1 files changed, 290 insertions, 0 deletions
diff --git a/vendor/golang.org/x/text/collate/build/trie.go b/vendor/golang.org/x/text/collate/build/trie.go
new file mode 100644
index 0000000..9404a34
--- /dev/null
+++ b/vendor/golang.org/x/text/collate/build/trie.go
@@ -0,0 +1,290 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The trie in this file is used to associate the first full character
+// in a UTF-8 string to a collation element.
+// All but the last byte in a UTF-8 byte sequence are
+// used to look up offsets in the index table to be used for the next byte.
+// The last byte is used to index into a table of collation elements.
+// This file contains the code for the generation of the trie.
+
+package build
+
+import (
+	"fmt"
+	"hash/fnv"
+	"io"
+	"reflect"
+)
+
+const (
+	blockSize   = 64
+	blockOffset = 2 // Subtract 2 blocks to compensate for the 0x80 added to continuation bytes.
+)
+
+type trieHandle struct {
+	lookupStart uint16 // offset in table for first byte
+	valueStart  uint16 // offset in table for first byte
+}
+
+type trie struct {
+	index  []uint16
+	values []uint32
+}
+
+// trieNode is the intermediate trie structure used for generating a trie.
+type trieNode struct {
+	index    []*trieNode
+	value    []uint32
+	b        byte
+	refValue uint16
+	refIndex uint16
+}
+
+func newNode() *trieNode {
+	return &trieNode{
+		index: make([]*trieNode, 64),
+		value: make([]uint32, 128), // root node size is 128 instead of 64
+	}
+}
+
+func (n *trieNode) isInternal() bool {
+	return n.value != nil
+}
+
+func (n *trieNode) insert(r rune, value uint32) {
+	const maskx = 0x3F // mask out two most-significant bits
+	str := string(r)
+	if len(str) == 1 {
+		n.value[str[0]] = value
+		return
+	}
+	for i := 0; i < len(str)-1; i++ {
+		b := str[i] & maskx
+		if n.index == nil {
+			n.index = make([]*trieNode, blockSize)
+		}
+		nn := n.index[b]
+		if nn == nil {
+			nn = &trieNode{}
+			nn.b = b
+			n.index[b] = nn
+		}
+		n = nn
+	}
+	if n.value == nil {
+		n.value = make([]uint32, blockSize)
+	}
+	b := str[len(str)-1] & maskx
+	n.value[b] = value
+}
+
+type trieBuilder struct {
+	t *trie
+
+	roots []*trieHandle
+
+	lookupBlocks []*trieNode
+	valueBlocks  []*trieNode
+
+	lookupBlockIdx map[uint32]*trieNode
+	valueBlockIdx  map[uint32]*trieNode
+}
+
+func newTrieBuilder() *trieBuilder {
+	index := &trieBuilder{}
+	index.lookupBlocks = make([]*trieNode, 0)
+	index.valueBlocks = make([]*trieNode, 0)
+	index.lookupBlockIdx = make(map[uint32]*trieNode)
+	index.valueBlockIdx = make(map[uint32]*trieNode)
+	// The third nil is the default null block.  The other two blocks
+	// are used to guarantee an offset of at least 3 for each block.
+	index.lookupBlocks = append(index.lookupBlocks, nil, nil, nil)
+	index.t = &trie{}
+	return index
+}
+
+func (b *trieBuilder) computeOffsets(n *trieNode) *trieNode {
+	hasher := fnv.New32()
+	if n.index != nil {
+		for i, nn := range n.index {
+			var vi, vv uint16
+			if nn != nil {
+				nn = b.computeOffsets(nn)
+				n.index[i] = nn
+				vi = nn.refIndex
+				vv = nn.refValue
+			}
+			hasher.Write([]byte{byte(vi >> 8), byte(vi)})
+			hasher.Write([]byte{byte(vv >> 8), byte(vv)})
+		}
+		h := hasher.Sum32()
+		nn, ok := b.lookupBlockIdx[h]
+		if !ok {
+			n.refIndex = uint16(len(b.lookupBlocks)) - blockOffset
+			b.lookupBlocks = append(b.lookupBlocks, n)
+			b.lookupBlockIdx[h] = n
+		} else {
+			n = nn
+		}
+	} else {
+		for _, v := range n.value {
+			hasher.Write([]byte{byte(v >> 24), byte(v >> 16), byte(v >> 8), byte(v)})
+		}
+		h := hasher.Sum32()
+		nn, ok := b.valueBlockIdx[h]
+		if !ok {
+			n.refValue = uint16(len(b.valueBlocks)) - blockOffset
+			n.refIndex = n.refValue
+			b.valueBlocks = append(b.valueBlocks, n)
+			b.valueBlockIdx[h] = n
+		} else {
+			n = nn
+		}
+	}
+	return n
+}
+
+func (b *trieBuilder) addStartValueBlock(n *trieNode) uint16 {
+	hasher := fnv.New32()
+	for _, v := range n.value[:2*blockSize] {
+		hasher.Write([]byte{byte(v >> 24), byte(v >> 16), byte(v >> 8), byte(v)})
+	}
+	h := hasher.Sum32()
+	nn, ok := b.valueBlockIdx[h]
+	if !ok {
+		n.refValue = uint16(len(b.valueBlocks))
+		n.refIndex = n.refValue
+		b.valueBlocks = append(b.valueBlocks, n)
+		// Add a dummy block to accommodate the double block size.
