641 lines
11 KiB
Go
641 lines
11 KiB
Go
package encoder
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import (
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"math/bits"
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"reflect"
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"unicode/utf8"
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"unsafe"
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)
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const (
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lsb = 0x0101010101010101
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msb = 0x8080808080808080
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)
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var needEscapeWithHTML = [256]bool{
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'"': true,
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'&': true,
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'<': true,
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'>': true,
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'\\': true,
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0x00: true,
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0x01: true,
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0x02: true,
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0x03: true,
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0x04: true,
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0x05: true,
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0x06: true,
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0x07: true,
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0x08: true,
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0x09: true,
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0x0a: true,
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0x0b: true,
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0x0c: true,
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0x0d: true,
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0x0e: true,
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0x0f: true,
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0x10: true,
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0x11: true,
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0x12: true,
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0x13: true,
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0x14: true,
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0x15: true,
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0x16: true,
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0x17: true,
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0x18: true,
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0x19: true,
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0x1a: true,
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0x1b: true,
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0x1c: true,
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0x1d: true,
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0x1e: true,
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0x1f: true,
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/* 0x20 - 0x7f */
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0x80: true,
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0x81: true,
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0x82: true,
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0x83: true,
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0x84: true,
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0x85: true,
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0x86: true,
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0x87: true,
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0x88: true,
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0x89: true,
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0x8a: true,
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0x8b: true,
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0x8c: true,
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0x8d: true,
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0x8e: true,
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0x8f: true,
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0x90: true,
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0x91: true,
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0x92: true,
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0x93: true,
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0x94: true,
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0x95: true,
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0x96: true,
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0x97: true,
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0x98: true,
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0x99: true,
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0x9a: true,
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0x9b: true,
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0x9c: true,
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0x9d: true,
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0x9e: true,
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0x9f: true,
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0xa0: true,
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0xa1: true,
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0xa2: true,
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0xa3: true,
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0xa4: true,
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0xa5: true,
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0xa6: true,
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0xa7: true,
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0xa8: true,
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0xa9: true,
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0xaa: true,
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0xab: true,
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0xac: true,
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0xad: true,
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0xae: true,
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0xaf: true,
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0xb0: true,
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0xb1: true,
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0xb2: true,
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0xb3: true,
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0xb4: true,
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0xb5: true,
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0xb6: true,
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0xb7: true,
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0xb8: true,
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0xb9: true,
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0xba: true,
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0xbb: true,
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0xbc: true,
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0xbd: true,
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0xbe: true,
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0xbf: true,
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0xc0: true,
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0xc1: true,
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0xc2: true,
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0xc3: true,
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0xc4: true,
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0xc5: true,
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0xc6: true,
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0xc7: true,
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0xc8: true,
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0xc9: true,
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0xca: true,
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0xcb: true,
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0xcc: true,
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0xcd: true,
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0xce: true,
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0xcf: true,
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0xd0: true,
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0xd1: true,
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0xd2: true,
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0xd3: true,
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0xd4: true,
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0xd5: true,
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0xd6: true,
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0xd7: true,
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0xd8: true,
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0xd9: true,
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0xda: true,
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0xdb: true,
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0xdc: true,
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0xdd: true,
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0xde: true,
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0xdf: true,
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0xe0: true,
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0xe1: true,
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0xe2: true,
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0xe3: true,
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0xe4: true,
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0xe5: true,
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0xe6: true,
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0xe7: true,
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0xe8: true,
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0xe9: true,
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0xea: true,
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0xeb: true,
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0xec: true,
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0xed: true,
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0xee: true,
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0xef: true,
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0xf0: true,
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0xf1: true,
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0xf2: true,
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0xf3: true,
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0xf4: true,
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0xf5: true,
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0xf6: true,
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0xf7: true,
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0xf8: true,
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0xf9: true,
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0xfa: true,
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0xfb: true,
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0xfc: true,
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0xfd: true,
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0xfe: true,
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0xff: true,
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}
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var needEscape = [256]bool{
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'"': true,
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'\\': true,
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0x00: true,
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0x01: true,
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0x02: true,
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0x03: true,
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0x04: true,
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0x05: true,
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0x06: true,
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0x07: true,
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0x08: true,
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0x09: true,
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0x0a: true,
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0x0b: true,
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0x0c: true,
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0x0d: true,
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0x0e: true,
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0x0f: true,
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0x10: true,
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0x11: true,
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0x12: true,
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0x13: true,
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0x14: true,
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0x15: true,
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0x16: true,
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0x17: true,
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0x18: true,
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0x19: true,
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0x1a: true,
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0x1b: true,
