time.Duration(t) * time.Microsecond)
}

//////////// String Functions ////////////

// Strpos strpos()
func Strpos(haystack, needle string, offset int) int {
	length := len(haystack)
	if length == 0 || offset > length || -offset > length {
		return -1
	}

	if offset < 0 {
		offset += length
	}
	pos := strings.Index(haystack[offset:], needle)
	if pos == -1 {
		return -1
	}
	return pos + offset
}

// Stripos stripos()
func Stripos(haystack, needle string, offset int) int {
	length := len(haystack)
	if length == 0 || offset > length || -offset > length {
		return -1
	}

	haystack = haystack[offset:]
	if offset < 0 {
		offset += length
	}
	pos := strings.Index(strings.ToLower(haystack), strings.ToLower(needle))
	if pos == -1 {
		return -1
	}
	return pos + offset
}

// Strrpos strrpos()
func Strrpos(haystack, needle string, offset int) int {
	pos, length := 0, len(haystack)
	if length == 0 || offset > length || -offset > length {
		return -1
	}

	if offset < 0 {
		haystack = haystack[:offset+length+1]
	} else {
		haystack = haystack[offset:]
	}
	pos = strings.LastIndex(haystack, needle)
	if offset > 0 && pos != -1 {
		pos += offset
	}
	return pos
}

// Strripos strripos()
func Strripos(haystack, needle string, offset int) int {
	pos, length := 0, len(haystack)
	if length == 0 || offset > length || -offset > length {
		return -1
	}

	if offset < 0 {
		haystack = haystack[:offset+length+1]
	} else {
		haystack = haystack[offset:]
	}
	pos = strings.LastIndex(strings.ToLower(haystack), strings.ToLower(needle))
	if offset > 0 && pos != -1 {
		pos += offset
	}
	return pos
}

// StrReplace str_replace()
func StrReplace(search, replace, subject string, count int) string {
	return strings.Replace(subject, search, replace, count)
}

// Strtoupper strtoupper()
func Strtoupper(str string) string {
	return strings.ToUpper(str)
}

// Strtolower strtolower()
func Strtolower(str string) string {
	return strings.ToLower(str)
}

// Ucfirst ucfirst()
func Ucfirst(str string) string {
	for _, v := range str {
		u := string(unicode.ToUpper(v))
		return u + str[len(u):]
	}
	return ""
}

// Lcfirst lcfirst()
func Lcfirst(str string) string {
	for _, v := range str {
		u := string(unicode.ToLower(v))
		return u + str[len(u):]
	}
	return ""
}

// Ucwords ucwords()
func Ucwords(str string) string {
	return strings.Title(str)
}

// Substr substr()
func Substr(str string, start uint, length int) string {
	if start < 0 || length < -1 {
		return str
	}
	switch {
	case length == -1:
		return str[start:]
	case length == 0:
		return ""
	}
	end := int(start) + length
	if end > len(str) {
		end = len(str)
	}
	return str[start:end]
}

// Strrev strrev()
func Strrev(str string) string {
	runes := []rune(str)
	for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
		runes[i], runes[j] = runes[j], runes[i]
	}
	return string(runes)
}

// ParseStr parse_str()
// f1=m&f2=n -> map[f1:m f2:n]
// f[a]=m&f[b]=n -> map[f:map[a:m b:n]]
// f[a][a]=m&f[a][b]=n -> map[f:map[a:map[a:m b:n]]]
// f[]=m&f[]=n -> map[f:[m n]]
// f[a][]=m&f[a][]=n -> map[f:map[a:[m n]]]
// f[][]=m&f[][]=n -> map[f:[map[]]] // Currently does not support nested slice.
// f=m&f[a]=n -> error // This is not the same as PHP.
// a .[[b=c -> map[a___[b:c]
func ParseStr(encodedString string, result map[string]interface{}) error {
	// build nested map.
	var build func(map[string]interface{}, []string, interface{}) error

	build = func(result map[string]interface{}, keys []string, value interface{}) error {
		length := len(keys)
		// trim ',"
		key := strings.Trim(keys[0], "'\"")
		if length == 1 {
			result[key] = value
			return nil
		}

		// The end is slice. like f[], f[a][]
		if keys[1] == "" && length == 2 {
			// todo nested slice
			if key == "" {
				return nil
			}
			val, ok := result[key]
			if !ok {
				result[key] = []interface{}{value}
				return nil
			}
			children, ok := val.([]interface{})
			if !ok {
				return fmt.Errorf("expected type '[]interface{}' for key '%s', but got '%T'", key, val)
			}
			result[key] = append(children, value)
			return nil
		}

		// The end is slice + map. like f[][a]
		if keys[1] == "" && length > 2 && keys[2] != "" {
			val, ok := result[key]
			if !ok {
				result[key] = []interface{}{}
				val = result[key]
			}
			children, ok := val.([]interface{})
			if !ok {
				return fmt.Errorf("expected type '[]interface{}' for key '%s', but got '%T'", key, val)
			}
			if l := len(children); l > 0 {
				if child, ok := children[l-1].(map[string]interface{}); ok {
					if _, ok := child[keys[2]]; !ok {
						_ = build(child, keys[2:], value)
						return nil
					}
				}
			}
			child := map[string]interface{}{}
			_ = build(child, keys[2:], value)
			result[key] = append(children, child)

			return nil
		}

		// map. like f[a], f[a][b]
		val, ok := result[key]
		if !ok {
			result[key] = map[string]interface{}{}
			val = result[key]
		}
		children, ok := val.(map[string]interface{})
		if !ok {
			return fmt.Errorf("expected type 'map[string]interface{}' for key '%s', but got '%T'", key, val)
		}

		return build(children, keys[1:], value)
	}

	// split encodedString.
	parts := strings.Split(encodedString, "&")
	for _, part := range parts {
		pos := strings.Index(part, "=")
		if pos <= 0 {
			continue
		}
		key, err := url.QueryUnescape(part[:pos])
		if err != nil {
			return err
		}
		for key[0] == ' ' {
			key = key[1:]
		}
		if key == "" || key[0] == '[' {
			continue
		}
		value, err := url.QueryUnescape(part[pos+1:])
		if err != nil {
			return err
		}

		// split into multiple keys
		var keys []string
		left := 0
		for i, k := range key {
			if k == '[' && left == 0 {
				left = i
			} else if k == ']' {
				if left > 0 {
					if len(keys) == 0 {
						keys = append(keys, key[:left])
					}
					keys = append(keys, key[left+1:i])
					left = 0
					if i+1 < len(key) && key[i+1] != '[' {
						break
					}
				}
			}
		}
		if len(keys) == 0 {
			keys = append(keys, key)
		}
		// first key
		first := ""
		for i, chr := range keys[0] {
			if chr == ' ' || chr == '.' || chr == '[' {
				first += "_"
			} else {
				first += string(chr)
			}
			if chr == '[' {
				first += keys[0][i+1:]
				break
			}
		}
		keys[0] = first

