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Diffstat (limited to 'tblcmp.c')
| -rw-r--r-- | tblcmp.c | 853 |
1 files changed, 0 insertions, 853 deletions
diff --git a/tblcmp.c b/tblcmp.c deleted file mode 100644 index a56aaab..0000000 --- a/tblcmp.c +++ /dev/null @@ -1,853 +0,0 @@ -/* tblcmp - table compression routines */ - -/* Copyright (c) 1990 The Regents of the University of California. */ -/* All rights reserved. */ - -/* This code is derived from software contributed to Berkeley by */ -/* Vern Paxson. */ - -/* The United States Government has rights in this work pursuant */ -/* to contract no. DE-AC03-76SF00098 between the United States */ -/* Department of Energy and the University of California. */ - -/* This file is part of flex. */ - -/* Redistribution and use in source and binary forms, with or without */ -/* modification, are permitted provided that the following conditions */ -/* are met: */ - -/* 1. Redistributions of source code must retain the above copyright */ -/* notice, this list of conditions and the following disclaimer. */ -/* 2. Redistributions in binary form must reproduce the above copyright */ -/* notice, this list of conditions and the following disclaimer in the */ -/* documentation and/or other materials provided with the distribution. */ - -/* Neither the name of the University nor the names of its contributors */ -/* may be used to endorse or promote products derived from this software */ -/* without specific prior written permission. */ - -/* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR */ -/* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED */ -/* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR */ -/* PURPOSE. */ - -#include "flexdef.h" - - -/* declarations for functions that have forward references */ - -void mkentry PROTO ((register int *, int, int, int, int)); -void mkprot PROTO ((int[], int, int)); -void mktemplate PROTO ((int[], int, int)); -void mv2front PROTO ((int)); -int tbldiff PROTO ((int[], int, int[])); - - -/* bldtbl - build table entries for dfa state - * - * synopsis - * int state[numecs], statenum, totaltrans, comstate, comfreq; - * bldtbl( state, statenum, totaltrans, comstate, comfreq ); - * - * State is the statenum'th dfa state. It is indexed by equivalence class and - * gives the number of the state to enter for a given equivalence class. - * totaltrans is the total number of transitions out of the state. Comstate - * is that state which is the destination of the most transitions out of State. - * Comfreq is how many transitions there are out of State to Comstate. - * - * A note on terminology: - * "protos" are transition tables which have a high probability of - * either being redundant (a state processed later will have an identical - * transition table) or nearly redundant (a state processed later will have - * many of the same out-transitions). A "most recently used" queue of - * protos is kept around with the hope that most states will find a proto - * which is similar enough to be usable, and therefore compacting the - * output tables. - * "templates" are a special type of proto. If a transition table is - * homogeneous or nearly homogeneous (all transitions go to the same - * destination) then the odds are good that future states will also go - * to the same destination state on basically the same character set. - * These homogeneous states are so common when dealing with large rule - * sets that they merit special attention. If the transition table were - * simply made into a proto, then (typically) each subsequent, similar - * state will differ from the proto for two out-transitions. One of these - * out-transitions will be that character on which the proto does not go - * to the common destination, and one will be that character on which the - * state does not go to the common destination. Templates, on the other - * hand, go to the common state on EVERY