| 1 | /* Calculate what line insertion or deletion to do, and do it |
| 2 | |
| 3 | Copyright (C) 1985-1986, 1990, 1993-1994, 2001-2013 Free Software |
| 4 | Foundation, Inc. |
| 5 | |
| 6 | This file is part of GNU Emacs. |
| 7 | |
| 8 | GNU Emacs is free software: you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation, either version 3 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | GNU Emacs is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */ |
| 20 | |
| 21 | |
| 22 | #include <config.h> |
| 23 | #include <stdio.h> |
| 24 | |
| 25 | #include "lisp.h" |
| 26 | #include "termchar.h" |
| 27 | #include "dispextern.h" |
| 28 | #include "keyboard.h" |
| 29 | #include "frame.h" |
| 30 | #include "window.h" |
| 31 | #include "termhooks.h" |
| 32 | |
| 33 | /* All costs measured in characters. |
| 34 | So no cost can exceed the area of a frame, measured in characters. |
| 35 | Let's hope this is never more than 1000000 characters. */ |
| 36 | |
| 37 | #define INFINITY 1000000 |
| 38 | |
| 39 | struct matrix_elt |
| 40 | { |
| 41 | /* Cost of outputting through this line |
| 42 | if no insert/delete is done just above it. */ |
| 43 | int writecost; |
| 44 | /* Cost of outputting through this line |
| 45 | if an insert is done just above it. */ |
| 46 | int insertcost; |
| 47 | /* Cost of outputting through this line |
| 48 | if a delete is done just above it. */ |
| 49 | int deletecost; |
| 50 | /* Number of inserts so far in this run of inserts, |
| 51 | for the cost in insertcost. */ |
| 52 | unsigned char insertcount; |
| 53 | /* Number of deletes so far in this run of deletes, |
| 54 | for the cost in deletecost. */ |
| 55 | unsigned char deletecount; |
| 56 | /* Number of writes so far since the last insert |
| 57 | or delete for the cost in writecost. */ |
| 58 | unsigned char writecount; |
| 59 | }; |
| 60 | |
| 61 | static void do_direct_scrolling (struct frame *, |
| 62 | struct glyph_matrix *, |
| 63 | struct matrix_elt *, |
| 64 | int, int); |
| 65 | static void do_scrolling (struct frame *, |
| 66 | struct glyph_matrix *, |
| 67 | struct matrix_elt *, |
| 68 | int, int); |
| 69 | |
| 70 | \f |
| 71 | /* Determine, in matrix[i,j], the cost of updating the first j old |
| 72 | lines into the first i new lines using the general scrolling method. |
| 73 | This involves using insert or delete somewhere if i != j. |
| 74 | For each matrix elements, three kinds of costs are recorded: |
| 75 | the smallest cost that ends with an insert, the smallest |
| 76 | cost that ends with a delete, and the smallest cost that |
| 77 | ends with neither one. These are kept separate because |
| 78 | on some terminals the cost of doing an insert varies |
| 79 | depending on whether one was just done, etc. */ |
| 80 | |
| 81 | /* draw_cost[VPOS] is the cost of outputting new line at VPOS. |
| 82 | old_hash[VPOS] is the hash code of the old line at VPOS. |
| 83 | new_hash[VPOS] is the hash code of the new line at VPOS. |
| 84 | Note that these are not true frame vpos's, but relative |
| 85 | to the place at which the first mismatch between old and |
| 86 | new contents appears. */ |
| 87 | |
| 88 | static void |
| 89 | calculate_scrolling (FRAME_PTR frame, |
| 90 | /* matrix is of size window_size + 1 on each side. */ |
| 91 | struct matrix_elt *matrix, |
| 92 | int window_size, int lines_below, |
| 93 | int *draw_cost, int *old_hash, int *new_hash, |
| 94 | int free_at_end) |
| 95 | { |
| 96 | register int i, j; |
| 97 | int frame_lines = FRAME_LINES (frame); |
| 98 | register struct matrix_elt *p, *p1; |
| 99 | register int cost, cost1; |
| 100 | |
| 101 | int lines_moved = window_size |
| 102 | + (FRAME_SCROLL_REGION_OK (frame) ? 0 : lines_below); |
