Initial Commit

src/crc32.c

@@ -0,0 +1,74 @@
+/**
+ * \file stdout
+ * Functions and types for CRC checks.
+ *
+ * Generated on Tue Jun 30 21:35:13 2009,
+ * by pycrc v0.7.1, http://www.tty1.net/pycrc/
+ * using the configuration:
+ *    Width        = 32
+ *    Poly         = 0x04c11db7
+ *    XorIn        = 0xffffffff
+ *    ReflectIn    = True
+ *    XorOut       = 0xffffffff
+ *    ReflectOut   = True
+ *    Algorithm    = bit-by-bit-fast
+ *    Direct       = True
+ *****************************************************************************/
+#include <stdint.h>
+#include "crc32.h"
+
+/**
+ * Reflect all bits of a \a data word of \a data_len bytes.
+ *
+ * \param data         The data word to be reflected.
+ * \param data_len     The width of \a data expressed in number of bits.
+ * \return     The reflected data.
+ *****************************************************************************/
+long crc_reflect(long data, size_t data_len)
+{
+    unsigned int i;
+    long ret;
+
+    ret = data & 0x01;
+    for (i = 1; i < data_len; i++)
+    {
+        data >>= 1;
+        ret = (ret << 1) | (data & 0x01);
+    }
+    return ret;
+}
+
+
+/**
+ * Update the crc value with new data.
+ *
+ * \param crc      The current crc value.
+ * \param data     Pointer to a buffer of \a data_len bytes.
+ * \param data_len Number of bytes in the \a data buffer.
+ * \return         The updated crc value.
+ *****************************************************************************/
+crc_t crc_update(crc_t crc, const unsigned char *data, size_t data_len)
+{
+    unsigned int i;
+    uint8_t bit;
+    unsigned char c;
+
+    while (data_len--) {
+        c = *data++;
+        for (i = 0x01; i & 0xff; i <<= 1) {
+            bit = ((crc & 0x80000000) ? 1 : 0);
+            if (c & i) {
+                bit ^= 1;
+            }
+            crc <<= 1;
+            if (bit) {
+                crc ^= 0x04c11db7;
+            }
+        }
+        crc &= 0xffffffff;
+    }
+    return crc & 0xffffffff;
+}
+
+
+