well-goknown/vendor/github.com/gobwas/ws/util.go

200 lines
4.4 KiB
Go

package ws
import (
"bufio"
"bytes"
"fmt"
"github.com/gobwas/httphead"
)
// SelectFromSlice creates accept function that could be used as Protocol/Extension
// select during upgrade.
func SelectFromSlice(accept []string) func(string) bool {
if len(accept) > 16 {
mp := make(map[string]struct{}, len(accept))
for _, p := range accept {
mp[p] = struct{}{}
}
return func(p string) bool {
_, ok := mp[p]
return ok
}
}
return func(p string) bool {
for _, ok := range accept {
if p == ok {
return true
}
}
return false
}
}
// SelectEqual creates accept function that could be used as Protocol/Extension
// select during upgrade.
func SelectEqual(v string) func(string) bool {
return func(p string) bool {
return v == p
}
}
// asciiToInt converts bytes to int.
func asciiToInt(bts []byte) (ret int, err error) {
// ASCII numbers all start with the high-order bits 0011.
// If you see that, and the next bits are 0-9 (0000 - 1001) you can grab those
// bits and interpret them directly as an integer.
var n int
if n = len(bts); n < 1 {
return 0, fmt.Errorf("converting empty bytes to int")
}
for i := 0; i < n; i++ {
if bts[i]&0xf0 != 0x30 {
return 0, fmt.Errorf("%s is not a numeric character", string(bts[i]))
}
ret += int(bts[i]&0xf) * pow(10, n-i-1)
}
return ret, nil
}
// pow for integers implementation.
// See Donald Knuth, The Art of Computer Programming, Volume 2, Section 4.6.3.
func pow(a, b int) int {
p := 1
for b > 0 {
if b&1 != 0 {
p *= a
}
b >>= 1
a *= a
}
return p
}
func bsplit3(bts []byte, sep byte) (b1, b2, b3 []byte) {
a := bytes.IndexByte(bts, sep)
b := bytes.IndexByte(bts[a+1:], sep)
if a == -1 || b == -1 {
return bts, nil, nil
}
b += a + 1
return bts[:a], bts[a+1 : b], bts[b+1:]
}
func btrim(bts []byte) []byte {
var i, j int
for i = 0; i < len(bts) && (bts[i] == ' ' || bts[i] == '\t'); {
i++
}
for j = len(bts); j > i && (bts[j-1] == ' ' || bts[j-1] == '\t'); {
j--
}
return bts[i:j]
}
func strHasToken(header, token string) (has bool) {
return btsHasToken(strToBytes(header), strToBytes(token))
}
func btsHasToken(header, token []byte) (has bool) {
httphead.ScanTokens(header, func(v []byte) bool {
has = bytes.EqualFold(v, token)
return !has
})
return has
}
const (
toLower = 'a' - 'A' // for use with OR.
toUpper = ^byte(toLower) // for use with AND.
toLower8 = uint64(toLower) |
uint64(toLower)<<8 |
uint64(toLower)<<16 |
uint64(toLower)<<24 |
uint64(toLower)<<32 |
uint64(toLower)<<40 |
uint64(toLower)<<48 |
uint64(toLower)<<56
)
// Algorithm below is like standard textproto/CanonicalMIMEHeaderKey, except
// that it operates with slice of bytes and modifies it inplace without copying.
func canonicalizeHeaderKey(k []byte) {
upper := true
for i, c := range k {
if upper && 'a' <= c && c <= 'z' {
k[i] &= toUpper
} else if !upper && 'A' <= c && c <= 'Z' {
k[i] |= toLower
}
upper = c == '-'
}
}
// readLine reads line from br. It reads until '\n' and returns bytes without
// '\n' or '\r\n' at the end.
// It returns err if and only if line does not end in '\n'. Note that read
// bytes returned in any case of error.
//
// It is much like the textproto/Reader.ReadLine() except the thing that it
// returns raw bytes, instead of string. That is, it avoids copying bytes read
// from br.
//
// textproto/Reader.ReadLineBytes() is also makes copy of resulting bytes to be
// safe with future I/O operations on br.
//
// We could control I/O operations on br and do not need to make additional
// copy for safety.
//
// NOTE: it may return copied flag to notify that returned buffer is safe to
// use.
func readLine(br *bufio.Reader) ([]byte, error) {
var line []byte
for {
bts, err := br.ReadSlice('\n')
if err == bufio.ErrBufferFull {
// Copy bytes because next read will discard them.
line = append(line, bts...)
continue
}
// Avoid copy of single read.
if line == nil {
line = bts
} else {
line = append(line, bts...)
}
if err != nil {
return line, err
}
// Size of line is at least 1.
// In other case bufio.ReadSlice() returns error.
n := len(line)
// Cut '\n' or '\r\n'.
if n > 1 && line[n-2] == '\r' {
line = line[:n-2]
} else {
line = line[:n-1]
}
return line, nil
}
}
func min(a, b int) int {
if a < b {
return a
}
return b
}
func nonZero(a, b int) int {
if a != 0 {
return a
}
return b
}