initial commit

.editorconfig

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+[*.cr]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+indent_style = space
+indent_size = 2
+trim_trailing_whitespace = true

.gitignore

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+/doc/
+/lib/
+/bin/
+/.shards/

.travis.yml

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+language: crystal

LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2018 Anton Maminov
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

README.md

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+# nanoid.cr
+
+Crystal implementation of original NanoID https://github.com/ai/nanoid
+
+## Installation
+
+Add this to your application's `shard.yml`:
+
+```yaml
+dependencies:
+  nanoid:
+    github: mamantoha/nanoid.cr
+```
+
+## Usage
+
+```crystal
+require "nanoid"
+
+Nanoid.generate
+# => 3gFI8yZxcfXsXGhB0036l
+
+Nanoid.generate(size: 8, alphabet: "1234567890abcdef")
+# => 86984b57
+```
+
+## Development
+
+Clone this repository and install dependencies:
+
+```
+shards install
+```
+
+Run tests:
+
+```
+crystal spec
+```
+
+## Contributing
+
+1. Fork it ( https://github.com/mamantoha/nanoid.cr/fork )
+2. Create your feature branch (git checkout -b my-new-feature)
+3. Commit your changes (git commit -am 'Add some feature')
+4. Push to the branch (git push origin my-new-feature)
+5. Create a new Pull Request
+
+## Contributors
+
+- [mamantoha](https://github.com/mamantoha) Anton Maminov - creator, maintainer
+
+## License
+
+Copyright: 2018 Anton Maminov (anton.maminov@gmail.com)
+
+This library is distributed under the MIT license. Please see the LICENSE file.

shard.yml

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+name: nanoid
+version: 0.1.0
+
+authors:
+  - Anton Maminov <anton.maminov@gmail.com>
+description: |
+  Crystal implementation of Nanoid, secure URL-friendly unique ID generator
+
+targets:
+  nanoid:
+    main: src/nanoid.cr
+
+crystal: 0.24.1
+
+license: MIT

spec/nanoid_spec.cr

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+require "./spec_helper"
+
+describe Nanoid do
+  it "has correct size" do
+    count = 100
+
+    count.times do
+      id = Nanoid.generate
+
+      (id.size).should eq(21)
+    end
+  end
+
+  it "generates URL-friendly IDs" do
+    count = 100
+
+    count.times do
+      id = Nanoid.generate
+
+      (0...id.size).each do |j|
+        (Nanoid::SAFE_ALPHABET.index(id[j])).should_not be_nil
+      end
+    end
+  end
+
+  it "has no collisions for million entries as 21 characters length" do
+    count = 100_000
+    generated = {} of String => Bool
+
+    count.times do
+      id = Nanoid.generate
+      (id.size).should eq(21)
+
+      (generated.has_key?(id)).should be_false
+      generated[id] = true
+    end
+  end
+
+  it "has no collisions for milion entries with 9 characters and base alphabet" do
+    count = 100_000
+    generated = {} of String => Bool
+
+    count.times do
+      id = Nanoid.generate(size: 9, alphabet: "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+      (id.size).should eq(9)
+
+      (generated.has_key?(id)).should be_false
+      generated[id] = true
+    end
+  end
+
+  it "generates with custom settings" do
+    Nanoid.generate(size: 12, alphabet: "1234567890abcdef")
+  end
+end

spec/spec_helper.cr

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+require "spec"
+require "../src/nanoid"

src/nanoid.cr

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+module Nanoid
+  SAFE_ALPHABET = "_~0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+
+  def self.generate(size = 21, alphabet = SAFE_ALPHABET) : String
+    return simple_generate(size) if alphabet == SAFE_ALPHABET
+
+    complex_generate(size: size, alphabet: alphabet)
+  end
+
+  private def self.simple_generate(size : Int32) : String
+    bytes = random_bytes(size)
+
+    (0...size).reduce("") do |acc, i|
+      acc + SAFE_ALPHABET[bytes[i] & 63]
+    end
+  end
+
+  private def self.complex_generate(size : Int32, alphabet : String) : String
+    alphabet_size = alphabet.size
+    mask = (2 << (Math.log(alphabet_size - 1) / Math.log(2)).to_i) - 1
+    step = (1.6 * mask * size / alphabet_size).ceil.to_i
+
+    result = ""
+
+    loop do
+      break if result.size == size
+
+      bytes = random_bytes(size)
+      (0...step).each do |i|
+        byte = bytes[i]? ? (bytes[i] & mask) : false
+
+        next unless byte.is_a?(Int)
+        char = byte && alphabet[byte]?
+        next unless char
+
+        result = "#{result}#{char}"
+        break if result.size == size
+      end
+    end
+
+    return result
+  end
+
+  private def self.random_bytes(size)
+    Random::Secure.random_bytes(size).map(&.to_i).to_a
+  end
+end

src/nanoid/version.rb

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+module NanoId
+  VERSION = "0.1.0"
+end