From f3e040230772f978540a71aea43dfde200992922 Mon Sep 17 00:00:00 2001
From: "John Wilbert M. Villamor" <lameguy64@gmail.com>
Date: Sat, 6 Apr 2019 10:11:07 +0800
Subject: First commit

---
 libpsn00b/lzp/crc.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 libpsn00b/lzp/crc.c

(limited to 'libpsn00b/lzp/crc.c')

diff --git a/libpsn00b/lzp/crc.c b/libpsn00b/lzp/crc.c
new file mode 100644
index 0000000..c5ab702
--- /dev/null
+++ b/libpsn00b/lzp/crc.c
@@ -0,0 +1,91 @@
+#include "lzp.h"
+
+void initTable16(unsigned short* table) {
+
+	int i, j;
+    unsigned short crc, c;
+
+    for (i=0; i<256; i++) {
+
+        crc = 0;
+        c   = (unsigned short) i;
+
+        for (j=0; j<8; j++) {
+
+            if ( (crc ^ c) & 0x0001 )
+				crc = ( crc >> 1 ) ^ 0xA001;
+            else
+				crc =   crc >> 1;
+
+            c = c >> 1;
+        }
+
+        table[i] = crc;
+    }
+
+}
+
+void initTable32(unsigned int* table) {
+
+	int i,j;
+	unsigned int crcVal;
+
+	for(i=0; i<256; i++) {
+
+		crcVal = i;
+
+		for(j=0; j<8; j++) {
+
+			if (crcVal&0x00000001L)
+				crcVal = (crcVal>>1)^0xEDB88320L;
+			else
+				crcVal = crcVal>>1;
+
+		}
+
+		table[i] = crcVal;
+
+	}
+
+}
+
+unsigned short lzCRC16(void* buff, int bytes, unsigned short crc) {
+
+	int i;
+	unsigned short tmp, short_c;
+	unsigned short crcTable[256];
+
+	initTable16(crcTable);
+
+	for(i=0; i<bytes; i++) {
+
+		short_c = 0x00ff & (unsigned short)((unsigned char*)buff)[i];
+
+		tmp =  crc       ^ short_c;
+		crc = (crc >> 8) ^ crcTable[tmp&0xff];
+
+	}
+
+    return(crc);
+
+}
+
+unsigned int lzCRC32(void* buff, int bytes, unsigned int crc) {
+
+	int	i;
+	unsigned char*	byteBuff = (unsigned char*)buff;
+	unsigned int	byte;
+	unsigned int	crcTable[256];
+
+    initTable32(crcTable);
+
+	for(i=0; i<bytes; i++) {
+
+		byte = 0x000000ffL&(unsigned int)byteBuff[i];
+		crc = (crc>>8)^crcTable[(crc^byte)&0xff];
+
+	}
+
+	return(crc^0xFFFFFFFF);
+
+}
-- 
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