		// build nested map
		if err := build(result, keys, value); err != nil {
			return err
		}
	}

	return nil
}

// NumberFormat number_format()
// decimals: Sets the number of decimal points.
// decPoint: Sets the separator for the decimal point.
// thousandsSep: Sets the thousands' separator.
func NumberFormat(number float64, decimals uint, decPoint, thousandsSep string) string {
	neg := false
	if number < 0 {
		number = -number
		neg = true
	}
	dec := int(decimals)
	// Will round off
	str := fmt.Sprintf("%."+strconv.Itoa(dec)+"F", number)
	prefix, suffix := "", ""
	if dec > 0 {
		prefix = str[:len(str)-(dec+1)]
		suffix = str[len(str)-dec:]
	} else {
		prefix = str
	}
	sep := []byte(thousandsSep)
	n, l1, l2 := 0, len(prefix), len(sep)
	// thousands sep num
	c := (l1 - 1) / 3
	tmp := make([]byte, l2*c+l1)
	pos := len(tmp) - 1
	for i := l1 - 1; i >= 0; i, n, pos = i-1, n+1, pos-1 {
		if l2 > 0 && n > 0 && n%3 == 0 {
			for j := range sep {
				tmp[pos] = sep[l2-j-1]
				pos--
			}
		}
		tmp[pos] = prefix[i]
	}
	s := string(tmp)
	if dec > 0 {
		s += decPoint + suffix
	}
	if neg {
		s = "-" + s
	}

	return s
}

// ChunkSplit chunk_split()
func ChunkSplit(body string, chunklen uint, end string) string {
	if end == "" {
		end = "\r\n"
	}
	runes, erunes := []rune(body), []rune(end)
	l := uint(len(runes))
	if l <= 1 || l < chunklen {
		return body + end
	}
	ns := make([]rune, 0, len(runes)+len(erunes))
	var i uint
	for i = 0; i < l; i += chunklen {
		if i+chunklen > l {
			ns = append(ns, runes[i:]...)
		} else {
			ns = append(ns, runes[i:i+chunklen]...)
		}
		ns = append(ns, erunes...)
	}
	return string(ns)
}

// StrWordCount str_word_count()
func StrWordCount(str string) []string {
	return strings.Fields(str)
}

// Wordwrap wordwrap()
func Wordwrap(str string, width uint, br string, cut bool) string {
	strlen := len(str)
	brlen := len(br)
	linelen := int(width)

	if strlen == 0 {
		return ""
	}
	if brlen == 0 {
		panic("break string cannot be empty")
	}
	if linelen == 0 && cut {
		panic("can't force cut when width is zero")
	}

	current, laststart, lastspace := 0, 0, 0
	var ns []byte
	for current = 0; current < strlen; current++ {
		if str[current] == br[0] && current+brlen < strlen && str[current:current+brlen] == br {
			ns = append(ns, str[laststart:current+brlen]...)
			current += brlen - 1
			lastspace = current + 1
			laststart = lastspace
		} else if str[current] == ' ' {
			if current-laststart >= linelen {
				ns = append(ns, str[laststart:current]...)
				ns = append(ns, br[:]...)
				laststart = current + 1
			}
			lastspace = current
		} else if current-laststart >= linelen && cut && laststart >= lastspace {
			ns = append(ns, str[laststart:current]...)
			ns = append(ns, br[:]...)
			laststart = current
			lastspace = current
		} else if current-laststart >= linelen && laststart < lastspace {
			ns = append(ns, str[laststart:lastspace]...)
			ns = append(ns, br[:]...)
			lastspace++
			laststart = lastspace
		}
	}

	if laststart != current {
		ns = append(ns, str[laststart:current]...)
	}
	return string(ns)
}

// Strlen strlen()
func Strlen(str string) int {
	return len(str)
}

// MbStrlen mb_strlen()
func MbStrlen(str string) int {
	return utf8.RuneCountInString(str)
}

// StrRepeat str_repeat()
func StrRepeat(input string, multiplier int) string {
	return strings.Repeat(input, multiplier)
}

// Strstr strstr()
func Strstr(haystack string, needle string) string {
	if needle == "" {
		return ""
	}
	idx := strings.Index(haystack, needle)
	if idx == -1 {
		return ""
	}
	return haystack[idx+len([]byte(needle))-1:]
}

// Strtr strtr()
//
// If the parameter length is 1, type is: map[string]string
// Strtr("baab", map[string]string{"ab": "01"}) will return "ba01"
// If the parameter length is 2, type is: string, string
// Strtr("baab", "ab", "01") will return "1001", a => 0; b => 1.
func Strtr(haystack string, params ...interface{}) string {
	ac := len(params)
	if ac == 1 {
		pairs := params[0].(map[string]string)
		length := len(pairs)
		if length == 0 {
			return haystack
		}
		oldnew := make([]string, length*2)
		for o, n := range pairs {
			if o == "" {
				return haystack
			}
			oldnew = append(oldnew, o, n)
		}
		return strings.NewReplacer(oldnew...).Replace(haystack)
	} else if ac == 2 {
		from := params[0].(string)
		to := params[1].(string)
		trlen, lt := len(from), len(to)
		if trlen > lt {
			trlen = lt
		}
		if trlen == 0 {
			return haystack
		}

		str := make([]uint8, len(haystack))
		var xlat [256]uint8
		var i int
		var j uint8
		if trlen == 1 {
			for i = 0; i < len(haystack); i++ {
				if haystack[i] == from[0] {
					str[i] = to[0]
				} else {
					str[i] = haystack[i]
				}
			}
			return string(str)
		}
		// trlen != 1
		for {
			xlat[j] = j
			if j++; j == 0 {
				break
			}
		}
		for i = 0; i < trlen; i++ {
			xlat[from[i]] = to[i]
		}
		for i = 0; i < len(haystack); i++ {
			str[i] = xlat[haystack[i]]
		}
		return string(str)
	}

	return haystack
}

// StrShuffle str_shuffle()
func StrShuffle(str string) string {
	runes := []rune(str)
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	s := make([]rune, len(runes))
	for i, v := range r.Perm(len(runes)) {
		s[i] = runes[v]
	}
	return string(s)
}

// Trim trim()
func Trim(str string, characterMask ...string) string {
	if len(characterMask) == 0 {
		return strings.TrimSpace(str)
	}
	return strings.Trim(str, characterMask[0])
}

// Ltrim ltrim()
func Ltrim(str string, characterMask ...string) string {
	if len(characterMask) == 0 {
		return strings.TrimLeftFunc(str, unicode.IsSpace)
	}
	return strings.TrimLeft(str, characterMask[0])
}

// Rtrim rtrim()
func Rtrim(str string, characterMask ...string) string {
	if len(characterMask) == 0 {
		return strings.TrimRightFunc(str, unicode.IsSpace)
	}
	return strings.TrimRight(str, characterMask[0])
}

// Explode explode()
func Explode(delimiter, str string) []string {
	return strings.Split(str, delimiter)
}

// Chr chr()
func Chr(ascii int) string {
	return string(rune(ascii))
}

// Ord ord()
func Ord(char string) int {
	r, _ := utf8.DecodeRune([]byte(char))
	return int(r)
}

