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package hdrhistogram
import "fmt"
const truncatedErrStr = "Truncated compressed histogram decode. Expected minimum length of %d bytes and got %d."
// Read an LEB128 ZigZag encoded long value from the given buffer
func zig_zag_decode_i64(buf []byte) (signedValue int64, n int, err error) {
buflen := len(buf)
if buflen < 1 {
return 0, 0, nil
}
var value = uint64(buf[0]) & 0x7f
n = 1
if (buf[0] & 0x80) != 0 {
if buflen < 2 {
err = fmt.Errorf(truncatedErrStr, 2, buflen)
return
}
value |= uint64(buf[1]) & 0x7f << 7
n = 2
if (buf[1] & 0x80) != 0 {
if buflen < 3 {
err = fmt.Errorf(truncatedErrStr, 3, buflen)
return
}
value |= uint64(buf[2]) & 0x7f << 14
n = 3
if (buf[2] & 0x80) != 0 {
if buflen < 4 {
err = fmt.Errorf(truncatedErrStr, 4, buflen)
return
}
value |= uint64(buf[3]) & 0x7f << 21
n = 4
if (buf[3] & 0x80) != 0 {
if buflen < 5 {
err = fmt.Errorf(truncatedErrStr, 5, buflen)
return
}
value |= uint64(buf[4]) & 0x7f << 28
n = 5
if (buf[4] & 0x80) != 0 {
if buflen < 6 {
err = fmt.Errorf(truncatedErrStr, 6, buflen)
return
}
value |= uint64(buf[5]) & 0x7f << 35
n = 6
if (buf[5] & 0x80) != 0 {
if buflen < 7 {
err = fmt.Errorf(truncatedErrStr, 7, buflen)
return
}
value |= uint64(buf[6]) & 0x7f << 42
n = 7
if (buf[6] & 0x80) != 0 {
if buflen < 8 {
err = fmt.Errorf(truncatedErrStr, 8, buflen)
return
}
value |= uint64(buf[7]) & 0x7f << 49
n = 8
if (buf[7] & 0x80) != 0 {
if buflen < 9 {
err = fmt.Errorf(truncatedErrStr, 9, buflen)
return
}
value |= uint64(buf[8]) << 56
n = 9
}
}
}
}
}
}
}
}
signedValue = int64((value >> 1) ^ -(value & 1))
return
}
// Writes a int64_t value to the given buffer in LEB128 ZigZag encoded format
// ZigZag encoding maps signed integers to unsigned integers so that numbers with a small
// absolute value (for instance, -1) have a small varint encoded value too.
// It does this in a way that "zig-zags" back and forth through the positive and negative integers,
// so that -1 is encoded as 1, 1 is encoded as 2, -2 is encoded as 3, and so on.
func zig_zag_encode_i64(signedValue int64) (buffer []byte) {
buffer = make([]byte, 0)
var value = uint64((signedValue << 1) ^ (signedValue >> 63))
if value>>7 == 0 {
buffer = append(buffer, byte(value))
} else {
buffer = append(buffer, byte((value&0x7F)|0x80))
if value>>14 == 0 {
buffer = append(buffer, byte(value>>7))
} else {
buffer = append(buffer, byte((value>>7)|0x80))
if value>>21 == 0 {
buffer = append(buffer, byte(value>>14))
} else {
buffer = append(buffer, byte((value>>14)|0x80))
if value>>28 == 0 {
buffer = append(buffer, byte(value>>21))
} else {
buffer = append(buffer, byte((value>>21)|0x80))
if value>>35 == 0 {
buffer = append(buffer, byte(value>>28))
} else {
buffer = append(buffer, byte((value>>28)|0x80))
if value>>42 == 0 {
buffer = append(buffer, byte(value>>35))
} else {
buffer = append(buffer, byte((value>>35)|0x80))
if value>>49 == 0 {
buffer = append(buffer, byte(value>>42))
} else {
buffer = append(buffer, byte((value>>42)|0x80))
if value>>56 == 0 {
buffer = append(buffer, byte(value>>49))
} else {
buffer = append(buffer, byte((value>>49)|0x80))
buffer = append(buffer, byte(value>>56))
}
}
}
}
}
}
}
}
return
}
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