119dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project/* Description of GNU message catalog format: string hashing function. 219dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project Copyright (C) 1995, 1997-1998, 2000-2003 Free Software Foundation, Inc. 319dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project 419dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project This program is free software; you can redistribute it and/or modify it 519dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project under the terms of the GNU Library General Public License as published 619dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project by the Free Software Foundation; either version 2, or (at your option) 719dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project any later version. 819dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project 919dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project This program is distributed in the hope that it will be useful, 1019dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project but WITHOUT ANY WARRANTY; without even the implied warranty of 1119dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 1219dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project Library General Public License for more details. 1319dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project 1419dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project You should have received a copy of the GNU Library General Public 1519dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project License along with this program; if not, write to the Free Software 1619dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 1719dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project USA. */ 1819dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project 1919dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project/* @@ end of prolog @@ */ 2019dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project 2119dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project/* We assume to have `unsigned long int' value with at least 32 bits. */ 2219dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project#define HASHWORDBITS 32 2319dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project 2419dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project 2519dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project/* Defines the so called `hashpjw' function by P.J. Weinberger 2619dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project [see Aho/Sethi/Ullman, COMPILERS: Principles, Techniques and Tools, 2719dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project 1986, 1987 Bell Telephone Laboratories, Inc.] */ 2819dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Projectstatic inline unsigned long int 2919dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Projecthash_string (const char *str_param) 3019dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project{ 3119dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project unsigned long int hval, g; 3219dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project const char *str = str_param; 3319dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project 3419dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project /* Compute the hash value for the given string. */ 3519dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project hval = 0; 3619dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project while (*str != '\0') 3719dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project { 3819dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project hval <<= 4; 3919dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project hval += (unsigned char) *str++; 4019dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project g = hval & ((unsigned long int) 0xf << (HASHWORDBITS - 4)); 4119dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project if (g != 0) 4219dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project { 4319dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project hval ^= g >> (HASHWORDBITS - 8); 4419dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project hval ^= g; 4519dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project } 4619dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project } 4719dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project return hval; 4819dacda2b02bb08c0ffb649f84526b249c749279The Android Open Source Project} 49