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
166 lines • 8.58 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 MiniStreamRW = /** @class */ (function () {
function MiniStreamRW(miniFAT, fat, firstMiniStreamSector, miniStreamLength, sectors, header) {
this.miniFAT = miniFAT;
this.fat = fat;
this.miniStreamLength = miniStreamLength;
if (firstMiniStreamSector >= 0) {
this.miniStreamSectorChain = fat.buildChain(firstMiniStreamSector);
}
else {
this.miniStreamSectorChain = [];
}
this.sectors = sectors;
this.header = header;
}
MiniStreamRW.prototype.read = function (startingSector, lengthOrFromIncl, toExcl) {
var _this = this;
if (toExcl == null) {
var result = utils_1.initializedWidth(lengthOrFromIncl, 0);
var position = 0;
for (var _i = 0, _a = this.miniFAT.buildChain(startingSector); _i < _a.length; _i++) {
var sectorNumber = _a[_i];
if (lengthOrFromIncl > 0) {
var data = this.getMiniSectorData(sectorNumber);
var bytesToRead = Math.min(data.getSize(), lengthOrFromIncl);
result.splice.apply(result, __spreadArrays([position, bytesToRead], data.subView(0, bytesToRead).getData()));
position += bytesToRead;
lengthOrFromIncl -= bytesToRead;
}
else {
break;
}
}
return result;
}
else {
return new VarSizeChunkedDataview_1.VariableSizeChunkedDataView(this.miniFAT.buildChain(startingSector).map(function (position) { return _this.getMiniSectorData(position); }))
.subView(lengthOrFromIncl, toExcl).getData();
}
};
MiniStreamRW.prototype.getMiniSectorData = function (position) {
var sectorPosition = Math.floor(position * this.header.getMiniSectorShift() / this.header.getSectorShift());
var shiftInsideSector = position * this.header.getMiniSectorShift() % this.header.getSectorShift();
return this.sectors.sector(this.miniStreamSectorChain[sectorPosition]).subView(shiftInsideSector, shiftInsideSector + this.header.getMiniSectorShift());
};
MiniStreamRW.prototype.write = function (data) {
if (data.length <= 0) {
throw new Error();
}
var numberOfChunks = this.howManyChunksNeeded(data.length);
var firstMiniSectorPosition = utils_1.ENDOFCHAIN_MARK_INT;
for (var i = 0; i < numberOfChunks; i++) {
var bytesFromPosition = i * this.header.getMiniSectorShift();
var bytesUpToPosition = Math.min((i + 1) * this.header.getMiniSectorShift(), data.length);
var bytesToWrite = data.slice(bytesFromPosition, bytesUpToPosition);
this.getDataHolderForNextChunk().writeAt(0, bytesToWrite);
var miniSectorPosition = this.miniStreamLength / this.header.getMiniSectorShift();
if (firstMiniSectorPosition === utils_1.ENDOFCHAIN_MARK_INT) {
firstMiniSectorPosition = miniSectorPosition;
}
if (i === 0) {
this.miniFAT.registerSector(miniSectorPosition, null);
}
else {
this.miniFAT.registerSector(miniSectorPosition, miniSectorPosition - 1);
}
this.miniStreamLength += this.header.getMiniSectorShift();
}
return firstMiniSectorPosition;
};
MiniStreamRW.prototype.howManyChunksNeeded = function (dataLength) {
var numberOfChunks;
if (dataLength % this.header.getMiniSectorShift() === 0) {
numberOfChunks = Math.floor(dataLength / this.header.getMiniSectorShift());
}
else {
numberOfChunks = Math.floor(dataLength / this.header.getMiniSectorShift()) + 1;
}
return numberOfChunks;
};
MiniStreamRW.prototype.writeAt = function (startingSector, position, data) {
var _this = this;
new VarSizeChunkedDataview_1.VariableSizeChunkedDataView(this.miniFAT.buildChain(startingSector).map(function (pos) { return _this.getMiniSectorData(pos); }))
.writeAt(position, data);
};
MiniStreamRW.prototype.append = function (startingSector, currentSize, data) {
var sectorChain = this.miniFAT.buildChain(startingSector);
if (sectorChain.length === 0) {
return this.write(data);
}
var lastSectorPosition = sectorChain[sectorChain.length - 1];
var lastSector = this.getMiniSectorData(lastSectorPosition);
var freeBytesInLastSector = 0;
var remainingBytes = data.length;
if (currentSize % this.header.getMiniSectorShift() !== 0) {
freeBytesInLastSector = lastSector.getSize() - currentSize % this.header.getMiniSectorShift();
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);
for (var i = 0; i < numberOfChunks; i++) {
var bytesFromPosition = i * this.header.getMiniSectorShift();
var bytesUpToPosition = Math.min((i + 1) * this.header.getMiniSectorShift(), data.length);
var bytesToWrite = data.slice(bytesFromPosition, bytesUpToPosition);
this.getDataHolderForNextChunk().writeAt(0, bytesToWrite);
var miniSectorPosition = this.miniStreamLength / this.header.getMiniSectorShift();
if (i === 0) {
this.miniFAT.registerSector(miniSectorPosition, lastSectorPosition);
}
else {
this.miniFAT.registerSector(miniSectorPosition, miniSectorPosition - 1);
}
this.miniStreamLength += this.header.getMiniSectorShift();
}
return startingSector;
};
MiniStreamRW.prototype.getDataHolderForNextChunk = function () {
var currentSector = this.getSectorForNextChunk();
var positionInCurrentSector = this.miniStreamLength % this.header.getSectorShift();
return currentSector.subView(positionInCurrentSector, positionInCurrentSector + this.header.getMiniSectorShift());
};
MiniStreamRW.prototype.getSectorForNextChunk = function () {
if (this.miniStreamSectorChain.length === 0) {
var sector = this.sectors.allocate();
this.fat.registerSector(sector.getPosition(), null);
this.miniStreamSectorChain.push(sector.getPosition());
return sector;
}
else if (this.miniStreamLength % this.header.getSectorShift() === 0) {
var sector = this.sectors.allocate();
this.fat.registerSector(sector.getPosition(), this.sectors.sector(this.miniStreamSectorChain[this.miniStreamSectorChain.length - 1]).getPosition());
this.miniStreamSectorChain.push(sector.getPosition());
return sector;
}
else {
return this.sectors.sector(this.miniStreamSectorChain[this.miniStreamSectorChain.length - 1]);
}
};
MiniStreamRW.prototype.getMiniStreamLength = function () {
return this.miniStreamLength;
};
MiniStreamRW.prototype.getMiniStreamFirstSectorPosition = function () {
return this.miniStreamLength <= 0 ? utils_1.FREESECT_MARK_OR_NOSTREAM_INT : this.miniStreamSectorChain[0];
};
MiniStreamRW.MINI_STREAM_CHUNK_SIZE = 64;
return MiniStreamRW;
}());
exports.MiniStreamRW = MiniStreamRW;
//# sourceMappingURL=MiniStreamRW.js.map