transition character, and therefore - * cost only one difference. - */ - -void bldtbl (state, statenum, totaltrans, comstate, comfreq) - int state[], statenum, totaltrans, comstate, comfreq; -{ - int extptr, extrct[2][CSIZE + 1]; - int mindiff, minprot, i, d; - - /* If extptr is 0 then the first array of extrct holds the result - * of the "best difference" to date, which is those transitions - * which occur in "state" but not in the proto which, to date, - * has the fewest differences between itself and "state". If - * extptr is 1 then the second array of extrct hold the best - * difference. The two arrays are toggled between so that the - * best difference to date can be kept around and also a difference - * just created by checking against a candidate "best" proto. - */ - - extptr = 0; - - /* If the state has too few out-transitions, don't bother trying to - * compact its tables. - */ - - if ((totaltrans * 100) < (numecs * PROTO_SIZE_PERCENTAGE)) - mkentry (state, numecs, statenum, JAMSTATE, totaltrans); - - else { - /* "checkcom" is true if we should only check "state" against - * protos which have the same "comstate" value. - */ - int checkcom = - - comfreq * 100 > totaltrans * CHECK_COM_PERCENTAGE; - - minprot = firstprot; - mindiff = totaltrans; - - if (checkcom) { - /* Find first proto which has the same "comstate". */ - for (i = firstprot; i != NIL; i = protnext[i]) - if (protcomst[i] == comstate) { - minprot = i; - mindiff = tbldiff (state, minprot, - extrct[extptr]); - break; - } - } - - else { - /* Since we've decided that the most common destination - * out of "state" does not occur with a high enough - * frequency, we set the "comstate" to zero, assuring - * that if this state is entered into the proto list, - * it will not be considered a template. - */ - comstate = 0; - - if (firstprot != NIL) { - minprot = firstprot; - mindiff = tbldiff (state, minprot, - extrct[extptr]); - } - } - - /* We now have the first interesting proto in "minprot". If - * it matches within the tolerances set for the first proto, - * we don't want to bother scanning the rest of the proto list - * to see if we have any other reasonable matches. - */ - - if (mindiff * 100 > - totaltrans * FIRST_MATCH_DIFF_PERCENTAGE) { - /* Not a good enough match. Scan the rest of the - * protos. - */ - for (i = minprot; i != NIL; i = protnext[i]) { - d = tbldiff (state, i, extrct[1 - extptr]); - if (d < mindiff) { - extptr = 1 - extptr; - mindiff = d; - minprot = i; - } - } - } - - /* Check if the proto we've decided on as our best bet is close - * enough to the state we want to match to be usable. - */ - - if (mindiff * 100 > - totaltrans * ACCEPTABLE_DIFF_PERCENTAGE) { - /* No good. If the state is homogeneous enough, - * we make a template out of it. Otherwise, we - * make a proto. - */ - - if (comfreq * 100 >= - totaltrans * TEMPLATE_SAME_PERCENTAGE) - mktemplate (state, statenum, - comstate); - - else { - mkprot (state, statenum, comstate); - mkentry (state, numecs, statenum, - JAMSTATE, totaltrans); - } - } - - else { /* use the proto */ - mkentry (extrct[extptr], numecs, statenum, - prottbl[minprot], mindiff); - - /* If this state was sufficiently different from the - * proto we built it from, make it, too, a proto. - */ - - if (mindiff * 100 >= - totaltrans * NEW_PROTO_DIFF_PERCENTAGE) - mkprot (state, statenum, comstate); - - /* Since mkprot added a new proto to the proto queue, - * it's possible that "minprot" is no longer on the - * proto queue (if it happened to have been the last - * entry, it would have been bumped off). If it's - * not there, then the new proto took its physical - * place (though logically the new proto is at the - * beginning of the queue), so in that case the - * following call will do nothing. - */ - - mv2front (minprot); - } - } -} - - -/* cmptmps - compress template table entries - * - * Template tables are compressed by using the 'template