Convert src/core/opentype_file_builder.js to use standard classes

This commit is contained in:
Jonas Jenwald 2021-05-02 11:54:05 +02:00
parent 1808b2dc96
commit 8c1d1a58f7

View File

@ -16,45 +16,43 @@
import { readUint32 } from "./core_utils.js"; import { readUint32 } from "./core_utils.js";
import { string32 } from "../shared/util.js"; import { string32 } from "../shared/util.js";
const OpenTypeFileBuilder = (function OpenTypeFileBuilderClosure() { function writeInt16(dest, offset, num) {
function writeInt16(dest, offset, num) { dest[offset] = (num >> 8) & 0xff;
dest[offset] = (num >> 8) & 0xff; dest[offset + 1] = num & 0xff;
dest[offset + 1] = num & 0xff; }
}
function writeInt32(dest, offset, num) { function writeInt32(dest, offset, num) {
dest[offset] = (num >> 24) & 0xff; dest[offset] = (num >> 24) & 0xff;
dest[offset + 1] = (num >> 16) & 0xff; dest[offset + 1] = (num >> 16) & 0xff;
dest[offset + 2] = (num >> 8) & 0xff; dest[offset + 2] = (num >> 8) & 0xff;
dest[offset + 3] = num & 0xff; dest[offset + 3] = num & 0xff;
} }
function writeData(dest, offset, data) { function writeData(dest, offset, data) {
let i, ii; if (data instanceof Uint8Array) {
if (data instanceof Uint8Array) { dest.set(data, offset);
dest.set(data, offset); } else if (typeof data === "string") {
} else if (typeof data === "string") { for (let i = 0, ii = data.length; i < ii; i++) {
for (i = 0, ii = data.length; i < ii; i++) { dest[offset++] = data.charCodeAt(i) & 0xff;
dest[offset++] = data.charCodeAt(i) & 0xff; }
} } else {
} else { // treating everything else as array
// treating everything else as array for (let i = 0, ii = data.length; i < ii; i++) {
for (i = 0, ii = data.length; i < ii; i++) { dest[offset++] = data[i] & 0xff;
dest[offset++] = data[i] & 0xff;
}
} }
} }
}
// eslint-disable-next-line no-shadow const OTF_HEADER_SIZE = 12;
function OpenTypeFileBuilder(sfnt) { const OTF_TABLE_ENTRY_SIZE = 16;
class OpenTypeFileBuilder {
constructor(sfnt) {
this.sfnt = sfnt; this.sfnt = sfnt;
this.tables = Object.create(null); this.tables = Object.create(null);
} }
OpenTypeFileBuilder.getSearchParams = function OpenTypeFileBuilder_getSearchParams( static getSearchParams(entriesCount, entrySize) {
entriesCount,
entrySize
) {
let maxPower2 = 1, let maxPower2 = 1,
log2 = 0; log2 = 0;
while ((maxPower2 ^ entriesCount) > maxPower2) { while ((maxPower2 ^ entriesCount) > maxPower2) {
@ -67,97 +65,90 @@ const OpenTypeFileBuilder = (function OpenTypeFileBuilderClosure() {
entry: log2, entry: log2,
rangeShift: entrySize * entriesCount - searchRange, rangeShift: entrySize * entriesCount - searchRange,
}; };
}; }
const OTF_HEADER_SIZE = 12; toArray() {
const OTF_TABLE_ENTRY_SIZE = 16; let sfnt = this.sfnt;
OpenTypeFileBuilder.prototype = { // Tables needs to be written by ascendant alphabetic order
toArray: function OpenTypeFileBuilder_toArray() { const tables = this.tables;
let sfnt = this.sfnt; const tablesNames = Object.keys(tables);
tablesNames.sort();
const numTables = tablesNames.length;
// Tables needs to be written by ascendant alphabetic order let i, j, jj, table, tableName;
const tables = this.tables; // layout the tables data
const tablesNames = Object.keys(tables); let offset = OTF_HEADER_SIZE + numTables * OTF_TABLE_ENTRY_SIZE;
tablesNames.sort(); const tableOffsets = [offset];
const numTables = tablesNames.length; for (i = 0; i < numTables; i++) {
table = tables[tablesNames[i]];
const paddedLength = ((table.length + 3) & ~3) >>> 0;
offset += paddedLength;
tableOffsets.push(offset);
}
let i, j, jj, table, tableName; const file = new Uint8Array(offset);
// layout the tables data // write the table data first (mostly for checksum)
