/*@z47.c:Environment Table:EnvReadRetrieve()@*********************************/ /* */ /* THE LOUT DOCUMENT FORMATTING SYSTEM (VERSION 3.41) */ /* COPYRIGHT (C) 1991, 2023 Jeffrey H. Kingston */ /* */ /* Jeffrey H. Kingston (jeff@it.usyd.edu.au) */ /* School of Information Technologies */ /* The University of Sydney 2006 */ /* AUSTRALIA */ /* */ /* This program 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 3, or (at your option) */ /* any later version. */ /* */ /* This program 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 program; if not, write to the Free Software */ /* Foundation, Inc., 59 Temple Place, Suite 330, Boston MA 02111-1307 USA */ /* */ /* FILE: z47.c */ /* MODULE: Environment Table */ /* EXTERNS: EnvInit(), EnvWriteRetrieve(), EnvWriteInsert(), */ /* EnvReadRetrieve(), EnvReadInsert() */ /* */ /*****************************************************************************/ #include "externs.h" #include "child.h" #define TAB_SIZE 211 #define MAX_CACHE 180 #define env_offset(x) back(x, ROWM) #define env_lnum(x) line_num(fpos(x)) #define env_fnum(x) file_num(fpos(x)) #define env_read(x) sized(x) static OBJECT env_cache; /* cache of envts in use */ static int cache_count; /* current size of cache */ static int stat_writes; /* calls to WriteRetrieve */ static int stat_write_hits; /* hits in WriteRetrieve */ static int stat_reads; /* calls to ReadRetrieve */ static int stat_read_hits; /* hits in ReadRetrieve */ static OBJECT tab[TAB_SIZE]; #define hash1(pos, env, fnum) \ { \ pos = ( (unsigned long) env + fnum ) % TAB_SIZE; \ } #define hash2(pos, fnum, offset) \ { \ pos = ( offset + fnum ) % TAB_SIZE; \ } /*****************************************************************************/ /* */ /* void EnvInit(void) */ /* */ /* Initialize this module. */ /* */ /*****************************************************************************/ void EnvInit(void) { int i; debug0(DET, DD, "EnvInit()"); stat_reads = 0; stat_read_hits = 0; stat_writes = 0; stat_write_hits = 0; New(env_cache, ACAT); cache_count = 0; for( i = 0; i < TAB_SIZE; i++ ) { tab[i] = nilobj; } debug0(DET, DD, "EnvInit returning"); } /* end EnvInit */ /*****************************************************************************/ /* */ /* BOOLEAN EnvWriteRetrieve(OBJECT env, FILE_NUM fnum, int *offset, *lnum) */ /* */ /* Return the offset in file fnum where environment env has been written, */ /* or FALSE if env has not been written to this file. */ /* */ /*****************************************************************************/ BOOLEAN EnvWriteRetrieve(OBJECT env, FILE_NUM fnum, int *offset, int *lnum) { unsigned int pos; OBJECT link, y, z; debug2(DET, DD, "EnvWriteRetrieve(env %d, %s)", (int) env, FileName(fnum)); debug1(DET, DDD, " %s", EchoObject(env)); stat_writes++; hash1(pos, env, fnum); if( tab[pos] != nilobj ) { for( link = Down(tab[pos]); link != tab[pos]; link = NextDown(link) ) { Child(y, link); Child(z, Down(y)); if( env_fnum(y) == fnum && z == env && !env_read(y) ) { MoveLink(LastUp(y), env_cache, PARENT); *offset = env_offset(y); *lnum = env_lnum(y); stat_write_hits++; debug2(DET, DD, "EnvWriteRetrieve returning TRUE (offset %d, lnum %d)", *offset, *lnum); return TRUE; } } } debug0(DET, DD, "EnvWriteRetrieve returning FALSE"); return FALSE; } /* end EnvWriteRetrieve */ /*****************************************************************************/ /* */ /* void EnvWriteInsert(OBJECT env, FILE_NUM fnum, int offset, int lnum) */ /* */ /* Record the fact that environment env has been written to file fnum */ /* at the given offset. */ /* */ /*****************************************************************************/ void EnvWriteInsert(OBJECT env, FILE_NUM fnum, int offset, int lnum) { unsigned int pos; OBJECT loser, x; debug3(DET, DD, "EnvWriteInsert(env %d, %s, %d)", (int) env, FileName(fnum), offset); /* to limit the cache size, remove least recently used entry if full */ if( cache_count >= MAX_CACHE ) { Child(loser, Down(env_cache)); DeleteLink(Up(loser)); DisposeChild(Up(loser)); cache_count--; } /* insert the new entry */ hash1(pos, env, fnum); if( tab[pos] == nilobj ) New(tab[pos], ACAT); New(x, ACAT); env_fnum(x) = fnum; env_offset(x) = offset; env_lnum(x) = lnum; env_read(x) = FALSE; Link(tab[pos], x); Link(env_cache, x); Link(x, env); cache_count++; debug1(DET, DD, "EnvWriteInsert returning (cache_count = %d)", cache_count); } /* end EnvWriteInsert */ /*****************************************************************************/ /* */ /* BOOLEAN EnvReadRetrieve(FILE_NUM fnum, int offset, OBJECT *env) */ /* */ /* Return the environment that appears in file fnum at the given offset, */ /* or FALSE if this is not currently known. */ /* */ /*****************************************************************************/ BOOLEAN EnvReadRetrieve(FILE_NUM fnum, int offset, OBJECT *env) { int pos; OBJECT link, y /* , z */; debug2(DET, DD, "EnvReadRetrieve(%s, %d)", FileName(fnum), offset); stat_reads++; hash2(pos, fnum, offset); if( tab[pos] != nilobj ) { for( link = Down(tab[pos]); link != tab[pos]; link = NextDown(link) ) { Child(y, link); /* Child(z, Down(y)); */ if( env_fnum(y) == fnum && env_offset(y) == offset && env_read(y) ) { MoveLink(LastUp(y), env_cache, PARENT); Child(*env, Down(y)); stat_read_hits++; debug1(DET, DD, "EnvReadRetrieve returning env %d", (int) *env); return TRUE; } } } debug0(DET, DD, "EnvReadRetrieve returning FALSE"); return FALSE; } /* end EnvReadRetrieve */ /*****************************************************************************/ /* */ /* void EnvReadInsert(FILE_NUM fnum, int offset, OBJECT env) */ /* */ /* Record the fact that environment env has just been read from file fnum */ /* at position offset. */ /* */ /*****************************************************************************/ void EnvReadInsert(FILE_NUM fnum, int offset, OBJECT env) { int pos; OBJECT x, loser; debug3(DET, DD, "EnvReadInsert(%s, %d, env %d)", FileName(fnum), offset, (int) env); /* to limit the cache size, remove least recently used entry if full */ if( cache_count >= MAX_CACHE ) { Child(loser, Down(env_cache)); DeleteLink(Up(loser)); DisposeChild(Up(loser)); cache_count--; } /* insert the new entry */ hash2(pos, fnum, offset); if( tab[pos] == nilobj ) New(tab[pos], ACAT); New(x, ACAT); env_fnum(x) = fnum; env_offset(x) = offset; env_read(x) = TRUE; Link(tab[pos], x); Link(env_cache, x); Link(x, env); cache_count++; debug1(DET, DD, "EnvReadInsert returning (cache_count = %d)", cache_count); } /* end EnvReadInsert */ #if DEBUG_ON /*****************************************************************************/ /* */ /* void EnvDebug() */ /* */ /* Debug statistics of this module's performance. */ /* */ /*****************************************************************************/ void EnvDebug(void) { debug3(DET, D, "Env Table %6s %6s %6s", "calls", "hits", "% hits"); debug3(DET, D, "reading %6d %6d %6.1f", stat_reads, stat_read_hits, stat_reads == 0 ? (float) 0 : (float) 100 * stat_read_hits / stat_reads); debug3(DET, D, "writing %6d %6d %6.1f", stat_writes, stat_write_hits, stat_writes == 0 ? (float) 0 : (float) 100 * stat_write_hits / stat_writes); } /* end EnvDebug */ #endif