// Nl2br nl2br()
// \n\r, \r\n, \r, \n
func Nl2br(str string, isXhtml bool) string {
	r, n, runes := '\r', '\n', []rune(str)
	var br []byte
	if isXhtml {
		br = []byte("<br />")
	} else {
		br = []byte("<br>")
	}
	skip := false
	length := len(runes)
	var buf bytes.Buffer
	for i, v := range runes {
		if skip {
			skip = false
			continue
		}
		switch v {
		case n, r:
			if (i+1 < length) && (v == r && runes[i+1] == n) || (v == n && runes[i+1] == r) {
				buf.Write(br)
				skip = true
				continue
			}
			buf.Write(br)
		default:
			buf.WriteRune(v)
		}
	}
	return buf.String()
}

// JSONDecode json_decode()
func JSONDecode(data []byte, val interface{}) error {
	return json.Unmarshal(data, val)
}

// JSONEncode json_encode()
func JSONEncode(val interface{}) ([]byte, error) {
	return json.Marshal(val)
}

// Addslashes addslashes()
func Addslashes(str string) string {
	var buf bytes.Buffer
	for _, char := range str {
		switch char {
		case '\'', '"', '\\':
			buf.WriteRune('\\')
		}
		buf.WriteRune(char)
	}
	return buf.String()
}

// Stripslashes stripslashes()
func Stripslashes(str string) string {
	var buf bytes.Buffer
	l, skip := len(str), false
	for i, char := range str {
		if skip {
			skip = false
		} else if char == '\\' {
			if i+1 < l && str[i+1] == '\\' {
				skip = true
			}
			continue
		}
		buf.WriteRune(char)
	}
	return buf.String()
}

// Quotemeta quotemeta()
func Quotemeta(str string) string {
	var buf bytes.Buffer
	for _, char := range str {
		switch char {
		case '.', '+', '\\', '(', '$', ')', '[', '^', ']', '*', '?':
			buf.WriteRune('\\')
		}
		buf.WriteRune(char)
	}
	return buf.String()
}

// Htmlentities htmlentities()
func Htmlentities(str string) string {
	return html.EscapeString(str)
}

// HTMLEntityDecode html_entity_decode()
func HTMLEntityDecode(str string) string {
	return html.UnescapeString(str)
}

// Md5 md5()
func Md5(str string) string {
	hash := md5.New()
	hash.Write([]byte(str))
	return hex.EncodeToString(hash.Sum(nil))
}

// Md5File md5_file()
func Md5File(path string) (string, error) {
	f, err := os.Open(path)
	if err != nil {
		return "", err
	}
	defer f.Close()

	fi, err := f.Stat()
	if err != nil {
		return "", err
	}

	var size int64 = 1048576 // 1M
	hash := md5.New()

	if fi.Size() < size {
		data, err := ioutil.ReadFile(path)
		if err != nil {
			return "", err
		}
		hash.Write(data)
	} else {
		b := make([]byte, size)
		for {
			n, err := f.Read(b)
			if err != nil {
				break
			}

			hash.Write(b[:n])
		}
	}

	return hex.EncodeToString(hash.Sum(nil)), nil
}

// Sha1 sha1()
func Sha1(str string) string {
	hash := sha1.New()
	hash.Write([]byte(str))
	return hex.EncodeToString(hash.Sum(nil))
}

// Sha1File sha1_file()
func Sha1File(path string) (string, error) {
	data, err := ioutil.ReadFile(path)
	if err != nil {
		return "", err
	}
	hash := sha1.New()
	hash.Write([]byte(data))
	return hex.EncodeToString(hash.Sum(nil)), nil
}

// Crc32 crc32()
func Crc32(str string) uint32 {
	return crc32.ChecksumIEEE([]byte(str))
}

// Levenshtein levenshtein()
// costIns: Defines the cost of insertion.
// costRep: Defines the cost of replacement.
// costDel: Defines the cost of deletion.
func Levenshtein(str1, str2 string, costIns, costRep, costDel int) int {
	var maxLen = 255
	l1 := len(str1)
	l2 := len(str2)
	if l1 == 0 {
		return l2 * costIns
	}
	if l2 == 0 {
		return l1 * costDel
	}
	if l1 > maxLen || l2 > maxLen {
		return -1
	}

	p1 := make([]int, l2+1)
	p2 := make([]int, l2+1)
	var c0, c1, c2 int
	var i1, i2 int
	for i2 := 0; i2 <= l2; i2++ {
		p1[i2] = i2 * costIns
	}
	for i1 = 0; i1 < l1; i1++ {
		p2[0] = p1[0] + costDel
		for i2 = 0; i2 < l2; i2++ {
			if str1[i1] == str2[i2] {
				c0 = p1[i2]
			} else {
				c0 = p1[i2] + costRep
			}
			c1 = p1[i2+1] + costDel
			if c1 < c0 {
				c0 = c1
			}
			c2 = p2[i2] + costIns
			if c2 < c0 {
				c0 = c2
			}
			p2[i2+1] = c0
		}
		tmp := p1
		p1 = p2
		p2 = tmp
	}
	c0 = p1[l2]

	return c0
}

// SimilarText similar_text()
func SimilarText(first, second string, percent *float64) int {
	var similarText func(string, string, int, int) int
	similarText = func(str1, str2 string, len1, len2 int) int {
		var sum, max int
		pos1, pos2 := 0, 0

		// Find the longest segment of the same section in two strings
		for i := 0; i < len1; i++ {
			for j := 0; j < len2; j++ {
				for l := 0; (i+l < len1) && (j+l < len2) && (str1[i+l] == str2[j+l]); l++ {
					if l+1 > max {
						max = l + 1
						pos1 = i
						pos2 = j
					}
				}
			}
		}

		if sum = max; sum > 0 {
			if pos1 > 0 && pos2 > 0 {
				sum += similarText(str1, str2, pos1, pos2)
			}
			if (pos1+max < len1) && (pos2+max < len2) {
				s1 := []byte(str1)
				s2 := []byte(str2)
				sum += similarText(string(s1[pos1+max:]), string(s2[pos2+max:]), len1-pos1-max, len2-pos2-max)
			}
		}

		return sum
	}

	l1, l2 := len(first), len(second)
	if l1+l2 == 0 {
		return 0
	}
	sim := similarText(first, second, l1, l2)
	if percent != nil {
		*percent = float64(sim*200) / float64(l1+l2)
	}
	return sim
}

// Soundex soundex()
// Calculate the soundex key of a string.
func Soundex(str string) string {
	if str == "" {
		panic("str: cannot be an empty string")
	}
	table := [26]rune{
		// A, B, C, D
		'0', '1', '2', '3',
		// E, F, G
		'0', '1', '2',
		// H
		'0',
		// I, J, K, L, M, N
		'0', '2', '2', '4', '5', '5',
		// O, P, Q, R, S, T
		'0', '1', '2', '6', '2', '3',
		// U, V
		'0', '1',
		// W, X
		'0', '2',
		// Y, Z
		'0', '2',
	}
	last, code, small := -1, 0, 0
	sd := make([]rune, 4)
	// build soundex string
	for i := 0; i < len(str) && small < 4; i++ {
		// ToUpper
		char := str[i]
		if char < '\u007F' && 'a' <= char && char <= 'z' {
			code = int(char - 'a' + 'A')
		} else {
			code = int(char)
		}
		if code >= 'A' && code <= 'Z' {
			if small == 0 {
				sd[small] = rune(code)
				small++
				last = int(table[code-'A'])
			} else {
				code = int(table[code-'A'])
				if code != last {
					if code != 0 {
						sd[small] = rune(code)
						small++
					}
					last = code
				}
			}
		}
	}
	// pad with "0"
	for ; small < 4; small++ {
		sd[small] = '0'
	}
	return string(sd)
}

