-fix paths

[oweals/gnunet.git] / src / util / crypto_crc.c

diff --git a/src/util/crypto_crc.c b/src/util/crypto_crc.c
index 35d1e257689dc6b698bdc32a32d0a9c505aa3704..cda6243bee2723d88494dba18397cd187aba4efc 100644 (file)
--- a/src/util/crypto_crc.c
+++ b/src/util/crypto_crc.c
@@ -4,7 +4,7 @@
 
      GNUnet is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published
 
      GNUnet is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published

-     by the Free Software Foundation; either version 2, or (at your
+     by the Free Software Foundation; either version 3, or (at your

      option) any later version.
 
      GNUnet is distributed in the hope that it will be useful, but
      option) any later version.
 
      GNUnet is distributed in the hope that it will be useful, but


@@ -17,20 +17,20 @@
      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
      Boston, MA 02111-1307, USA.
 
      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
      Boston, MA 02111-1307, USA.
 

-     For the actual CRC code:
+     For the actual CRC-32 code:

      Copyright abandoned; this code is in the public domain.
      Provided to GNUnet by peter@horizon.com
 */
 
 /**
  * @file util/crypto_crc.c
      Copyright abandoned; this code is in the public domain.
      Provided to GNUnet by peter@horizon.com
 */
 
 /**
  * @file util/crypto_crc.c

- * @brief implementation of CRC32
+ * @brief implementation of CRC16 and CRC32

  * @author Christian Grothoff
  */
  * @author Christian Grothoff
  */

-

 #include "platform.h"
 #include "platform.h"

-#include "gnunet_common.h"
-#include "gnunet_crypto_lib.h"
+#include "gnunet_util_lib.h"
+
+#define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)

 
 /* Avoid wasting space on 8-byte longs. */
 #if UINT_MAX >= 0xffffffff
 
 /* Avoid wasting space on 8-byte longs. */
 #if UINT_MAX >= 0xffffffff


@@ -49,21 +49,27 @@ static uLong crc_table[256];
 
 /*
  * This routine writes each crc_table entry exactly once,
 
 /*
  * This routine writes each crc_table entry exactly once,

- * with the ccorrect final value.  Thus, it is safe to call
+ * with the correct final value.  Thus, it is safe to call

  * even on a table that someone else is using concurrently.
  */
  * even on a table that someone else is using concurrently.
  */

-void __attribute__ ((constructor)) GNUNET_CRYPTO_crc_init ()
+static void
+crc_init ()

 {
 {

+  static int once;

   unsigned int i, j;
   uLong h = 1;
   unsigned int i, j;
   uLong h = 1;

+
+  if (once)
+    return;
+  once = 1;

   crc_table[0] = 0;
   for (i = 128; i; i >>= 1)
   crc_table[0] = 0;
   for (i = 128; i; i >>= 1)

-    {
-      h = (h >> 1) ^ ((h & 1) ? POLYNOMIAL : 0);
-      /* h is now crc_table[i] */
-      for (j = 0; j < 256; j += 2 * i)
-        crc_table[i + j] = crc_table[j] ^ h;
-    }
+  {
+    h = (h >> 1) ^ ((h & 1) ? POLYNOMIAL : 0);
+    /* h is now crc_table[i] */
+    for (j = 0; j < 256; j += 2 * i)
+      crc_table[i + j] = crc_table[j] ^ h;
+  }

 }
 
 /*
 }
 
 /*


@@ -79,6 +85,7 @@ void __attribute__ ((constructor)) GNUNET_CRYPTO_crc_init ()
 static uLong
 crc32 (uLong crc, const char *buf, size_t len)
 {
 static uLong
 crc32 (uLong crc, const char *buf, size_t len)
 {

+  crc_init ();

   GNUNET_assert (crc_table[255] != 0);
   crc ^= 0xffffffff;
   while (len--)
   GNUNET_assert (crc_table[255] != 0);
   crc ^= 0xffffffff;
   while (len--)


@@ -94,13 +101,69 @@ crc32 (uLong crc, const char *buf, size_t len)
  * @param len the length of the buffer
  * @return the resulting CRC32 checksum
  */
  * @param len the length of the buffer
  * @return the resulting CRC32 checksum
  */

-int
-GNUNET_CRYPTO_crc32_n (const void *buf, unsigned int len)
+int32_t
+GNUNET_CRYPTO_crc32_n (const void *buf, size_t len)

 {
   uLong crc;
 {
   uLong crc;

+

   crc = crc32 (0L, Z_NULL, 0);
   crc = crc32 (crc, (char *) buf, len);
   return crc;
 }
 
   crc = crc32 (0L, Z_NULL, 0);
   crc = crc32 (crc, (char *) buf, len);
   return crc;
 }
 

-/* end of crc32.c */
+
+/**
+ * Perform an incremental step in a CRC16 (for TCP/IP) calculation.
+ *
+ * @param sum current sum, initially 0
+ * @param buf buffer to calculate CRC over (must be 16-bit aligned)
+ * @param len number of bytes in hdr, must be multiple of 2
+ * @return updated crc sum (must be subjected to GNUNET_CRYPTO_crc16_finish to get actual crc16)
+ */
+uint32_t
+GNUNET_CRYPTO_crc16_step (uint32_t sum, const void *buf, size_t len)
+{
+  const uint16_t *hdr = buf;
+  for (; len >= 2; len -= 2)
+    sum += *(hdr++);
+  if (len == 1)
+    sum += (*hdr) & ntohs(0xFF00);
+  return sum;
+}
+
+
+/**
+ * Convert results from GNUNET_CRYPTO_crc16_step to final crc16.
+ *
+ * @param sum cummulative sum
+ * @return crc16 value
+ */
+uint16_t
+GNUNET_CRYPTO_crc16_finish (uint32_t sum)
+{
+  sum = (sum >> 16) + (sum & 0xFFFF);
+  sum += (sum >> 16);
+
+  return ~sum;
+}
+
+
+/**
+ * Calculate the checksum of a buffer in one step.
+ *
+ * @param buf buffer to  calculate CRC over (must be 16-bit aligned)
+ * @param len number of bytes in hdr, must be multiple of 2
+ * @return crc16 value
+ */
+uint16_t
+GNUNET_CRYPTO_crc16_n (const void *buf, size_t len)
+{
+  const uint16_t *hdr = buf;
+  uint32_t sum = GNUNET_CRYPTO_crc16_step (0, hdr, len);
+
+  return GNUNET_CRYPTO_crc16_finish (sum);
+}
+
+
+
+/* end of crypto_crc.c */