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z47.c
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z47.c
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/*@z47.c:Environment Table:EnvReadRetrieve()@*********************************/
/* */
/* THE LOUT DOCUMENT FORMATTING SYSTEM (VERSION 3.39) */
/* COPYRIGHT (C) 1991, 2008 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"
#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 int) 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