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import r from 'restructure';
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const Base128 = {
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decode(stream) {
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let result = 0;
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let iterable = [0, 1, 2, 3, 4];
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for (let j = 0; j < iterable.length; j++) {
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let i = iterable[j];
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let code = stream.readUInt8();
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// If any of the top seven bits are set then we're about to overflow.
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if (result & 0xe0000000) {
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throw new Error('Overflow');
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}
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result = (result << 7) | (code & 0x7f);
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if ((code & 0x80) === 0) {
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return result;
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}
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}
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throw new Error('Bad base 128 number');
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}
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};
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let knownTags = [
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'cmap', 'head', 'hhea', 'hmtx', 'maxp', 'name', 'OS/2', 'post', 'cvt ',
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'fpgm', 'glyf', 'loca', 'prep', 'CFF ', 'VORG', 'EBDT', 'EBLC', 'gasp',
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'hdmx', 'kern', 'LTSH', 'PCLT', 'VDMX', 'vhea', 'vmtx', 'BASE', 'GDEF',
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'GPOS', 'GSUB', 'EBSC', 'JSTF', 'MATH', 'CBDT', 'CBLC', 'COLR', 'CPAL',
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'SVG ', 'sbix', 'acnt', 'avar', 'bdat', 'bloc', 'bsln', 'cvar', 'fdsc',
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'feat', 'fmtx', 'fvar', 'gvar', 'hsty', 'just', 'lcar', 'mort', 'morx',
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'opbd', 'prop', 'trak', 'Zapf', 'Silf', 'Glat', 'Gloc', 'Feat', 'Sill'
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];
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let WOFF2DirectoryEntry = new r.Struct({
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flags: r.uint8,
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customTag: new r.Optional(new r.String(4), t => (t.flags & 0x3f) === 0x3f),
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tag: t => t.customTag || knownTags[t.flags & 0x3f],// || (() => { throw new Error(`Bad tag: ${flags & 0x3f}`); })(); },
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length: Base128,
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transformVersion: t => (t.flags >>> 6) & 0x03,
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transformed: t => (t.tag === 'glyf' || t.tag === 'loca') ? t.transformVersion === 0 : t.transformVersion !== 0,
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transformLength: new r.Optional(Base128, t => t.transformed)
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});
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let WOFF2Directory = new r.Struct({
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tag: new r.String(4), // should be 'wOF2'
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flavor: r.uint32,
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length: r.uint32,
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numTables: r.uint16,
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reserved: new r.Reserved(r.uint16),
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totalSfntSize: r.uint32,
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totalCompressedSize: r.uint32,
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majorVersion: r.uint16,
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minorVersion: r.uint16,
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metaOffset: r.uint32,
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metaLength: r.uint32,
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metaOrigLength: r.uint32,
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privOffset: r.uint32,
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privLength: r.uint32,
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tables: new r.Array(WOFF2DirectoryEntry, 'numTables')
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});
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WOFF2Directory.process = function() {
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let tables = {};
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for (let i = 0; i < this.tables.length; i++) {
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let table = this.tables[i];
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tables[table.tag] = table;
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}
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return this.tables = tables;
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};
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export default WOFF2Directory;
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