Module trie
-
-
+Trie implementation in LuaJIT.
++ This module provides an optimized Trie data structure using LuaJIT's Foreign Function Interface (FFI). + It supports operations like insertion, search, finding the longest prefix, and converting the Trie into a table format. +
Dynamic Allocation: + The implementation uses dynamic memory allocation for efficient storage and manipulation of nodes: + - Each Trie node dynamically allocates memory for its `children` and `keys` arrays using `ffi.C.malloc` and `ffi.C.realloc`. + - Arrays are initially allocated with a small capacity and are resized as needed to accommodate more child nodes. +
Node Structure: + Each Trie node contains the following fields: + - **`is_leaf`** (boolean): Indicates whether the node represents the end of a string. + - **`capacity`** (number): The current maximum number of children the node can hold. + - Starts at a small initial value (e.g., 8) and doubles as needed. + - **`size`** (number): The current number of children the node has. + - Always ≤ `capacity`. + - **`children`** (array): A dynamically allocated array of pointers to child nodes. + - **`keys`** (array): A dynamically allocated array of ASCII values corresponding to the `children` nodes. +
Dynamic Resizing: + - If a node's `size` exceeds its `capacity` during insertion, the `capacity` is doubled. + - The `children` and `keys` arrays are reallocated to match the new capacity using `ffi.C.realloc`. + - Resizing ensures efficient use of memory while avoiding frequent allocations. +
Memory Management: + - Memory is manually managed: + - **Allocation**: Done using `ffi.C.malloc` for new nodes and `ffi.C.realloc` for resizing arrays. + - **Deallocation**: Performed recursively for all child nodes using `ffi.C.free`. + - The implementation includes safeguards to handle allocation failures and ensure proper cleanup. +
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