equivalence - * classes', which are collections of transition character equivalence - * classes which always appear together in templates - really meta-equivalence - * classes. - */ - -void cmptmps () -{ - int tmpstorage[CSIZE + 1]; - register int *tmp = tmpstorage, i, j; - int totaltrans, trans; - - peakpairs = numtemps * numecs + tblend; - - if (usemecs) { - /* Create equivalence classes based on data gathered on - * template transitions. - */ - nummecs = cre8ecs (tecfwd, tecbck, numecs); - } - - else - nummecs = numecs; - - while (lastdfa + numtemps + 1 >= current_max_dfas) - increase_max_dfas (); - - /* Loop through each template. */ - - for (i = 1; i <= numtemps; ++i) { - /* Number of non-jam transitions out of this template. */ - totaltrans = 0; - - for (j = 1; j <= numecs; ++j) { - trans = tnxt[numecs * i + j]; - - if (usemecs) { - /* The absolute value of tecbck is the - * meta-equivalence class of a given - * equivalence class, as set up by cre8ecs(). - */ - if (tecbck[j] > 0) { - tmp[tecbck[j]] = trans; - - if (trans > 0) - ++totaltrans; - } - } - - else { - tmp[j] = trans; - - if (trans > 0) - ++totaltrans; - } - } - - /* It is assumed (in a rather subtle way) in the skeleton - * that if we're using meta-equivalence classes, the def[] - * entry for all templates is the jam template, i.e., - * templates never default to other non-jam table entries - * (e.g., another template) - */ - - /* Leave room for the jam-state after the last real state. */ - mkentry (tmp, nummecs, lastdfa + i + 1, JAMSTATE, - totaltrans); - } -} - - - -/* expand_nxt_chk - expand the next check arrays */ - -void expand_nxt_chk () -{ - register int old_max = current_max_xpairs; - - current_max_xpairs += MAX_XPAIRS_INCREMENT; - - ++num_reallocs; - - nxt = reallocate_integer_array (nxt, current_max_xpairs); - chk = reallocate_integer_array (chk, current_max_xpairs); - - zero_out ((char *) (chk + old_max), - (size_t) (MAX_XPAIRS_INCREMENT * sizeof (int))); -} - - -/* find_table_space - finds a space in the table for a state to be placed - * - * synopsis - * int *state, numtrans, block_start; - * int find_table_space(); - * - * block_start = find_table_space( state, numtrans ); - * - * State is the state to be added to the full speed transition table. - * Numtrans is the number of out-transitions for the state. - * - * find_table_space() returns the position of the start of the first block (in - * chk) able to accommodate the state - * - * In determining if a state will or will not fit, find_table_space() must take - * into account the fact that an end-of-buffer state will be added at [0], - * and an action number will be added in [-1]. - */ - -int find_table_space (state, numtrans) - int *state, numtrans; -{ - /* Firstfree is the position of the first possible occurrence of two - * consecutive unused records in the chk and nxt arrays. - */ - register int i; - register int *state_ptr, *chk_ptr; - register int *ptr_to_last_entry_in_state; - - /* If there are too many out-transitions, put the state at the end of - * nxt and chk. - */ - if (numtrans > MAX_XTIONS_FULL_INTERIOR_FIT) { - /* If table is empty, return the first available spot in - * chk/nxt, which should be 1. - */ - if (tblend < 2) - return 1; - - /* Start searching for table space near the end of - * chk/nxt arrays. - */ - i = tblend - numecs; - } - - else - /* Start searching for table space from the beginning - * (skipping only the elements which will definitely not - * hold the new state). - */ - i = firstfree; - - while (1) { /* loops until a space is found */ - while (i + numecs >= current_max_xpairs) - expand_nxt_chk (); - - /* Loops until space for end-of-buffer and action number - * are found. - */ - while (1) { - /* Check for action number space. */ - if (chk[i - 1] == 0) { - /* Check for end-of-buffer space. */ - if (chk[i] == 0) - break; - - else - /* Since i != 0, there is no use - * checking to see if (++i) - 