| 103 | /* first_insert_cost[I] is the cost of doing the first insert-line |
| 104 | at the i'th line of the lines we are considering, |
| 105 | where I is origin 1 (as it is below). */ |
| 106 | int *first_insert_cost |
| 107 | = &FRAME_INSERT_COST (frame)[frame_lines - 1 - lines_moved]; |
| 108 | int *first_delete_cost |
| 109 | = &FRAME_DELETE_COST (frame)[frame_lines - 1 - lines_moved]; |
| 110 | int *next_insert_cost |
| 111 | = &FRAME_INSERTN_COST (frame)[frame_lines - 1 - lines_moved]; |
| 112 | int *next_delete_cost |
| 113 | = &FRAME_DELETEN_COST (frame)[frame_lines - 1 - lines_moved]; |
| 114 | |
| 115 | /* Discourage long scrolls on fast lines. |
| 116 | Don't scroll nearly a full frame height unless it saves |
| 117 | at least 1/4 second. */ |
| 118 | int extra_cost = (int) (baud_rate / (10 * 4 * FRAME_LINES (frame))); |
| 119 | |
| 120 | if (baud_rate <= 0) |
| 121 | extra_cost = 1; |
| 122 | |
| 123 | /* initialize the top left corner of the matrix */ |
| 124 | matrix->writecost = 0; |
| 125 | matrix->insertcost = INFINITY; |
| 126 | matrix->deletecost = INFINITY; |
| 127 | matrix->insertcount = 0; |
| 128 | matrix->deletecount = 0; |
| 129 | |
| 130 | /* initialize the left edge of the matrix */ |
| 131 | cost = first_insert_cost[1] - next_insert_cost[1]; |
| 132 | for (i = 1; i <= window_size; i++) |
| 133 | { |
| 134 | p = matrix + i * (window_size + 1); |
| 135 | cost += draw_cost[i] + next_insert_cost[i] + extra_cost; |
| 136 | p->insertcost = cost; |
| 137 | p->writecost = INFINITY; |
| 138 | p->deletecost = INFINITY; |
| 139 | p->insertcount = i; |
| 140 | p->deletecount = 0; |
| 141 | } |
| 142 | |
| 143 | /* initialize the top edge of the matrix */ |
| 144 | cost = first_delete_cost[1] - next_delete_cost[1]; |
| 145 | for (j = 1; j <= window_size; j++) |
| 146 | { |
| 147 | cost += next_delete_cost[j]; |
| 148 | matrix[j].deletecost = cost; |
| 149 | matrix[j].writecost = INFINITY; |
| 150 | matrix[j].insertcost = INFINITY; |
| 151 | matrix[j].deletecount = j; |
| 152 | matrix[j].insertcount = 0; |
| 153 | } |
| 154 | |
| 155 | /* `i' represents the vpos among new frame contents. |
| 156 | `j' represents the vpos among the old frame contents. */ |
| 157 | p = matrix + window_size + 2; /* matrix [1, 1] */ |
| 158 | for (i = 1; i <= window_size; i++, p++) |
| 159 | for (j = 1; j <= window_size; j++, p++) |
| 160 | { |
| 161 | /* p contains the address of matrix [i, j] */ |
| 162 | |
| 163 | /* First calculate the cost assuming we do |
| 164 | not insert or delete above this line. |
| 165 | That is, if we update through line i-1 |
| 166 | based on old lines through j-1, |
| 167 | and then just change old line j to new line i. */ |
| 168 | p1 = p - window_size - 2; /* matrix [i-1, j-1] */ |
| 169 | cost = p1->writecost; |
| 170 | if (cost > p1->insertcost) |
| 171 | cost = p1->insertcost; |
| 172 | if (cost > p1->deletecost) |
| 173 | cost = p1->deletecost; |
| 174 | if (old_hash[j] != new_hash[i]) |
| 175 | cost += draw_cost[i]; |
| 176 | p->writecost = cost; |
| 177 | |
| 178 | /* Calculate the cost if we do an insert-line |
| 179 | before outputting this line. |
| 180 | That is, we update through line i-1 |
| 181 | based on old lines through j, |
| 182 | do an insert-line on line i, |
| 183 | and then output line i from scratch, |
| 184 | leaving old lines starting from j for reuse below. */ |
| 185 | p1 = p - window_size - 1; /* matrix [i-1, j] */ |
| 186 | /* No need to think about doing a delete followed |
| 187 | immediately by an insert. It cannot be as good |
| 188 | as not doing either of them. */ |
| 189 | if (free_at_end == i) |
| 190 | { |
| 191 | cost = p1->writecost; |
| 192 | cost1 = p1->insertcost; |
| 193 | } |
| 194 | else |
| 195 | { |
| 196 | cost = p1->writecost + first_insert_cost[i]; |