let offset = OTF_HEADER_SIZE + numTables * OTF_TABLE_ENTRY_SIZE; for (i = 0; i < numTables; i++) {
const tableOffsets = [offset]; table = tables[tablesNames[i]];
for (i = 0; i < numTables; i++) { writeData(file, tableOffsets[i], table);
table = tables[tablesNames[i]]; }
const paddedLength = ((table.length + 3) & ~3) >>> 0;
offset += paddedLength; // sfnt version (4 bytes)
tableOffsets.push(offset); if (sfnt === "true") {
// Windows hates the Mac TrueType sfnt version number
sfnt = string32(0x00010000);
}
file[0] = sfnt.charCodeAt(0) & 0xff;
file[1] = sfnt.charCodeAt(1) & 0xff;
file[2] = sfnt.charCodeAt(2) & 0xff;
file[3] = sfnt.charCodeAt(3) & 0xff;
// numTables (2 bytes)
writeInt16(file, 4, numTables);
const searchParams = OpenTypeFileBuilder.getSearchParams(numTables, 16);
// searchRange (2 bytes)
writeInt16(file, 6, searchParams.range);
// entrySelector (2 bytes)
writeInt16(file, 8, searchParams.entry);
// rangeShift (2 bytes)
writeInt16(file, 10, searchParams.rangeShift);
offset = OTF_HEADER_SIZE;
// writing table entries
for (i = 0; i < numTables; i++) {
tableName = tablesNames[i];
file[offset] = tableName.charCodeAt(0) & 0xff;
file[offset + 1] = tableName.charCodeAt(1) & 0xff;
file[offset + 2] = tableName.charCodeAt(2) & 0xff;
file[offset + 3] = tableName.charCodeAt(3) & 0xff;
// checksum
let checksum = 0;
for (j = tableOffsets[i], jj = tableOffsets[i + 1]; j < jj; j += 4) {
const quad = readUint32(file, j);
checksum = (checksum + quad) >>> 0;
} }
writeInt32(file, offset + 4, checksum);
const file = new Uint8Array(offset); // offset
// write the table data first (mostly for checksum) writeInt32(file, offset + 8, tableOffsets[i]);
for (i = 0; i < numTables; i++) { // length
table = tables[tablesNames[i]]; writeInt32(file, offset + 12, tables[tableName].length);
writeData(file, tableOffsets[i], table);
}
// sfnt version (4 bytes) offset += OTF_TABLE_ENTRY_SIZE;
if (sfnt === "true") { }
// Windows hates the Mac TrueType sfnt version number return file;
sfnt = string32(0x00010000); }
}
file[0] = sfnt.charCodeAt(0) & 0xff;
file[1] = sfnt.charCodeAt(1) & 0xff;
file[2] = sfnt.charCodeAt(2) & 0xff;
file[3] = sfnt.charCodeAt(3) & 0xff;
// numTables (2 bytes) addTable(tag, data) {
writeInt16(file, 4, numTables); if (tag in this.tables) {
throw new Error("Table " + tag + " already exists");
const searchParams = OpenTypeFileBuilder.getSearchParams(numTables, 16); }
this.tables[tag] = data;
// searchRange (2 bytes) }
writeInt16(file, 6, searchParams.range); }
// entrySelector (2 bytes)
writeInt16(file, 8, searchParams.entry);
// rangeShift (2 bytes)
writeInt16(file, 10, searchParams.rangeShift);
offset = OTF_HEADER_SIZE;
// writing table entries
for (i = 0; i < numTables; i++) {
tableName = tablesNames[i];
file[offset] = tableName.charCodeAt(0) & 0xff;
file[offset + 1] = tableName.charCodeAt(1) & 0xff;
file[offset + 2] = tableName.charCodeAt(2) & 0xff;
file[offset + 3] = tableName.charCodeAt(3) & 0xff;
// checksum
let checksum = 0;
for (j = tableOffsets[i], jj = tableOffsets[i + 1]; j < jj; j += 4) {
const quad = readUint32(file, j);
checksum = (checksum + quad) >>> 0;
}
writeInt32(file, offset + 4, checksum);
// offset
writeInt32(file, offset + 8, tableOffsets[i]);
// length
writeInt32(file, offset + 12, tables[tableName].length);
offset += OTF_TABLE_ENTRY_SIZE;
}
return file;
},
addTable: function OpenTypeFileBuilder_addTable(tag, data) {
if (tag in this.tables) {
throw new Error("Table " + tag + " already exists");
}
this.tables[tag] = data;
},
};
return OpenTypeFileBuilder;
})();
export { OpenTypeFileBuilder }; export { OpenTypeFileBuilder };