solidity-utils

This library implements the missing usable and iterable dictionary in solidity.
Current implementations:

• dic(uint, bytes)
• dic(bytes32, bytes)
• dic(bytes32, uint)

Dictionary

mapping + keys iteration.
Inspired by Dictionary in python or 'Objectin javascript,Dictionaryis an improved and faster mapping data-structure that allows you to retrieve all the keys in a mapping object while minimizing storage usage. The data-stucture combines linked-list iteration style with soliditymapping` hash-table.

Using

pragma solidity ^0.4.0;
// import the contract
import "github.com/RaphCayou/solidity-utils/contracts/lib/Dictionary.sol";

contract FooUint {
    // declare and use new Dictionary structure
    using Dictionary for Dictionary.Data;
    Dictionary.Data private dic;

    function Foo() public view returns (uint) {
        dic.set(1, "value");
        dic.set(2, "foo");
        // get an item
        dic.get(2); // => '0x666f6f' (byte hex of 'foo')
        // update an item's value
        dic.set(2, "value");
        // get all keys
        dic.keys(); // => [1, 2]
        // check if key exists
        var exists = dic.exists(1);
    }
}
contract FooBytes32 {
    // declare and use new Dictionary structure
    using DictionaryBytes32 for DictionaryBytes32.Data;
    DictionaryBytes32.Data private dic;

    function Foo() public view returns (uint) {
        dic.set(0xab12, "value");
        dic.set(0x45ba, "foo");
        // get an item
        dic.get(0x45ba); // => '0x666f6f' (byte hex of 'foo')
        // update an item's value
        dic.set(0x45ba, "value");
        // get all keys
        dic.keys(); // => [0xab12, 0x45ba]
        // check if key exists
        dic.exists(0xab12); // => true
    }
}
contract FooBytes32Uint {
    // declare and use new Dictionary structure
    using DictionaryBytes32Uint for DictionaryBytes32Uint.Data;
    DictionaryBytes32Uint.Data private dic;

    function Foo() public view returns (uint) {
        dic.set(0xab12, 1);
        dic.set(0x45ba, 2);
        // get an item
        dic.get(0x45ba); // => 2
        // update an item's value
        dic.set(0x45ba, 3);
        // get all keys
        dic.keys(); // => [0xab12, 0x45ba]
        // check if key exists
        dic.exists(0xab12); // => true
    }
}

Basic Operations

set(uint id, bytes data)
get(uint id) --> bytes data
remove(uint id)
getSize() --> uint num of keys
exists(uint id) --> bool id exists

set(bytes32 id, bytes data)
get(bytes32 id) --> bytes data
remove(bytes32 id)
getSize() --> uint num of keys
exists(bytes32 id) --> bool id exists

set(bytes32 id, uint data)
get(bytes32 id) --> uint data
remove(bytes32 id)
getSize() --> uint num of keys
exists(bytes32 id) --> bool id exists

Iteration operations

Keys are stored based on the order you specify, allows you to iterate over keys.
keys() - return an array of all the keys.
next(uint id) / prev(uint id) - return the next/prev key for a given key.
firstNodeId / lastNodeId - return the first/last key.
Example iteration:

uint nodeId = dic.firstNodeId;
while (nodeId != 0) {
  // do something
  nodeId = dic.next(nodeId);
}

Insertion Options

insertBeginning(uint id, bytes data) - add a node to the begining of the list.
insertEnd(uint id, bytes data) - add a node to the end of the list.
insertBefore(uint beforeId, uint id, bytes data) - add a node before another.
insertEnd(uint beforeId, uint id, bytes data) - add a node after another.
The default order for .set(uint id, bytes data) is insertEnd.

Limitation

Key must be bigger than 0.