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#ifndef lint |
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static const char RCSid[] = "$Id$"; |
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#endif |
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/* |
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* savestr.c - routines for efficient string storage. |
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* |
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* Savestr(s) stores a shared read-only string. |
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* Freestr(s) indicates a client is finished with a string. |
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* All strings must be null-terminated. There is |
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* no imposed length limit. |
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* Strings stored with savestr(s) can be equated |
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* reliably using their pointer values. |
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* Calls to savestr(s) and freestr(s) should be |
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* balanced (obviously). The last call to freestr(s) |
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* frees memory associated with the string; it should |
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* never be referenced again. |
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* |
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* External symbols declared in standard.h |
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*/ |
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|
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/* ==================================================================== |
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* The Radiance Software License, Version 1.0 |
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* |
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* Copyright (c) 1990 - 2002 The Regents of the University of California, |
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* through Lawrence Berkeley National Laboratory. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* |
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* 3. The end-user documentation included with the redistribution, |
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* if any, must include the following acknowledgment: |
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* "This product includes Radiance software |
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* (http://radsite.lbl.gov/) |
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* developed by the Lawrence Berkeley National Laboratory |
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* (http://www.lbl.gov/)." |
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* Alternately, this acknowledgment may appear in the software itself, |
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* if and wherever such third-party acknowledgments normally appear. |
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* |
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* 4. The names "Radiance," "Lawrence Berkeley National Laboratory" |
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* and "The Regents of the University of California" must |
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* not be used to endorse or promote products derived from this |
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* software without prior written permission. For written |
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* permission, please contact [email protected]. |
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* |
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* 5. Products derived from this software may not be called "Radiance", |
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* nor may "Radiance" appear in their name, without prior written |
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* permission of Lawrence Berkeley National Laboratory. |
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* |
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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* DISCLAIMED. IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR |
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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* ==================================================================== |
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* |
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* This software consists of voluntary contributions made by many |
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* individuals on behalf of Lawrence Berkeley National Laboratory. For more |
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* information on Lawrence Berkeley National Laboratory, please see |
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* <http://www.lbl.gov/>. |
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*/ |
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|
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#ifndef NHASH |
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#define NHASH 509 /* hash table size (prime!) */ |
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#endif |
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|
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typedef struct s_head { |
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struct s_head *next; /* next in hash list */ |
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int nl; /* links count */ |
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} S_HEAD; /* followed by the string itself */ |
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|
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static S_HEAD *stab[NHASH]; |
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|
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#define hash(s) (shash(s)%NHASH) |
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|
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extern char *savestr(), *strcpy(), *malloc(); |
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|
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#define NULL 0 |
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|
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#define string(sp) ((char *)((sp)+1)) |
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|
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#define salloc(str) (S_HEAD *)malloc(sizeof(S_HEAD)+1+strlen(str)) |
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|
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#define sfree(sp) free((void *)(sp)) |
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|
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|
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char * |
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savestr(str) /* save a string */ |
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char *str; |
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{ |
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register int hval; |
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register S_HEAD *sp; |
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|
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if (str == NULL) |
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return(NULL); |
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hval = hash(str); |
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for (sp = stab[hval]; sp != NULL; sp = sp->next) |
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if (!strcmp(str, string(sp))) { |
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sp->nl++; |
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return(string(sp)); |
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} |
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if ((sp = salloc(str)) == NULL) { |
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eputs("Out of memory in savestr\n"); |
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quit(1); |
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} |
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strcpy(string(sp), str); |
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sp->nl = 1; |
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sp->next = stab[hval]; |
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stab[hval] = sp; |
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return(string(sp)); |
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} |
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|
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|
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void |
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freestr(s) /* free a string */ |
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char *s; |
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{ |
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int hval; |
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register S_HEAD *spl, *sp; |
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|
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if (s == NULL) |
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return; |
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hval = hash(s); |
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for (spl = NULL, sp = stab[hval]; sp != NULL; spl = sp, sp = sp->next) |
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if (s == string(sp)) { |
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if (--sp->nl > 0) |
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return; |
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if (spl != NULL) |
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spl->next = sp->next; |
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else |
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stab[hval] = sp->next; |
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sfree(sp); |
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return; |
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} |
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} |
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|
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|
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int |
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shash(s) |
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register char *s; |
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{ |
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register int h = 0; |
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|
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while (*s) |
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h = (h<<1 & 0x7fff) ^ (*s++ & 0xff); |
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return(h); |
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} |