Display bin size range in `largebins` command output (#1613)

* Display bin size range in `largebins` command

* Remove `infinity_symbol` variable

* Remove unnecessary assignment

pwndbg/commands/heap.py

@@ -81,7 +81,15 @@ def format_bin(bins: Bins, verbose=False, offset=None):
             formatted_chain = pwndbg.chain.format(chain_fd[0], offset=offset, safe_linking=safe_lnk)
 
         if isinstance(size, int):
-            size = hex(size)
+            if bins_type == BinType.LARGE:
+                start_size, end_size = allocator.largebin_size_range_from_index(size)
+                size = hex(start_size) + "-"
+                if end_size != pwndbg.gdblib.arch.ptrmask:
+                    size += hex(end_size)
+                else:
+                    size += "\u221e"  # Unicode "infinity"
+            else:
+                size = hex(size)
 
         if is_chain_corrupted:
             line = message.hint(size) + message.error(" [corrupted]") + "\n"

pwndbg/heap/ptmalloc.py

@@ -658,6 +658,22 @@ class GlibcMemoryAllocator(pwndbg.heap.heap.MemoryAllocator):
         # ptmalloc cache for current thread
         self._thread_cache: gdb.Value = None
 
+    def largebin_size_range_from_index(self, index):
+        index += NSMALLBINS
+        spaces_table = self._spaces_table()
+        largest_largebin = self.largebin_index(pwndbg.gdblib.arch.ptrmask)
+        start_size = (NSMALLBINS * self.malloc_alignment) - self.malloc_alignment
+
+        for i in range(NSMALLBINS, index + 1):
+            start_size += spaces_table[i]
+
+        if index != largest_largebin:
+            end_size = start_size + spaces_table[index + 1] - self.malloc_alignment
+        else:
+            end_size = pwndbg.gdblib.arch.ptrmask
+
+        return (start_size, end_size)
+
     def can_be_resolved(self):
         raise NotImplementedError()