1 == 0, - * because that's the same as i == 0, - * so we skip a space. - */ - i += 2; - } - - else - ++i; - - while (i + numecs >= current_max_xpairs) - expand_nxt_chk (); - } - - /* If we started search from the beginning, store the new - * firstfree for the next call of find_table_space(). - */ - if (numtrans <= MAX_XTIONS_FULL_INTERIOR_FIT) - firstfree = i + 1; - - /* Check to see if all elements in chk (and therefore nxt) - * that are needed for the new state have not yet been taken. - */ - - state_ptr = &state[1]; - ptr_to_last_entry_in_state = &chk[i + numecs + 1]; - - for (chk_ptr = &chk[i + 1]; - chk_ptr != ptr_to_last_entry_in_state; ++chk_ptr) - if (*(state_ptr++) != 0 && *chk_ptr != 0) - break; - - if (chk_ptr == ptr_to_last_entry_in_state) - return i; - - else - ++i; - } -} - - -/* inittbl - initialize transition tables - * - * Initializes "firstfree" to be one beyond the end of the table. Initializes - * all "chk" entries to be zero. - */ -void inittbl () -{ - register int i; - - zero_out ((char *) chk, - - (size_t) (current_max_xpairs * sizeof (int))); - - tblend = 0; - firstfree = tblend + 1; - numtemps = 0; - - if (usemecs) { - /* Set up doubly-linked meta-equivalence classes; these - * are sets of equivalence classes which all have identical - * transitions out of TEMPLATES. - */ - - tecbck[1] = NIL; - - for (i = 2; i <= numecs; ++i) { - tecbck[i] = i - 1; - tecfwd[i - 1] = i; - } - - tecfwd[numecs] = NIL; - } -} - - -/* mkdeftbl - make the default, "jam" table entries */ - -void mkdeftbl () -{ - int i; - - jamstate = lastdfa + 1; - - ++tblend; /* room for transition on end-of-buffer character */ - - while (tblend + numecs >= current_max_xpairs) - expand_nxt_chk (); - - /* Add in default end-of-buffer transition. */ - nxt[tblend] = end_of_buffer_state; - chk[tblend] = jamstate; - - for (i = 1; i <= numecs; ++i) { - nxt[tblend + i] = 0; - chk[tblend + i] = jamstate; - } - - jambase = tblend; - - base[jamstate] = jambase; - def[jamstate] = 0; - - tblend += numecs; - ++numtemps; -} - - -/* mkentry - create base/def and nxt/chk entries for transition array - * - * synopsis - * int state[numchars + 1], numchars, statenum, deflink, totaltrans; - * mkentry( state, numchars, statenum, deflink, totaltrans ); - * - * "state" is a transition array "numchars" characters in size, "statenum" - * is the offset to be used into the base/def tables, and "deflink" is the - * entry to put in the "def" table entry. If "deflink" is equal to - * "JAMSTATE", then no attempt will be made to fit zero entries of "state" - * (i.e., jam entries) into the table. It is assumed that by linking to - * "JAMSTATE" they will be taken care of. In any case, entries in "state" - * marking transitions to "SAME_TRANS" are treated as though they will be - * taken care of by whereever "deflink" points. "totaltrans" is the total - * number of transitions out of the state. If it is below a certain threshold, - * the tables are searched for an interior spot that will accommodate the - * state array. - */ - -void mkentry (state, numchars, statenum, deflink, totaltrans) - register int *state; - int numchars, statenum, deflink, totaltrans; -{ - register int minec, maxec, i, baseaddr; - int tblbase, tbllast; - - if (totaltrans == 0) { /* there are no out-transitions */ - if (deflink == JAMSTATE) - base[statenum] = JAMSTATE; - else - base[statenum] = 0; - - def[statenum] = deflink; - return; - } - - for (minec = 1; minec <= numchars; ++minec) { - if (state[minec] != SAME_TRANS) - if (state[minec] != 0 || deflink != JAMSTATE) - break; - } - - if (totaltrans == 1) { - /* There's only one out-transition. Save it for later to fill - * in holes in the tables. - */ - stack1 (statenum, minec, state[minec], deflink); - return; - } - - for (maxec = numchars; maxec > 0; --maxec) { - if (state[maxec] != SAME_TRANS) - if (state[maxec] != 0 || deflink != JAMSTATE) - break; - } - - /* Whether we