+		b.valueBlocks = append(b.valueBlocks, nil)
+		b.valueBlockIdx[h] = n
+	} else {
+		n = nn
+	}
+	return n.refValue
+}
+
+func genValueBlock(t *trie, n *trieNode) {
+	if n != nil {
+		for _, v := range n.value {
+			t.values = append(t.values, v)
+		}
+	}
+}
+
+func genLookupBlock(t *trie, n *trieNode) {
+	for _, nn := range n.index {
+		v := uint16(0)
+		if nn != nil {
+			if n.index != nil {
+				v = nn.refIndex
+			} else {
+				v = nn.refValue
+			}
+		}
+		t.index = append(t.index, v)
+	}
+}
+
+func (b *trieBuilder) addTrie(n *trieNode) *trieHandle {
+	h := &trieHandle{}
+	b.roots = append(b.roots, h)
+	h.valueStart = b.addStartValueBlock(n)
+	if len(b.roots) == 1 {
+		// We insert a null block after the first start value block.
+		// This ensures that continuation bytes UTF-8 sequences of length
+		// greater than 2 will automatically hit a null block if there
+		// was an undefined entry.
+		b.valueBlocks = append(b.valueBlocks, nil)
+	}
+	n = b.computeOffsets(n)
+	// Offset by one extra block as the first byte starts at 0xC0 instead of 0x80.
+	h.lookupStart = n.refIndex - 1
+	return h
+}
+
+// generate generates and returns the trie for n.
+func (b *trieBuilder) generate() (t *trie, err error) {
+	t = b.t
+	if len(b.valueBlocks) >= 1<<16 {
+		return nil, fmt.Errorf("maximum number of value blocks exceeded (%d > %d)", len(b.valueBlocks), 1<<16)
+	}
+	if len(b.lookupBlocks) >= 1<<16 {
+		return nil, fmt.Errorf("maximum number of lookup blocks exceeded (%d > %d)", len(b.lookupBlocks), 1<<16)
+	}
+	genValueBlock(t, b.valueBlocks[0])
+	genValueBlock(t, &trieNode{value: make([]uint32, 64)})
+	for i := 2; i < len(b.valueBlocks); i++ {
+		genValueBlock(t, b.valueBlocks[i])
+	}
+	n := &trieNode{index: make([]*trieNode, 64)}
+	genLookupBlock(t, n)
+	genLookupBlock(t, n)
+	genLookupBlock(t, n)
+	for i := 3; i < len(b.lookupBlocks); i++ {
+		genLookupBlock(t, b.lookupBlocks[i])
+	}
+	return b.t, nil
+}
+
+func (t *trie) printArrays(w io.Writer, name string) (n, size int, err error) {
+	p := func(f string, a ...interface{}) {
+		nn, e := fmt.Fprintf(w, f, a...)
+		n += nn
+		if err == nil {
+			err = e
+		}
+	}
+	nv := len(t.values)
+	p("// %sValues: %d entries, %d bytes\n", name, nv, nv*4)
+	p("// Block 2 is the null block.\n")
+	p("var %sValues = [%d]uint32 {", name, nv)
+	var printnewline bool
+	for i, v := range t.values {
+		if i%blockSize == 0 {
+			p("\n\t// Block %#x, offset %#x", i/blockSize, i)
+		}
+		if i%4 == 0 {
+			printnewline = true
+		}
+		if v != 0 {
+			if printnewline {
+				p("\n\t")
+				printnewline = false
+			}
+			p("%#04x:%#08x, ", i, v)
+		}
+	}
+	p("\n}\n\n")
+	ni := len(t.index)
+	p("// %sLookup: %d entries, %d bytes\n", name, ni, ni*2)
+	p("// Block 0 is the null block.\n")
+	p("var %sLookup = [%d]uint16 {", name, ni)
+	printnewline = false
+	for i, v := range t.index {
+		if i%blockSize == 0 {
+			p("\n\t// Block %#x, offset %#x", i/blockSize, i)
+		}
+		if i%8 == 0 {
+			printnewline = true
+		}
+		if v != 0 {
+			if printnewline {
+				p("\n\t")
+				printnewline = false
+			}
+			p("%#03x:%#02x, ", i, v)
+		}
+	}
+	p("\n}\n\n")
+	return n, nv*4 + ni*2, err
+}
+
+func (t *trie) printStruct(w io.Writer, handle *trieHandle, name string) (n, sz int, err error) {
+	const msg = "trie{ %sLookup[%d:], %sValues[%d:], %sLookup[:], %sValues[:]}"
+	n, err = fmt.Fprintf(w, msg, name, handle.lookupStart*blockSize, name, handle.valueStart*blockSize, name, name)
+	sz += int(reflect.TypeOf(trie{}).Size())
+	return
+}