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Diffstat (limited to 'ber/int.go')
-rw-r--r--ber/int.go46
1 files changed, 46 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
+}