| 197 | if ((int) p1->insertcount > i) |
| 198 | emacs_abort (); |
| 199 | cost1 = p1->insertcost + next_insert_cost[i - p1->insertcount]; |
| 200 | } |
| 201 | p->insertcost = min (cost, cost1) + draw_cost[i] + extra_cost; |
| 202 | p->insertcount = (cost < cost1) ? 1 : p1->insertcount + 1; |
| 203 | if ((int) p->insertcount > i) |
| 204 | emacs_abort (); |
| 205 | |
| 206 | /* Calculate the cost if we do a delete line after |
| 207 | outputting this line. |
| 208 | That is, we update through line i |
| 209 | based on old lines through j-1, |
| 210 | and throw away old line j. */ |
| 211 | p1 = p - 1; /* matrix [i, j-1] */ |
| 212 | /* No need to think about doing an insert followed |
| 213 | immediately by a delete. */ |
| 214 | if (free_at_end == i) |
| 215 | { |
| 216 | cost = p1->writecost; |
| 217 | cost1 = p1->deletecost; |
| 218 | } |
| 219 | else |
| 220 | { |
| 221 | cost = p1->writecost + first_delete_cost[i]; |
| 222 | cost1 = p1->deletecost + next_delete_cost[i]; |
| 223 | } |
| 224 | p->deletecost = min (cost, cost1); |
| 225 | p->deletecount = (cost < cost1) ? 1 : p1->deletecount + 1; |
| 226 | } |
| 227 | } |
| 228 | |
| 229 | |
| 230 | \f |
| 231 | /* Perform insert-lines and delete-lines operations on CURRENT_MATRIX |
| 232 | according to the costs in MATRIX, using the general scrolling |
| 233 | method that is used if the terminal does not support the setting of |
| 234 | scroll windows (scroll_region_ok == 0). |
| 235 | |
| 236 | WINDOW_SIZE is the number of lines being considered for scrolling |
| 237 | and UNCHANGED_AT_TOP is the vpos of the first line being |
| 238 | considered. These two arguments can specify any contiguous range |
| 239 | of lines. */ |
| 240 | |
| 241 | static void |
| 242 | do_scrolling (struct frame *frame, struct glyph_matrix *current_matrix, |
| 243 | struct matrix_elt *matrix, int window_size, |
| 244 | int unchanged_at_top) |
| 245 | { |
| 246 | struct matrix_elt *p; |
| 247 | int i, j, k; |
| 248 | |
| 249 | /* Set to 1 if we have set a terminal window with |
| 250 | set_terminal_window. It's unsigned to work around GCC bug 48228. */ |
| 251 | unsigned int terminal_window_p = 0; |
| 252 | |
| 253 | /* A queue for line insertions to be done. */ |
| 254 | struct queue { int count, pos; }; |
| 255 | struct queue *queue_start |
| 256 | = alloca (current_matrix->nrows * sizeof *queue_start); |
| 257 | struct queue *queue = queue_start; |
| 258 | |
| 259 | char *retained_p = alloca (window_size * sizeof *retained_p); |
| 260 | int *copy_from = alloca (window_size * sizeof *copy_from); |
| 261 | |
| 262 | /* Zero means line is empty. */ |
| 263 | memset (retained_p, 0, window_size * sizeof (char)); |
| 264 | for (k = 0; k < window_size; ++k) |
| 265 | copy_from[k] = -1; |
| 266 | |
| 267 | #ifdef GLYPH_DEBUG |
| 268 | # define CHECK_BOUNDS \ |
| 269 | do \ |
| 270 | { \ |
| 271 | int ck; \ |
| 272 | for (ck = 0; ck < window_size; ++ck) \ |
| 273 | eassert (copy_from[ck] == -1 \ |
| 274 | || (copy_from[ck] >= 0 && copy_from[ck] < window_size)); \ |
| 275 | } \ |
| 276 | while (0); |
| 277 | #endif |
| 278 | |
| 279 | /* When j is advanced, this corresponds to deleted lines. |
| 280 | When i is advanced, this corresponds to inserted lines. */ |
| 281 | i = j = window_size; |
| 282 | while (i > 0 || j > 0) |
| 283 | { |
| 284 | p = matrix + i * (window_size + 1) + j; |
| 285 | |
| 286 | if (p->insertcost < p->writecost && p->insertcost < p->deletecost) |
| 287 | { |
| 288 | /* Insert should be done at vpos i-1, plus maybe some before. |
| 289 | Queue the screen operation to be performed. */ |
| 290 | queue->count = p->insertcount; |
| 291 | queue->pos = i + unchanged_at_top - p->insertcount; |
| 292 | ++queue; |
| 293 | |
