Add Mumble support (#1245)

vendor/layeh.com/gumble/gumble/varint/read.go

@@ -0,0 +1,52 @@
+package varint
+
+import (
+	"encoding/binary"
+)
+
+// Decode reads the first varint encoded number from the given buffer.
+//
+// On success, the function returns the varint as an int64, and the number of
+// bytes read (0 if there was an error).
+func Decode(b []byte) (int64, int) {
+	if len(b) == 0 {
+		return 0, 0
+	}
+	// 0xxxxxxx 7-bit positive number
+	if (b[0] & 0x80) == 0 {
+		return int64(b[0]), 1
+	}
+	// 10xxxxxx + 1 byte 14-bit positive number
+	if (b[0]&0xC0) == 0x80 && len(b) >= 2 {
+		return int64(b[0]&0x3F)<<8 | int64(b[1]), 2
+	}
+	// 110xxxxx + 2 bytes 21-bit positive number
+	if (b[0]&0xE0) == 0xC0 && len(b) >= 3 {
+		return int64(b[0]&0x1F)<<16 | int64(b[1])<<8 | int64(b[2]), 3
+	}
+	// 1110xxxx + 3 bytes 28-bit positive number
+	if (b[0]&0xF0) == 0xE0 && len(b) >= 4 {
+		return int64(b[0]&0xF)<<24 | int64(b[1])<<16 | int64(b[2])<<8 | int64(b[3]), 4
+	}
+	// 111100__ + int (32-bit) 32-bit positive number
+	if (b[0]&0xFC) == 0xF0 && len(b) >= 5 {
+		return int64(binary.BigEndian.Uint32(b[1:])), 5
+	}
+	// 111101__ + long (64-bit) 64-bit number
+	if (b[0]&0xFC) == 0xF4 && len(b) >= 9 {
+		return int64(binary.BigEndian.Uint64(b[1:])), 9
+	}
+	// 111110__ + varint Negative recursive varint
+	if b[0]&0xFC == 0xF8 {
+		if v, n := Decode(b[1:]); n > 0 {
+			return -v, n + 1
+		}
+		return 0, 0
+	}
+	// 111111xx Byte-inverted negative two bit number (~xx)
+	if b[0]&0xFC == 0xFC {
+		return ^int64(b[0] & 0x03), 1
+	}
+
+	return 0, 0
+}

vendor/layeh.com/gumble/gumble/varint/write.go

@@ -0,0 +1,64 @@
+package varint
+
+import (
+	"encoding/binary"
+	"math"
+)
+
+// MaxVarintLen is the maximum number of bytes required to encode a varint
+// number.
+const MaxVarintLen = 10
+
+// Encode encodes the given value to varint format.
+func Encode(b []byte, value int64) int {
+	// 111111xx Byte-inverted negative two bit number (~xx)
+	if value <= -1 && value >= -4 {
+		b[0] = 0xFC | byte(^value&0xFF)
+		return 1
+	}
+	// 111110__ + varint Negative recursive varint
+	if value < 0 {
+		b[0] = 0xF8
+		return 1 + Encode(b[1:], -value)
+	}
+	// 0xxxxxxx 7-bit positive number
+	if value <= 0x7F {
+		b[0] = byte(value)
+		return 1
+	}
+	// 10xxxxxx + 1 byte 14-bit positive number
+	if value <= 0x3FFF {
+		b[0] = byte(((value >> 8) & 0x3F) | 0x80)
+		b[1] = byte(value & 0xFF)
+		return 2
+	}
+	// 110xxxxx + 2 bytes 21-bit positive number
+	if value <= 0x1FFFFF {
+		b[0] = byte((value>>16)&0x1F | 0xC0)
+		b[1] = byte((value >> 8) & 0xFF)
+		b[2] = byte(value & 0xFF)
+		return 3
+	}
+	// 1110xxxx + 3 bytes 28-bit positive number
+	if value <= 0xFFFFFFF {
+		b[0] = byte((value>>24)&0xF | 0xE0)
+		b[1] = byte((value >> 16) & 0xFF)
+		b[2] = byte((value >> 8) & 0xFF)
+		b[3] = byte(value & 0xFF)
+		return 4
+	}
+	// 111100__ + int (32-bit) 32-bit positive number
+	if value <= math.MaxInt32 {
+		b[0] = 0xF0
+		binary.BigEndian.PutUint32(b[1:], uint32(value))
+		return 5
+	}
+	// 111101__ + long (64-bit) 64-bit number
+	if value <= math.MaxInt64 {
+		b[0] = 0xF4
+		binary.BigEndian.PutUint64(b[1:], uint64(value))
+		return 9
+	}
+
+	return 0
+}