Source file src/vendor/golang.org/x/net/idna/trie.go

     1	// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
     2	
     3	// Copyright 2016 The Go Authors. All rights reserved.
     4	// Use of this source code is governed by a BSD-style
     5	// license that can be found in the LICENSE file.
     6	
     7	package idna
     8	
     9	// appendMapping appends the mapping for the respective rune. isMapped must be
    10	// true. A mapping is a categorization of a rune as defined in UTS #46.
    11	func (c info) appendMapping(b []byte, s string) []byte {
    12		index := int(c >> indexShift)
    13		if c&xorBit == 0 {
    14			s := mappings[index:]
    15			return append(b, s[1:s[0]+1]...)
    16		}
    17		b = append(b, s...)
    18		if c&inlineXOR == inlineXOR {
    19			// TODO: support and handle two-byte inline masks
    20			b[len(b)-1] ^= byte(index)
    21		} else {
    22			for p := len(b) - int(xorData[index]); p < len(b); p++ {
    23				index++
    24				b[p] ^= xorData[index]
    25			}
    26		}
    27		return b
    28	}
    29	
    30	// Sparse block handling code.
    31	
    32	type valueRange struct {
    33		value  uint16 // header: value:stride
    34		lo, hi byte   // header: lo:n
    35	}
    36	
    37	type sparseBlocks struct {
    38		values []valueRange
    39		offset []uint16
    40	}
    41	
    42	var idnaSparse = sparseBlocks{
    43		values: idnaSparseValues[:],
    44		offset: idnaSparseOffset[:],
    45	}
    46	
    47	// Don't use newIdnaTrie to avoid unconditional linking in of the table.
    48	var trie = &idnaTrie{}
    49	
    50	// lookup determines the type of block n and looks up the value for b.
    51	// For n < t.cutoff, the block is a simple lookup table. Otherwise, the block
    52	// is a list of ranges with an accompanying value. Given a matching range r,
    53	// the value for b is by r.value + (b - r.lo) * stride.
    54	func (t *sparseBlocks) lookup(n uint32, b byte) uint16 {
    55		offset := t.offset[n]
    56		header := t.values[offset]
    57		lo := offset + 1
    58		hi := lo + uint16(header.lo)
    59		for lo < hi {
    60			m := lo + (hi-lo)/2
    61			r := t.values[m]
    62			if r.lo <= b && b <= r.hi {
    63				return r.value + uint16(b-r.lo)*header.value
    64			}
    65			if b < r.lo {
    66				hi = m
    67			} else {
    68				lo = m + 1
    69			}
    70		}
    71		return 0
    72	}
    73	

View as plain text