Grading library files.

diff --git a/grading/lib/arc4.c b/grading/lib/arc4.c
new file mode 100644 (file)
index 0000000..26798d3
--- /dev/null
+++ b/grading/lib/arc4.c
@@ -0,0 +1,53 @@
+#include <stdint.h>
+#include "../lib/arc4.h"
+
+/* Swap bytes. */
+static inline void
+swap_byte (uint8_t *a, uint8_t *b)
+{
+  uint8_t t = *a;
+  *a = *b;
+  *b = t;
+}
+
+void
+arc4_init (struct arc4 *arc4, const void *key_, size_t size)
+{
+  const uint8_t *key = key_;
+  size_t key_idx;
+  uint8_t *s;
+  int i, j;
+
+  s = arc4->s;
+  arc4->i = arc4->j = 0;
+  for (i = 0; i < 256; i++)
+    s[i] = i;
+  for (key_idx = 0, i = j = 0; i < 256; i++)
+    {
+      j = (j + s[i] + key[key_idx]) & 255;
+      swap_byte (s + i, s + j);
+      if (++key_idx >= size)
+        key_idx = 0;
+    }
+}
+
+void
+arc4_crypt (struct arc4 *arc4, void *buf_, size_t size)
+{
+  uint8_t *buf = buf_;
+  uint8_t *s;
+  uint8_t i, j;
+
+  s = arc4->s;
+  i = arc4->i;
+  j = arc4->j;
+  while (size-- > 0)
+    {
+      i += 1;
+      j += s[i];
+      swap_byte (s + i, s + j);
+      *buf++ ^= s[(s[i] + s[j]) & 255];
+    }
+  arc4->i = i;
+  arc4->j = j;
+}

diff --git a/grading/lib/arc4.h b/grading/lib/arc4.h
new file mode 100644 (file)
index 0000000..ccb260c
--- /dev/null
+++ b/grading/lib/arc4.h
@@ -0,0 +1,18 @@
+#ifndef ARC4_H
+#define ARC4_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+/* Alleged RC4 algorithm encryption state. */
+struct arc4
+  {
+    uint8_t s[256];
+    uint8_t i, j;
+  };
+
+void arc4_init (struct arc4 *, const void *, size_t);
+void arc4_crypt (struct arc4 *, void *, size_t);
+
+
+#endif /* arc4.h */

diff --git a/grading/lib/cksum.c b/grading/lib/cksum.c
new file mode 100644 (file)
index 0000000..b38a5b1
--- /dev/null
+++ b/grading/lib/cksum.c
@@ -0,0 +1,86 @@
+/* crctab[] and cksum() are from the `cksum' entry in SUSv3. */
+
+#include "../lib/cksum.h"
+
+static unsigned long crctab[] = {
+  0x00000000,
+  0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b,
+  0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6,
+  0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
+  0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac,
+  0x5bd4b01b, 0x569796c2, 0x52568b75, 0x6a1936c8, 0x6ed82b7f,
+  0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a,
+  0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
+  0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58,
+  0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033,
+  0xa4ad16ea, 0xa06c0b5d, 0xd4326d90, 0xd0f37027, 0xddb056fe,
+  0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
+  0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4,
+  0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0,
+  0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5,
+  0x2ac12072, 0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
+  0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, 0x7897ab07,
+  0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c,
+  0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1,
+  0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
+  0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b,
+  0xbb60adfc, 0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698,
+  0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d,
+  0x94ea7b2a, 0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
+  0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, 0xc6bcf05f,
+  0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34,
+  0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80,
+  0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
+  0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a,
+  0x58c1663d, 0x558240e4, 0x51435d53, 0x251d3b9e, 0x21dc2629,
+  0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c,
+  0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
+  0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e,
+  0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65,
+  0xeba91bbc, 0xef68060b, 0xd727bbb6, 0xd3e6a601, 0xdea580d8,
+  0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
+  0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2,
+  0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71,
+  0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74,
+  0x857130c3, 0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
+  0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, 0x7b827d21,
+  0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a,
+  0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e, 0x18197087,
+  0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
+  0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d,
+  0x2056cd3a, 0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce,
+  0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb,
+  0xdbee767c, 0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
+  0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, 0x89b8fd09,
+  0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662,
+  0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf,
+  0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
+};
+
+/* This is the algorithm used by the Posix `cksum' utility. */
+unsigned long cksum(const unsigned char *b, size_t n)
+{
+  register unsigned   i, c, s = 0;
+  for (i = n; i > 0; --i) {
+    c = (unsigned)(*b++);
+    s = (s << 8) ^ crctab[(s >> 24) ^ c];
+  }
+  while (n != 0) {
+    c = n & 0377;
+    n >>= 8;
+    s = (s << 8) ^ crctab[(s >> 24) ^ c];
+  }
+  return ~s;
+}
+
+#ifdef STANDALONE_TEST
+#include <stdio.h>
+int
+main (void) 
+{
+  char buf[65536];
+  int n = fread (buf, 1, sizeof buf, stdin);
+  printf ("%lu\n", cksum (buf, n));
+  return 0;
+}
+#endif

diff --git a/grading/lib/cksum.h b/grading/lib/cksum.h
new file mode 100644 (file)
index 0000000..79b7c42
--- /dev/null
+++ b/grading/lib/cksum.h
@@ -0,0 +1,8 @@
+#ifndef CKSUM_H
+#define CKSUM_H
+
+#include <stddef.h>
+
+unsigned long cksum(const unsigned char *b, size_t n);
+
+#endif /* cksum.h */