expert/crc.html at main · rcorex/expert · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Devialet Expert Pro CRC Calculator</title>
    <style>
        body { font-family: sans-serif; margin: 2em; max-width: 800px; margin: auto; }
        .box { display: flex; flex-direction: column; width: 100%; margin-top: 1em; }
        textarea { width: 100%; height: 300px; margin-top: 0.5em; box-sizing: border-box; font-family: monospace; }
        button { margin-top: 1em; padding: 0.5em 1em; font-size: 1em; }
        #controls { margin-top: 1em; }
    </style>
</head>
<body>

    <h1>Devialet Expert Pro CRC Calculator</h1>
    <p>Upload your configuration file. Click recalculate and download the file with the correct CRC.</p>
    <p>Disclaimer: Use this tool at your own risk.</p>

    <div id="controls">
        <label for="fileInput">Upload File:</label>
        <input type="file" id="fileInput">
    </div>

    <div class="box">
        <h2>Input File</h2>
        <textarea id="inputFileContent" placeholder="Upload a file..."></textarea>
    </div>

    <button id="recalculateButton">Recalculate Checksum</button>

    <div class="box">
        <h2>Output File</h2>
        <textarea id="outputFileContent" readonly></textarea>
        <button id="downloadButton" style="display: none; align-self: flex-start;">Download Output File</button>
    </div>

    <script>
        document.getElementById('fileInput').addEventListener('change', handleFileSelect, false);
        document.getElementById('recalculateButton').addEventListener('click', runCalculation, false);
        document.getElementById('downloadButton').addEventListener('click', downloadOutputFile, false);

        let outputContent = '';
        let originalFilename = 'recalculated_file.txt'; // Default filename

        function handleFileSelect(event) {
            const file = event.target.files[0];
            if (!file) return;

            originalFilename = file.name;
            const reader = new FileReader();

            reader.onload = function(e) {
                document.getElementById('inputFileContent').value = e.target.result;
            };

            reader.readAsText(file);
        }

        function runCalculation() {
            const contentsFromTextarea = document.getElementById('inputFileContent').value;
            if (!contentsFromTextarea) {
                alert("Input box is empty.");
                return;
            }

            // **FIX:** Normalize all line endings to CRLF (\r\n) to ensure consistency.
            // This replaces any standalone \n or \r\n with \r\n.
            const contents = contentsFromTextarea.replace(/\r?\n/g, '\r\n');

            if (contents.length < 7 || !contents.toUpperCase().startsWith('CRC')) {
                alert('The input text must start with "CRCxxxx" (e.g., CRC0000).');
                return;
            }

            // The data to be hashed is everything AFTER the first 7 bytes ('CRCxxxx')
            const dataToHash = contents.substring(7);

            // Calculate the new CRC on the CRLF-normalized data
            const crc = crc16_ccitt_false(dataToHash);
            const crcHex = crc.toString(16).toUpperCase().padStart(4, '0');
            const newCrcLine = 'CRC' + crcHex;

            // Find the end of the first line to get the rest of the file content
            const firstLineEndIndex = contents.indexOf('\r\n');
            let restOfContent = '';

            if (firstLineEndIndex !== -1) {
                // If a CRLF is found, the rest of the content starts from there
                restOfContent = contents.substring(firstLineEndIndex);
            }

            // Reconstruct the final output with the new CRC
            outputContent = newCrcLine + restOfContent;

            // Update the UI
            document.getElementById('outputFileContent').value = outputContent;
            document.getElementById('downloadButton').style.display = 'block';
        }

        function downloadOutputFile() {
            // The outputContent string already has the correct CRLF line endings
            const blob = new Blob([outputContent], { type: 'text/plain' });
            const link = document.createElement('a');
            link.href = URL.createObjectURL(blob);
            link.download = originalFilename;
            document.body.appendChild(link);
            link.click();
            document.body.removeChild(link);
        }

        function crc16_ccitt_false(str) {
            let crc = 0xFFFF; // Initial value
            const polynomial = 0x1021;

            for (let i = 0; i < str.length; i++) {
                crc ^= str.charCodeAt(i) << 8;
                for (let j = 0; j < 8; j++) {
                    if ((crc & 0x8000) !== 0) {
                        crc = (crc << 1) ^ polynomial;
                    } else {
                        crc <<= 1;
                    }
                }
            }

            return crc & 0xFFFF;
        }
    </script>

</body>
</html>