Function parseEmfContent

apps/sim/lib/pptx-renderer/utils/emf-parser.ts:42–87

(data: Uint8Array)

 * Parse an EMF file and extract its embedded content.
 */
export function parseEmfContent(data: Uint8Array): EmfContent {
  if (data.length < 44) return { type: 'unsupported' }

  const view = new DataView(data.buffer, data.byteOffset, data.byteLength)

  // Validate EMF signature at offset 40
  if (view.getUint32(40, true) !== EMF_SIGNATURE) {
    return { type: 'unsupported' }
  }

  let offset = 0
  let recordCount = 0

  while (offset + 8 <= data.length) {
    const recordType = view.getUint32(offset, true)
    const recordSize = view.getUint32(offset + 4, true)

    // Sanity check record size
    if (recordSize < 8 || offset + recordSize > data.length) break

    recordCount++

    if (recordType === EMR_EOF) break

    // Check GDI Comment records for embedded PDF
    if (recordType === EMR_COMMENT && recordSize > 16) {
      const result = parseGdiComment(data, view, offset, recordSize)
      if (result) return result
    }

    // Check STRETCHDIBITS for embedded bitmaps
    if (recordType === EMR_STRETCHDIBITS && recordSize > 80) {
      const result = parseStretchDibits(data, view, offset, recordSize)
      if (result) return result
    }

    offset += recordSize
  }

  // Only HEADER + EOF → empty
  if (recordCount <= 2) {
    return { type: 'empty' }
  }

  return { type: 'unsupported' }
}

/**
 * Parse a GDI Comment record looking for embedded PDF data.