mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 16:44:23 +08:00
93 lines
2.9 KiB
Go
93 lines
2.9 KiB
Go
// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
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//
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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package ofdgo
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import (
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"cmp"
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"fmt"
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"slices"
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"strconv"
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"strings"
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)
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// ParsePageRange 解析一基页码及闭区间，返回升序去重的零基页面索引
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// 入参: value 页码表达式，如1-6,7,8-10, count 文档总页数
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// 返回: []int 页面索引, error 错误信息
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func ParsePageRange(value string, count int) ([]int, error) {
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var intervals [][2]int
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for _, part := range strings.Split(strings.ReplaceAll(value, "，", ","), ",") {
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first, last, interval := strings.Cut(strings.TrimSpace(part), "-")
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start, err := strconv.Atoi(strings.TrimSpace(first))
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if err != nil {
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return nil, fmt.Errorf("invalid page range %q", part)
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}
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end := start
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if interval {
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end, err = strconv.Atoi(strings.TrimSpace(last))
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if err != nil {
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return nil, fmt.Errorf("invalid page range %q", part)
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}
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}
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if start < 1 || end < start || end > count {
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return nil, fmt.Errorf("page range %q outside 1-%d", part, count)
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}
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intervals = append(intervals, [2]int{start - 1, end})
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}
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slices.SortFunc(intervals, func(a, b [2]int) int { return cmp.Compare(a[0], b[0]) })
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merged := intervals[:0]
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for _, interval := range intervals {
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if len(merged) != 0 && interval[0] <= merged[len(merged)-1][1] {
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merged[len(merged)-1][1] = max(merged[len(merged)-1][1], interval[1])
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} else {
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merged = append(merged, interval)
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}
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}
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length := 0
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for _, interval := range merged {
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length += interval[1] - interval[0]
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}
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indices := make([]int, 0, length)
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for _, interval := range merged {
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for index := interval[0]; index < interval[1]; index++ {
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indices = append(indices, index)
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}
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}
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return indices, nil
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}
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// exportPageIndices 校验导出索引并按原页序去重，省略索引时选取全部页面
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// 入参: count 文档总页数, indices 零基页面索引
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// 返回: []int 页面索引, error 错误信息
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func exportPageIndices(count int, indices []int) ([]int, error) {
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if count == 0 {
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return nil, fmt.Errorf("no pages found")
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}
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if len(indices) == 0 {
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indices = make([]int, count)
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for index := range indices {
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indices[index] = index
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}
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return indices, nil
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}
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for _, index := range indices {
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if index < 0 || index >= count {
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return nil, fmt.Errorf("page index %d out of range", index)
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}
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}
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indices = slices.Clone(indices)
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slices.Sort(indices)
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return slices.Compact(indices), nil
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}
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