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bptc: fixes

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This commit is contained in:
Wijnand Modderman-Lenstra 2015-12-09 01:03:18 +01:00
parent 250b87e9c0
commit 95fe1d034c
2 changed files with 62 additions and 18 deletions
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45
bptc/bptc.go
View file

@ -152,22 +152,31 @@ func Dump(bits bit.Bits) {
var row, col int
fmt.Println(" BPTC(196, 96) matrix:")
fmt.Println("BPTC(196, 96) matrix:")
fmt.Print(" |")
for col = 0; col < 15; col++ {
fmt.Printf("%x", col)
if col == 10 {
fmt.Print(" ")
}
}
fmt.Println("\n --+----------- ----")
for row = 0; row < 13; row++ {
fmt.Printf(" %.2d|", row)
for col = 0; col < 11; col++ {
// +1 because the first bit is R(3) and it's not used
// so we can ignore that.
fmt.Printf(" #%.2u ", bits[col+row*15+1])
fmt.Printf("%d", bits[col+row*15+1])
}
fmt.Print(" ")
for ; col < 15; col++ {
// +1 because the first bit is R(3) and it's not used
// so we can ignore that.
fmt.Printf("%u", bits[col+row*15+1])
fmt.Printf("%d", bits[col+row*15+1])
}
fmt.Println("")
if row == 8 {
fmt.Println("")
fmt.Println(" :")
}
}
}
@ -190,7 +199,7 @@ func CheckAndRepair(bits bit.Bits) (bool, error) {
if !hamming_13_9_3_check(cb, &errorVector) {
wrong := hamming_13_9_3_error_position(&errorVector)
if wrong < 0 {
return false, fmt.Errorf("dmr/bptc(196, 96): hamming(13, 9) check error in column #%u, can't repair", col)
return false, fmt.Errorf("dmr/bptc(196, 96): hamming(13, 9) check error in column #%d, can't repair", col)
}
// Fix bit error
@ -201,7 +210,7 @@ func CheckAndRepair(bits bit.Bits) (bool, error) {
}
if !hamming_13_9_3_check(cb, &errorVector) {
return false, fmt.Errorf("dmr/bptc(196, 96): hamming(13, 9) check error in column #%u, couldn't repair", col)
return false, fmt.Errorf("dmr/bptc(196, 96): hamming(13, 9) check error in column #%d, couldn't repair", col)
}
}
}
@ -211,13 +220,13 @@ func CheckAndRepair(bits bit.Bits) (bool, error) {
if !hamming_15_11_3_check(bits[row*15+1:], &errorVector) {
wrong := hamming_15_11_3_error_position(&errorVector)
if wrong < 0 {
return false, fmt.Errorf("dmr/bptc(196, 96): hamming(15, 11) check error in row #%u, can't repair", row)
return false, fmt.Errorf("dmr/bptc(196, 96): hamming(15, 11) check error in row #%d, can't repair", row)
}
// Fix bit error
bits[row*15+wrong+1] ^= 1
if !hamming_15_11_3_check(bits[row*15+1:], &errorVector) {
return false, fmt.Errorf("dmr/bptc (196,96): hamming(15,11) check error, couldn't repair row #%u", row)
return false, fmt.Errorf("dmr/bptc (196,96): hamming(15,11) check error, couldn't repair row #%d", row)
}
}
}
@ -263,23 +272,23 @@ func New(bits bit.Bits) bit.Bits {
}
}
// +1 because the first bit is R(3) and it's not used so we can ignore that.
hamming_15_11_3_parity(bits[row*15+1:], &errorVector)
bits[row*15+11+1] = errorVector[0]
bits[row*15+12+1] = errorVector[1]
bits[row*15+13+1] = errorVector[2]
bits[row*15+14+1] = errorVector[3]
hamming_15_11_3_parity(p[row*15+1:], &errorVector)
p[row*15+11+1] = errorVector[0]
p[row*15+12+1] = errorVector[1]
p[row*15+13+1] = errorVector[2]
p[row*15+14+1] = errorVector[3]
}
for col := 0; col < 15; col++ {
var cb = make([]bit.Bit, 9)
for row := 0; row < 9; row++ {
cb[row] = bits[col+row*15+1]
cb[row] = p[col+row*15+1]
}
hamming_13_9_3_parity(cb, &errorVector)
bits[col+135+1] = errorVector[0]
bits[col+135+15+1] = errorVector[1]
bits[col+135+30+1] = errorVector[2]
bits[col+135+45+1] = errorVector[3]
p[col+135+1] = errorVector[0]
p[col+135+15+1] = errorVector[1]
p[col+135+30+1] = errorVector[2]
p[col+135+45+1] = errorVector[3]
}
return p

35
bptc/bptc_test.go Normal file
View file

@ -0,0 +1,35 @@
package bptc
import (
"math/rand"
"pd0mz/go-dmr/bit"
)
import "testing"
func Test(t *testing.T) {
for i := 0; i < 100; i++ {
test := make(bit.Bits, 96)
for b := 0; b < 96; b++ {
if rand.Uint32() > 0x7fffffff {
test[b].Flip()
}
}
bptc := New(test)
if len(bptc) != 196 {
t.Fatalf("expected 196 bits, got %d", len(bptc))
}
if testing.Verbose() {
Dump(bptc)
}
corrupt := rand.Intn(10)
bptc[corrupt].Flip()
if ok, err := CheckAndRepair(bptc); !ok {
t.Fatalf("check and repair failed: %v", err)
}
bptc[corrupt].Flip()
back := Extract(bptc)
if len(test) != len(back) {
t.Fatalf("expected %d bits, got %d", len(test), len(back))
}
}
}