@eventmsg/core/dist/internal/byte-stuffing.cjs.map

EventMsgV3 TypeScript library - Core protocol implementation with transport abstraction

{"version":3,"file":"byte-stuffing.cjs","names":["result: number[]"],"sources":["../../src/internal/byte-stuffing.ts"],"sourcesContent":["/**\n * EventMsgV3 Byte Stuffing Implementation\n *\n * Implements the exact byte stuffing algorithm from the C implementation\n * to ensure protocol compatibility.\n */\n\n/**\n * Control characters used in EventMsgV3 protocol\n */\nexport const CONTROL_CHARS = {\n  SOH: 0x01, // Start of Header\n  STX: 0x02, // Start of Text\n  EOT: 0x04, // End of Transmission\n  US: 0x1f, // Unit Separator\n  ESC: 0x1b, // Escape Character\n} as const;\n\n/**\n * XOR mask for byte stuffing\n */\nconst STUFF_MASK = 0x20;\n\n/**\n * Check if a byte is a control character that needs stuffing\n */\nfunction isControlChar(byte: number): boolean {\n  return (\n    byte === CONTROL_CHARS.SOH ||\n    byte === CONTROL_CHARS.STX ||\n    byte === CONTROL_CHARS.EOT ||\n    byte === CONTROL_CHARS.US ||\n    byte === CONTROL_CHARS.ESC\n  );\n}\n\n/**\n * Stuff (encode) bytes by escaping control characters\n *\n * Algorithm:\n * - If byte is a control character: Insert ESC, then XOR byte with 0x20\n * - Otherwise: Insert byte as-is\n *\n * @param data Input data to stuff\n * @returns Stuffed data\n */\nexport function stuff(data: Uint8Array): Uint8Array {\n  const result: number[] = [];\n\n  for (let i = 0; i < data.length; i++) {\n    const byte = data[i];\n    if (byte === undefined) {\n      continue;\n    }\n\n    if (isControlChar(byte)) {\n      // Escape the control character\n      result.push(CONTROL_CHARS.ESC);\n      result.push(byte ^ STUFF_MASK);\n    } else {\n      // Normal byte, no stuffing needed\n      result.push(byte);\n    }\n  }\n\n  return new Uint8Array(result);\n}\n\n/**\n * Unstuff (decode) bytes by handling escaped characters\n *\n * Algorithm:\n * - If byte is ESC: Mark next byte as escaped, continue\n * - If previous byte was ESC: XOR current byte with 0x20, add to output\n * - Otherwise: Add byte as-is to output\n *\n * @param data Stuffed data to unstuff\n * @returns Unstuffed data\n * @throws {Error} If data contains invalid escape sequences\n */\nexport function unstuff(data: Uint8Array): Uint8Array {\n  const result: number[] = [];\n  let escaped = false;\n\n  for (let i = 0; i < data.length; i++) {\n    const byte = data[i];\n    if (byte === undefined) {\n      continue;\n    }\n    if (escaped) {\n      // Previous byte was ESC, so this byte is escaped\n      result.push(byte ^ STUFF_MASK);\n      escaped = false;\n    } else if (byte === CONTROL_CHARS.ESC) {\n      // This is an escape character, next byte will be escaped\n      escaped = true;\n    } else {\n      // Normal byte\n      result.push(byte);\n    }\n  }\n\n  // Check for incomplete escape sequence\n  if (escaped) {\n    throw new Error(\n      \"Invalid byte stuffing: data ends with incomplete escape sequence\"\n    );\n  }\n\n  return new Uint8Array(result);\n}\n\n/**\n * Calculate the maximum possible size after stuffing\n * In worst case, every byte could be a control character, doubling the size\n *\n * @param originalSize Original data size\n * @returns Maximum size after stuffing\n */\nexport function getMaxStuffedSize(originalSize: number): number {\n  return originalSize * 2; // Worst case: every byte is stuffed\n}\n\n/**\n * Calculate the minimum possible size after unstuffing\n * In best case, no bytes are stuffed\n *\n * @param stuffedSize Stuffed data size\n * @returns Minimum size after unstuffing\n */\nexport function getMinUnstuffedSize(stuffedSize: number): number {\n  return Math.floor(stuffedSize / 2); // Worst case: every pair is stuffed\n}\n\n/**\n * Test if data contains any control characters that would need stuffing\n *\n * @param data Data to test\n * @returns True if data contains control characters\n */\nexport function needsStuffing(data: Uint8Array): boolean {\n  for (let i = 0; i < data.length; i++) {\n    const byte = data[i];\n\n    if (byte !== undefined && isControlChar(byte)) {\n      return true;\n    }\n  }\n  return false;\n}\n\n/**\n * Validate that stuffed data has proper escape sequences\n *\n * @param data Stuffed data to validate\n * @returns True if data has valid stuffing\n */\nexport function isValidStuffing(data: Uint8Array): boolean {\n  let escaped = false;\n\n  for (let i = 0; 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