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Diffstat (limited to 'ncurses-5.3/ncurses/tty/hashmap.c')
| -rw-r--r-- | ncurses-5.3/ncurses/tty/hashmap.c | 538 |
1 files changed, 538 insertions, 0 deletions
diff --git a/ncurses-5.3/ncurses/tty/hashmap.c b/ncurses-5.3/ncurses/tty/hashmap.c new file mode 100644 index 0000000..e8edae3 --- /dev/null +++ b/ncurses-5.3/ncurses/tty/hashmap.c @@ -0,0 +1,538 @@ +/**************************************************************************** + * Copyright (c) 1998-2001,2002 Free Software Foundation, Inc. * + * * + * Permission is hereby granted, free of charge, to any person obtaining a * + * copy of this software and associated documentation files (the * + * "Software"), to deal in the Software without restriction, including * + * without limitation the rights to use, copy, modify, merge, publish, * + * distribute, distribute with modifications, sublicense, and/or sell * + * copies of the Software, and to permit persons to whom the Software is * + * furnished to do so, subject to the following conditions: * + * * + * The above copyright notice and this permission notice shall be included * + * in all copies or substantial portions of the Software. * + * * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * + * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * + * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, * + * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * + * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR * + * THE USE OR OTHER DEALINGS IN THE SOFTWARE. * + * * + * Except as contained in this notice, the name(s) of the above copyright * + * holders shall not be used in advertising or otherwise to promote the * + * sale, use or other dealings in this Software without prior written * + * authorization. * + ****************************************************************************/ + +/**************************************************************************** + * Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995 * + * and: Eric S. Raymond <esr@snark.thyrsus.com> * + ****************************************************************************/ + +/****************************************************************************** + +NAME + hashmap.c -- fill in scramble vector based on text hashes + +SYNOPSIS + void _nc_hash_map(void) + +DESCRIPTION: + This code attempts to recognize pairs of old and new lines in the physical +and virtual screens. When a line pair is recognized, the old line index is +placed in the oldindex member of the virtual screen line, to be used by the +vertical-motion optimizer portion of the update logic (see hardscroll.c). + + Line pairs are recognized by applying a modified Heckel's algorithm, +sped up by hashing. If a line hash is unique in both screens, those +lines must be a pair. Then if the lines just before or after the pair +are the same or similar, they are a pair too. + + We don't worry about false pairs produced by hash collisions, on the +assumption that such cases are rare and will only make the latter stages +of update less efficient, not introduce errors. + +HOW TO TEST THIS: + +Use the following production: + +hashmap: hashmap.c + $(CC) -g -DHASHDEBUG hashmap.c hardscroll.c ../objects/lib_trace.o -o hashmap + +AUTHOR + Eric S. Raymond <esr@snark.thyrsus.com>, May 1996 + Bug fixes and improvements by Alexander V. Lukyanov <lav@yars.free.net>, 1997 + +*****************************************************************************/ + +#include <curses.priv.h> +#include <term.h> /* for back_color_erase */ + +MODULE_ID("$Id$") + +#ifdef HASHDEBUG + +# define _tracef printf +# undef TR +# define TR(n, a) if (_nc_tracing & (n)) { _tracef a ; putchar('\n'); } +# undef screen_lines +# define screen_lines MAXLINES +# define TEXTWIDTH 1 +int oldnums[MAXLINES], reallines[MAXLINES]; +static chtype oldtext[MAXLINES][TEXTWIDTH], newtext[MAXLINES][TEXTWIDTH]; +# define OLDNUM(n) oldnums[n] +# define OLDTEXT(n) oldtext[n] +# define NEWTEXT(m) newtext[m] +# define PENDING(n) 1 + +#else /* !HASHDEBUG */ + +# define OLDNUM(n) _nc_oldnums[n] +# define OLDTEXT(n) curscr->_line[n].text +# define NEWTEXT(m) newscr->_line[m].text +# define TEXTWIDTH (curscr->_maxx+1) +# define PENDING(n) (newscr->_line[n].firstchar != _NOCHANGE) + +#endif /* !HASHDEBUG */ + +#define oldhash (SP->oldhash) +#define newhash (SP->newhash) +#define hashtab (SP->hashtab) +#define lines_alloc (SP->hashtab_len) + +#if USE_WIDEC_SUPPORT +#define HASH_VAL(ch) (ch.chars[0]) +#else +#define HASH_VAL(ch) (ch) +#endif + +static inline unsigned long +hash(NCURSES_CH_T * text) +{ + int i; + NCURSES_CH_T ch; + unsigned long result = 0; + for (i = TEXTWIDTH; i > 0; i--) { + ch = *text++; + result += (result << 5) + HASH_VAL(ch); + } + return result; +} + +/* approximate update cost */ +static int +update_cost(NCURSES_CH_T * from, NCURSES_CH_T * to) +{ + int cost = 0; + int i; + + for (i = TEXTWIDTH; i > 0; i--) + if (!(CharEq(*from++, *to++))) + cost++; + + return cost; +} + +static int +update_cost_from_blank(NCURSES_CH_T * to) +{ + int cost = 0; + int i; + NCURSES_CH_T blank = NewChar2(BLANK_TEXT, BLANK_ATTR); + + if (back_color_erase) + AddAttr(blank, (AttrOf(stdscr->_nc_bkgd) & A_COLOR)); + + for (i = TEXTWIDTH; i > 0; i--) + if (!(CharEq(blank, *to++))) + cost++; + + return cost; +} + +/* + * Returns true when moving line 'from' to line 'to' seems to be cost + * effective. 'blank' indicates whether the line 'to' would become blank. + */ +static inline bool +cost_effective(const int from, const int to, const bool blank) +{ + int new_from; + + if (from == to) + return FALSE; + + new_from = OLDNUM(from); + if (new_from == _NEWINDEX) + new_from = from; + + /* + * On the left side of >= is the cost before moving; + * on the right side -- cost after moving. + */ + return (((blank ? update_cost_from_blank(NEWTEXT(to)) + : update_cost(OLDTEXT(to), NEWTEXT(to))) + + update_cost(OLDTEXT(new_from), NEWTEXT(from))) + >= ((new_from == from ? update_cost_from_blank(NEWTEXT(from)) + : update_cost(OLDTEXT(new_from), NEWTEXT(from))) + + update_cost(OLDTEXT(from), NEWTEXT(to)))) ? TRUE : FALSE; +} + +static void +grow_hunks(void) +{ + int start, end, shift; + int back_limit, forward_limit; /* limits for cells to fill */ + int back_ref_limit, forward_ref_limit; /* limits for refrences */ + int i; + int next_hunk; + + /* + * This is tricky part. We have unique pairs to use as anchors. + * Use these to deduce the presence of spans of identical lines. + */ + back_limit = 0; + back_ref_limit = 0; + + i = 0; + while (i < screen_lines && OLDNUM(i) == _NEWINDEX) + i++; + for (; i < screen_lines; i = next_hunk) { + start = i; + shift = OLDNUM(i) - i; + + /* get forward limit */ + i = start + 1; + while (i < screen_lines && OLDNUM(i) != _NEWINDEX && OLDNUM(i) - i + == shift) + i++; + end = i; + while (i < screen_lines && OLDNUM(i) == _NEWINDEX) + i++; + next_hunk = i; + forward_limit = i; + if (i >= screen_lines || OLDNUM(i) >= i) + forward_ref_limit = i; + else + forward_ref_limit = OLDNUM(i); + + i = start - 1; + /* grow back */ + if (shift < 0) + back_limit = back_ref_limit + (-shift); + while (i >= back_limit) { + if (newhash[i] == oldhash[i + shift] + || cost_effective(i + shift, i, shift < 0)) { + OLDNUM(i) = i + shift; + TR(TRACE_UPDATE | TRACE_MOVE, + ("connected new line %d to old line %d (backward continuation)", + i, i + shift)); + } else { + TR(TRACE_UPDATE | TRACE_MOVE, + ("not connecting new line %d to old line %d (backward continuation)", + i, i + shift)); + break; + } + i--; + } + + i = end; + /* grow forward */ + if (shift > 0) + forward_limit = forward_ref_limit - shift; + while (i < forward_limit) { + if (newhash[i] == oldhash[i + shift] + || cost_effective(i + shift, i, shift > 0)) { + OLDNUM(i) = i + shift; + TR(TRACE_UPDATE | TRACE_MOVE, + ("connected new line %d to old line %d (forward continuation)", + i, i + shift)); + } else { + TR(TRACE_UPDATE | TRACE_MOVE, + ("not connecting new line %d to old line %d (forward continuation)", + i, i + shift)); + break; + } + i++; + } + + back_ref_limit = back_limit = i; + if (shift > 0) + back_ref_limit += shift; + } +} + +NCURSES_EXPORT(void) +_nc_hash_map(void) +{ + HASHMAP *sp; + register int i; + int start, shift, size; + + if (screen_lines > lines_alloc) { + if (hashtab) + free(hashtab); + hashtab = typeMalloc(HASHMAP, (screen_lines + 1) * 2); + if (!hashtab) { + if (oldhash) { + FreeAndNull(oldhash); + } + lines_alloc = 0; + return; + } + lines_alloc = screen_lines; + } + + if (oldhash && newhash) { + /* re-hash only changed lines */ + for (i = 0; i < screen_lines; i++) { + if (PENDING(i)) + newhash[i] = hash(NEWTEXT(i)); + } + } else { + /* re-hash all */ + if (oldhash == 0) + oldhash = typeCalloc(unsigned long, (unsigned) screen_lines); + if (newhash == 0) + newhash = typeCalloc(unsigned long, (unsigned) screen_lines); + if (!oldhash || !newhash) + return; /* malloc failure */ + for (i = 0; i < screen_lines; i++) { + newhash[i] = hash(NEWTEXT(i)); + oldhash[i] = hash(OLDTEXT(i)); + } + } + +#ifdef HASH_VERIFY + for (i = 0; i < screen_lines; i++) { + if (newhash[i] != hash(NEWTEXT(i))) + fprintf(stderr, "error in newhash[%d]\n", i); + if (oldhash[i] != hash(OLDTEXT(i))) + fprintf(stderr, "error in oldhash[%d]\n", i); + } +#endif + + /* + * Set up and count line-hash values. + */ + memset(hashtab, '\0', sizeof(*hashtab) * (screen_lines + 1) * 2); + for (i = 0; i < screen_lines; i++) { + unsigned long hashval = oldhash[i]; + + for (sp = hashtab; sp->hashval; sp++) + if (sp->hashval == hashval) + break; + sp->hashval = hashval; /* in case this is a new entry */ + sp->oldcount++; + sp->oldindex = i; + } + for (i = 0; i < screen_lines; i++) { + unsigned long hashval = newhash[i]; + + for (sp = hashtab; sp->hashval; sp++) + if (sp->hashval == hashval) + break; + sp->hashval = hashval; /* in case this is a new entry */ + sp->newcount++; + sp->newindex = i; + + OLDNUM(i) = _NEWINDEX; /* initialize old indices array */ + } + + /* + * Mark line pairs corresponding to unique hash pairs. + * + * We don't mark lines with offset 0, because it can make fail + * extending hunks by cost_effective. Otherwise, it does not + * have any side effects. + */ + for (sp = hashtab; sp->hashval; sp++) + if (sp->oldcount == 1 && sp->newcount == 1 + && sp->oldindex != sp->newindex) { + TR(TRACE_UPDATE | TRACE_MOVE, + ("new line %d is hash-identical to old line %d (unique)", + sp->newindex, sp->oldindex)); + OLDNUM(sp->newindex) = sp->oldindex; + } + + grow_hunks(); + + /* + * Eliminate bad or impossible shifts -- this includes removing + * those hunks which could not grow because of conflicts, as well + * those which are to be moved too far, they are likely to destroy + * more