| 294 | /* By incrementing I, we leave room in the result rows |
| 295 | for the empty rows opened up. */ |
| 296 | i -= p->insertcount; |
| 297 | } |
| 298 | else if (p->deletecost < p->writecost) |
| 299 | { |
| 300 | /* Old line at vpos j-1, and maybe some before it, should be |
| 301 | deleted. By decrementing J, we skip some lines in the |
| 302 | temp_rows which is equivalent to omitting these lines in |
| 303 | the result rows, thus deleting them. */ |
| 304 | j -= p->deletecount; |
| 305 | |
| 306 | /* Set the terminal window, if not done already. */ |
| 307 | if (! terminal_window_p) |
| 308 | { |
| 309 | set_terminal_window (frame, window_size + unchanged_at_top); |
| 310 | terminal_window_p = 1; |
| 311 | } |
| 312 | |
| 313 | /* Delete lines on the terminal. */ |
| 314 | ins_del_lines (frame, j + unchanged_at_top, - p->deletecount); |
| 315 | } |
| 316 | else |
| 317 | { |
| 318 | /* Best thing done here is no insert or delete, i.e. a write. */ |
| 319 | --i, --j; |
| 320 | eassert (i >= 0 && i < window_size); |
| 321 | eassert (j >= 0 && j < window_size); |
| 322 | copy_from[i] = j; |
| 323 | retained_p[j] = 1; |
| 324 | |
| 325 | #ifdef GLYPH_DEBUG |
| 326 | CHECK_BOUNDS; |
| 327 | #endif |
| 328 | } |
| 329 | } |
| 330 | |
| 331 | /* Now do all insertions queued above. */ |
| 332 | if (queue > queue_start) |
| 333 | { |
| 334 | int next = -1; |
| 335 | |
| 336 | /* Set the terminal window if not yet done. */ |
| 337 | if (!terminal_window_p) |
| 338 | { |
| 339 | set_terminal_window (frame, window_size + unchanged_at_top); |
| 340 | terminal_window_p = 1; |
| 341 | } |
| 342 | |
| 343 | do |
| 344 | { |
| 345 | --queue; |
| 346 | |
| 347 | /* Do the deletion on the terminal. */ |
| 348 | ins_del_lines (frame, queue->pos, queue->count); |
| 349 | |
| 350 | /* All lines in the range deleted become empty in the glyph |
| 351 | matrix. Assign to them glyph rows that are not retained. |
| 352 | K is the starting position of the deleted range relative |
| 353 | to the window we are working in. */ |
| 354 | k = queue->pos - unchanged_at_top; |
| 355 | for (j = 0; j < queue->count; ++j) |
| 356 | { |
| 357 | /* Find the next row not retained. */ |
| 358 | while (retained_p[++next]) |
| 359 | ; |
| 360 | |
| 361 | /* Record that this row is to be used for the empty |
| 362 | glyph row j. */ |
| 363 | copy_from[k + j] = next; |
| 364 | } |
| 365 | } |
| 366 | while (queue > queue_start); |
| 367 | |
| 368 | } |
| 369 | |
| 370 | for (k = 0; k < window_size; ++k) |
| 371 | eassert (copy_from[k] >= 0 && copy_from[k] < window_size); |
| 372 | |
| 373 | /* Perform the row swizzling. */ |
| 374 | mirrored_line_dance (current_matrix, unchanged_at_top, window_size, |
| 375 | copy_from, retained_p); |
| 376 | |
| 377 | /* Some sanity checks if GLYPH_DEBUG is defined. */ |
| 378 | CHECK_MATRIX (current_matrix); |
| 379 | |
| 380 | if (terminal_window_p) |
| 381 | set_terminal_window (frame, 0); |
| 382 | } |
| 383 | |
| 384 | \f |
| 385 | /* Determine, in matrix[i,j], the cost of updating the first j |
| 386 | old lines into the first i new lines using the direct |
| 387 | scrolling method. When the old line and the new line have |
| 388 | different hash codes, the calculated cost of updating old |
| 389 | line j into new line i includes the cost of outputting new |
| 390 | line i, and if i != j, the cost of outputting the old line j |
| 391 | is also included, as a penalty for moving the line and then |
| 392 | erasing it. In addition, the cost of updating a sequence of |
| 393 | lines with constant i - j includes the cost of scrolling the |
| 394 | old lines into their new positions, unless i == j. Scrolling |
| 395 | is achieved by setting the screen window to avoid affecting |
