mirror of
https://github.com/kataras/iris.git
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121 lines
3.3 KiB
Go
121 lines
3.3 KiB
Go
package utils
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import (
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"bytes"
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"encoding/base64"
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"encoding/gob"
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"math/rand"
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"reflect"
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"strings"
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"time"
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"unsafe"
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)
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//THESE ARE FROM Go Authors
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var htmlReplacer = strings.NewReplacer(
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"&", "&",
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"<", "<",
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">", ">",
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// """ is shorter than """.
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`"`, """,
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// "'" is shorter than "'" and apos was not in HTML until HTML5.
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"'", "'",
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)
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// HtmlEscape returns a string which has no valid html code
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func HtmlEscape(s string) string {
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return htmlReplacer.Replace(s)
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}
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// FindLower returns the smaller number between a and b
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func FindLower(a, b int) int {
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if a <= b {
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return a
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}
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return b
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}
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// BytesToString accepts bytes and returns their string presentation
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// instead of string() this method doesn't generate memory allocations,
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// BUT it is not safe to use anywhere because it points
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// this helps on 0 memory allocations
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func BytesToString(b []byte) string {
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bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
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sh := reflect.StringHeader{bh.Data, bh.Len}
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return *(*string)(unsafe.Pointer(&sh))
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}
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// StringToBytes accepts string and returns their []byte presentation
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// instead of byte() this method doesn't generate memory allocations,
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// BUT it is not safe to use anywhere because it points
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// this helps on 0 memory allocations
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func StringToBytes(s string) []byte {
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sh := (*reflect.StringHeader)(unsafe.Pointer(&s))
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bh := reflect.SliceHeader{sh.Data, sh.Len, 0}
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return *(*[]byte)(unsafe.Pointer(&bh))
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}
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//
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const (
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letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
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letterIdxBits = 6 // 6 bits to represent a letter index
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letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
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letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits
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)
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var src = rand.NewSource(time.Now().UnixNano())
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// Random takes a parameter (int) and returns random slice of byte
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// ex: var randomstrbytes []byte; randomstrbytes = utils.Random(32)
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func Random(n int) []byte {
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b := make([]byte, n)
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// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
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for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
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if remain == 0 {
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cache, remain = src.Int63(), letterIdxMax
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}
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if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
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b[i] = letterBytes[idx]
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i--
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}
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cache >>= letterIdxBits
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remain--
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}
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return b
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}
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// RandomString accepts a number(10 for example) and returns a random string using simple but fairly safe random algorithm
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func RandomString(n int) string {
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return string(Random(n))
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}
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// Serialize serialize any type to gob bytes and after returns its the base64 encoded string
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func Serialize(m interface{}) (string, error) {
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b := bytes.Buffer{}
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encoder := gob.NewEncoder(&b)
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err := encoder.Encode(m)
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if err != nil {
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return "", err
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}
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return base64.StdEncoding.EncodeToString(b.Bytes()), nil
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}
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// Deserialize accepts an encoded string and a data struct which will be filled with the desierialized string
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// using gob decoder
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func Deserialize(str string, m interface{}) error {
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by, err := base64.StdEncoding.DecodeString(str)
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if err != nil {
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return err
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}
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b := bytes.Buffer{}
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b.Write(by)
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d := gob.NewDecoder(&b)
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// d := gob.NewDecoder(bytes.NewBufferString(str))
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err = d.Decode(&m)
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if err != nil {
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return err
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}
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return nil
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}
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