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0x1c: true,
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0x1d: true,
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0x1e: true,
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0x1f: true,
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/* 0x20 - 0x7f */
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0x80: true,
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0x81: true,
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0x82: true,
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0x83: true,
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0x84: true,
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0x85: true,
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0x86: true,
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0x87: true,
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0x88: true,
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0x89: true,
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0x8a: true,
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0x8b: true,
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0x8c: true,
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0x8d: true,
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0x8e: true,
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0x8f: true,
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0x90: true,
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0x91: true,
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0x92: true,
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0x93: true,
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0x94: true,
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0x95: true,
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0x96: true,
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0x97: true,
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0x98: true,
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0x99: true,
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0x9a: true,
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0x9b: true,
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0x9c: true,
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0x9d: true,
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0x9e: true,
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0x9f: true,
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0xa0: true,
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0xa1: true,
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0xa2: true,
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0xa3: true,
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0xa4: true,
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0xa5: true,
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0xa6: true,
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0xa7: true,
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0xa8: true,
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0xa9: true,
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0xaa: true,
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0xab: true,
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0xac: true,
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0xad: true,
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0xae: true,
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0xaf: true,
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0xb0: true,
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0xb1: true,
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0xb2: true,
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0xb3: true,
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0xb4: true,
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0xb5: true,
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0xb6: true,
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0xb7: true,
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0xb8: true,
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0xb9: true,
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0xba: true,
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0xbb: true,
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0xbc: true,
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0xbd: true,
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0xbe: true,
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0xbf: true,
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0xc0: true,
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0xc1: true,
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0xc2: true,
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0xc3: true,
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0xc4: true,
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0xc5: true,
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0xc6: true,
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0xc7: true,
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0xc8: true,
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0xc9: true,
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0xca: true,
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0xcb: true,
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0xcc: true,
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0xcd: true,
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0xce: true,
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0xcf: true,
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0xd0: true,
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0xd1: true,
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0xd2: true,
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0xd3: true,
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0xd4: true,
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0xd5: true,
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0xd6: true,
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0xd7: true,
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0xd8: true,
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0xd9: true,
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0xda: true,
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0xdb: true,
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0xdc: true,
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0xdd: true,
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0xde: true,
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0xdf: true,
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0xe0: true,
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0xe1: true,
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0xe2: true,
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0xe3: true,
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0xe4: true,
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0xe5: true,
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0xe6: true,
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0xe7: true,
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0xe8: true,
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0xe9: true,
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0xea: true,
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0xeb: true,
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0xec: true,
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0xed: true,
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0xee: true,
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0xef: true,
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0xf0: true,
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0xf1: true,
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0xf2: true,
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0xf3: true,
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0xf4: true,
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0xf5: true,
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0xf6: true,
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0xf7: true,
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0xf8: true,
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0xf9: true,
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0xfa: true,
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0xfb: true,
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0xfc: true,
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0xfd: true,
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0xfe: true,
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0xff: true,
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}
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var hex = "0123456789abcdef"
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// escapeIndex finds the index of the first char in `s` that requires escaping.
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// A char requires escaping if it's outside of the range of [0x20, 0x7F] or if
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// it includes a double quote or backslash.
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// If no chars in `s` require escaping, the return value is -1.
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func escapeIndex(s string) int {
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chunks := stringToUint64Slice(s)
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for _, n := range chunks {
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// combine masks before checking for the MSB of each byte. We include
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// `n` in the mask to check whether any of the *input* byte MSBs were
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// set (i.e. the byte was outside the ASCII range).
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mask := n | below(n, 0x20) | contains(n, '"') | contains(n, '\\')
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if (mask & msb) != 0 {
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return bits.TrailingZeros64(mask&msb) / 8
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}
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}
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valLen := len(s)
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for i := len(chunks) * 8; i < valLen; i++ {
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if needEscape[s[i]] {
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return i
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}
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}
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return -1
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}
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// below return a mask that can be used to determine if any of the bytes
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// in `n` are below `b`. If a byte's MSB is set in the mask then that byte was
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// below `b`. The result is only valid if `b`, and each byte in `n`, is below
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// 0x80.
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func below(n uint64, b byte) uint64 {
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return n - expand(b)
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}
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// contains returns a mask that can be used to determine if any of the
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// bytes in `n` are equal to `b`. If a byte's MSB is set in the mask then
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// that byte is equal to `b`. The result is only valid if `b`, and each
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// byte in `n`, is below 0x80.
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func contains(n uint64, b byte) uint64 {
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return (n ^ expand(b)) - lsb
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}
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// expand puts the specified byte into each of the 8 bytes of a uint64.
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func expand(b byte) uint64 {
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return lsb * uint64(b)
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}
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//nolint:govet
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func stringToUint64Slice(s string) []uint64 {
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return *(*[]uint64)(unsafe.Pointer(&reflect.SliceHeader{
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Data: ((*reflect.StringHeader)(unsafe.Pointer(&s))).Data,
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Len: len(s) / 8,
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Cap: len(s) / 8,
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}))
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}
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func AppendString(ctx *RuntimeContext, buf []byte, s string) []byte {
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if ctx.Option.Flag&HTMLEscapeOption == 0 {
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return appendString(buf, s)
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}
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valLen := len(s)
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if valLen == 0 {
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return append(buf, `""`...)
