block: move CompressionStats code

Author: RaduBerinde

sstable/block/compression_stats.go

@@ -0,0 +1,83 @@
+// Copyright 2025 The LevelDB-Go and Pebble Authors. All rights reserved. Use
+// of this source code is governed by a BSD-style license that can be found in
+// the LICENSE file.
+
+package block
+
+import (
+	"fmt"
+	"iter"
+	"strings"
+
+	"github.com/cockroachdb/pebble/internal/compression"
+)
+
+// CompressionStats collects compression statistics for a single file - the
+// total compressed and uncompressed sizes for each distinct compression.Setting
+// used.
+type CompressionStats struct {
+	n int
+	// Compression profiles have three settings (data, value, other) and
+	// NoCompression can also be used for data that didn't compress.
+	buf [4]CompressionStatsForSetting
+}
+
+type CompressionStatsForSetting struct {
+	Setting           compression.Setting
+	UncompressedBytes uint64
+	CompressedBytes   uint64
+}
+
+// add updates the stats to reflect a block that was compressed with the given setting.
+func (c *CompressionStats) add(
+	setting compression.Setting, sizeUncompressed, sizeCompressed uint64,
+) {
+	for i := 0; i < c.n; i++ {
+		if c.buf[i].Setting == setting {
+			c.buf[i].UncompressedBytes += sizeUncompressed
+			c.buf[i].CompressedBytes += sizeCompressed
+			return
+		}
+	}
+	if c.n >= len(c.buf)-1 {
+		panic("too many compression settings")
+	}
+	c.buf[c.n] = CompressionStatsForSetting{
+		Setting:           setting,
+		UncompressedBytes: sizeUncompressed,
+		CompressedBytes:   sizeCompressed,
+	}
+	c.n++
+}
+
+// MergeWith updates the receiver stats to include the other stats.
+func (c *CompressionStats) MergeWith(other *CompressionStats) {
+	for i := 0; i < other.n; i++ {
+		c.add(other.buf[i].Setting, other.buf[i].UncompressedBytes, other.buf[i].CompressedBytes)
+	}
+}
+
+// All returns an iterator over the collected stats, in arbitrary order.
+func (c CompressionStats) All() iter.Seq[CompressionStatsForSetting] {
+	return func(yield func(cs CompressionStatsForSetting) bool) {
+		for i := 0; i < c.n; i++ {
+			if !yield(c.buf[i]) {
+				return
+			}
+		}
+	}
+}
+
+// String returns a string representation of the stats, in the format:
+// "<setting1>:<compressed1>/<uncompressed1>,<setting2>:<compressed2>/<uncompressed2>,..."
+func (c CompressionStats) String() string {
+	var buf strings.Builder
+	buf.Grow(c.n * 64)
+	for i := 0; i < c.n; i++ {
+		if i > 0 {
+			buf.WriteString(",")
+		}
+		fmt.Fprintf(&buf, "%s:%d/%d", c.buf[i].Setting.String(), c.buf[i].CompressedBytes, c.buf[i].UncompressedBytes)
+	}
+	return buf.String()
+}

sstable/block/compressor.go

@@ -1,10 +1,11 @@
+// Copyright 2025 The LevelDB-Go and Pebble Authors. All rights reserved. Use
+// of this source code is governed by a BSD-style license that can be found in
+// the LICENSE file.
+
 package block
 
 import (
-	"fmt"
-	"iter"
 	"math/rand"
-	"strings"
 
 	"github.com/cockroachdb/pebble/internal/compression"
 	"github.com/cockroachdb/pebble/sstable/block/blockkind"
@@ -108,76 +109,6 @@ func (c *Compressor) Stats() *CompressionStats {
 	return &c.stats
 }
 
-// CompressionStats collects compression statistics for a single file - the
-// total compressed and uncompressed sizes for each distinct compression.Setting
-// used.
-type CompressionStats struct {
-	n int
-	// Compression profiles have three settings (data, value, other) and
-	// NoCompression can also be used for data that didn't compress.
-	buf [4]CompressionStatsForSetting
-}
-
-type CompressionStatsForSetting struct {
-	Setting           compression.Setting
-	UncompressedBytes uint64
-	CompressedBytes   uint64
-}
-
-// add updates the stats to reflect a block that was compressed with the given setting.
-func (c *CompressionStats) add(
-	setting compression.Setting, sizeUncompressed, sizeCompressed uint64,
-) {
-	for i := 0; i < c.n; i++ {
-		if c.buf[i].Setting == setting {
-			c.buf[i].UncompressedBytes += sizeUncompressed
-			c.buf[i].CompressedBytes += sizeCompressed
-			return
-		}
-	}
-	if c.n >= len(c.buf)-1 {
-		panic("too many compression settings")
-	}
-	c.buf[c.n] = CompressionStatsForSetting{
-		Setting:           setting,
-		UncompressedBytes: sizeUncompressed,
-		CompressedBytes:   sizeCompressed,
-	}
-	c.n++
-}
-
-// MergeWith updates the receiver stats to include the other stats.
-func (c *CompressionStats) MergeWith(other *CompressionStats) {
-	for i := 0; i < other.n; i++ {
-		c.add(other.buf[i].Setting, other.buf[i].UncompressedBytes, other.buf[i].CompressedBytes)
-	}
-}
-
-// All returns an iterator over the collected stats, in arbitrary order.
-func (c CompressionStats) All() iter.Seq[CompressionStatsForSetting] {
-	return func(yield func(cs CompressionStatsForSetting) bool) {
-		for i := 0; i < c.n; i++ {
-			if !yield(c.buf[i]) {
-				return
-			}
-		}
-	}
-}
-
-// String returns a string representation of the stats, in the format:
-// "<setting1>:<compressed1>/<uncompressed1>,<setting2>:<compressed2>/<uncompressed2>,..."
-func (c CompressionStats) String() string {
-	var buf strings.Builder
-	buf.Grow(c.n * 64)
-	for i := 0; i < c.n; i++ {
-		if i > 0 {
-			buf.WriteString(",")
-		}
-		fmt.Fprintf(&buf, "%s:%d/%d", c.buf[i].Setting.String(), c.buf[i].CompressedBytes, c.buf[i].UncompressedBytes)
-	}
-	return buf.String()
-}
-
 type Decompressor = compression.Decompressor
 
 func GetDecompressor(c CompressionIndicator) Decompressor {