X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/rsbs2/blobdiff_plain/a97855ded317db6025710edc487d337cbd5f0ad2..05b6bf30040b7d3f2219919168b4c159045a909b:/src/rsb-crc.c

diff --git a/src/rsb-crc.c b/src/rsb-crc.c
new file mode 100644
index 0000000..6a2bf99
--- /dev/null
+++ b/src/rsb-crc.c
@@ -0,0 +1,54 @@
+#include <stdio.h>
+
+#define POLY 0x04c11db7
+
+unsigned int rsb_crc(unsigned int r11_crc, unsigned char *r10_buf, unsigned int r14_len) {
+	unsigned int r6_pos = 0;
+	unsigned int r3_data;
+	int r5_bit;
+
+	while (r6_pos < r14_len) {
+		r3_data = (*(r6_pos+r10_buf)) << 24;
+		r11_crc = r11_crc ^ r3_data;
+
+		r5_bit = 8;
+		
+		do {
+			r3_data = r11_crc & 0x80000000;
+
+			if (r3_data != 0) {
+				r3_data = r11_crc << 1;
+				r11_crc = r3_data ^ POLY;
+			} else {
+				r11_crc = r11_crc << 1;
+			}
+			r5_bit--;
+		} while (r5_bit);
+
+		r6_pos++;
+	}
+
+	return r11_crc;
+}
+
+unsigned int rsb_crc2(unsigned char *r0_buf, unsigned int r1_buflen, unsigned int r2_magic, unsigned int *crc_out) {
+	unsigned int r4_len;
+	unsigned int file_crc;
+
+	r4_len = *(unsigned int*)(r0_buf + 0x20);
+
+	if (*((unsigned int*)(r0_buf + 0x24)) != r2_magic)
+		return 2; /* MAGIC does not match */
+	
+	if (r1_buflen < r4_len)
+		return 3; /* image to small */
+	
+	*crc_out = ~rsb_crc(~0x0, r0_buf, r4_len);
+
+	file_crc = *((unsigned int*)(r0_buf + r4_len));
+
+	if (file_crc != *crc_out)
+		return 4;
+
+	return 0;
+}