189 lines
3.9 KiB
Go
189 lines
3.9 KiB
Go
// Copyright 2015 Brett Vickers.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package etree
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import (
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"io"
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"strings"
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)
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// A simple stack
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type stack struct {
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data []interface{}
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}
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func (s *stack) empty() bool {
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return len(s.data) == 0
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}
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func (s *stack) push(value interface{}) {
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s.data = append(s.data, value)
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}
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func (s *stack) pop() interface{} {
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value := s.data[len(s.data)-1]
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s.data[len(s.data)-1] = nil
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s.data = s.data[:len(s.data)-1]
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return value
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}
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func (s *stack) peek() interface{} {
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return s.data[len(s.data)-1]
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}
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// A fifo is a simple first-in-first-out queue.
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type fifo struct {
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data []interface{}
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head, tail int
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}
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func (f *fifo) add(value interface{}) {
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if f.len()+1 >= len(f.data) {
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f.grow()
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}
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f.data[f.tail] = value
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if f.tail++; f.tail == len(f.data) {
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f.tail = 0
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}
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}
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func (f *fifo) remove() interface{} {
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value := f.data[f.head]
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f.data[f.head] = nil
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if f.head++; f.head == len(f.data) {
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f.head = 0
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}
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return value
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}
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func (f *fifo) len() int {
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if f.tail >= f.head {
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return f.tail - f.head
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}
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return len(f.data) - f.head + f.tail
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}
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func (f *fifo) grow() {
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c := len(f.data) * 2
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if c == 0 {
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c = 4
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}
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buf, count := make([]interface{}, c), f.len()
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if f.tail >= f.head {
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copy(buf[0:count], f.data[f.head:f.tail])
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} else {
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hindex := len(f.data) - f.head
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copy(buf[0:hindex], f.data[f.head:])
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copy(buf[hindex:count], f.data[:f.tail])
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}
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f.data, f.head, f.tail = buf, 0, count
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}
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// countReader implements a proxy reader that counts the number of
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// bytes read from its encapsulated reader.
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type countReader struct {
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r io.Reader
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bytes int64
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}
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func newCountReader(r io.Reader) *countReader {
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return &countReader{r: r}
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}
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func (cr *countReader) Read(p []byte) (n int, err error) {
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b, err := cr.r.Read(p)
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cr.bytes += int64(b)
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return b, err
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}
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// countWriter implements a proxy writer that counts the number of
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// bytes written by its encapsulated writer.
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type countWriter struct {
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w io.Writer
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bytes int64
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}
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func newCountWriter(w io.Writer) *countWriter {
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return &countWriter{w: w}
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}
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func (cw *countWriter) Write(p []byte) (n int, err error) {
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b, err := cw.w.Write(p)
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cw.bytes += int64(b)
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return b, err
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}
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// isWhitespace returns true if the byte slice contains only
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// whitespace characters.
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func isWhitespace(s string) bool {
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for i := 0; i < len(s); i++ {
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if c := s[i]; c != ' ' && c != '\t' && c != '\n' && c != '\r' {
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return false
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}
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}
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return true
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}
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// spaceMatch returns true if namespace a is the empty string
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// or if namespace a equals namespace b.
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func spaceMatch(a, b string) bool {
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switch {
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case a == "":
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return true
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default:
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return a == b
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}
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}
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// spaceDecompose breaks a namespace:tag identifier at the ':'
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// and returns the two parts.
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func spaceDecompose(str string) (space, key string) {
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colon := strings.IndexByte(str, ':')
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if colon == -1 {
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return "", str
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}
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return str[:colon], str[colon+1:]
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}
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// Strings used by crIndent
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const (
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crsp = "\n "
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crtab = "\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t"
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)
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// crIndent returns a carriage return followed by n copies of the
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// first non-CR character in the source string.
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func crIndent(n int, source string) string {
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switch {
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case n < 0:
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return source[:1]
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case n < len(source):
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return source[:n+1]
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default:
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return source + strings.Repeat(source[1:2], n-len(source)+1)
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}
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}
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// nextIndex returns the index of the next occurrence of sep in s,
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// starting from offset. It returns -1 if the sep string is not found.
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func nextIndex(s, sep string, offset int) int {
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switch i := strings.Index(s[offset:], sep); i {
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case -1:
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return -1
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default:
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return offset + i
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}
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}
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// isInteger returns true if the string s contains an integer.
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func isInteger(s string) bool {
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for i := 0; i < len(s); i++ {
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if (s[i] < '0' || s[i] > '9') && !(i == 0 && s[i] == '-') {
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return false
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}
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}
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return true
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}
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