forked from sheetjs/sheetjs
73 lines
2.4 KiB
JavaScript
73 lines
2.4 KiB
JavaScript
/* [MS-XLSB] 2.1.4 Record */
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function recordhopper(data, cb/*:RecordHopperCB*/, opts/*:?any*/) {
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if(!data) return;
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var tmpbyte, cntbyte, length;
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prep_blob(data, data.l || 0);
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var L = data.length, RT = 0, tgt = 0;
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while(data.l < L) {
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RT = data.read_shift(1);
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if(RT & 0x80) RT = (RT & 0x7F) + ((data.read_shift(1) & 0x7F)<<7);
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var R = XLSBRecordEnum[RT] || XLSBRecordEnum[0xFFFF];
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tmpbyte = data.read_shift(1);
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length = tmpbyte & 0x7F;
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for(cntbyte = 1; cntbyte <4 && (tmpbyte & 0x80); ++cntbyte) length += ((tmpbyte = data.read_shift(1)) & 0x7F)<<(7*cntbyte);
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tgt = data.l + length;
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var d = R.f && R.f(data, length, opts);
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data.l = tgt;
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if(cb(d, R.n, RT)) return;
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}
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}
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/* control buffer usage for fixed-length buffers */
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function buf_array()/*:BufArray*/ {
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var bufs/*:Array<Block>*/ = [], blksz = has_buf ? 256 : 2048;
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var newblk = function ba_newblk(sz/*:number*/)/*:Block*/ {
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var o/*:Block*/ = (new_buf(sz)/*:any*/);
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prep_blob(o, 0);
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return o;
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};
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var curbuf/*:Block*/ = newblk(blksz);
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var endbuf = function ba_endbuf() {
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if(!curbuf) return;
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if(curbuf.length > curbuf.l) { curbuf = curbuf.slice(0, curbuf.l); curbuf.l = curbuf.length; }
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if(curbuf.length > 0) bufs.push(curbuf);
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curbuf = null;
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};
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var next = function ba_next(sz/*:number*/)/*:Block*/ {
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if(curbuf && (sz < (curbuf.length - curbuf.l))) return curbuf;
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endbuf();
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return (curbuf = newblk(Math.max(sz+1, blksz)));
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};
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var end = function ba_end() {
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endbuf();
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return bconcat(bufs);
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};
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var push = function ba_push(buf) { endbuf(); curbuf = buf; if(curbuf.l == null) curbuf.l = curbuf.length; next(blksz); };
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return ({ next:next, push:push, end:end, _bufs:bufs }/*:any*/);
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}
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function write_record(ba/*:BufArray*/, type/*:string*/, payload, length/*:?number*/) {
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var t/*:number*/ = +XLSBRE[type], l;
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if(isNaN(t)) return; // TODO: throw something here?
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if(!length) length = XLSBRecordEnum[t].p || (payload||[]).length || 0;
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l = 1 + (t >= 0x80 ? 1 : 0) + 1/* + length*/;
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if(length >= 0x80) ++l; if(length >= 0x4000) ++l; if(length >= 0x200000) ++l;
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var o = ba.next(l);
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if(t <= 0x7F) o.write_shift(1, t);
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else {
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o.write_shift(1, (t & 0x7F) + 0x80);
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o.write_shift(1, (t >> 7));
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}
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for(var i = 0; i != 4; ++i) {
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if(length >= 0x80) { o.write_shift(1, (length & 0x7F)+0x80); length >>= 7; }
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else { o.write_shift(1, length); break; }
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}
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if(/*:: length != null &&*/length > 0 && is_buf(payload)) ba.push(payload);
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}
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