51 lines
1.5 KiB
TypeScript
51 lines
1.5 KiB
TypeScript
/**
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* NodeId 解码工具
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*/
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const ROOT_BITS = 4,
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TYPE_BITS = 4,
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SUBJ_BITS = 20,
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STAGE_BITS = 4,
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GRADE_BITS = 4,
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NODE_BITS = 28;
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const ROOT_MASK = mask(ROOT_BITS),
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TYPE_MASK = mask(TYPE_BITS),
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SUBJ_MASK = mask(SUBJ_BITS),
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STAGE_MASK = mask(STAGE_BITS),
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GRADE_MASK = mask(GRADE_BITS),
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NODE_MASK = mask(NODE_BITS);
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function mask(bits: number) {
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return (1n << BigInt(bits)) - 1n;
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}
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function intToSubject(n: number) {
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if (n === 0) return null;
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return n <= 6 ? `SUB0${n}` : `SUB${n}`;
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}
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/**
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* 解码入口：long → 普通对象
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* @param {string|number} compositeId 后端传来的 long 字符串或数字
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* @returns {Object}
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*/
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export function decodeNodeId(compositeId: number | string) {
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const id = BigInt(compositeId);
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const root = Number((id >> BigInt(TYPE_BITS + SUBJ_BITS + STAGE_BITS + GRADE_BITS + NODE_BITS)) & ROOT_MASK);
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const type = Number((id >> BigInt(SUBJ_BITS + STAGE_BITS + GRADE_BITS + NODE_BITS)) & TYPE_MASK);
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const subNum = Number((id >> BigInt(STAGE_BITS + GRADE_BITS + NODE_BITS)) & SUBJ_MASK);
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const stage = Number((id >> BigInt(GRADE_BITS + NODE_BITS)) & STAGE_MASK);
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const grade = Number((id >> BigInt(NODE_BITS)) & GRADE_MASK);
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const nodeId = Number(id & NODE_MASK);
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return {
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rootType: root === 0 ? null : root,
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nodeType: type === 0 ? null : type,
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subject: intToSubject(subNum),
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stage: stage === 0 ? null : stage,
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grade: grade === 0 ? null : grade,
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nodeId: nodeId === 0 ? null : nodeId,
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};
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}
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