amxmodx/dlls/geoip/geolib/libGeoIP/GeoIPBitReader.c
2004-06-29 05:31:05 +00:00

56 lines
1.8 KiB
C
Executable File

/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 2; tab-width: 2 -*- */
/* GeoIPBitReader.c
*
* Copyright (C) 2002 MaxMind.com. All Rights Reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "GeoIPBitReader.h"
GeoIPBitReader * GeoIPBitReader_new(const char * filename) {
GeoIPBitReader *gibr = (GeoIPBitReader *)malloc(sizeof(GeoIPBitReader));
gibr->GeoIPBitFH = fopen(filename,"rb");
if (gibr->GeoIPBitFH == NULL) {
fprintf(stderr, "Error Opening file %s\n",filename);
return NULL;
}
gibr->position = 8;
return gibr;
}
unsigned long GeoIPBitReader_read(GeoIPBitReader * gibr, short int numBits) {
unsigned long num = 0;
int i, bit;
int bytes_read;
for (i = 0; i < numBits; ++i) {
if (BITS_IN_BYTE == gibr->position) {
/* read in next byte */
bytes_read = fread(&gibr->bits, 1, 1, gibr->GeoIPBitFH);
if (bytes_read == 0) {
fprintf(stderr, "Warning: EOF reached\n");
gibr->bits = 0;
}
gibr->position = 0;
}
bit = ((gibr->bits & (1 << (BITS_IN_BYTE - gibr->position - 1))) > 0) ? 1 : 0;
bit <<= i;
num += bit;
++(gibr->position);
}
return num;
}