//////////// URL Functions ////////////

// ParseURL parse_url()
// Parse a URL and return its components
// -1: all; 1: scheme; 2: host; 4: port; 8: user; 16: pass; 32: path; 64: query; 128: fragment
func ParseURL(str string, component int) (map[string]string, error) {
	u, err := url.Parse(str)
	if err != nil {
		return nil, err
	}
	if component == -1 {
		component = 1 | 2 | 4 | 8 | 16 | 32 | 64 | 128
	}
	var components = make(map[string]string)
	if (component & 1) == 1 {
		components["scheme"] = u.Scheme
	}
	if (component & 2) == 2 {
		components["host"] = u.Hostname()
	}
	if (component & 4) == 4 {
		components["port"] = u.Port()
	}
	if (component & 8) == 8 {
		components["user"] = u.User.Username()
	}
	if (component & 16) == 16 {
		components["pass"], _ = u.User.Password()
	}
	if (component & 32) == 32 {
		components["path"] = u.Path
	}
	if (component & 64) == 64 {
		components["query"] = u.RawQuery
	}
	if (component & 128) == 128 {
		components["fragment"] = u.Fragment
	}
	return components, nil
}

// URLEncode urlencode()
func URLEncode(str string) string {
	return url.QueryEscape(str)
}

// URLDecode urldecode()
func URLDecode(str string) (string, error) {
	return url.QueryUnescape(str)
}

// Rawurlencode rawurlencode()
func Rawurlencode(str string) string {
	return strings.Replace(url.QueryEscape(str), "+", "%20", -1)
}

// Rawurldecode rawurldecode()
func Rawurldecode(str string) (string, error) {
	return url.QueryUnescape(strings.Replace(str, "%20", "+", -1))
}

// HTTPBuildQuery http_build_query()
func HTTPBuildQuery(queryData url.Values) string {
	return queryData.Encode()
}

// Base64Encode base64_encode()
func Base64Encode(str string) string {
	return base64.StdEncoding.EncodeToString([]byte(str))
}

// Base64Decode base64_decode()
func Base64Decode(str string) (string, error) {
	switch len(str) % 4 {
	case 2:
		str += "=="
	case 3:
		str += "="
	}

	data, err := base64.StdEncoding.DecodeString(str)
	if err != nil {
		return "", err
	}
	return string(data), nil
}

//////////// Array(Slice/Map) Functions ////////////

// ArrayFill array_fill()
func ArrayFill(startIndex int, num uint, value interface{}) map[int]interface{} {
	m := make(map[int]interface{})
	var i uint
	for i = 0; i < num; i++ {
		m[startIndex] = value
		startIndex++
	}
	return m
}

// ArrayFlip array_flip()
func ArrayFlip(m map[interface{}]interface{}) map[interface{}]interface{} {
	n := make(map[interface{}]interface{})
	for i, v := range m {
		n[v] = i
	}
	return n
}

// ArrayKeys array_keys()
func ArrayKeys(elements map[interface{}]interface{}) []interface{} {
	i, keys := 0, make([]interface{}, len(elements))
	for key := range elements {
		keys[i] = key
		i++
	}
	return keys
}

// ArrayValues array_values()
func ArrayValues(elements map[interface{}]interface{}) []interface{} {
	i, vals := 0, make([]interface{}, len(elements))
	for _, val := range elements {
		vals[i] = val
		i++
	}
	return vals
}

// ArrayMerge array_merge()
func ArrayMerge(ss ...[]interface{}) []interface{} {
	n := 0
	for _, v := range ss {
		n += len(v)
	}
	s := make([]interface{}, 0, n)
	for _, v := range ss {
		s = append(s, v...)
	}
	return s
}

// ArrayChunk array_chunk()
func ArrayChunk(s []interface{}, size int) [][]interface{} {
	if size < 1 {
		panic("size: cannot be less than 1")
	}
	length := len(s)
	chunks := int(math.Ceil(float64(length) / float64(size)))
	var n [][]interface{}
	for i, end := 0, 0; chunks > 0; chunks-- {
		end = (i + 1) * size
		if end > length {
			end = length
		}
		n = append(n, s[i*size:end])
		i++
	}
	return n
}

// ArrayPad array_pad()
func ArrayPad(s []interface{}, size int, val interface{}) []interface{} {
	if size == 0 || (size > 0 && size < len(s)) || (size < 0 && size > -len(s)) {
		return s
	}
	n := size
	if size < 0 {
		n = -size
	}
	n -= len(s)
	tmp := make([]interface{}, n)
	for i := 0; i < n; i++ {
		tmp[i] = val
	}
	if size > 0 {
		return append(s, tmp...)
	}
	return append(tmp, s...)
}

// ArraySlice array_slice()
func ArraySlice(s []interface{}, offset, length uint) []interface{} {
	if offset > uint(len(s)) {
		panic("offset: the offset is less than the length of s")
	}
	end := offset + length
	if end < uint(len(s)) {
		return s[offset:end]
	}
	return s[offset:]
}

// ArrayRand array_rand()
func ArrayRand(elements []interface{}) []interface{} {
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	n := make([]interface{}, len(elements))
	for i, v := range r.Perm(len(elements)) {
		n[i] = elements[v]
	}
	return n
}

// ArrayColumn array_column()
func ArrayColumn(input map[string]map[string]interface{}, columnKey string) []interface{} {
	columns := make([]interface{}, 0, len(input))
	for _, val := range input {
		if v, ok := val[columnKey]; ok {
			columns = append(columns, v)
		}
	}
	return columns
}

// ArrayPush array_push()
// Push one or more elements onto the end of slice
func ArrayPush(s *[]interface{}, elements ...interface{}) int {
	*s = append(*s, elements...)
	return len(*s)
}

// ArrayPop array_pop()
// Pop the element off the end of slice
func ArrayPop(s *[]interface{}) interface{} {
	if len(*s) == 0 {
		return nil
	}
	ep := len(*s) - 1
	e := (*s)[ep]
	*s = (*s)[:ep]
	return e
}

// ArrayUnshift array_unshift()
// Prepend one or more elements to the beginning of a slice
func ArrayUnshift(s *[]interface{}, elements ...interface{}) int {
	*s = append(elements, *s...)
	return len(*s)
}

// ArrayShift array_shift()
// Shift an element off the beginning of slice
func ArrayShift(s *[]interface{}) interface{} {
	if len(*s) == 0 {
		return nil
	}
	f := (*s)[0]
	*s = (*s)[1:]
	return f
}

// ArrayKeyExists array_key_exists()
func ArrayKeyExists(key interface{}, m map[interface{}]interface{}) bool {
	_, ok := m[key]
	return ok
}

// ArrayCombine array_combine()
func ArrayCombine(s1, s2 []interface{}) map[interface{}]interface{} {
	if len(s1) != len(s2) {
		panic("the number of elements for each slice isn't equal")
	}
	m := make(map[interface{}]interface{}, len(s1))
	for i, v := range s1 {
		m[v] = s2[i]
	}
	return m
}