than carry. + */ + for (i = 0; i < screen_lines;) { + while (i < screen_lines && OLDNUM(i) == _NEWINDEX) + i++; + if (i >= screen_lines) + break; + start = i; + shift = OLDNUM(i) - i; + i++; + while (i < screen_lines && OLDNUM(i) != _NEWINDEX && OLDNUM(i) - i + == shift) + i++; + size = i - start; + if (size < 3 || size + min(size / 8, 2) < abs(shift)) { + while (start < i) { + OLDNUM(start) = _NEWINDEX; + start++; + } + } + } + + /* After clearing invalid hunks, try grow the rest. */ + grow_hunks(); +} + +NCURSES_EXPORT(void) +_nc_make_oldhash(int i) +{ + if (oldhash) + oldhash[i] = hash(OLDTEXT(i)); +} + +NCURSES_EXPORT(void) +_nc_scroll_oldhash(int n, int top, int bot) +{ + size_t size; + int i; + + if (!oldhash) + return; + + size = sizeof(*oldhash) * (bot - top + 1 - abs(n)); + if (n > 0) { + memmove(oldhash + top, oldhash + top + n, size); + for (i = bot; i > bot - n; i--) + oldhash[i] = hash(OLDTEXT(i)); + } else { + memmove(oldhash + top - n, oldhash + top, size); + for (i = top; i < top - n; i++) + oldhash[i] = hash(OLDTEXT(i)); + } +} + +#ifdef HASHDEBUG +static void +usage(void) +{ + static const char *table[] = + { + "hashmap test-driver", + "", + "# comment", + "l get initial line number vector", + "n use following letters as text of new lines", + "o use following letters as text of old lines", + "d dump state of test arrays", + "h apply hash mapper and see scroll optimization", + "? this message" + }; + size_t n; + for (n = 0; n < sizeof(table) / sizeof(table[0]); n++) + fprintf(stderr, "%s\n", table[n]); +} + +int +main(int argc GCC_UNUSED, char *argv[]GCC_UNUSED) +{ + char line[BUFSIZ], *st; + int n; + + SP = typeCalloc(SCREEN, 1); + for (n = 0; n < screen_lines; n++) { + reallines[n] = n; + oldnums[n] = _NEWINDEX; + oldtext[n][0] = newtext[n][0] = '.'; + } + + if (isatty(fileno(stdin))) + usage(); + +#ifdef TRACE + _nc_tracing = TRACE_MOVE; +#endif + for (;;) { + /* grab a test command */ + if (fgets(line, sizeof(line), stdin) == (char *) NULL) + exit(EXIT_SUCCESS); + + switch (line[0]) { + case '#': /* comment */ + (void) fputs(line, stderr); + break; + + case 'l': /* get initial line number vector */ + for (n = 0; n < screen_lines; n++) { + reallines[n] = n; + oldnums[n] = _NEWINDEX; + } + n = 0; + st = strtok(line, " "); + do { + oldnums[n++] = atoi(st); + } while + ((st = strtok((char *) NULL, " ")) != 0); + break; + + case 'n': /* use following letters as text of new lines */ + for (n = 0; n < screen_lines; n++) + newtext[n][0] = '.'; + for (n = 0; n < screen_lines; n++) + if (line[n + 1] == '\n') + break; + else + newtext[n][0] = line[n + 1]; + break; + + case 'o': /* use following letters as text of old lines */ + for (n = 0; n < screen_lines; n++) + oldtext[n][0] = '.'; + for (n = 0; n < screen_lines; n++) + if (line[n + 1] == '\n') + break; + else + oldtext[n][0] = line[n + 1]; + break; + + case 'd': /* dump state of test arrays */ +#ifdef TRACE + _nc_linedump(); +#endif + (void) fputs("Old lines: [", stdout); + for (n = 0; n < screen_lines; n++) + putchar(oldtext[n][0]); + putchar(']'); + putchar('\n'); + (void) fputs("New lines: [", stdout); + for (n = 0; n < screen_lines; n++) + putchar(newtext[n][0]); + putchar(']'); + putchar('\n'); + break; + + case 'h': /* apply hash mapper and see scroll optimization */ + _nc_hash_map(); + (void) fputs("Result:\n", stderr); +#ifdef TRACE + _nc_linedump(); +#endif + _nc_scroll_optimize(); + (void) fputs("Done.\n", stderr); + break; + case '?': + usage(); + break; + } + } + return EXIT_SUCCESS; +} + +#endif /* HASHDEBUG */ + +/* hashmap.c ends here */ |