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bigbang

Jiri Kuthan authored on 15/08/2002 12:57:47
Showing 2 changed files
hash_func.c
History View file @ 3828f84113
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+/*
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+ * $Id$
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+ */
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+
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+
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+#ifndef _CRC_H_
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+#define _CRC_H_
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+
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+extern unsigned long int crc_32_tab[];
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+extern unsigned short int ccitt_tab[];
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+extern unsigned short int crc_16_tab[];
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+
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+#endif
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+
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+#include <stdio.h>
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+#include <string.h>
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+#include <stdlib.h>
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+#include "hash_func.h"
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+#include "dprint.h"
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+#include "crc.h"
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+#include "ut.h"
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+
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+int old_hash( str  call_id, str cseq_nr )
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+{
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+   int  hash_code = 0;
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+   int  i;
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+
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+#if 0 /*def i386*/
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+   int ci_len, cs_len;
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+   char *ci, *cs;
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+
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+	trim_len( ci_len, ci, call_id );
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+	trim_len( cs_len, cs, cseq_nr );
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+
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+		int dummy1;
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+		if (call_id.len>=4){
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+			asm(
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+				"1: \n\r"
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+				"addl (%1), %0 \n\r"
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+				"add $4, %1 \n\r"
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+				"cmp %2, %1 \n\r"
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+				"jl 1b  \n\r"
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+				: "=r"(hash_code), "=r"(dummy1)
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+				:  "0" (hash_code), "1"(ci),
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+				"r"( (ci_len & (~3)) +ci)
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+			);
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+		}
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+#else
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+    if ( call_id.len>0 )
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+      for( i=0 ; i<call_id.len ; hash_code+=call_id.s[i++]  );
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+#endif
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+
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+#if 0 /*def i386*/
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+
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+		int dummy2;
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+		if (cseq_nr.len>=4){
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+			asm(
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+				"1: \n\r"
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+				"addl (%1), %0 \n\r"
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+				"add $4, %1 \n\r"
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+				"cmp %2, %1 \n\r"
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+				"jl 1b  \n\r"
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+				: "=r"(hash_code), "=r"(dummy2)
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+				:  "0" (hash_code), "1"(cs),
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+				"r"((cs_len & (~3) )+ cs)
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+			);
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+		}
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+#else
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+    if ( cseq_nr.len>0 )
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+      for( i=0 ; i<cseq_nr.len ; hash_code+=cseq_nr.s[i++] );
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+#endif
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+   return hash_code &= (TABLE_ENTRIES-1); /* TABLE_ENTRIES = 2^k */
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+}
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+
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+int new_hash( str call_id, str cseq_nr )
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+{
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+	int hash_code = 0;
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+	int i,j, k, third;
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+	int ci_len, cs_len;
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+	char *ci, *cs;
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+
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+	/* trim EoLs */
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+/*
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+	ci_len = call_id.len;
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+	while (ci_len && ((c=call_id.s[ci_len-1])==0 || c=='\r' || c=='\n'))
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+		ci_len--;
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+	cs_len = cseq_nr.len;
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+	while (cs_len && ((c=cseq_nr.s[cs_len-1])==0 || c=='\r' || c=='\n'))
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+		cs_len--;
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+*/
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+	trim_len( ci_len, ci, call_id );
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+	trim_len( cs_len, cs, cseq_nr );
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+
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+	/* run the cycle from the end ... we are interested in the
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+	   most-right digits ... and just take the %10 value of it
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+	*/
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+	third=(ci_len-1)/3;
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+	for ( i=ci_len-1, j=2*third, k=third;
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+		k>0 ; i--, j--, k-- ) {
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+		hash_code+=crc_16_tab[(unsigned char)(*(ci+i)) /*+7*/ ]+
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+			ccitt_tab[*(ci+k)+63]+
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+			ccitt_tab[*(ci+j)+13];
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+	}
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+	for( i=0 ; i<cs_len ; i++ )
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+		//hash_code+=crc_32_tab[(cseq_nr.s[i]+hash_code)%243];
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+		hash_code+=ccitt_tab[*(cs+i)+123];
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+
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+	hash_code &= (TABLE_ENTRIES-1); /* TABLE_ENTRIES = 2^k */
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+   	return hash_code;
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+}
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+
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+void hashtest_cycle( int hits[TABLE_ENTRIES], char *ip )
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+{
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+	long int i,j,k, l;
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+	int  hashv;
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+	static char buf1[1024];
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+	static char buf2[1024];
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+	str call_id;
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+	str cseq;
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+
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+	call_id.s=buf1;
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+	cseq.s=buf2;
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+
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+	for (i=987654328;i<987654328+10;i++)
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+		for (j=85296341;j<85296341+10;j++)
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+			for (k=987654;k<=987654+10;k++)
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+				for (l=101;l<201;l++) {
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+					call_id.len=sprintf( buf1, "%d-%d-%d@%s",(int)i,(int)j,
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+						(int)k, ip );
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+					cseq.len=sprintf( buf2, "%d", (int)l );
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+					printf("%s\t%s\n", buf1, buf2 );
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+					hashv=hash( call_id, cseq );
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+					hits[ hashv ]++;
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+				}
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+}
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+
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+void hashtest()
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+{
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+	int hits[TABLE_ENTRIES];
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+	int i;
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+
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+	memset( hits, 0, sizeof hits );
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+	hashtest_cycle( hits, "192.168.99.100" );
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+	hashtest_cycle( hits, "172.168.99.100" );
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+	hashtest_cycle( hits, "142.168.99.100" );
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+	for (i=0; i<TABLE_ENTRIES; i++)
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+		printf("[%d. %d]\n", i, hits[i] );
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+	exit(0);
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+}
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+
hash_func.h
History View file @ 3828f84113
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new file mode 100644
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+/*
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+ * $Id$
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+ */
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+
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+
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+#ifndef _HASH_H
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+#define _HASH_H
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+
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+#include "str.h"
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+
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+/* always use a power of 2 for hash table size */
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+#define T_TABLE_POWER    12
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+#define TABLE_ENTRIES    (1 << (T_TABLE_POWER))
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+
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+int new_hash( str  call_id, str cseq_nr );
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+int old_hash( str  call_id, str cseq_nr );
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+
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+#define hash( cid, cseq) new_hash( cid, cseq )
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+
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+#endif