// ArrayReverse array_reverse()
func ArrayReverse(s []interface{}) []interface{} {
	for i, j := 0, len(s)-1; i < j; i, j = i+1, j-1 {
		s[i], s[j] = s[j], s[i]
	}
	return s
}

// ArrayDiff array_diff()
func ArrayDiff(array1 []string, arrayOthers ...[]string) []string {
	c := make(map[string]bool)
	for i := 0; i < len(array1); i++ {
		if _, hasKey := c[array1[i]]; hasKey {
			c[array1[i]] = true
		} else {
			c[array1[i]] = false
		}
	}
	for i := 0; i < len(arrayOthers); i++ {
		for j := 0; j < len(arrayOthers[i]); j++ {
			if _, hasKey := c[arrayOthers[i][j]]; hasKey {
				c[arrayOthers[i][j]] = true
			} else {
				c[arrayOthers[i][j]] = false
			}
		}
	}
	result := make([]string, 0)
	for k, v := range c {
		if !v {
			result = append(result, k)
		}
	}
	return result
}

// ArrayUnique array_unique()
func ArrayUnique(arr []string) []string {
	size := len(arr)
	result := make([]string, 0, size)
	temp := map[string]struct{}{}
	for i := 0; i < size; i++ {
		if _, ok := temp[arr[i]]; ok != true {
			temp[arr[i]] = struct{}{}
			result = append(result, arr[i])
		}
	}
	return result
}

// ArrayUniqueInt array_unique()
func ArrayUniqueInt(arr []int) []int {
	size := len(arr)
	result := make([]int, 0, size)
	temp := map[int]struct{}{}
	for i := 0; i < size; i++ {
		if _, ok := temp[arr[i]]; ok != true {
			temp[arr[i]] = struct{}{}
			result = append(result, arr[i])
		}
	}
	return result
}

// Implode implode()
func Implode(glue string, pieces []string) string {
	var buf bytes.Buffer
	l := len(pieces)
	for _, str := range pieces {
		buf.WriteString(str)
		if l--; l > 0 {
			buf.WriteString(glue)
		}
	}
	return buf.String()
}

// InArray in_array()
// haystack supported types: slice, array or map
func InArray(needle interface{}, haystack interface{}) bool {
	val := reflect.ValueOf(haystack)
	switch val.Kind() {
	case reflect.Slice, reflect.Array:
		for i := 0; i < val.Len(); i++ {
			if reflect.DeepEqual(needle, val.Index(i).Interface()) {
				return true
			}
		}
	case reflect.Map:
		for _, k := range val.MapKeys() {
			if reflect.DeepEqual(needle, val.MapIndex(k).Interface()) {
				return true
			}
		}
	default:
		panic("haystack: haystack type muset be slice, array or map")
	}

	return false
}

//////////// Mathematical Functions ////////////

// Abs abs()
func Abs(number float64) float64 {
	return math.Abs(number)
}

// Rand rand()
// Range: [0, 2147483647]
func Rand(min, max int) int {
	if min > max {
		panic("min: min cannot be greater than max")
	}
	// PHP: getrandmax()
	if int31 := 1<<31 - 1; max > int31 {
		panic("max: max can not be greater than " + strconv.Itoa(int31))
	}
	if min == max {
		return min
	}
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	return r.Intn(max+1-min) + min
}

// Round round()
func Round(value float64, precision int) float64 {
	p := math.Pow10(precision)
	return math.Trunc((value+0.5/p)*p) / p
}

// Floor floor()
func Floor(value float64) float64 {
	return math.Floor(value)
}

// Ceil ceil()
func Ceil(value float64) float64 {
	return math.Ceil(value)
}

// Pi pi()
func Pi() float64 {
	return math.Pi
}

// Max max()
func Max(nums ...float64) float64 {
	if len(nums) < 2 {
		panic("nums: the nums length is less than 2")
	}
	max := nums[0]
	for i := 1; i < len(nums); i++ {
		max = math.Max(max, nums[i])
	}
	return max
}

// Min min()
func Min(nums ...float64) float64 {
	if len(nums) < 2 {
		panic("nums: the nums length is less than 2")
	}
	min := nums[0]
	for i := 1; i < len(nums); i++ {
		min = math.Min(min, nums[i])
	}
	return min
}

// Decbin decbin()
func Decbin(number int64) string {
	return strconv.FormatInt(number, 2)
}

// Bindec bindec()
func Bindec(str string) (int64, error) {
	i, err := strconv.ParseInt(str, 2, 0)
	if err != nil {
		return 0, err
	}
	return i, nil
}

// Hexbin hexbin()
func Hexbin(str string) (string, error) {
	i, err := Hexdec(str)
	if err != nil {
		return "", err
	}
	return Decbin(i), nil
}

// Binhex binhex()
func Binhex(str string) (string, error) {
	i, err := Bindec(str)
	if err != nil {
		return "", err
	}
	return DecHex(i), nil
}

// Hex2bin hex2bin() to AscII
func Hex2bin(h string) (str string, err error) {
	l := len(h)
	length, k := l, 0
	bHex := make([]byte, l/2)
	for i := 0; i < length; i += 2 {
		if l == 1 {
			break
		}
		//每两个字符转换成一个字节
		s := string(h[i : i+2])
		//十六进制
		bt, err := strconv.ParseInt(s, 16, 32)
		if err != nil {
			return "", err
		}
		bHex[k] = byte(bt)
		k++
		l -= 2
	}
	return string(bHex), nil
}

// Bin2hex bin2hex()
func Bin2hex(str string) (string, error) {
	i, err := strconv.ParseInt(str, 2, 0)
	if err != nil {
		// If input is not binary number
		if err.(*strconv.NumError).Err == strconv.ErrSyntax {
			byteArray := []byte(str)
			var out string
			for i := 0; i < len(byteArray); i++ {
				out += strconv.FormatInt(int64(byteArray[i]), 16)
			}
			return out, nil
		} else {
			return "", err
		}
	}
	return strconv.FormatInt(i, 16), nil
}

// Dechex dechex()
func Dechex(number int64) string {
	return strconv.FormatInt(number, 16)
}

// Hexdec hexdec()
func Hexdec(str string) (int64, error) {
	return strconv.ParseInt(str, 16, 0)
}

// Decoct decoct()
func Decoct(number int64) string {
	return strconv.FormatInt(number, 8)
}

// Octdec Octdec()
func Octdec(str string) (int64, error) {
	return strconv.ParseInt(str, 8, 0)
}

// BaseConvert base_convert()
func BaseConvert(number string, frombase, tobase int) (string, error) {
	i, err := strconv.ParseInt(number, frombase, 0)
	if err != nil {
		return "", err
	}
	return strconv.FormatInt(i, tobase), nil
}

// IsNan is_nan()
func IsNan(val float64) bool {
	return math.IsNaN(val)
}

//////////// CSPRNG Functions ////////////

// RandomBytes random_bytes()
func RandomBytes(length int) ([]byte, error) {
	bs := make([]byte, length)
	_, err := crand.Read(bs)
	if err != nil {
		return nil, err
	}

	return bs, nil
}

// RandomInt random_int()
func RandomInt(min, max int) (int, error) {
	if min > max {
		panic("argument #1 must be less than or equal to argument #2")
	}

	if min == max {
		return min, nil
	}
	nb, err := crand.Int(crand.Reader, big.NewInt(int64(max+1-min)))
	if err != nil {
		return 0, err
	}
	return int(nb.Int64()) + min, nil
}

