Dave Jarvis' Repositories

<?php
require_once __DIR__ . '/StreamReader.php';

class GitPackStream implements StreamReader {
  private StreamReader $stream;

  public function __construct( StreamReader $stream ) {
    $this->stream = $stream;
  }

  public function isOpen(): bool {
    return $this->stream->isOpen();
  }

  public function read( int $length ): string {
    return $this->stream->read( $length );
  }

  public function write( string $data ): bool {
    return $this->stream->write( $data );
  }

  public function seek( int $offset, int $whence = SEEK_SET ): bool {
    return $this->stream->seek( $offset, $whence );
  }

  public function tell(): int {
    return $this->stream->tell();
  }

  public function eof(): bool {
    return $this->stream->eof();
  }

  public function rewind(): void {
    $this->stream->rewind();
  }

  public function readVarInt(): array {
    $data = $this->stream->read( 12 );
    $byte = isset( $data[0] ) ? \ord( $data[0] ) : 0;
    $val  = $byte & 15;
    $shft = 4;
    $fst  = $byte;
    $pos  = 1;

    while( $byte & 128 ) {
      $byte  = isset( $data[$pos] )
        ? \ord( $data[$pos++] )
        : 0;
      $val  |= ($byte & 127) << $shft;
      $shft += 7;
    }

    $rem = \strlen( $data ) - $pos;

    if( $rem > 0 ) {
      $this->stream->seek( -$rem, SEEK_CUR );
    }

    return [
      'type' => $fst >> 4 & 7,
      'size' => $val
    ];
  }

  public function readOffsetDelta(): int {
    $data   = $this->stream->read( 12 );
    $byte   = isset( $data[0] ) ? \ord( $data[0] ) : 0;
    $result = $byte & 127;
    $pos    = 1;

    while( $byte & 128 ) {
      $byte   = isset( $data[$pos] )
        ? \ord( $data[$pos++] )
        : 0;
      $result = ($result + 1) << 7 | $byte & 127;
    }

    $rem = \strlen( $data ) - $pos;

    if( $rem > 0 ) {
      $this->stream->seek( -$rem, SEEK_CUR );
    }

    return $result;
  }
}