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|
package encoder
import (
"math/bits"
"reflect"
"unsafe"
)
const (
lsb = 0x0101010101010101
msb = 0x8080808080808080
)
var hex = "0123456789abcdef"
//nolint:govet
func stringToUint64Slice(s string) []uint64 {
return *(*[]uint64)(unsafe.Pointer(&reflect.SliceHeader{
Data: ((*reflect.StringHeader)(unsafe.Pointer(&s))).Data,
Len: len(s) / 8,
Cap: len(s) / 8,
}))
}
func AppendString(ctx *RuntimeContext, buf []byte, s string) []byte {
if ctx.Option.Flag&HTMLEscapeOption != 0 {
if ctx.Option.Flag&NormalizeUTF8Option != 0 {
return appendNormalizedHTMLString(buf, s)
}
return appendHTMLString(buf, s)
}
if ctx.Option.Flag&NormalizeUTF8Option != 0 {
return appendNormalizedString(buf, s)
}
return appendString(buf, s)
}
func appendNormalizedHTMLString(buf []byte, s string) []byte {
valLen := len(s)
if valLen == 0 {
return append(buf, `""`...)
}
buf = append(buf, '"')
var (
i, j int
)
if valLen >= 8 {
chunks := stringToUint64Slice(s)
for _, n := range chunks {
// combine masks before checking for the MSB of each byte. We include
// `n` in the mask to check whether any of the *input* byte MSBs were
// set (i.e. the byte was outside the ASCII range).
mask := n | (n - (lsb * 0x20)) |
((n ^ (lsb * '"')) - lsb) |
((n ^ (lsb * '\\')) - lsb) |
((n ^ (lsb * '<')) - lsb) |
((n ^ (lsb * '>')) - lsb) |
((n ^ (lsb * '&')) - lsb)
if (mask & msb) != 0 {
j = bits.TrailingZeros64(mask&msb) / 8
goto ESCAPE_END
}
}
for i := len(chunks) * 8; i < valLen; i++ {
if needEscapeHTMLNormalizeUTF8[s[i]] {
j = i
goto ESCAPE_END
}
}
// no found any escape characters.
return append(append(buf, s...), '"')
}
ESCAPE_END:
for j < valLen {
c := s[j]
if !needEscapeHTMLNormalizeUTF8[c] {
// fast path: most of the time, printable ascii characters are used
j++
continue
}
switch c {
case '\\', '"':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', c)
i = j + 1
j = j + 1
continue
case '\n':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', 'n')
i = j + 1
j = j + 1
continue
case '\r':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', 'r')
i = j + 1
j = j + 1
continue
case '\t':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', 't')
i = j + 1
j = j + 1
continue
case '<', '>', '&':
buf = append(buf, s[i:j]...)
buf = append(buf, `\u00`...)
buf = append(buf, hex[c>>4], hex[c&0xF])
i = j + 1
j = j + 1
continue
case 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x0B, 0x0C, 0x0E, 0x0F, // 0x00-0x0F
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F: // 0x10-0x1F
buf = append(buf, s[i:j]...)
buf = append(buf, `\u00`...)
buf = append(buf, hex[c>>4], hex[c&0xF])
i = j + 1
j = j + 1
continue
}
state, size := decodeRuneInString(s[j:])
switch state {
case runeErrorState:
buf = append(buf, s[i:j]...)
buf = append(buf, `\ufffd`...)
i = j + 1
j = j + 1
continue
// U+2028 is LINE SEPARATOR.
// U+2029 is PARAGRAPH SEPARATOR.
// They are both technically valid characters in JSON strings,
// but don't work in JSONP, which has to be evaluated as JavaScript,
// and can lead to security holes there. It is valid JSON to
// escape them, so we do so unconditionally.
// See http://timelessrepo.com/json-isnt-a-javascript-subset for discussion.
case lineSepState:
buf = append(buf, s[i:j]...)
buf = append(buf, `\u2028`...)
i = j + 3
j = j + 3
continue
case paragraphSepState:
buf = append(buf, s[i:j]...)
buf = append(buf, `\u2029`...)
i = j + 3
j = j + 3
continue
}
j += size
}
return append(append(buf, s[i:]...), '"')
}
func appendHTMLString(buf []byte, s string) []byte {
valLen := len(s)
if valLen == 0 {
return append(buf, `""`...)
}
buf = append(buf, '"')
var (
i, j int
)
if valLen >= 8 {
chunks := stringToUint64Slice(s)
for _, n := range chunks {
// combine masks before checking for the MSB of each byte. We include
// `n` in the mask to check whether any of the *input* byte MSBs were
// set (i.e. the byte was outside the ASCII range).
mask := n | (n - (lsb * 0x20)) |
((n ^ (lsb * '"')) - lsb) |
((n ^ (lsb * '\\')) - lsb) |
((n ^ (lsb * '<')) - lsb) |
((n ^ (lsb * '>')) - lsb) |
((n ^ (lsb * '&')) - lsb)
if (mask & msb) != 0 {
j = bits.TrailingZeros64(mask&msb) / 8
goto ESCAPE_END
}
}
for i := len(chunks) * 8; i < valLen; i++ {
if needEscapeHTML[s[i]] {
j = i
goto ESCAPE_END
}
}
// no found any escape characters.
