exceljs
Version:
Excel Workbook Manager - Read and Write xlsx and csv Files.
74 lines (68 loc) • 1.99 kB
JavaScript
"use strict";
// StringBuf - a way to keep string memory operations to a minimum
// while building the strings for the xml files
class StringBuf {
constructor(options) {
this._buf = Buffer.alloc(options && options.size || 16384);
this._encoding = options && options.encoding || 'utf8';
// where in the buffer we are at
this._inPos = 0;
// for use by toBuffer()
this._buffer = undefined;
}
get length() {
return this._inPos;
}
get capacity() {
return this._buf.length;
}
get buffer() {
return this._buf;
}
toBuffer() {
// return the current data as a single enclosing buffer
if (!this._buffer) {
this._buffer = Buffer.alloc(this.length);
this._buf.copy(this._buffer, 0, 0, this.length);
}
return this._buffer;
}
reset(position) {
position = position || 0;
this._buffer = undefined;
this._inPos = position;
}
_grow(min) {
let size = this._buf.length * 2;
while (size < min) {
size *= 2;
}
const buf = Buffer.alloc(size);
this._buf.copy(buf, 0);
this._buf = buf;
}
addText(text) {
this._buffer = undefined;
let inPos = this._inPos + this._buf.write(text, this._inPos, this._encoding);
// if we've hit (or nearing capacity), grow the buf
while (inPos >= this._buf.length - 4) {
this._grow(this._inPos + text.length);
// keep trying to write until we've completely written the text
inPos = this._inPos + this._buf.write(text, this._inPos, this._encoding);
}
this._inPos = inPos;
}
addStringBuf(inBuf) {
if (inBuf.length) {
this._buffer = undefined;
if (this.length + inBuf.length > this.capacity) {
this._grow(this.length + inBuf.length);
}
// eslint-disable-next-line no-underscore-dangle
inBuf._buf.copy(this._buf, this._inPos, 0, inBuf.length);
this._inPos += inBuf.length;
}
}
}
module.exports = StringBuf;
//# sourceMappingURL=string-buf.js.map