117 lines
2.2 KiB
Go
117 lines
2.2 KiB
Go
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/*
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Copyright (c) 2020 Denis Tingajkin
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SPDX-License-Identifier: Apache-2.0
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at:
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package goheader
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func NewReader(text string) *Reader {
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return &Reader{source: text}
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}
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type Reader struct {
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source string
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position int
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location Location
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offset Location
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}
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func (r *Reader) SetOffset(offset Location) {
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r.offset = offset
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}
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func (r *Reader) Position() int {
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return r.position
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}
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func (r *Reader) Location() Location {
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return r.location.Add(r.offset)
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}
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func (r *Reader) Peek() rune {
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if r.Done() {
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return rune(0)
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}
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return rune(r.source[r.position])
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}
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func (r *Reader) Done() bool {
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return r.position >= len(r.source)
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}
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func (r *Reader) Next() rune {
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if r.Done() {
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return rune(0)
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}
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reuslt := r.Peek()
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if reuslt == '\n' {
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r.location.Line++
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r.location.Position = 0
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} else {
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r.location.Position++
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}
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r.position++
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return reuslt
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}
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func (r *Reader) Finish() string {
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if r.position >= len(r.source) {
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return ""
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}
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defer r.till()
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return r.source[r.position:]
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}
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func (r *Reader) SetPosition(pos int) {
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if pos < 0 {
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r.position = 0
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}
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r.position = pos
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r.location = r.calculateLocation()
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}
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func (r *Reader) ReadWhile(match func(rune) bool) string {
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if match == nil {
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return ""
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}
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start := r.position
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for !r.Done() && match(r.Peek()) {
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r.Next()
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}
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return r.source[start:r.position]
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}
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func (r *Reader) till() {
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r.position = len(r.source)
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r.location = r.calculateLocation()
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}
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func (r *Reader) calculateLocation() Location {
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min := len(r.source)
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if min > r.position {
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min = r.position
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}
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x, y := 0, 0
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for i := 0; i < min; i++ {
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if r.source[i] == '\n' {
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y++
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x = 0
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} else {
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x++
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}
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}
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return Location{Line: y, Position: x}
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}
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