compound-binary-file-js
Version:
This is an implementation of [Compound Binary File v.3](https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-cfb/53989ce4-7b05-4f8d-829b-d08d6148375b) \ Allows reading existing files, creation of the/write operation
110 lines • 5.43 kB
JavaScript
"use strict";
var __spreadArrays = (this && this.__spreadArrays) || function () {
for (var s = 0, i = 0, il = arguments.length; i < il; i++) s += arguments[i].length;
for (var r = Array(s), k = 0, i = 0; i < il; i++)
for (var a = arguments[i], j = 0, jl = a.length; j < jl; j++, k++)
r[k] = a[j];
return r;
};
Object.defineProperty(exports, "__esModule", { value: true });
var utils_1 = require("../utils");
var VarSizeChunkedDataview_1 = require("../dataview/VarSizeChunkedDataview");
var RegularStreamRW = /** @class */ (function () {
function RegularStreamRW(fat, sectors, header) {
this.fat = fat;
this.sectors = sectors;
this.header = header;
}
RegularStreamRW.prototype.read = function (startingSector, lengthOrFromIncl, toExcl) {
var _this = this;
if (toExcl == null) {
var result = utils_1.initializedWidth(lengthOrFromIncl, 0);
var positionInResult = 0;
for (var _i = 0, _a = this.fat.buildChain(startingSector); _i < _a.length; _i++) {
var sectorPosition = _a[_i];
if (lengthOrFromIncl > 0) {
var sector = this.sectors.sector(sectorPosition);
var bytesToRead = Math.min(sector.getSize(), lengthOrFromIncl);
result.splice.apply(result, __spreadArrays([positionInResult, bytesToRead], sector.subView(0, bytesToRead).getData()));
positionInResult += bytesToRead;
lengthOrFromIncl -= bytesToRead;
}
else {
break;
}
}
return result;
}
else {
return new VarSizeChunkedDataview_1.VariableSizeChunkedDataView(this.fat.buildChain(startingSector).map(function (sectorPosition) { return _this.sectors.sector(sectorPosition); }))
.subView(lengthOrFromIncl, toExcl).getData();
}
};
RegularStreamRW.prototype.write = function (data) {
var firstSectorPosition = null;
var previousSectorPosition = null;
for (var i = 0; i < data.length; i += this.header.getSectorShift()) {
var sector = this.sectors.allocate();
var writeBytes = Math.min(this.header.getSectorShift(), data.length - i);
sector.writeAt(0, data.slice(i, i + writeBytes));
var sectorPosition = sector.getPosition();
this.fat.registerSector(sectorPosition, previousSectorPosition);
if (firstSectorPosition == null) {
firstSectorPosition = sectorPosition;
}
previousSectorPosition = sectorPosition;
}
return firstSectorPosition;
};
RegularStreamRW.prototype.writeAt = function (startingSector, position, data) {
var _this = this;
new VarSizeChunkedDataview_1.VariableSizeChunkedDataView(this.fat.buildChain(startingSector).map(function (pos) { return _this.sectors.sector(pos); }))
.writeAt(position, data);
};
RegularStreamRW.prototype.append = function (startingSector, currentSize, data) {
var sectorChain = this.fat.buildChain(startingSector);
if (sectorChain.length === 0) {
return this.write(data);
}
var lastSectorPosition = sectorChain[sectorChain.length - 1];
var lastSector = this.sectors.sector(lastSectorPosition);
var freeBytesInLastSector = 0;
var remainingBytes = data.length;
if (currentSize % this.header.getSectorShift() !== 0) {
freeBytesInLastSector = lastSector.getSize() - currentSize % this.header.getSectorShift();
if (freeBytesInLastSector > 0) {
var byteToWrite = Math.min(freeBytesInLastSector, data.length);
lastSector.writeAt(lastSector.getSize() - freeBytesInLastSector, data.slice(0, byteToWrite));
freeBytesInLastSector -= byteToWrite;
remainingBytes -= byteToWrite;
}
}
if (freeBytesInLastSector > 0 || remainingBytes === 0) {
return startingSector;
}
var numberOfChunks = this.howManyChunksNeeded(remainingBytes);
var previousSectorPosition = lastSectorPosition;
for (var i = 0; i < numberOfChunks; i += this.header.getSectorShift()) {
var sector = this.sectors.allocate();
var writeBytes = Math.min(this.header.getSectorShift(), data.length - i);
sector.writeAt(0, data.slice(i, i + writeBytes));
var sectorPosition = sector.getPosition();
this.fat.registerSector(sectorPosition, previousSectorPosition);
previousSectorPosition = sectorPosition;
}
return startingSector;
};
RegularStreamRW.prototype.howManyChunksNeeded = function (dataLength) {
var numberOfChunks;
if (dataLength % this.header.getSectorShift() === 0) {
numberOfChunks = Math.floor(dataLength / this.header.getSectorShift());
}
else {
numberOfChunks = Math.floor(dataLength / this.header.getSectorShift()) + 1;
}
return numberOfChunks;
};
return RegularStreamRW;
}());
exports.RegularStreamRW = RegularStreamRW;
//# sourceMappingURL=RegularStream.js.map