| 396 | other lines below, and inserting or deleting lines at the top |
| 397 | of the scrolled region. The cost of scrolling a sequence of |
| 398 | lines includes the fixed cost of specifying a scroll region, |
| 399 | plus a variable cost which can depend upon the number of lines |
| 400 | involved and the distance by which they are scrolled, and an |
| 401 | extra cost to discourage long scrolls. |
| 402 | |
| 403 | As reflected in the matrix, an insert or delete does not |
| 404 | correspond directly to the insertion or deletion which is |
| 405 | used in scrolling lines. An insert means that the value of i |
| 406 | has increased without a corresponding increase in the value |
| 407 | of j. A delete means that the value of j has increased |
| 408 | without a corresponding increase in the value of i. A write |
| 409 | means that i and j are both increased by the same amount, and |
| 410 | that the old lines will be moved to their new positions. |
| 411 | |
| 412 | An insert following a delete is allowed only if i > j. |
| 413 | A delete following an insert is allowed only if i < j. |
| 414 | These restrictions ensure that the new lines in an insert |
| 415 | will always be blank as an effect of the neighboring writes. |
| 416 | Thus the calculated cost of an insert is simply the cost of |
| 417 | outputting the new line contents. The direct cost of a |
| 418 | delete is zero. Inserts and deletes indirectly affect the |
| 419 | total cost through their influence on subsequent writes. */ |
| 420 | |
| 421 | /* The vectors draw_cost, old_hash, and new_hash have the same |
| 422 | meanings here as in calculate_scrolling, and old_draw_cost |
| 423 | is the equivalent of draw_cost for the old line contents */ |
| 424 | |
| 425 | static void |
| 426 | calculate_direct_scrolling (FRAME_PTR frame, |
| 427 | /* matrix is of size window_size + 1 on each side. */ |
| 428 | struct matrix_elt *matrix, |
| 429 | int window_size, int lines_below, |
| 430 | int *draw_cost, int *old_draw_cost, |
| 431 | int *old_hash, int *new_hash, |
| 432 | int free_at_end) |
| 433 | { |
| 434 | register int i, j; |
| 435 | int frame_lines = FRAME_LINES (frame); |
| 436 | register struct matrix_elt *p, *p1; |
| 437 | register int cost, cost1, delta; |
| 438 | |
| 439 | /* first_insert_cost[-I] is the cost of doing the first insert-line |
| 440 | at a position I lines above the bottom line in the scroll window. */ |
| 441 | int *first_insert_cost |
| 442 | = &FRAME_INSERT_COST (frame)[frame_lines - 1]; |
| 443 | int *first_delete_cost |
| 444 | = &FRAME_DELETE_COST (frame)[frame_lines - 1]; |
| 445 | int *next_insert_cost |
| 446 | = &FRAME_INSERTN_COST (frame)[frame_lines - 1]; |
| 447 | int *next_delete_cost |
| 448 | = &FRAME_DELETEN_COST (frame)[frame_lines - 1]; |
| 449 | |
| 450 | int scroll_overhead; |
| 451 | |
| 452 | /* Discourage long scrolls on fast lines. |
| 453 | Don't scroll nearly a full frame height unless it saves |
| 454 | at least 1/4 second. */ |
| 455 | int extra_cost = (int) (baud_rate / (10 * 4 * FRAME_LINES (frame))); |
| 456 | |
| 457 | if (baud_rate <= 0) |
| 458 | extra_cost = 1; |
| 459 | |
| 460 | /* Overhead of setting the scroll window, plus the extra cost |
| 461 | cost of scrolling by a distance of one. The extra cost is |
| 462 | added once for consistency with the cost vectors */ |
| 463 | scroll_overhead |
| 464 | = FRAME_SCROLL_REGION_COST (frame) + extra_cost; |
| 465 | |
| 466 | /* initialize the top left corner of the matrix */ |
| 467 | matrix->writecost = 0; |
| 468 | matrix->insertcost = INFINITY; |
| 469 | matrix->deletecost = INFINITY; |
| 470 | matrix->writecount = 0; |
| 471 | matrix->insertcount = 0; |
| 472 | matrix->deletecount = 0; |
| 473 | |
| 474 | /* initialize the left edge of the matrix */ |
