feat: add qol stuff for block ids

src/models/block/block_id.rs

@@ -127,6 +127,44 @@ pub struct BlockIdShort {
     pub seqno: u32,
 }
 
+impl BlockIdShort {
+    /// Returns `true` if this block id is for a masterchain block.
+    ///
+    /// See [`ShardIdent::MASTERCHAIN`]
+    #[inline]
+    pub const fn is_masterchain(&self) -> bool {
+        self.shard.is_masterchain()
+    }
+
+    /// Returns a previous block id.
+    pub fn saturating_prev(&self) -> Self {
+        self.saturating_sub(1)
+    }
+
+    /// Returns a next block id.
+    pub fn saturating_next(&self) -> Self {
+        self.saturating_add(1)
+    }
+
+    /// Returns a new block id with the seqno
+    /// increased at most by the specified value.
+    pub fn saturating_add(&self, seqno: u32) -> Self {
+        Self {
+            shard: self.shard,
+            seqno: self.seqno.saturating_add(seqno),
+        }
+    }
+
+    /// Returns a new block id with the seqno
+    /// decreased at most by the specified value.
+    pub fn saturating_sub(&self, seqno: u32) -> Self {
+        Self {
+            shard: self.shard,
+            seqno: self.seqno.saturating_sub(seqno),
+        }
+    }
+}
+
 impl std::fmt::Display for BlockIdShort {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         f.write_fmt(format_args!("{}:{}", self.shard, self.seqno))

src/models/block/shard_hashes.rs

@@ -442,6 +442,16 @@ impl ShardDescription {
     const TAG_V4: u8 = 0xd;
     #[cfg(feature = "venom")]
     const TAG_V5: u8 = 0xe;
+
+    /// Converts a `ShardDescription` to a `BlockId` given a shard identifier.
+    pub fn as_block_id(&self, shard: ShardIdent) -> BlockId {
+        BlockId {
+            shard,
+            seqno: self.seqno,
+            root_hash: self.root_hash,
+            file_hash: self.file_hash,
+        }
+    }
 }
 
 impl Store for ShardDescription {