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}
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buf = append(buf, '"')
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var (
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i, j int
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)
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if valLen >= 8 {
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chunks := stringToUint64Slice(s)
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for _, n := range chunks {
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// combine masks before checking for the MSB of each byte. We include
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// `n` in the mask to check whether any of the *input* byte MSBs were
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// set (i.e. the byte was outside the ASCII range).
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mask := n | (n - (lsb * 0x20)) |
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((n ^ (lsb * '"')) - lsb) |
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((n ^ (lsb * '\\')) - lsb) |
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((n ^ (lsb * '<')) - lsb) |
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((n ^ (lsb * '>')) - lsb) |
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((n ^ (lsb * '&')) - lsb)
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if (mask & msb) != 0 {
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j = bits.TrailingZeros64(mask&msb) / 8
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goto ESCAPE_END
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}
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}
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for i := len(chunks) * 8; i < valLen; i++ {
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if needEscapeWithHTML[s[i]] {
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j = i
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goto ESCAPE_END
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}
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}
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// no found any escape characters.
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return append(append(buf, s...), '"')
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}
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ESCAPE_END:
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for j < valLen {
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c := s[j]
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if !needEscapeWithHTML[c] {
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// fast path: most of the time, printable ascii characters are used
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j++
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continue
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}
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switch c {
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case '\\', '"':
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buf = append(buf, s[i:j]...)
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buf = append(buf, '\\', c)
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i = j + 1
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j = j + 1
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continue
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case '\n':
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buf = append(buf, s[i:j]...)
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buf = append(buf, '\\', 'n')
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i = j + 1
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j = j + 1
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continue
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case '\r':
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buf = append(buf, s[i:j]...)
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buf = append(buf, '\\', 'r')
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i = j + 1
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j = j + 1
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continue
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case '\t':
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buf = append(buf, s[i:j]...)
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buf = append(buf, '\\', 't')
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i = j + 1
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j = j + 1
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continue
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case '<', '>', '&':
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buf = append(buf, s[i:j]...)
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buf = append(buf, `\u00`...)
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buf = append(buf, hex[c>>4], hex[c&0xF])
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i = j + 1
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j = j + 1
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continue
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}
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// This encodes bytes < 0x20 except for \t, \n and \r.
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if c < 0x20 {
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buf = append(buf, s[i:j]...)
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buf = append(buf, `\u00`...)
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buf = append(buf, hex[c>>4], hex[c&0xF])
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i = j + 1
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j = j + 1
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continue
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}
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r, size := utf8.DecodeRuneInString(s[j:])
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if r == utf8.RuneError && size == 1 {
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buf = append(buf, s[i:j]...)
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buf = append(buf, `\ufffd`...)
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i = j + size
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j = j + size
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continue
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}
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switch r {
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case '\u2028', '\u2029':
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// U+2028 is LINE SEPARATOR.
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// U+2029 is PARAGRAPH SEPARATOR.
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// They are both technically valid characters in JSON strings,
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// but don't work in JSONP, which has to be evaluated as JavaScript,
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// and can lead to security holes there. It is valid JSON to
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// escape them, so we do so unconditionally.
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// See http://timelessrepo.com/json-isnt-a-javascript-subset for discussion.
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buf = append(buf, s[i:j]...)
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buf = append(buf, `\u202`...)
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buf = append(buf, hex[r&0xF])
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i = j + size
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j = j + size
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continue
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}
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j += size
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}
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return append(append(buf, s[i:]...), '"')
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}
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func appendString(buf []byte, s string) []byte {
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valLen := len(s)
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if valLen == 0 {
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return append(buf, `""`...)
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}
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buf = append(buf, '"')
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var escapeIdx int
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if valLen >= 8 {
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if escapeIdx = escapeIndex(s); escapeIdx < 0 {
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return append(append(buf, s...), '"')
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}
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}
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i := 0
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j := escapeIdx
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for j < valLen {
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c := s[j]
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if c >= 0x20 && c <= 0x7f && c != '\\' && c != '"' {
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// fast path: most of the time, printable ascii characters are used
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j++
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continue
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}
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|
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
|
|
}
|
|
|
|
// This encodes bytes < 0x20 except for \t, \n and \r.
|
|
if c < 0x20 {
|
|
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
|
|
}
|
|
|
|
r, size := utf8.DecodeRuneInString(s[j:])
|
|
|
|
if r == utf8.RuneError && size == 1 {
|
|
buf = append(buf, s[i:j]...)
|
|
buf = append(buf, `\ufffd`...)
|
|
i = j + size
|
|
j = j + size
|
|
continue
|
|
}
|
|
|
|
switch r {
|
|
case '\u2028', '\u2029':
|
|
// 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.
|
|
buf = append(buf, s[i:j]...)
|
|
buf = append(buf, `\u202`...)
|
|
buf = append(buf, hex[r&0xF])
|
|
i = j + size
|
|
j = j + size
|
|
continue
|
|
}
|
|
|
|
j += size
|
|
}
|
|
|
|
return append(append(buf, s[i:]...), '"')
|
|
}
|