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authorDimitri Sokolyuk <demon@dim13.org>2015-06-26 19:28:01 +0200
committerDimitri Sokolyuk <demon@dim13.org>2015-06-26 19:28:01 +0200
commitee6b497e0ddeb186e7d0edff150ad8b6b52a87c3 (patch)
tree87afab53d739c604937b3f5859d80cc3594e2d58 /ber
parent08c8c24b423a649e3e058c9f040d08ae49233b96 (diff)
Add ASN.1 Integer coder/decoder
Diffstat (limited to 'ber')
-rw-r--r--ber/int.go46
-rw-r--r--ber/int_test.go32
2 files changed, 78 insertions, 0 deletions
diff --git a/ber/int.go b/ber/int.go
new file mode 100644
index 0000000..32cc9af
--- /dev/null
+++ b/ber/int.go
@@ -0,0 +1,46 @@
+package ber
+
+func intLen(i int) int {
+ n := 1
+ for i > 255 {
+ n++
+ i >>= 8
+ }
+ for i < -256 {
+ n++
+ i >>= 8
+ }
+ return n
+}
+
+func unmarshalInt(b []byte) (i int) {
+ nn := len(b)
+ neg := b[0]&0x80 != 0
+ if b[0] == 0xFF {
+ b = b[1:]
+ nn -= 1
+ }
+ for n, v := range b {
+ if neg {
+ v = ^v
+ }
+ i += int(v) << uint((nn-n-1)*8)
+ }
+ if neg {
+ i = -i - 1
+ }
+ return
+}
+
+func marshalInt(i int) (b []byte) {
+ for n := intLen(i); n > 0; n-- {
+ b = append(b, byte(i>>uint((n-1)*8)))
+ }
+ if i > 0 && b[0]&0x80 != 0 {
+ b = append([]byte{0x00}, b...)
+ }
+ if i < 0 && b[0]&0x80 == 0 {
+ b = append([]byte{0xFF}, b...)
+ }
+ return
+}
diff --git a/ber/int_test.go b/ber/int_test.go
new file mode 100644
index 0000000..f0bd182
--- /dev/null
+++ b/ber/int_test.go
@@ -0,0 +1,32 @@
+package ber
+
+import (
+ "testing"
+ "bytes"
+)
+
+func test(t *testing.T, i int, b []byte) {
+ a := marshalInt(i)
+ if !bytes.Equal(a, b) {
+ t.Error("BER", i, "expected", b, "got", a)
+ }
+
+ n := unmarshalInt(b)
+ if n != i {
+ t.Error("UnBER", b, "expected", i, "got", n)
+ }
+
+}
+
+func TestInt(t *testing.T) {
+ test(t, 0, []byte{0x00})
+ test(t, 127, []byte{0x7F})
+ test(t, 128, []byte{0x00, 0x80})
+ test(t, 256, []byte{0x01, 0x00})
+ test(t, -128, []byte{0x80})
+ test(t, -129, []byte{0xFF, 0x7F})
+
+ test(t, 8388607, []byte{0x7f, 0xFF, 0xFF})
+ test(t, -136, []byte{0xFF, 0x78})
+ test(t, -8388607, []byte{0x80, 0x00, 0x01})
+}