| 475 | cost = 0; |
| 476 | for (i = 1; i <= window_size; i++) |
| 477 | { |
| 478 | p = matrix + i * (window_size + 1); |
| 479 | cost += draw_cost[i]; |
| 480 | p->insertcost = cost; |
| 481 | p->writecost = INFINITY; |
| 482 | p->deletecost = INFINITY; |
| 483 | p->insertcount = i; |
| 484 | p->writecount = 0; |
| 485 | p->deletecount = 0; |
| 486 | } |
| 487 | |
| 488 | /* initialize the top edge of the matrix */ |
| 489 | for (j = 1; j <= window_size; j++) |
| 490 | { |
| 491 | matrix[j].deletecost = 0; |
| 492 | matrix[j].writecost = INFINITY; |
| 493 | matrix[j].insertcost = INFINITY; |
| 494 | matrix[j].deletecount = j; |
| 495 | matrix[j].writecount = 0; |
| 496 | matrix[j].insertcount = 0; |
| 497 | } |
| 498 | |
| 499 | /* `i' represents the vpos among new frame contents. |
| 500 | `j' represents the vpos among the old frame contents. */ |
| 501 | p = matrix + window_size + 2; /* matrix [1, 1] */ |
| 502 | |
| 503 | for (i = 1; i <= window_size; i++, p++) |
| 504 | for (j = 1; j <= window_size; j++, p++) |
| 505 | { |
| 506 | /* p contains the address of matrix [i, j] */ |
| 507 | |
| 508 | /* First calculate the cost assuming we do |
| 509 | not insert or delete above this line. |
| 510 | That is, if we update through line i-1 |
| 511 | based on old lines through j-1, |
| 512 | and then just change old line j to new line i. |
| 513 | |
| 514 | Depending on which choice gives the lower cost, |
| 515 | this usually involves either scrolling a single line |
| 516 | or extending a sequence of scrolled lines, but |
| 517 | when i == j, no scrolling is required. */ |
| 518 | p1 = p - window_size - 2; /* matrix [i-1, j-1] */ |
| 519 | cost = p1->insertcost; |
| 520 | if (cost > p1->deletecost) |
| 521 | cost = p1->deletecost; |
| 522 | cost1 = p1->writecost; |
| 523 | if (i == j) |
| 524 | { |
| 525 | if (cost > cost1) |
| 526 | { |
| 527 | cost = cost1; |
| 528 | p->writecount = p1->writecount + 1; |
| 529 | } |
| 530 | else |
| 531 | p->writecount = 1; |
| 532 | if (old_hash[j] != new_hash[i]) |
| 533 | { |
| 534 | cost += draw_cost[i]; |
| 535 | } |
| 536 | } |
| 537 | else |
| 538 | { |
| 539 | if (i > j) |
| 540 | { |
| 541 | delta = i - j; |
| 542 | |
| 543 | /* The cost added here for scrolling the first line by |
| 544 | a distance N includes the overhead of setting the |
| 545 | scroll window, the cost of inserting N lines at a |
| 546 | position N lines above the bottom line of the window, |
| 547 | and an extra cost which is proportional to N. */ |
| 548 | cost += scroll_overhead + first_insert_cost[-delta] + |
| 549 | (delta-1) * (next_insert_cost[-delta] + extra_cost); |
| 550 | |
| 551 | /* In the most general case, the insertion overhead and |
| 552 | the multiply factor can grow linearly as the distance |
| 553 | from the bottom of the window increases. The incremental |
| 554 | cost of scrolling an additional line depends upon the |
| 555 | rate of change of these two parameters. Each of these |
| 556 | growth rates can be determined by a simple difference. |
| 557 | To reduce the cumulative effects of rounding error, we |
| 558 | vary the position at which the difference is computed. */ |
| 559 | cost1 += first_insert_cost[-j] - first_insert_cost[1-j] + |
| 560 | (delta-1) * (next_insert_cost[-j] - next_insert_cost[1-j]); |
| 561 | } |
| 562 | else |
| 563 | { |
| 564 | delta = j - i; |
| 565 | cost += scroll_overhead + first_delete_cost[-delta] + |
| 566 | (delta-1) * (next_delete_cost[-delta] + extra_cost); |
| 567 | cost1 += first_delete_cost[-i] - first_delete_cost[1-i] + |
| 568 | (delta-1) * ( next_delete_cost[-i] - next_delete_cost[1-i]); |
| 569 | } |
| 570 | if (cost1 < cost) |
| 571 | { |
| 572 | cost = cost1; |
