ReadOnlyFile.md

ReadOnlyFile

Namespace: \ParagonIE\Halite\Stream

This represents a file that we are reading from, which should never be altered while our cryptography operations are being performed.

Constants

    const ALLOWED_MODES = ['rb'];
    // PHP's fread() buffer is set to 8192 by default
    const CHUNK = 8192;

Properties

• $fp (private) - File pointer
• int $pos (private) - Position within the stream (via ftell())
• array $stat (private) - Statistics about the file (via fstat())

Methods

Constructor

Arguments:

• $file - Either a string containing a file location or a resource (file handle opened by fopen())

getHash()

public getHash() : string

Returns the BLAKE2b hash of the file contents.

readBytes()

public readBytes(int $num) : string

Read the desired number of bytes from the internal stream, preventing partial reads. Also performs runtime checks to prevent TOCTOU attacks (race conditions).

remainingBytes()

public remainingBytes() : int

Returns the number of bytes between the current location and the end of the stream.

reset()

public reset(int $i = 0)

Set the current position in the stream to the desired value.

toctouTest()

public toctouTest()

Verifies that the file location (ftell($this->fp)) has not diverged from our current location ($this->loc), and that the file size has not changed.

writeBytes()

public writeBytes(string $buf, int $num = null)

Just returns false.