flate: Add examples

[klauspost]

Fixes minor difference to stdlib, which doesn't do a 0 byte write.

Summary by CodeRabbit

• Bug Fixes

  • Prevents unnecessary zero-byte writes during compression flushes, improving stability and reducing I/O overhead.

• Tests

  • Added example-based tests demonstrating reset and reuse of compressor/decompressor.
  • Added example for dictionary-based compression and decompression.
  • Added example simulating synchronized streaming over pipes.

[coderabbitai]

📝 Walkthrough

Walkthrough

Adds example tests in flate/example_test.go demonstrating Reset reuse, dictionary-based compression, and streaming synchronization. Modifies huffmanBitWriter.flush to conditionally write buffered bytes only when present (n > 0). No exported API changes.

Changes

Cohort / File(s)	Summary
Examples and tests flate/example_test.go	New example tests: Example_reset (reuse Reader/Writer via Reset), Example_dictionary (use of NewWriterDict/NewReaderDict), Example_synchronization (streaming over io.Pipe with framing and goroutines).
Huffman bit writer flush logic flate/huffman_bit_writer.go	flush now writes the remaining buffered bytes only if count n > 0; other flush steps unchanged.

Sequence Diagram(s)

sequenceDiagram
  autonumber
  participant C as Caller
  participant BW as huffmanBitWriter
  participant W as underlying io.Writer

  C->>BW: flush()
  BW->>BW: finalize bits/EOB, compute n
  alt n > 0
    BW->>W: Write(buffer[0:n])
    W-->>BW: bytes written / error
  else n == 0
    BW-->>BW: skip final write
  end
  BW-->>C: return error (if any)

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Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title Check	✅ Passed	The title "flate: Add examples" is concise and clearly describes the primary change — adding three example tests under flate/example_test.go — and is easy for a reviewer to scan in history. It is specific and not noisy, though it does not mention a small additional fix in huffman_bit_writer.go to avoid a 0-byte write. Overall the title accurately reflects a major, visible part of the changeset.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

✨ Finishing touches

• 📝 Generate Docstrings

🧪 Generate unit tests

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch add-examples

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[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (1)

flate/example_test.go (1)

128-129: Use consistent Reader source for clarity.

Mixing bytes.NewReader(b.Bytes()) and &b works, but using bytes.NewReader in both places avoids relying on bytes.Buffer read state if this example is edited later.

-	zr = flate.NewReaderDict(&b, hashDict)
+	zr = flate.NewReaderDict(bytes.NewReader(b.Bytes()), hashDict)

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between f44517c and c158c11.

📒 Files selected for processing (2)

• flate/example_test.go (1 hunks)
• flate/huffman_bit_writer.go (1 hunks)

🧰 Additional context used

🧬 Code graph analysis (1)

flate/example_test.go (1)

flate/deflate.go (1)

• NewWriterDict (905-913)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (15)

• GitHub Check: build (1.23.x, windows-latest)
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• GitHub Check: fuzz-s2 ("noasm,nounsafe")
• GitHub Check: build (1.25.x, macos-latest)
• GitHub Check: build (1.24.x, windows-latest)
• GitHub Check: fuzz-other ("noasm,nounsafe")
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🔇 Additional comments (4)

flate/huffman_bit_writer.go (1)

214-216: Great: avoid zero-byte writes in flush.

Conditionally writing only when n > 0 matches stdlib behavior and avoids spurious writes to underlying writers (e.g., pipes/sockets) with no downside.

flate/example_test.go (3)

22-63: Examples: Reset usage looks solid.

Clear demonstration of reusing writer/reader with shared buffers and proper Close/Reset ordering.

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189-193: Flush semantics align with the writer change.

Per-message Flush is correct here; combined with the flush fix, there are no zero-byte writes on empty buffers.

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158-246: Synchronization example reads well.

Good use of io.Pipe, framing, and graceful shutdown with wg.Wait and Close/EOF handling.