forked from sheetjs/sheetjs
67 lines
1.9 KiB
JavaScript
67 lines
1.9 KiB
JavaScript
/* [MS-XLSB] 2.1.4 Record */
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function recordhopper(data, cb, opts) {
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var tmpbyte, cntbyte, length;
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prep_blob(data, data.l || 0);
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while(data.l < data.length) {
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var 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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var d = R.f(data, length, opts);
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if(cb(d, R, 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() {
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var bufs = [], blksz = 2048;
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var newblk = function ba_newblk(sz) {
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var o = new_buf(sz);
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prep_blob(o, 0);
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return o;
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};
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var curbuf = newblk(blksz);
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var endbuf = function ba_endbuf() {
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curbuf.length = curbuf.l;
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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) {
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if(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 __toBuffer([bufs]);
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};
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var push = function ba_push(buf) { endbuf(); curbuf = buf; next(blksz); };
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return { next:next, push:push, end:end, _bufs:bufs };
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}
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function write_record(ba, type, payload, length) {
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var t = evert_RE[type], l;
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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 > 0 && is_buf(payload)) ba.push(payload);
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}
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