Codex
28 lines
2.0 KiB
JavaScript
28 lines
2.0 KiB
JavaScript
'use strict';
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// Pure range logic shared by the UI and regression tests. All ranges are [start,end).
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const RecordingRanges=(()=>{
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// Date truncates fractional milliseconds. Round the query start inward so
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// MediaMTX never receives a time before this segment's microsecond timestamp.
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function firstMillisecond(value){
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const time=+new Date(value),fraction=typeof value==='string'&&value.match(/\.(\d+)(?:Z|[+-]\d{2}:\d{2})$/);
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return time+(fraction&&/[1-9]/.test(fraction[1].slice(3))?1:0);
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}
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function normalize(items,start,end){
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const lo=+start,hi=+end;if(!Number.isFinite(lo)||!Number.isFinite(hi)||hi<=lo)return [];
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const ranges=(Array.isArray(items)?items:[]).filter(s=>s&&Number.isFinite(+new Date(s.start))&&Number.isFinite(Number(s.duration))&&Number(s.duration)>0).map(s=>({start:Math.max(lo,firstMillisecond(s.start)),end:Math.min(hi,Math.floor(+new Date(s.start)+Number(s.duration)*1000))}))
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.filter(s=>Number.isFinite(s.start)&&Number.isFinite(s.end)&&s.end>s.start).sort((a,b)=>a.start-b.start);
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const result=[];for(const r of ranges){const last=result.at(-1);if(last&&r.start<=last.end)last.end=Math.max(last.end,r.end);else result.push({...r});}return result;
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}
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function at(ranges,time){const t=+time,s=ranges.find(s=>t>=s.start&&t<s.end);return s?{start:t,end:Math.min(s.end,t+300000)}:null;}
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function next(ranges,end){const s=ranges.find(s=>s.end>+end);return s?at(ranges,Math.max(s.start,+end)):null;}
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function clip(ranges,start,end){
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const a=+start,b=+end;
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if(!Number.isFinite(a)||!Number.isFinite(b)||b<=a)throw Error('结束时间必须晚于开始时间');
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if(b-a>3600000)throw Error('一次下载最多一小时，请缩短片段');
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if(!ranges.some(s=>a>=s.start&&b<=s.end))throw Error('所选片段跨越无录像时段或超出查询日期，请选择同一连续录像时段');
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return {start:a,end:b};
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}
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return {normalize,at,next,clip};
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})();
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if(typeof module!=='undefined')module.exports=RecordingRanges;
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