[project @ zyp-20060126190715-557e941315671b81]

[project @ 18]
Moved disccat and pyanidb to the right location.
Added pyqtmpc and ophidia.

1 files changed, 41 insertions, 0 deletions

diff --git a/hash/crc32.cpp b/hash/crc32.cpp
new file mode 100644
index 0000000..55d6dd2
--- /dev/null
+++ b/hash/crc32.cpp
@@ -0,0 +1,41 @@
+#include "crc32.h"
+
+int* CRC32::crc_table;
+
+int* CRC32::generate_table() {
+	int crc;
+	int* table = new int[256];
+	for(int i = 0; i < 256; i++) {
+		crc = i << 24;
+		for(int j = 0; j < 8; j++) {
+			if(crc & 0x80000000) {
+				crc = (crc << 1) ^ 0x04c11db7;
+			} else {
+				crc = crc << 1;
+			}
+		}
+		table[i] = crc;
+	}
+	return table;
+}
+
+int CRC32::reflect(int data, int bits) {
+	int x = 0;
+	for(int i = 0; i < bits; i++) {
+		x = x << 1;
+		x |= data & 1;
+		data = data >> 1;
+	}
+	return x;
+}
+
+int CRC32::crc32(int crc, const char* data, int length) {
+	crc = ~reflect(crc, 32);
+	if(!crc_table) {
+		crc_table = generate_table();
+	}
+	for (int i = 0; i < length;  i++) {
+		crc = (crc << 8) ^ crc_table[((crc >> 24) ^ reflect(data[i], 8)) & 0xff];
+	}
+	return ~reflect(crc, 32);
+}