flate: Simplify L4-6 loading #1043
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📝 WalkthroughWalkthroughThe pull request introduces modifications to the Changes
Sequence DiagramsequenceDiagram
participant Encoder as Compression Encoder
participant Matcher as Offset Matcher
participant DataSource as Source Data
Encoder->>Matcher: Calculate potential match offsets
Matcher->>DataSource: Compare offsets with current position
Matcher-->>Encoder: Return match candidates
Encoder->>Encoder: Process and encode matches
The sequence diagram illustrates the high-level flow of the offset matching process, highlighting how the modifications aim to streamline the offset calculation and comparison steps in the compression encoder. ✨ Finishing Touches
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Actionable comments posted: 0
🧹 Nitpick comments (1)
flate/level4.go (1)
101-101: Excellent optimization of offset calculations!The changes effectively reuse the pre-calculated offset
tinstead of recalculating it in each comparison. This not only makes the code more readable but also potentially helps the compiler optimize better by eliminating redundant calculations.Consider adding a comment explaining that
tis the pre-calculated offset to help future maintainers understand the optimization:+ // t is the pre-calculated offset, already adjusted by e.cur t = lCandidate.offset - e.curAlso applies to: 107-107, 113-113
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flate/level4.go(1 hunks)flate/level5.go(10 hunks)flate/level6.go(6 hunks)
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🔇 Additional comments (3)
flate/level5.go (1)
114-114: Well-structured optimization consistently applied across implementations!The optimization pattern of reusing pre-calculated offsets is consistently applied in both
fastEncL5andfastEncL5Windowimplementations. This systematic approach:
- Reduces redundant calculations in more complex match detection logic
- Maintains consistency between different compression levels
- Improves code maintainability
Also applies to: 121-121, 133-133, 143-143, 156-156, 167-167, 426-426, 433-433, 445-445, 455-455, 468-468, 479-479
flate/level6.go (2)
116-116: Optimization brings most value in this complex implementation!The reuse of pre-calculated offsets is particularly beneficial in this level 6 implementation where:
- Multiple candidate comparisons are performed
- Complex match detection logic is used
- Previous matches are checked frequently
The optimization effectively reduces redundant calculations in the most computation-intensive compression level.
Also applies to: 126-126, 139-139, 149-149, 178-178, 189-189
Line range hint
101-189: Verify the impact of offset calculation optimization.The optimization pattern of reusing pre-calculated offsets is consistently applied across all compression levels. Let's verify the extent of this optimization.
✅ Verification successful
Optimization pattern is correctly and consistently applied
The offset calculation optimization is properly implemented across all compression levels (4, 5, and 6), maintaining the same functionality while improving efficiency through value reuse.
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Analyze the impact of offset calculation optimization # Count the number of offset calculations removed echo "Analyzing removed offset calculations..." git diff -U0 | grep -B1 '@@ ' | grep 'lCandidate.*offset.*e.cur' | wc -l # Verify no functional changes were introduced echo "Verifying no functional changes..." rg -A 2 'lCandidate.*offset.*e.cur' | grep -v 't ='Length of output: 3182
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We already calculate the buffer offset. Reuse in case the compiler doesn't pick it up.
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Actionable comments posted: 0
🧹 Nitpick comments (1)
flate/level4.go (1)
101-113: Great systematic optimization approach!The changes demonstrate a consistent pattern of optimizing offset calculations by:
- Reusing pre-calculated values
- Extracting repeated calculations into variables
- Maintaining code readability while improving efficiency
This approach could be beneficial to apply to similar patterns elsewhere in the codebase.
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📒 Files selected for processing (3)
flate/level4.go(1 hunks)flate/level5.go(10 hunks)flate/level6.go(6 hunks)
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- flate/level6.go
- flate/level5.go
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🔇 Additional comments (3)
flate/level4.go (3)
101-101: LGTM! Good optimization.Reusing the pre-calculated offset
tinstead of recalculatinglCandidate.offset - e.curis a good optimization. This change simplifies the code while maintaining the same logic.
107-107: LGTM! Consistent optimization.The optimization pattern is consistently applied here for the short candidate comparison, reusing the pre-calculated offset
t. This maintains code consistency and improves readability.
112-113: LGTM! Good variable extraction.Extracting the offset calculation into
lOffis a good improvement that:
- Avoids recalculating the same offset multiple times
- Makes the code more maintainable
- Potentially helps the compiler optimize the code better
We already calculate the buffer offset. Reuse in case the compiler doesn't pick it up.
Summary by CodeRabbit
Performance Improvements
Technical Refinements