try to fit the state table in the middle of the table - * entries we have already generated, or if we just take the state - * table at the end of the nxt/chk tables, we must make sure that we - * have a valid base address (i.e., non-negative). Note that - * negative base addresses dangerous at run-time (because indexing - * the nxt array with one and a low-valued character will access - * memory before the start of the array. - */ - - /* Find the first transition of state that we need to worry about. */ - if (totaltrans * 100 <= numchars * INTERIOR_FIT_PERCENTAGE) { - /* Attempt to squeeze it into the middle of the tables. */ - baseaddr = firstfree; - - while (baseaddr < minec) { - /* Using baseaddr would result in a negative base - * address below; find the next free slot. - */ - for (++baseaddr; chk[baseaddr] != 0; ++baseaddr) ; - } - - while (baseaddr + maxec - minec + 1 >= current_max_xpairs) - expand_nxt_chk (); - - for (i = minec; i <= maxec; ++i) - if (state[i] != SAME_TRANS && - (state[i] != 0 || deflink != JAMSTATE) && - chk[baseaddr + i - minec] != 0) { /* baseaddr unsuitable - find another */ - for (++baseaddr; - baseaddr < current_max_xpairs && - chk[baseaddr] != 0; ++baseaddr) ; - - while (baseaddr + maxec - minec + 1 >= - current_max_xpairs) - expand_nxt_chk (); - - /* Reset the loop counter so we'll start all - * over again next time it's incremented. - */ - - i = minec - 1; - } - } - - else { - /* Ensure that the base address we eventually generate is - * non-negative. - */ - baseaddr = MAX (tblend + 1, minec); - } - - tblbase = baseaddr - minec; - tbllast = tblbase + maxec; - - while (tbllast + 1 >= current_max_xpairs) - expand_nxt_chk (); - - base[statenum] = tblbase; - def[statenum] = deflink; - - for (i = minec; i <= maxec; ++i) - if (state[i] != SAME_TRANS) - if (state[i] != 0 || deflink != JAMSTATE) { - nxt[tblbase + i] = state[i]; - chk[tblbase + i] = statenum; - } - - if (baseaddr == firstfree) - /* Find next free slot in tables. */ - for (++firstfree; chk[firstfree] != 0; ++firstfree) ; - - tblend = MAX (tblend, tbllast); -} - - -/* mk1tbl - create table entries for a state (or state fragment) which - * has only one out-transition - */ - -void mk1tbl (state, sym, onenxt, onedef) - int state, sym, onenxt, onedef; -{ - if (firstfree < sym) - firstfree = sym; - - while (chk[firstfree] != 0) - if (++firstfree >= current_max_xpairs) - expand_nxt_chk (); - - base[state] = firstfree - sym; - def[state] = onedef; - chk[firstfree] = state; - nxt[firstfree] = onenxt; - - if (firstfree > tblend) { - tblend = firstfree++; - - if (firstfree >= current_max_xpairs) - expand_nxt_chk (); - } -} - - -/* mkprot - create new proto entry */ - -void mkprot (state, statenum, comstate) - int state[], statenum, comstate; -{ - int i, slot, tblbase; - - if (++numprots >= MSP || numecs * numprots >= PROT_SAVE_SIZE) { - /* Gotta make room for the new proto by dropping last entry in - * the queue. - */ - slot = lastprot; - lastprot = protprev[lastprot]; - protnext[lastprot] = NIL; - } - - else - slot = numprots; - - protnext[slot] = firstprot; - - if (firstprot != NIL) - protprev[firstprot] = slot; - - firstprot = slot; - prottbl[slot] = statenum; - protcomst[slot] = comstate; - - /* Copy state into save area so it can be compared with rapidly. */ - tblbase = numecs * (slot - 1); - - for (i = 1; i <= numecs; ++i) - protsave[tblbase + i] = state[i]; -} - - -/* mktemplate - create a template entry based on a state, and connect the state - * to it - */ - -void mktemplate (state, statenum, comstate) - int state[], statenum, comstate; -{ - int i, numdiff, tmpbase, tmp[CSIZE + 1]; - Char transset[CSIZE + 1]; - int tsptr; - - ++numtemps; - - tsptr = 0; - - /* Calculate where we will temporarily store the transition table - * of the template in the tnxt[] array. The final transition table - * gets created by cmptmps(). - */ - - tmpbase = numtemps * numecs; - - if (tmpbase + numecs >= current_max_template_xpairs) { - current_max_template_xpairs += - MAX_TEMPLATE_XPAIRS_INCREMENT; - - ++num_reallocs; - - tnxt = reallocate_integer_array (tnxt, - current_max_template_xpairs); - } - - for (i = 1; i <= numecs; ++i) - if (state[i] == 0) - tnxt[tmpbase + i] = 0; - else { - transset[tsptr++] = i; - tnxt[tmpbase + i] = comstate; - } - - if (usemecs) - mkeccl (transset, tsptr, tecfwd, tecbck, numecs, 0); - - mkprot (tnxt + tmpbase, -numtemps, comstate); - - /* We rely on the fact that mkprot adds things to the beginning - * of the proto queue. - */ - - numdiff = tbldiff (state, firstprot, tmp); - mkentry (tmp, numecs, statenum, -numtemps, numdiff); -} - - -/* mv2front - move proto queue element to front of queue */ - -void mv2front (qelm) - int qelm; -{ - if (firstprot != qelm) { - if (qelm == lastprot) - lastprot = protprev[lastprot]; - - protnext[protprev[qelm]] = protnext[qelm]; - - if (protnext[qelm] != NIL) - protprev[protnext[qelm]] = protprev[qelm]; - - protprev[qelm] = NIL; - protnext[qelm] = firstprot; - protprev[firstprot] = qelm; - firstprot = qelm; - } -} - - -/* place_state - place a state into full speed transition table - * - * State is the statenum'th state. It is indexed by equivalence class and - * gives the number of the state to enter for a given equivalence class. - * Transnum is the number of out-transitions for the state. - */ - -void place_state (state, statenum, transnum) - int *state, statenum, transnum; -{ - register int i; - register int *state_ptr; - int position = find_table_space (state, transnum); - - /* "base" is the table of start positions. */ - base[statenum] = position; - - /* Put in action number marker; this non-zero number makes sure that - * find_table_space() knows that this position in chk/nxt is taken - * and should not be used for another accepting number in another - * state. - */ - chk[position - 1] = 1; - - /* Put in end-of-buffer marker; this is for the same purposes as - * above. - */ - chk[position] = 1; - - /* Place the state into chk and nxt. */ - state_ptr = &state[1]; - - for (i = 1; i <= numecs; ++i, ++state_ptr) - if (*state_ptr != 0) { - chk[position + i] = i; - nxt[position + i] = *state_ptr; - } - - if (position + numecs > tblend) - tblend = position + numecs; -} - - -/* stack1 - save states with only one out-transition to be processed later - * - * If there's room for another state on the "one-transition" stack, the - * state is pushed onto it, to be processed later by mk1tbl. If there's - * no room, we process the sucker right now. - */ - -void stack1 (statenum, sym, nextstate, deflink) - int statenum, sym, nextstate, deflink; -{ - if (onesp >= ONE_STACK_SIZE - 1) - mk1tbl (statenum, sym, nextstate, deflink); - - else { - ++onesp; - onestate[onesp] = statenum; - onesym[onesp] = sym; - onenext[onesp] = nextstate; - onedef[onesp] = deflink; - } -} - - -/* tbldiff - compute differences between two state tables - * - * "state" is the state array which is to be extracted from the pr'th - * proto. "pr" is both the number of the proto we are extracting from - * and an index into the save area where we can find the proto's complete - * state table. Each entry in "state" which differs from the corresponding - * entry of "pr" will appear in "ext". - * - * Entries which are the same in both "state" and "pr" will be marked - * as transitions to "SAME_TRANS" in "ext". The total number of differences - * between "state" and "pr" is returned as function value. Note that this - * number is "numecs" minus the number of "SAME_TRANS" entries in "ext". - */ - -int tbldiff (state, pr, ext) - int state[], pr, ext[]; -{ - register int i, *sp = state, *ep = ext, *protp; - register int numdiff = 0; - - protp = &protsave[numecs * (pr - 1)]; - - for (i = numecs; i > 0; --i) { - if (*++protp == *++sp) - *++ep = SAME_TRANS; - else { - *++ep = *sp; - ++numdiff; - } - } - - return numdiff; -} |