<?php
/**
 * Shared helpers for the symbology encoders.
 *
 * @package Barcodegen
 */

defined( 'ABSPATH' ) || exit;

/**
 * Encoding utilities.
 */
class BCGN_Encoder {

	/**
	 * Split a string into an array of byte values.
	 *
	 * @param string $text Raw string.
	 * @return array<int,int>
	 */
	public static function to_byte_array( $text ) {
		$text = (string) $text;

		if ( '' === $text ) {
			return array();
		}

		$bytes = unpack( 'C*', $text );

		return is_array( $bytes ) ? array_values( $bytes ) : array();
	}

	/**
	 * Run length encode a module string into alternating bar and space widths.
	 *
	 * The module string is expected to start with a bar, so the first returned
	 * width is a bar width.
	 *
	 * @param string $bits Module string made of "0" and "1".
	 * @return array<int,int>
	 */
	public static function rle( $bits ) {
		$elements = array();
		$previous = null;
		$run      = 0;
		$length   = strlen( $bits );

		for ( $i = 0; $i < $length; $i++ ) {
			$bit = $bits[ $i ];

			if ( $bit === $previous ) {
				++$run;
				continue;
			}

			if ( null !== $previous ) {
				$elements[] = $run;
			}

			$previous = $bit;
			$run      = 1;
		}

		if ( null !== $previous ) {
			$elements[] = $run;
		}

		return $elements;
	}
}