| 573 | p->writecount = p1->writecount + 1; |
| 574 | } |
| 575 | else |
| 576 | p->writecount = 1; |
| 577 | if (old_hash[j] != new_hash[i]) |
| 578 | { |
| 579 | cost += draw_cost[i] + old_draw_cost[j]; |
| 580 | } |
| 581 | } |
| 582 | p->writecost = cost; |
| 583 | |
| 584 | /* Calculate the cost if we do an insert-line |
| 585 | before outputting this line. |
| 586 | That is, we update through line i-1 |
| 587 | based on old lines through j, |
| 588 | do an insert-line on line i, |
| 589 | and then output line i from scratch, |
| 590 | leaving old lines starting from j for reuse below. */ |
| 591 | p1 = p - window_size - 1; /* matrix [i-1, j] */ |
| 592 | cost = p1->writecost; |
| 593 | /* If i > j, an insert is allowed after a delete. */ |
| 594 | if (i > j && p1->deletecost < cost) |
| 595 | cost = p1->deletecost; |
| 596 | if (p1->insertcost <= cost) |
| 597 | { |
| 598 | cost = p1->insertcost; |
| 599 | p->insertcount = p1->insertcount + 1; |
| 600 | } |
| 601 | else |
| 602 | p->insertcount = 1; |
| 603 | cost += draw_cost[i]; |
| 604 | p->insertcost = cost; |
| 605 | |
| 606 | /* Calculate the cost if we do a delete line after |
| 607 | outputting this line. |
| 608 | That is, we update through line i |
| 609 | based on old lines through j-1, |
| 610 | and throw away old line j. */ |
| 611 | p1 = p - 1; /* matrix [i, j-1] */ |
| 612 | cost = p1->writecost; |
| 613 | /* If i < j, a delete is allowed after an insert. */ |
| 614 | if (i < j && p1->insertcost < cost) |
| 615 | cost = p1->insertcost; |
| 616 | cost1 = p1->deletecost; |
| 617 | if (p1->deletecost <= cost) |
| 618 | { |
| 619 | cost = p1->deletecost; |
| 620 | p->deletecount = p1->deletecount + 1; |
| 621 | } |
| 622 | else |
| 623 | p->deletecount = 1; |
| 624 | p->deletecost = cost; |
| 625 | } |
| 626 | } |
| 627 | |
| 628 | |
| 629 | \f |
| 630 | /* Perform insert-lines and delete-lines operations on CURRENT_MATRIX |
| 631 | according to the costs in MATRIX, using the direct scrolling method |
| 632 | which is used when the terminal supports setting a scroll window |
| 633 | (scroll_region_ok). |
| 634 | |
| 635 | WINDOW_SIZE is the number of lines being considered for scrolling |
| 636 | and UNCHANGED_AT_TOP is the vpos of the first line being |
| 637 | considered. These two arguments can specify any contiguous range |
| 638 | of lines. |
| 639 | |
| 640 | In the direct scrolling method, a new scroll window is selected |
| 641 | before each insertion or deletion, so that groups of lines can be |
| 642 | scrolled directly to their final vertical positions. This method |
| 643 | is described in more detail in calculate_direct_scrolling, where |
| 644 | the cost matrix for this approach is constructed. */ |
| 645 | |
| 646 | static void |
| 647 | do_direct_scrolling (struct frame *frame, struct glyph_matrix *current_matrix, |
| 648 | struct matrix_elt *cost_matrix, int window_size, |
| 649 | int unchanged_at_top) |
| 650 | { |
| 651 | struct matrix_elt *p; |
| 652 | int i, j; |
| 653 | |
| 654 | /* A queue of deletions and insertions to be performed. */ |
| 655 | struct alt_queue { int count, pos, window; }; |
| 656 | struct alt_queue *queue_start = (struct alt_queue *) |
| 657 | alloca (window_size * sizeof *queue_start); |
| 658 | struct alt_queue *queue = queue_start; |
| 659 | |
| 660 | /* Set to 1 if a terminal window has been set with |
| 661 | set_terminal_window: */ |
| 662 | int terminal_window_p = 0; |
| 663 | |
| 664 | /* A nonzero value of write_follows indicates that a write has been |
| 665 | selected, allowing either an insert or a delete to be selected |
| 666 | next. When write_follows is zero, a delete cannot be selected |
| 667 | unless j < i, and an insert cannot be selected unless i < j. |