return append(append(buf, s...), '"')
}
ESCAPE_END:
for j < valLen {
c := s[j]
if !needEscapeHTML[c] {
// fast path: most of the time, printable ascii characters are used
j++
continue
}
switch c {
case '\\', '"':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', c)
i = j + 1
j = j + 1
continue
case '\n':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', 'n')
i = j + 1
j = j + 1
continue
case '\r':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', 'r')
i = j + 1
j = j + 1
continue
case '\t':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', 't')
i = j + 1
j = j + 1
continue
case '<', '>', '&':
buf = append(buf, s[i:j]...)
buf = append(buf, `\u00`...)
buf = append(buf, hex[c>>4], hex[c&0xF])
i = j + 1
j = j + 1
continue
case 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x0B, 0x0C, 0x0E, 0x0F, // 0x00-0x0F
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F: // 0x10-0x1F
buf = append(buf, s[i:j]...)
buf = append(buf, `\u00`...)
buf = append(buf, hex[c>>4], hex[c&0xF])
i = j + 1
j = j + 1
continue
}
j++
}
return append(append(buf, s[i:]...), '"')
}
func appendNormalizedString(buf []byte, s string) []byte {
valLen := len(s)
if valLen == 0 {
return append(buf, `""`...)
}
buf = append(buf, '"')
var (
i, j int
)
if valLen >= 8 {
chunks := stringToUint64Slice(s)
for _, n := range chunks {
// combine masks before checking for the MSB of each byte. We include
// `n` in the mask to check whether any of the *input* byte MSBs were
// set (i.e. the byte was outside the ASCII range).
mask := n | (n - (lsb * 0x20)) |
((n ^ (lsb * '"')) - lsb) |
((n ^ (lsb * '\\')) - lsb)
if (mask & msb) != 0 {
j = bits.TrailingZeros64(mask&msb) / 8
goto ESCAPE_END
}
}
valLen := len(s)
for i := len(chunks) * 8; i < valLen; i++ {
if needEscapeNormalizeUTF8[s[i]] {
j = i
goto ESCAPE_END
}
}
return append(append(buf, s...), '"')
}
ESCAPE_END:
for j < valLen {
c := s[j]
if !needEscapeNormalizeUTF8[c] {
// fast path: most of the time, printable ascii characters are used
j++
continue
}
switch c {
case '\\', '"':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', c)
i = j + 1
j = j + 1
continue
case '\n':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', 'n')
i = j + 1
j = j + 1
continue
case '\r':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', 'r')
i = j + 1
j = j + 1
continue
case '\t':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', 't')
i = j + 1
j = j + 1
continue
case 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x0B, 0x0C, 0x0E, 0x0F, // 0x00-0x0F
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F: // 0x10-0x1F
buf = append(buf, s[i:j]...)
buf = append(buf, `\u00`...)
buf = append(buf, hex[c>>4], hex[c&0xF])
i = j + 1
j = j + 1
continue
}
state, size := decodeRuneInString(s[j:])
switch state {
case runeErrorState:
buf = append(buf, s[i:j]...)
buf = append(buf, `\ufffd`...)
i = j + 1
j = j + 1
continue
// U+2028 is LINE SEPARATOR.
// U+2029 is PARAGRAPH SEPARATOR.
// They are both technically valid characters in JSON strings,
// but don't work in JSONP, which has to be evaluated as JavaScript,
// and can lead to security holes there. It is valid JSON to
// escape them, so we do so unconditionally.
// See http://timelessrepo.com/json-isnt-a-javascript-subset for discussion.
case lineSepState:
buf = append(buf, s[i:j]...)
buf = append(buf, `\u2028`...)
i = j + 3
j = j + 3
continue
case paragraphSepState:
buf = append(buf, s[i:j]...)
buf = append(buf, `\u2029`...)
i = j + 3
j = j + 3
continue
}
j += size
}
return append(append(buf, s[i:]...), '"')
}
func appendString(buf []byte, s string) []byte {
valLen := len(s)
if valLen == 0 {
return append(buf, `""`...)
}
buf = append(buf, '"')
var (
i, j int
)
if valLen >= 8 {
chunks := stringToUint64Slice(s)
for _, n := range chunks {
// combine masks before checking for the MSB of each byte. We include
// `n` in the mask to check whether any of the *input* byte MSBs were
// set (i.e. the byte was outside the ASCII range).
mask := n | (n - (lsb * 0x20)) |
((n ^ (lsb * '"')) - lsb) |
((n ^ (lsb * '\\')) - lsb)
if (mask & msb) != 0 {
j = bits.TrailingZeros64(mask&msb) / 8
goto ESCAPE_END
}
}
valLen := len(s)
for i := len(chunks) * 8; i < valLen; i++ {
if needEscape[s[i]] {
j = i
goto ESCAPE_END
}
}
return append(append(buf, s...), '"')
}
ESCAPE_END:
for j < valLen {
c := s[j]
if !needEscape[c] {
// fast path: most of the time, printable ascii characters are used
j++
continue
}
switch c {
case '\\', '"':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', c)
i = j + 1
j = j + 1
continue
case '\n':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', 'n')
i = j + 1
j = j + 1
continue
case '\r':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', 'r')
i = j + 1
j = j + 1
continue
case '\t':
buf = append(buf, s[i:j]...)
buf = append(buf, '\\', 't')
i = j + 1
j = j + 1
continue
case 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x0B, 0x0C, 0x0E, 0x0F, // 0x00-0x0F
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F: // 0x10-0x1F
buf = append(buf, s[i:j]...)
buf = append(buf, `\u00`...)
buf = append(buf, hex[c>>4], hex[c&0xF])
i = j + 1
j = j + 1
continue
}
j++
}
return append(append(buf, s[i:]...), '"')
}
|
