Added CRC32 and CRC32C classes to stdlib. (0.31.0)

lib/crypt/crc32.fun

@@ -0,0 +1,156 @@
+/*
+ * This file is part of the Fun programming language.
+ * https://fun-lang.xyz/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ *
+ * Added: 2025-11-26
+ */
+
+// lib/crypt/crc32.fun
+// Pure Fun implementation of CRC-32 (IEEE 802.3) operating on hex-string input.
+// Reflected polynomial: 0xEDB88320
+// Initial value: 0xFFFFFFFF, Final XOR: 0xFFFFFFFF
+//
+// Public API (class methods):
+//   crc32_hex(hexStr) -> 8-char lowercase hex string
+//   crc32_str(str)    -> 8-char lowercase string (ASCII input)
+//
+// Example:
+//   // "123456789" CRC32 is cbf43926
+//   c = CRC32()
+//   print(c.crc32_str("123456789"))
+
+#include <strings.fun>
+
+class CRC32()
+  // 32-bit helpers
+  fun u32(this, x)
+    m = 4294967296
+    while x < 0
+      x = x + m
+    while x >= m
+      x = x - m
+    return x
+
+  fun shr32(this, x, s)
+    return shr(this.u32(x), s)
+
+  fun shl32(this, x, s)
+    return shl(this.u32(x), s)
+
+  fun xor32(this, a, b)
+    return bxor(this.u32(a), this.u32(b))
+
+  fun and32(this, a, b)
+    return band(this.u32(a), this.u32(b))
+
+  // hex helpers (mirroring style from lib/crypt/md5.fun)
+  fun hex_val(this, ch)
+    if (ch == "0")
+      return 0
+    else if (ch == "1")
+      return 1
+    else if (ch == "2")
+      return 2
+    else if (ch == "3")
+      return 3
+    else if (ch == "4")
+      return 4
+    else if (ch == "5")
+      return 5
+    else if (ch == "6")
+      return 6
+    else if (ch == "7")
+      return 7
+    else if (ch == "8")
+      return 8
+    else if (ch == "9")
+      return 9
+    else if (ch == "a" || ch == "A")
+      return 10
+    else if (ch == "b" || ch == "B")
+      return 11
+    else if (ch == "c" || ch == "C")
+      return 12
+    else if (ch == "d" || ch == "D")
+      return 13
+    else if (ch == "e" || ch == "E")
+      return 14
+    else if (ch == "f" || ch == "F")
+      return 15
+    else
+      return 0
+
+  fun byte_from_hex_pair(this, hh)
+    hi = this.hex_val(substr(hh, 0, 1))
+    lo = this.hex_val(substr(hh, 1, 1))
+    return hi * 16 + lo
+
+  fun from_hex(this, hex)
+    arr = []
+    i = 0
+    n = len(hex)
+    while i + 1 < n
+      b = this.byte_from_hex_pair(substr(hex, i, 2))
+      push(arr, b)
+      i = i + 2
+    return arr
+
+  fun two_hex(this, n)
+    n = n % 256
+    d = ["0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"]
+    hi = n / 16
+    lo = n % 16
+    parts = [d[hi], d[lo]]
+    return join(parts, "")
+
+  fun bytes_to_hex(this, arr)
+    i = 0
+    out = []
+    while i < len(arr)
+      push(out, this.two_hex(arr[i]))
+      i = i + 1
+    return join(out, "")
+
+  fun u32_to_hex8(this, n)
+    // big-endian printing (MSB first), common for CRC displays
+    b3 = this.and32(this.shr32(n, 24), 255)
+    b2 = this.and32(this.shr32(n, 16), 255)
+    b1 = this.and32(this.shr32(n, 8), 255)
+    b0 = this.and32(n, 255)
+    return this.bytes_to_hex([b3, b2, b1, b0])
+
+  // Bitwise update (no table needed) using reflected polynomial 0xEDB88320
+  POLY = 3988292384 // 0xEDB88320
+
+  // Compute CRC32 over byte array, return u32 value (bitwise, reflected)
+  fun crc32_bytes_value(this, bytes)
+    crc = 4294967295 // 0xFFFFFFFF
+    i = 0
+    n = len(bytes)
+    while i < n
+      crc = this.xor32(crc, bytes[i])
+      j = 0
+      while j < 8
+        if (this.and32(crc, 1) == 1)
+          crc = this.xor32(this.shr32(crc, 1), this.POLY)
+        else
+          crc = this.shr32(crc, 1)
+        j = j + 1
+      i = i + 1
+    return this.xor32(crc, 4294967295) // final XOR
+
+  // Public: compute CRC32 of hex string of bytes, return 8-char hex
+  fun crc32_hex(this, hexStr)
+    bytes = this.from_hex(hexStr)
+    v = this.crc32_bytes_value(bytes)
+    return this.u32_to_hex8(v)
+
+  // Convenience: compute CRC32 of ASCII string
+  fun crc32_str(this, str)
+    bytes = string_to_bytes_ascii(str)
+    v = this.crc32_bytes_value(bytes)
+    return this.u32_to_hex8(v)