github.com/v2pro/plz@v0.0.0-20221028024117-e5f9aec5b631/parse/utf8.go (about)

     1  package parse
     2  
     3  const (
     4  	// These names of these constants are chosen to give nice alignment in the
     5  	// table below. The first nibble is an index into acceptRanges or F for
     6  	// special one-byte cases. The second nibble is the Rune length or the
     7  	// Status for the special one-byte case.
     8  	xx = 0xF1 // invalid: size 1
     9  	as = 0xF0 // ASCII: size 1
    10  	s1 = 0x02 // accept 0, size 2
    11  	s2 = 0x13 // accept 1, size 3
    12  	s3 = 0x03 // accept 0, size 3
    13  	s4 = 0x23 // accept 2, size 3
    14  	s5 = 0x34 // accept 3, size 4
    15  	s6 = 0x04 // accept 0, size 4
    16  	s7 = 0x44 // accept 4, size 4
    17  )
    18  
    19  // first is information about the first byte in a UTF-8 sequence.
    20  var first = [256]uint8{
    21  	//   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F
    22  	as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, // 0x00-0x0F
    23  	as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, // 0x10-0x1F
    24  	as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, // 0x20-0x2F
    25  	as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, // 0x30-0x3F
    26  	as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, // 0x40-0x4F
    27  	as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, // 0x50-0x5F
    28  	as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, // 0x60-0x6F
    29  	as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, as, // 0x70-0x7F
    30  	//   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F
    31  	xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, // 0x80-0x8F
    32  	xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, // 0x90-0x9F
    33  	xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, // 0xA0-0xAF
    34  	xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, // 0xB0-0xBF
    35  	xx, xx, s1, s1, s1, s1, s1, s1, s1, s1, s1, s1, s1, s1, s1, s1, // 0xC0-0xCF
    36  	s1, s1, s1, s1, s1, s1, s1, s1, s1, s1, s1, s1, s1, s1, s1, s1, // 0xD0-0xDF
    37  	s2, s3, s3, s3, s3, s3, s3, s3, s3, s3, s3, s3, s3, s4, s3, s3, // 0xE0-0xEF
    38  	s5, s6, s6, s6, s7, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, // 0xF0-0xFF
    39  }