initia custom

Author: beer-1

core/bloombits/docs.go

@@ -0,0 +1,18 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Package bloombits implements bloom filtering on batches of data.
+package bloombits

core/bloombits/generator.go

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+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package bloombits
+
+import (
+	"errors"
+
+	"github.com/ethereum/go-ethereum/core/types"
+)
+
+var (
+	// errSectionOutOfBounds is returned if the user tried to add more bloom filters
+	// to the batch than available space, or if tries to retrieve above the capacity.
+	errSectionOutOfBounds = errors.New("section out of bounds")
+
+	// errBloomBitOutOfBounds is returned if the user tried to retrieve specified
+	// bit bloom above the capacity.
+	errBloomBitOutOfBounds = errors.New("bloom bit out of bounds")
+)
+
+// Generator takes a number of bloom filters and generates the rotated bloom bits
+// to be used for batched filtering.
+type Generator struct {
+	blooms   [types.BloomBitLength][]byte // Rotated blooms for per-bit matching
+	sections uint                         // Number of sections to batch together
+	nextSec  uint                         // Next section to set when adding a bloom
+}
+
+// NewGenerator creates a rotated bloom generator that can iteratively fill a
+// batched bloom filter's bits.
+func NewGenerator(sections uint) (*Generator, error) {
+	if sections%8 != 0 {
+		return nil, errors.New("section count not multiple of 8")
+	}
+	b := &Generator{sections: sections}
+	for i := 0; i < types.BloomBitLength; i++ {
+		b.blooms[i] = make([]byte, sections/8)
+	}
+	return b, nil
+}
+
+// AddBloom takes a single bloom filter and sets the corresponding bit column
+// in memory accordingly.
+func (b *Generator) AddBloom(index uint, bloom types.Bloom) error {
+	// Make sure we're not adding more bloom filters than our capacity
+	if b.nextSec >= b.sections {
+		return errSectionOutOfBounds
+	}
+	if b.nextSec != index {
+		return errors.New("bloom filter with unexpected index")
+	}
+	// Rotate the bloom and insert into our collection
+	byteIndex := b.nextSec / 8
+	bitIndex := byte(7 - b.nextSec%8)
+	for byt := 0; byt < types.BloomByteLength; byt++ {
+		bloomByte := bloom[types.BloomByteLength-1-byt]
+		if bloomByte == 0 {
+			continue
+		}
+		base := 8 * byt
+		b.blooms[base+7][byteIndex] |= ((bloomByte >> 7) & 1) << bitIndex
+		b.blooms[base+6][byteIndex] |= ((bloomByte >> 6) & 1) << bitIndex
+		b.blooms[base+5][byteIndex] |= ((bloomByte >> 5) & 1) << bitIndex
+		b.blooms[base+4][byteIndex] |= ((bloomByte >> 4) & 1) << bitIndex
+		b.blooms[base+3][byteIndex] |= ((bloomByte >> 3) & 1) << bitIndex
+		b.blooms[base+2][byteIndex] |= ((bloomByte >> 2) & 1) << bitIndex
+		b.blooms[base+1][byteIndex] |= ((bloomByte >> 1) & 1) << bitIndex
+		b.blooms[base][byteIndex] |= (bloomByte & 1) << bitIndex
+	}
+	b.nextSec++
+	return nil
+}
+
+// Bitset returns the bit vector belonging to the given bit index after all
+// blooms have been added.
+func (b *Generator) Bitset(idx uint) ([]byte, error) {
+	if b.nextSec != b.sections {
+		return nil, errors.New("bloom not fully generated yet")
+	}
+	if idx >= types.BloomBitLength {
+		return nil, errBloomBitOutOfBounds
+	}
+	return b.blooms[idx], nil
+}

core/bloombits/generator_test.go

@@ -0,0 +1,100 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package bloombits
+
+import (
+	"bytes"
+	crand "crypto/rand"
+	"math/rand"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/core/types"
+)
+
+// Tests that batched bloom bits are correctly rotated from the input bloom
+// filters.
+func TestGenerator(t *testing.T) {
+	// Generate the input and the rotated output
+	var input, output [types.BloomBitLength][types.BloomByteLength]byte
+
+	for i := 0; i < types.BloomBitLength; i++ {
+		for j := 0; j < types.BloomBitLength; j++ {
+			bit := byte(rand.Int() % 2)
+
+			input[i][j/8] |= bit << byte(7-j%8)
+			output[types.BloomBitLength-1-j][i/8] |= bit << byte(7-i%8)
+		}
+	}
+	// Crunch the input through the generator and verify the result
+	gen, err := NewGenerator(types.BloomBitLength)
+	if err != nil {
+		t.Fatalf("failed to create bloombit generator: %v", err)
+	}
+	for i, bloom := range input {
+		if err := gen.AddBloom(uint(i), bloom); err != nil {
+			t.Fatalf("bloom %d: failed to add: %v", i, err)
+		}
+	}
+	for i, want := range output {
+		have, err := gen.Bitset(uint(i))
+		if err != nil {
+			t.Fatalf("output %d: failed to retrieve bits: %v", i, err)
+		}
+		if !bytes.Equal(have, want[:]) {
+			t.Errorf("output %d: bit vector mismatch have %x, want %x", i, have, want)
+		}
+	}
+}
+
+func BenchmarkGenerator(b *testing.B) {
+	var input [types.BloomBitLength][types.BloomByteLength]byte
+	b.Run("empty", func(b *testing.B) {
+		b.ReportAllocs()
+		b.ResetTimer()
+		for i := 0; i < b.N; i++ {
+			// Crunch the input through the generator and verify the result
+			gen, err := NewGenerator(types.BloomBitLength)
+			if err != nil {
+				b.Fatalf("failed to create bloombit generator: %v", err)
+			}
+			for j, bloom := range &input {
+				if err := gen.AddBloom(uint(j), bloom); err != nil {
+					b.Fatalf("bloom %d: failed to add: %v", i, err)
+				}
+			}
+		}
+	})
+	for i := 0; i < types.BloomBitLength; i++ {
+		crand.Read(input[i][:])
+	}
+	b.Run("random", func(b *testing.B) {
+		b.ReportAllocs()
+		b.ResetTimer()
+		for i := 0; i < b.N; i++ {
+			// Crunch the input through the generator and verify the result
+			gen, err := NewGenerator(types.BloomBitLength)
+			if err != nil {
+				b.Fatalf("failed to create bloombit generator: %v", err)
+			}
+			for j, bloom := range &input {
+				if err := gen.AddBloom(uint(j), bloom); err != nil {
+					b.Fatalf("bloom %d: failed to add: %v", i, err)
+				}
+			}
+		}
+	})
+}