//////////// Directory/Filesystem Functions ////////////

// Stat stat()
func Stat(filename string) (os.FileInfo, error) {
	return os.Stat(filename)
}

// Pathinfo pathinfo()
// -1: all; 1: dirname; 2: basename; 4: extension; 8: filename
// Usage:
// Pathinfo("/home/go/path/src/php2go/php2go.go", 1|2|4|8)
func Pathinfo(path string, options int) map[string]string {
	if options == -1 {
		options = 1 | 2 | 4 | 8
	}
	info := make(map[string]string)
	if (options & 1) == 1 {
		info["dirname"] = filepath.Dir(path)
	}
	if (options & 2) == 2 {
		info["basename"] = filepath.Base(path)
	}
	if ((options & 4) == 4) || ((options & 8) == 8) {
		basename := ""
		if (options & 2) == 2 {
			basename, _ = info["basename"]
		} else {
			basename = filepath.Base(path)
		}
		p := strings.LastIndex(basename, ".")
		filename, extension := "", ""
		if p > 0 {
			filename, extension = basename[:p], basename[p+1:]
		} else if p == -1 {
			filename = basename
		} else if p == 0 {
			extension = basename[p+1:]
		}
		if (options & 4) == 4 {
			info["extension"] = extension
		}
		if (options & 8) == 8 {
			info["filename"] = filename
		}
	}
	return info
}

// FileExists file_exists()
func FileExists(filename string) bool {
	_, err := os.Stat(filename)
	if err != nil && os.IsNotExist(err) {
		return false
	}
	return true
}

// IsFile is_file()
func IsFile(filename string) bool {
	_, err := os.Stat(filename)
	if err != nil && os.IsNotExist(err) {
		return false
	}
	return true
}

// IsDir is_dir()
func IsDir(filename string) (bool, error) {
	fd, err := os.Stat(filename)
	if err != nil {
		return false, err
	}
	fm := fd.Mode()
	return fm.IsDir(), nil
}

// FileSize filesize()
func FileSize(filename string) (int64, error) {
	info, err := os.Stat(filename)
	if err != nil && os.IsNotExist(err) {
		return 0, err
	}
	return info.Size(), nil
}

// FilePutContents file_put_contents()
func FilePutContents(filename string, data string, mode os.FileMode) error {
	return ioutil.WriteFile(filename, []byte(data), mode)
}

// FileGetContents file_get_contents()
func FileGetContents(filename string) (string, error) {
	data, err := ioutil.ReadFile(filename)
	return string(data), err
}

// Unlink unlink()
func Unlink(filename string) error {
	return os.Remove(filename)
}

// Delete delete()
func Delete(filename string) error {
	return os.Remove(filename)
}

// Copy copy()
func Copy(source, dest string) (bool, error) {
	fd1, err := os.Open(source)
	if err != nil {
		return false, err
	}
	defer fd1.Close()
	fd2, err := os.OpenFile(dest, os.O_WRONLY|os.O_CREATE, 0644)
	if err != nil {
		return false, err
	}
	defer fd2.Close()
	_, e := io.Copy(fd2, fd1)
	if e != nil {
		return false, e
	}
	return true, nil
}

// IsReadable is_readable()
func IsReadable(filename string) bool {
	fd, err := syscall.Open(filename, syscall.O_RDONLY, 0)
	if err != nil {
		return false
	}
	syscall.Close(fd)
	return true
}

// IsWriteable is_writeable()
func IsWriteable(filename string) bool {
	fd, err := syscall.Open(filename, syscall.O_WRONLY, 0)
	if err != nil {
		return false
	}
	syscall.Close(fd)
	return true
}

// Rename rename()
func Rename(oldname, newname string) error {
	return os.Rename(oldname, newname)
}

// Touch touch()
func Touch(filename string) (bool, error) {
	fd, err := os.OpenFile(filename, os.O_RDONLY|os.O_CREATE, 0666)
	if err != nil {
		return false, err
	}
	fd.Close()
	return true, nil
}

// Mkdir mkdir()
func Mkdir(filename string, mode os.FileMode) error {
	return os.Mkdir(filename, mode)
}

// Getcwd getcwd()
func Getcwd() (string, error) {
	dir, err := os.Getwd()
	return dir, err
}

// Realpath realpath()
func Realpath(path string) (string, error) {
	return filepath.Abs(path)
}

// Basename basename()
func Basename(path string) string {
	return filepath.Base(path)
}

// Chmod chmod()
func Chmod(filename string, mode os.FileMode) bool {
	return os.Chmod(filename, mode) == nil
}

// Chown chown()
func Chown(filename string, uid, gid int) bool {
	return os.Chown(filename, uid, gid) == nil
}

// Fclose fclose()
func Fclose(handle *os.File) error {
	return handle.Close()
}

// Filemtime filemtime()
func Filemtime(filename string) (int64, error) {
	fd, err := os.Open(filename)
	if err != nil {
		return 0, err
	}
	defer fd.Close()
	fileinfo, err := fd.Stat()
	if err != nil {
		return 0, err
	}
	return fileinfo.ModTime().Unix(), nil
}

// Fgetcsv fgetcsv()
func Fgetcsv(handle *os.File, length int, delimiter rune) ([][]string, error) {
	reader := csv.NewReader(handle)
	reader.Comma = delimiter
	// TODO length limit
	return reader.ReadAll()
}

// Glob glob()
func Glob(pattern string) ([]string, error) {
	return filepath.Glob(pattern)
}

//////////// Variable handling Functions ////////////

// Empty empty()
func Empty(val interface{}) bool {
	if val == nil {
		return true
	}
	v := reflect.ValueOf(val)
	switch v.Kind() {
	case reflect.String, reflect.Array:
		return v.Len() == 0
	case reflect.Map, reflect.Slice:
		return v.Len() == 0 || v.IsNil()
	case reflect.Bool:
		return !v.Bool()
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		return v.Int() == 0
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
		return v.Uint() == 0
	case reflect.Float32, reflect.Float64:
		return v.Float() == 0
	case reflect.Interface, reflect.Ptr:
		return v.IsNil()
	}

	return reflect.DeepEqual(val, reflect.Zero(v.Type()).Interface())
}

// IsNumeric is_numeric()
// Numeric strings consist of optional sign, any number of digits, optional decimal part and optional exponential part.
// Thus +0123.45e6 is a valid numeric value.
// In PHP hexadecimal (e.g. 0xf4c3b00c) is not supported, but IsNumeric is supported.
func IsNumeric(val interface{}) bool {
	switch val.(type) {
	case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64:
		return true
	case float32, float64, complex64, complex128:
		return true
	case string:
		str := val.(string)
		if str == "" {
			return false
		}
		// Trim any whitespace
		str = strings.TrimSpace(str)
		if str[0] == '-' || str[0] == '+' {
			if len(str) == 1 {
				return false
			}
			str = str[1:]
		}
		// hex
		if len(str) > 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X') {
			for _, h := range str[2:] {
				if !((h >= '0' && h <= '9') || (h >= 'a' && h <= 'f') || (h >= 'A' && h <= 'F')) {
					return false
				}
			}
			return true
		}
		// 0-9, Point, Scientific
		p, s, l := 0, 0, len(str)
		for i, v := range str {
			if v == '.' { // Point
				if p > 0 || s > 0 || i+1 == l {
					return false
				}
				p = i
			} else if v == 'e' || v == 'E' { // Scientific
				if i == 0 || s > 0 || i+1 == l {
					return false
				}
				s = i
			} else if v < '0' || v > '9' {
				return false
			}
		}
		return true
	}

