X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Futil%2Fscid_utils.rs;h=7902a5271a6bcab604627fcd454634fd479ec2a9;hb=a146ef2be28d9f4e4daeb8f88797115931824578;hp=2b9e6fed2be8db8b21554ba64e9541d75c076c10;hpb=0b14e97c499df77c2610026d0cc73ab9086e4fe2;p=rust-lightning

diff --git a/lightning/src/util/scid_utils.rs b/lightning/src/util/scid_utils.rs
index 2b9e6fed..7902a527 100644
--- a/lightning/src/util/scid_utils.rs
+++ b/lightning/src/util/scid_utils.rs
@@ -7,32 +7,47 @@
 // You may not use this file except in accordance with one or both of these
 // licenses.
 
+/// Maximum block height that can be used in a `short_channel_id`. This
+/// value is based on the 3-bytes available for block height.
+pub const MAX_SCID_BLOCK: u64 = 0x00ffffff;
+
+/// Maximum transaction index that can be used in a `short_channel_id`.
+/// This value is based on the 3-bytes available for tx index.
+pub const MAX_SCID_TX_INDEX: u64 = 0x00ffffff;
+
+/// Maximum vout index that can be used in a `short_channel_id`. This
+/// value is based on the 2-bytes available for the vout index.
+pub const MAX_SCID_VOUT_INDEX: u64 = 0xffff;
+
 /// A `short_channel_id` construction error
 #[derive(Debug, PartialEq)]
 pub enum ShortChannelIdError {
 	BlockOverflow,
 	TxIndexOverflow,
+	VoutIndexOverflow,
 }
 
 /// Extracts the block height (most significant 3-bytes) from the `short_channel_id`
-#[allow(dead_code)]
 pub fn block_from_scid(short_channel_id: &u64) -> u32 {
 	return (short_channel_id >> 40) as u32;
 }
 
 /// Constructs a `short_channel_id` using the components pieces. Results in an error
-/// if the block height or tx index overflow the 3-bytes for each component.
-#[allow(dead_code)]
-pub fn scid_from_parts(block: u32, tx_index: u32, vout_index: u16) -> Result<u64, ShortChannelIdError> {
-	if block > 0x00ffffff {
+/// if the block height, tx index, or vout index overflow the maximum sizes.
+pub fn scid_from_parts(block: u64, tx_index: u64, vout_index: u64) -> Result<u64, ShortChannelIdError> {
+	if block > MAX_SCID_BLOCK {
 		return Err(ShortChannelIdError::BlockOverflow);
 	}
 
-	if	tx_index > 0x00ffffff {
+	if tx_index > MAX_SCID_TX_INDEX {
 		return Err(ShortChannelIdError::TxIndexOverflow);
 	}
 
-	Ok(((block as u64) << 40) | ((tx_index as u64) << 16) | (vout_index as u64))
+	if vout_index > MAX_SCID_VOUT_INDEX {
+		return Err(ShortChannelIdError::VoutIndexOverflow);
+	}
+
+	Ok((block << 40) | (tx_index << 16) | vout_index)
 }
 
 #[cfg(test)]
@@ -56,5 +71,6 @@ mod tests {
 		assert_eq!(scid_from_parts(0x00ffffff, 0x00ffffff, 0xffff).unwrap(), 0xffffff_ffffff_ffff);
 		assert_eq!(scid_from_parts(0x01ffffff, 0x00000000, 0x0000).err().unwrap(), ShortChannelIdError::BlockOverflow);
 		assert_eq!(scid_from_parts(0x00000000, 0x01ffffff, 0x0000).err().unwrap(), ShortChannelIdError::TxIndexOverflow);
+		assert_eq!(scid_from_parts(0x00000000, 0x00000000, 0x010000).err().unwrap(), ShortChannelIdError::VoutIndexOverflow);
 	}
 }