js-cfb/README.md

# Compound File Binary Format

Pure-JS implementation of MS-CFB: Compound File Binary File Format, a container
format used in many Microsoft file types (XLS, DOC, VBA blobs in XLSX and XLSB)

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## Installation

In the browser:

```html
<script src="dist/cfb.min.js" type="text/javascript"></script>
```

With [npm](https://www.npmjs.org/package/cfb):

```bash
$ npm install cfb
```

The `xlscfb.js` file is designed to be embedded in [js-xlsx](http://git.io/xlsx)


## Library Usage

In node:

```js
var CFB = require('cfb');
```

For example, to get the Workbook content from an XLS file:

```js
var cfb = CFB.read(filename, {type: 'file'});
var workbook = CFB.find(cfb, 'Workbook');
var data = workbook.content;
```


## Command-Line Utility Usage

It is preferable to install the library globally with npm:

```bash
$ npm install -g cfb
```

The global installation adds a command `cfb` which can work with existing files:

- `cfb file` will extract the contents of the file to the current directory.
  It will make the corresponding subdirectories.
- `cfb --list-files file` will show a listing of the contained files.
  The format follows the `unzip -l` "short format".
- `cfb --repair file` will attempt to repair by reading and re-writing the file.
  This fixes some issues with files generated by non-standard tools.


## JS API

TypeScript definitions are maintained in `types/index.d.ts`.

The CFB object exposes the following methods and properties:

`CFB.parse(blob)` takes a nodejs Buffer or an array of bytes and returns an
parsed representation of the data.

`CFB.read(blob, opts)` wraps `parse`.  `opts.type` controls the behavior:

- `file`:   `blob` is interpreted as a file name that will be read
- `base64`: `blob` is interpreted as base64 string
- `binary`: `blob` is interpreted as binary string
- default:  `blob` is interpreted as nodejs buffer or array of bytes

`CFB.find(cfb, path)` performs a case-insensitive match for the path (or file
name, if there are no slashes) and returns an entry object or null if not found.

`CFB.write(cfb, opts)` generates a file based on the container.  `opts.type`
controls the behavior:

- `base64`: returns a base64 string
- `binary`: returns a binary string
- default:  returns a nodejs buffer or array of bytes

`CFB.writeFile(cfb, filename, opts)` creates a file with the specified name.


## Utility Functions

The utility functions are available in the `CFB.utils` object.  Functions that
accept a `name` argument strictly deal with absolute file names:

- `.cfb_new(?opts)` creates a new container object.
- `.cfb_add(cfb, name, ?content, ?opts)` adds a new file to the `cfb`.
- `.cfb_del(cfb, name)` deletes the specified file
- `.cfb_mov(cfb, old_name, new_name)` moves the old file to new path and name


## Container Object Description

The objects returned by `parse` and `read` have the following properties:

- `.FullPaths` is an array of the names of all of the streams (files) and
  storages (directories) in the container.  The paths are properly prefixed from
  the root entry (so the entries are unique)

- `.FullPathDir` is an object whose keys are entries in `.FullPaths` and whose
  values are objects with metadata and content (described below)

- `.FileIndex` is an array of the objects from `.FullPathDir`, in the same order
  as `.FullPaths`.

- `.raw` contains the raw header and sectors


## Entry Object Description

The entry objects are available from `FullPathDir` and `FileIndex` elements of
the container object:

```typescript
interface CFBEntry {
  name: string; /** Case-sensitive internal name */
  type: number; /** 1 = dir, 2 = file, 5 = root ; see [MS-CFB] 2.6.1 */
  content: Buffer | number[] | Uint8Array; /** Raw Content */
  ct?: Date; /** Creation Time */
  mt?: Date; /** Modification Time */
}
```


## License

Please consult the attached LICENSE file for details.  All rights not explicitly
granted by the Apache 2.0 License are reserved by the Original Author.


## References


<details>
	<summary><b>OSP-covered Specifications</b> (click to show)</summary>

 - [MS-CFB]: Compound File Binary File Format

</details>