CRC-32: Difference between revisions

Content added Content deleted

Inline

@@ Line 984: / Line 984: @@
     'use strict';
+    // --------------------- CRC-32 ----------------------
-    const main = () =>
-        showHex(
-            crc32('The quick brown fox jumps over the lazy dog')
-        );
     // crc32 :: String -> Int
     const crc32 = str => {
         // table :: [Int]
-        const table = map(
+        const table = enumFromTo(0)(255).map(
-            n => take(9,
+            n => take(9)(
                 iterate(
                     x => (
-                        x & 1 ? z => 0xEDB88320 ^ z : id
+                        x & 1 ? (
-                    )(x >>> 1),
+                            z => 0xEDB88320 ^ z
-                    n
+                        ) : identity
-                )
+                    )(x >>> 1)
-            )[8],
+                )(n)
-            enumFromTo(0, 255)
+            )[8]
-        );
-        return (
-            foldl(
-                (a, c) => (a >>> 8) ^ table[
-                    (a ^ c.charCodeAt(0)) & 255
-                ],
-                -1,
-                chars(str)
-            ) ^ -1
         );
+        return chars(str).reduce(
+            (a, c) => (a >>> 8) ^ table[
+                (a ^ c.charCodeAt(0)) & 255
+            ],
+            -1
+        ) ^ -1;
     };
-    // GENERIC ABSTRACTIONS -------------------------------
+    // ---------------------- TEST -----------------------
+    // main :: IO ()
+    const main = () =>
+        showHex(
+            crc32('The quick brown fox jumps over the lazy dog')
+        );
+    // --------------------- GENERIC ---------------------
     // chars :: String -> [Char]
-    const chars = s => s.split('');
+    const chars = s =>
+        s.split('');
     // enumFromTo :: Int -> Int -> [Int]
-    const enumFromTo = (m, n) =>
+    const enumFromTo = m =>
-        Array.from({
+        n => !isNaN(m) ? (
-            length: 1 + n - m
+            Array.from({
-        }, (_, i) => m + i);
+                length: 1 + n - m
+            }, (_, i) => m + i)
+        ) : enumFromTo_(m)(n);
-    // foldl :: (a -> b -> a) -> a -> [b] -> a
-    const foldl = (f, a, xs) => xs.reduce(f, a);
-    // id :: a -> a
+    // identity :: a -> a
-    const id = x => x;
+    const identity = x =>
+        // The identity function.
+        x;
     // iterate :: (a -> a) -> a -> Gen [a]
-    function* iterate(f, x) {
+    const iterate = f =>
-        let v = x;
+        // An infinite list of repeated
-        while (true) {
+        // applications of f to x.
-            yield(v);
+        function* (x) {
-            v = f(v);
+            let v = x;
-        }
+            while (true) {
+                yield(v);
-    }
+                v = f(v);
+            }
+        };
-    // map :: (a -> b) -> [a] -> [b]
-    const map = (f, xs) => xs.map(f);
     // showHex :: Int -> String
     const showHex = n =>
+        // Hexadecimal string for a given integer.
-        n.toString(16);
+        '0x' + n.toString(16);
     // take :: Int -> [a] -> [a]
     // take :: Int -> String -> String
-    const take = (n, xs) =>
+    const take = n =>
+        // The first n elements of a list,
-        xs.constructor.constructor.name !== 'GeneratorFunction' ? (
+        // string of characters, or stream.
+        xs => 'GeneratorFunction' !== xs
+        .constructor.constructor.name ? (
             xs.slice(0, n)
         ) : [].concat.apply([], Array.from({
@@ Line 1,069: / Line 1,080: @@
 })();</lang>
 {{Out}}
-<pre>414fa339</pre>
+<pre>0x414fa339</pre>
 =={{header|Jsish}}==