Module streaming_reader 

Streaming reader for XLSX files with optimized memory usage

This module provides a reader that processes data row-by-row with an iterator interface.

Memory Usage:

• Shared Strings Table (SST): Loaded fully (~3-5 MB for typical files)
• Worksheet XML: Loaded fully from ZIP (uncompressed size)
• Total memory ≈ SST + Uncompressed XML size

Important Notes:

• XLSX files are compressed. A 86 MB file may contain 1.2 GB uncompressed XML
• For small-medium files (< 100 MB): Memory usage is reasonable
• For large files with huge XML: Memory = uncompressed XML size
• Still faster than calamine (no style parsing) and uses optimized SST

Trade-offs:

• Only supports simple XLSX files (no complex formatting)
• Sequential read only (can’t jump to random rows)
• Best for: Fast iteration, simple data extraction, no formatting needs

Structs

RowIterator

Iterator over rows in a worksheet Streams XML data from ZIP without loading entire worksheet into memory

RowStructIterator

Iterator wrapper that returns Row structs instead of Vec for backward compatibility with the old calamine-based API

StreamingReader

Streaming reader for XLSX files