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bytesconv.go
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bytesconv.go
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package fasthttp
import (
"bufio"
"fmt"
"io"
"math"
"sync"
"time"
"unsafe"
)
var (
maxIntChars = func() int {
switch ^uint(0) {
case 0xffffffff:
// 32 bit
return 9
case 0xffffffffffffffff:
// 64 bit
return 18
default:
panic("Unsupported architecture :)")
}
}()
maxHexIntChars = func() int {
switch ^uint(0) {
case 0xffffffff:
// 32 bit
return 7
case 0xffffffffffffffff:
// 64 bit
return 15
default:
panic("Unsupported architecture :)")
}
}()
gmtLocation = func() *time.Location {
x, err := time.LoadLocation("GMT")
if err != nil {
panic(fmt.Sprintf("cannot load GMT location: %s", err))
}
return x
}()
)
// AppendHTTPDate appends HTTP-compliant (RFC1123) representation of date
// to dst and returns dst (which may be newly allocated).
func AppendHTTPDate(dst []byte, date time.Time) []byte {
return date.In(gmtLocation).AppendFormat(dst, time.RFC1123)
}
// AppendUint appends n to dst and returns dst (which may be newly allocated).
func AppendUint(dst []byte, n int) []byte {
if n < 0 {
panic("BUG: int must be positive")
}
v := uintBufPool.Get()
if v == nil {
v = make([]byte, maxIntChars+8)
}
buf := v.([]byte)
i := len(buf) - 1
for {
buf[i] = '0' + byte(n%10)
n /= 10
if n == 0 {
break
}
i--
}
dst = append(dst, buf[i:]...)
uintBufPool.Put(v)
return dst
}
// ParseUint parses uint from buf.
func ParseUint(buf []byte) (int, error) {
v, n, err := parseUintBuf(buf)
if n != len(buf) {
return -1, fmt.Errorf("only %b bytes out of %d bytes exhausted when parsing int %q", n, len(buf), buf)
}
return v, err
}
func parseUintBuf(b []byte) (int, int, error) {
n := len(b)
if n == 0 {
return -1, 0, fmt.Errorf("empty integer")
}
v := 0
for i := 0; i < n; i++ {
c := b[i]
k := c - '0'
if k > 9 {
if i == 0 {
return -1, i, fmt.Errorf("unexpected first char %c. Expected 0-9", c)
}
return v, i, nil
}
if i >= maxIntChars {
return -1, i, fmt.Errorf("too long int %q", b[:i+1])
}
v = 10*v + int(k)
}
return v, n, nil
}
// ParseUfloat parses unsigned float from buf.
func ParseUfloat(buf []byte) (float64, error) {
if len(buf) == 0 {
return -1, fmt.Errorf("empty float number")
}
b := buf
var v uint64
var offset float64 = 1.0
var pointFound bool
for i, c := range b {
if c < '0' || c > '9' {
if c == '.' {
if pointFound {
return -1, fmt.Errorf("duplicate point found in %q", buf)
}
pointFound = true
continue
}
if c == 'e' || c == 'E' {
if i+1 >= len(b) {
return -1, fmt.Errorf("unexpected end of float after %c. num=%q", c, buf)
}
b = b[i+1:]
minus := -1
switch b[0] {
case '+':
b = b[1:]
minus = 1
case '-':
b = b[1:]
default:
minus = 1
}
vv, err := ParseUint(b)
if err != nil {
return -1, fmt.Errorf("cannot parse exponent part of %q: %s", buf, err)
}
return float64(v) * offset * math.Pow10(minus*int(vv)), nil
}
return -1, fmt.Errorf("unexpected char found %c in %q", c, buf)
}
v = 10*v + uint64(c-'0')
if pointFound {
offset /= 10
}
}
return float64(v) * offset, nil
}
func readHexInt(r *bufio.Reader) (int, error) {
n := 0
i := 0
var k int
for {
c, err := r.ReadByte()
if err != nil {
if err == io.EOF && i > 0 {
return n, nil
}
return -1, err
}
k = hexbyte2int(c)
if k < 0 {
if i == 0 {
return -1, fmt.Errorf("cannot read hex num from empty string")
}
r.UnreadByte()
return n, nil
}
if i >= maxHexIntChars {
return -1, fmt.Errorf("cannot read hex num with more than %d digits", maxHexIntChars)
}
n = (n << 4) | k
i++
}
}
var uintBufPool sync.Pool
func writeHexInt(w *bufio.Writer, n int) error {
if n < 0 {
panic("BUG: int must be positive")
}
v := uintBufPool.Get()
if v == nil {
v = make([]byte, maxIntChars+8)
}
buf := v.([]byte)
i := len(buf) - 1
for {
buf[i] = int2hexbyte(n & 0xf)
n >>= 4
if n == 0 {
break
}
i--
}
_, err := w.Write(buf[i:])
uintBufPool.Put(v)
return err
}
func int2hexbyte(n int) byte {
if n < 10 {
return '0' + byte(n)
}
return 'a' + byte(n) - 10
}
func hexbyte2int(c byte) int {
if c >= '0' && c <= '9' {
return int(c - '0')
}
if c >= 'a' && c <= 'f' {
return int(c - 'a' + 10)
}
if c >= 'A' && c <= 'F' {
return int(c - 'A' + 10)
}
return -1
}
const toLower = 'a' - 'A'
func uppercaseByte(p *byte) {
c := *p
if c >= 'a' && c <= 'z' {
*p = c - toLower
}
}
func lowercaseByte(p *byte) {
c := *p
if c >= 'A' && c <= 'Z' {
*p = c + toLower
}
}
func lowercaseBytes(b []byte) {
for i, n := 0, len(b); i < n; i++ {
lowercaseByte(&b[i])
}
}
// Converts byte slice to a string without memory allocation.
// See https://groups.google.com/forum/#!msg/Golang-Nuts/ENgbUzYvCuU/90yGx7GUAgAJ .
//
// Note it may break if string and/or slice header will change
// in the future go versions.
func unsafeBytesToStr(b []byte) string {
return *(*string)(unsafe.Pointer(&b))
}
func unhex(c byte) int {
if c >= '0' && c <= '9' {
return int(c - '0')
}
if c >= 'a' && c <= 'f' {
return 10 + int(c-'a')
}
if c >= 'A' && c <= 'F' {
return 10 + int(c-'A')
}
return -1
}
func appendQuotedArg(dst, v []byte) []byte {
for _, c := range v {
if c >= '0' && c <= '9' || c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z' || c == '/' || c == '.' {
dst = append(dst, c)
} else {
dst = append(dst, '%', hexChar(c>>4), hexChar(c&15))
}
}
return dst
}
func hexChar(c byte) byte {
if c < 10 {
return '0' + c
}
return c - 10 + 'A'
}
// EqualBytesStr returns true if string(b) == s.
//
// It doesn't allocate memory unlike string(b) do.
func EqualBytesStr(b []byte, s string) bool {
if len(s) != len(b) {
return false
}
for i, n := 0, len(s); i < n; i++ {
if s[i] != b[i] {
return false
}
}
return true
}
// AppendBytesStr appends src to dst and returns dst
// (which may be newly allocated).
func AppendBytesStr(dst []byte, src string) []byte {
for i, n := 0, len(src); i < n; i++ {
dst = append(dst, src[i])
}
return dst
}