	return false
}

//////////// Program execution Functions ////////////

// Exec exec()
// returnVar, 0: succ; 1: fail
// Return the last line from the result of the command.
// command format eg:
//
//	"ls -a"
//	"/bin/bash -c \"ls -a\""
func Exec(command string, output *[]string, returnVar *int) string {
	q := rune(0)
	parts := strings.FieldsFunc(command, func(r rune) bool {
		switch {
		case r == q:
			q = rune(0)
			return false
		case q != rune(0):
			return false
		case unicode.In(r, unicode.Quotation_Mark):
			q = r
			return false
		default:
			return unicode.IsSpace(r)
		}
	})
	// remove the " and ' on both sides
	for i, v := range parts {
		f, l := v[0], len(v)
		if l >= 2 && (f == '"' || f == '\'') {
			parts[i] = v[1 : l-1]
		}
	}
	cmd := exec.Command(parts[0], parts[1:]...)
	out, err := cmd.CombinedOutput()
	if err != nil {
		*returnVar = 1
		return ""
	}
	*returnVar = 0
	*output = strings.Split(strings.TrimRight(string(out), "\n"), "\n")
	if l := len(*output); l > 0 {
		return (*output)[l-1]
	}
	return ""
}

// System system()
// returnVar, 0: succ; 1: fail
// Returns the last line of the command output on success, and "" on failure.
func System(command string, returnVar *int) string {
	*returnVar = 0
	var stdBuf bytes.Buffer
	var err, err1, err2, err3 error

	// split command
	q := rune(0)
	parts := strings.FieldsFunc(command, func(r rune) bool {
		switch {
		case r == q:
			q = rune(0)
			return false
		case q != rune(0):
			return false
		case unicode.In(r, unicode.Quotation_Mark):
			q = r
			return false
		default:
			return unicode.IsSpace(r)
		}
	})
	// remove the " and ' on both sides
	for i, v := range parts {
		f, l := v[0], len(v)
		if l >= 2 && (f == '"' || f == '\'') {
			parts[i] = v[1 : l-1]
		}
	}
	cmd := exec.Command(parts[0], parts[1:]...)
	stdoutIn, _ := cmd.StdoutPipe()
	stderrIn, _ := cmd.StderrPipe()
	stdout := io.MultiWriter(os.Stdout, &stdBuf)
	stderr := io.MultiWriter(os.Stderr, &stdBuf)

	err = cmd.Start()
	if err != nil {
		*returnVar = 1
		return ""
	}

	go func() {
		_, err1 = io.Copy(stdout, stdoutIn)
	}()
	go func() {
		_, err2 = io.Copy(stderr, stderrIn)
	}()

	err3 = cmd.Wait()
	if err1 != nil || err2 != nil || err3 != nil {
		if err1 != nil {
			fmt.Println(err1)
		}
		if err2 != nil {
			fmt.Println(err2)
		}
		if err3 != nil {
			fmt.Println(err3)
		}
		*returnVar = 1
		return ""
	}
	if output := strings.TrimRight(stdBuf.String(), "\n"); output != "" {
		pos := strings.LastIndex(output, "\n")
		if pos == -1 {
			return output
		}
		return output[pos+1:]
	}
	return ""
}

// Passthru passthru()
// returnVar, 0: succ; 1: fail
func Passthru(command string, returnVar *int) {
	q := rune(0)
	parts := strings.FieldsFunc(command, func(r rune) bool {
		switch {
		case r == q:
			q = rune(0)
			return false
		case q != rune(0):
			return false
		case unicode.In(r, unicode.Quotation_Mark):
			q = r
			return false
		default:
			return unicode.IsSpace(r)
		}
	})
	// remove the " and ' on both sides
	for i, v := range parts {
		f, l := v[0], len(v)
		if l >= 2 && (f == '"' || f == '\'') {
			parts[i] = v[1 : l-1]
		}
	}
	cmd := exec.Command(parts[0], parts[1:]...)
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	err := cmd.Run()
	if err != nil {
		*returnVar = 1
		fmt.Println(err)
	} else {
		*returnVar = 0
	}
}

//////////// Network Functions ////////////

// Gethostname gethostname()
func Gethostname() (string, error) {
	return os.Hostname()
}

// Gethostbyname gethostbyname()
// Get the IPv4 address corresponding to a given Internet host name
func Gethostbyname(hostname string) (string, error) {
	ips, err := net.LookupIP(hostname)
	if ips != nil {
		for _, v := range ips {
			if v.To4() != nil {
				return v.String(), nil
			}
		}
		return "", nil
	}
	return "", err
}

// Gethostbynamel gethostbynamel()
// Get a list of IPv4 addresses corresponding to a given Internet host name
func Gethostbynamel(hostname string) ([]string, error) {
	ips, err := net.LookupIP(hostname)
	if ips != nil {
		var ipstrs []string
		for _, v := range ips {
			if v.To4() != nil {
				ipstrs = append(ipstrs, v.String())
			}
		}
		return ipstrs, nil
	}
	return nil, err
}

// Gethostbyaddr gethostbyaddr()
// Get the Internet host name corresponding to a given IP address
func Gethostbyaddr(ipAddress string) (string, error) {
	names, err := net.LookupAddr(ipAddress)
	if names != nil {
		return strings.TrimRight(names[0], "."), nil
	}
	return "", err
}

// IP2long ip2long()
// IPv4
func IP2long(ipAddress string) uint32 {
	ip := net.ParseIP(ipAddress)
	if ip == nil {
		return 0
	}
	return binary.BigEndian.Uint32(ip.To4())
}

// Long2ip long2ip()
// IPv4
func Long2ip(properAddress uint32) string {
	ipByte := make([]byte, 4)
	binary.BigEndian.PutUint32(ipByte, properAddress)
	ip := net.IP(ipByte)
	return ip.String()
}

//////////// Misc. Functions ////////////

// Echo echo
func Echo(args ...interface{}) {
	fmt.Print(args...)
}

// Uniqid uniqid()
func Uniqid(prefix string) string {
	now := time.Now()
	return fmt.Sprintf("%s%08x%05x", prefix, now.Unix(), now.UnixNano()%0x100000)
}

// Exit exit()
func Exit(status int) {
	os.Exit(status)
}

// Die die()
func Die(status int) {
	os.Exit(status)
}

// Getenv getenv()
func Getenv(varname string) string {
	return os.Getenv(varname)
}

// Putenv putenv()
// The setting, like "FOO=BAR"
func Putenv(setting string) error {
	s := strings.Split(setting, "=")
	if len(s) != 2 {
		panic("setting: invalid")
	}
	return os.Setenv(s[0], s[1])
}

// MemoryGetUsage memory_get_usage()
// return in bytes
func MemoryGetUsage(realUsage bool) uint64 {
	stat := new(runtime.MemStats)
	runtime.ReadMemStats(stat)
	return stat.Alloc
}

