patch-2.4.22 linux-2.4.22/lib/gen_crc32table.c

• Lines: 83
• Date: 2003-08-25 04:44:44.000000000 -0700
• Orig file: linux-2.4.21/lib/gen_crc32table.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.21/lib/gen_crc32table.c linux-2.4.22/lib/gen_crc32table.c
@@ -0,0 +1,82 @@
+#include <stdio.h>
+#include "crc32defs.h"
+#include <sys/types.h>
+
+#define ENTRIES_PER_LINE 4
+
+#define LE_TABLE_SIZE (1 << CRC_LE_BITS)
+#define BE_TABLE_SIZE (1 << CRC_BE_BITS)
+
+static u_int32_t crc32table_le[LE_TABLE_SIZE];
+static u_int32_t crc32table_be[BE_TABLE_SIZE];
+
+/**
+ * crc32init_le() - allocate and initialize LE table data
+ *
+ * crc is the crc of the byte i; other entries are filled in based on the
+ * fact that crctable[i^j] = crctable[i] ^ crctable[j].
+ *
+ */
+static void crc32init_le(void)
+{
+	unsigned i, j;
+	u_int32_t crc = 1;
+
+	crc32table_le[0] = 0;
+
+	for (i = 1 << (CRC_LE_BITS - 1); i; i >>= 1) {
+		crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0);
+		for (j = 0; j < LE_TABLE_SIZE; j += 2 * i)
+			crc32table_le[i + j] = crc ^ crc32table_le[j];
+	}
+}
+
+/**
+ * crc32init_be() - allocate and initialize BE table data
+ */
+static void crc32init_be(void)
+{
+	unsigned i, j;
+	u_int32_t crc = 0x80000000;
+
+	crc32table_be[0] = 0;
+
+	for (i = 1; i < BE_TABLE_SIZE; i <<= 1) {
+		crc = (crc << 1) ^ ((crc & 0x80000000) ? CRCPOLY_BE : 0);
+		for (j = 0; j < i; j++)
+			crc32table_be[i + j] = crc ^ crc32table_be[j];
+	}
+}
+
+static void output_table(u_int32_t table[], int len, char *trans)
+{
+	int i;
+
+	for (i = 0; i < len - 1; i++) {
+		if (i % ENTRIES_PER_LINE == 0)
+			printf("\n");
+		printf("%s(0x%8.8xL), ", trans, table[i]);
+	}
+	printf("%s(0x%8.8xL)\n", trans, table[len - 1]);
+}
+
+int main(int argc, char** argv)
+{
+	printf("/* this file is generated - do not edit */\n\n");
+
+	if (CRC_LE_BITS > 1) {
+		crc32init_le();
+		printf("static const u32 crc32table_le[] = {");
+		output_table(crc32table_le, LE_TABLE_SIZE, "tole");
+		printf("};\n");
+	}
+
+	if (CRC_BE_BITS > 1) {
+		crc32init_be();
+		printf("static const u32 crc32table_be[] = {");
+		output_table(crc32table_be, BE_TABLE_SIZE, "tobe");
+		printf("};\n");
+	}
+
+	return 0;
+}