// MemoryGetPeakUsage memory_get_peak_usage()
// return in bytes
func MemoryGetPeakUsage(realUsage bool) uint64 {
	stat := new(runtime.MemStats)
	runtime.ReadMemStats(stat)
	return stat.TotalAlloc
}

// VersionCompare version_compare()
// The possible operators are: <, lt, <=, le, >, gt, >=, ge, ==, =, eq, !=, <>, ne respectively.
// special version strings these are handled in the following order,
// (any string not found) < dev < alpha = a < beta = b < RC = rc < # < pl = p
// Usage:
// VersionCompare("1.2.3-alpha", "1.2.3RC7", '>=')
// VersionCompare("1.2.3-beta", "1.2.3pl", 'lt')
// VersionCompare("1.1_dev", "1.2any", 'eq')
func VersionCompare(version1, version2, operator string) bool {
	var vcompare func(string, string) int
	var canonicalize func(string) string
	var special func(string, string) int

	// version compare
	vcompare = func(origV1, origV2 string) int {
		if origV1 == "" || origV2 == "" {
			if origV1 == "" && origV2 == "" {
				return 0
			}
			if origV1 == "" {
				return -1
			}
			return 1
		}

		ver1, ver2, compare := "", "", 0
		if origV1[0] == '#' {
			ver1 = origV1
		} else {
			ver1 = canonicalize(origV1)
		}
		if origV2[0] == '#' {
			ver2 = origV2
		} else {
			ver2 = canonicalize(origV2)
		}
		n1, n2 := 0, 0
		for {
			p1, p2 := "", ""
			n1 = strings.IndexByte(ver1, '.')
			if n1 == -1 {
				p1, ver1 = ver1[:], ""
			} else {
				p1, ver1 = ver1[:n1], ver1[n1+1:]
			}
			n2 = strings.IndexByte(ver2, '.')
			if n2 == -1 {
				p2, ver2 = ver2, ""
			} else {
				p2, ver2 = ver2[:n2], ver2[n2+1:]
			}

			if (p1[0] >= '0' && p1[0] <= '9') && (p2[0] >= '0' && p2[0] <= '9') { // all is digit
				l1, _ := strconv.Atoi(p1)
				l2, _ := strconv.Atoi(p2)
				if l1 > l2 {
					compare = 1
				} else if l1 == l2 {
					compare = 0
				} else {
					compare = -1
				}
			} else if !(p1[0] >= '0' && p1[0] <= '9') && !(p2[0] >= '0' && p2[0] <= '9') { // all digit
				compare = special(p1, p2)
			} else { // part is digit
				if p1[0] >= '0' && p1[0] <= '9' { // is digit
					compare = special("#N#", p2)
				} else {
					compare = special(p1, "#N#")
				}
			}

			if compare != 0 || n1 == -1 || n2 == -1 {
				break
			}
		}

		if compare == 0 {
			if ver1 != "" {
				if ver1[0] >= '0' && ver1[0] <= '9' {
					compare = 1
				} else {
					compare = vcompare(ver1, "#N#")
				}
			} else if ver2 != "" {
				if ver2[0] >= '0' && ver2[0] <= '9' {
					compare = -1
				} else {
					compare = vcompare("#N#", ver2)
				}
			}
		}

		return compare
	}

	// canonicalize
	canonicalize = func(version string) string {
		ver := []byte(version)
		l := len(ver)
		if l == 0 {
			return ""
		}
		var buf = make([]byte, l*2)
		j := 0
		for i, v := range ver {
			next := uint8(0)
			if i+1 < l { // Have the next one
				next = ver[i+1]
			}
			if v == '-' || v == '_' || v == '+' { // replace '-', '_', '+' to '.'
				if j > 0 && buf[j-1] != '.' {
					buf[j] = '.'
					j++
				}
			} else if (next > 0) &&
				(!(next >= '0' && next <= '9') && (v >= '0' && v <= '9')) ||
				(!(v >= '0' && v <= '9') && (next >= '0' && next <= '9')) { // Insert '.' before and after a non-digit
				buf[j] = v
				j++
				if v != '.' && next != '.' {
					buf[j] = '.'
					j++
				}
				continue
			} else if !((v >= '0' && v <= '9') ||
				(v >= 'a' && v <= 'z') || (v >= 'A' && v <= 'Z')) { // Non-letters and numbers
				if j > 0 && buf[j-1] != '.' {
					buf[j] = '.'
					j++
				}
			} else {
				buf[j] = v
				j++
			}
		}

		return string(buf[:j])
	}

	// compare special version forms
	special = func(form1, form2 string) int {
		found1, found2, len1, len2 := -1, -1, len(form1), len(form2)
		// (Any string not found) < dev < alpha = a < beta = b < RC = rc < # < pl = p
		forms := map[string]int{
			"dev":   0,
			"alpha": 1,
			"a":     1,
			"beta":  2,
			"b":     2,
			"RC":    3,
			"rc":    3,
			"#":     4,
			"pl":    5,
			"p":     5,
		}

		for name, order := range forms {
			if len1 < len(name) {
				continue
			}
			if strings.Compare(form1[:len(name)], name) == 0 {
				found1 = order
				break
			}
		}
		for name, order := range forms {
			if len2 < len(name) {
				continue
			}
			if strings.Compare(form2[:len(name)], name) == 0 {
				found2 = order
				break
			}
		}

		if found1 == found2 {
			return 0
		} else if found1 > found2 {
			return 1
		} else {
			return -1
		}
	}

	compare := vcompare(version1, version2)

	switch operator {
	case "<", "lt":
		return compare == -1
	case "<=", "le":
		return compare != 1
	case ">", "gt":
		return compare == 1
	case ">=", "ge":
		return compare != -1
	case "==", "=", "eq":
		return compare == 0
	case "!=", "<>", "ne":
		return compare != 0
	default:
		panic("operator: invalid")
	}
}

// ZipOpen zip_open()
func ZipOpen(filename string) (*zip.ReadCloser, error) {
	return zip.OpenReader(filename)
}

// Pack pack() only number
func Pack(format []string, args ...int64) string {
	p := &Protocol{}
	p.Format = format
	ret := p.Pack16(args...)
	return ret
}

// Unpack unpack() only number
func Unpack(format []string, data string) []int64 {
	p := &Protocol{}
	p.Format = format
	ret := p.UnPack16(data)
	return ret
}

// Ternary Ternary expression
// max := Ternary(a > b, a, b).(int)
func Ternary(condition bool, trueVal, falseVal interface{}) interface{} {
	if condition {
		return trueVal
	}
	return falseVal
}

// RandomString - Generate a random string of a-z chars with len = l
func RandomString(l int) string {
	bytes := make([]byte, l)
	for i := 0; i < l; i++ {
		bytes[i] = byte(97 + rand.Intn(25))
	}
	return string(bytes)
}

// RandStringRunes - generate random string using random int
func RandStringRunes(l int, runes string) string {
	if runes == "" {
		runes = HexChar
	}
	var letters = []rune(runes)
	b := make([]rune, l)
	for i := range b {
		b[i] = letters[rand.Intn(len(letters))]
	}
	return string(b)
}