| 668 | This corresponds to a similar restriction (with the ordering |
| 669 | reversed) in calculate_direct_scrolling, which is intended to |
| 670 | ensure that lines marked as inserted will be blank. */ |
| 671 | int write_follows_p = 1; |
| 672 | |
| 673 | /* For each row in the new matrix what row of the old matrix it is. */ |
| 674 | int *copy_from = alloca (window_size * sizeof *copy_from); |
| 675 | |
| 676 | /* Non-zero for each row in the new matrix that is retained from the |
| 677 | old matrix. Lines not retained are empty. */ |
| 678 | char *retained_p = alloca (window_size * sizeof *retained_p); |
| 679 | |
| 680 | memset (retained_p, 0, window_size * sizeof (char)); |
| 681 | |
| 682 | /* Perform some sanity checks when GLYPH_DEBUG is on. */ |
| 683 | CHECK_MATRIX (current_matrix); |
| 684 | |
| 685 | /* We are working on the line range UNCHANGED_AT_TOP ... |
| 686 | UNCHANGED_AT_TOP + WINDOW_SIZE (not including) in CURRENT_MATRIX. |
| 687 | We step through lines in this range from the end to the start. I |
| 688 | is an index into new lines, j an index into old lines. The cost |
| 689 | matrix determines what to do for ranges of indices. |
| 690 | |
| 691 | If i is decremented without also decrementing j, this corresponds |
| 692 | to inserting empty lines in the result. If j is decremented |
| 693 | without also decrementing i, this corresponds to omitting these |
| 694 | lines in the new rows, i.e. rows are deleted. */ |
| 695 | i = j = window_size; |
| 696 | |
| 697 | while (i > 0 || j > 0) |
| 698 | { |
| 699 | p = cost_matrix + i * (window_size + 1) + j; |
| 700 | |
| 701 | if (p->insertcost < p->writecost |
| 702 | && p->insertcost < p->deletecost |
| 703 | && (write_follows_p || i < j)) |
| 704 | { |
| 705 | /* Insert is cheaper than deleting or writing lines. Leave |
| 706 | a hole in the result display that will be filled with |
| 707 | empty lines when the queue is emptied. */ |
| 708 | queue->count = 0; |
| 709 | queue->window = i; |
| 710 | queue->pos = i - p->insertcount; |
| 711 | ++queue; |
| 712 | |
| 713 | i -= p->insertcount; |
| 714 | write_follows_p = 0; |
| 715 | } |
| 716 | else if (p->deletecost < p->writecost |
| 717 | && (write_follows_p || i > j)) |
| 718 | { |
| 719 | /* Deleting lines is cheaper. By decrementing J, omit |
| 720 | deletecount lines from the original. */ |
| 721 | write_follows_p = 0; |
| 722 | j -= p->deletecount; |
| 723 | } |
| 724 | else |
| 725 | { |
| 726 | /* One or more lines should be written. In the direct |
| 727 | scrolling method we do this by scrolling the lines to the |
| 728 | place they belong. */ |
| 729 | int n_to_write = p->writecount; |
| 730 | write_follows_p = 1; |
| 731 | eassert (n_to_write > 0); |
| 732 | |
| 733 | if (i > j) |
| 734 | { |
| 735 | /* Immediately insert lines */ |
| 736 | set_terminal_window (frame, i + unchanged_at_top); |
| 737 | terminal_window_p = 1; |
| 738 | ins_del_lines (frame, j - n_to_write + unchanged_at_top, i - j); |
| 739 | } |
| 740 | else if (i < j) |
| 741 | { |
| 742 | /* Queue the deletion of a group of lines */ |
| 743 | queue->pos = i - n_to_write + unchanged_at_top; |
| 744 | queue->window = j + unchanged_at_top; |
| 745 | queue->count = i - j; |
| 746 | ++queue; |
| 747 | } |
| 748 | |
| 749 | while (n_to_write > 0) |
| 750 | { |
| 751 | --i, --j, --n_to_write; |
| 752 | copy_from[i] = j; |
| 753 | retained_p[j] = 1; |
| 754 | } |
| 755 | } |
| 756 | } |
| 757 | |
| 758 | /* Do queued operations. */ |
| 759 | if (queue > queue_start) |
| 760 | { |
| 761 | int next = -1; |
| 762 | |
| 763 | do |
| 764 | { |
| 765 | --queue; |
| 766 | if (queue->count) |
| 767 | { |
| 768 | set_terminal_window (frame, queue->window); |
| 769 | terminal_window_p = 1; |
| 770 | ins_del_lines (frame, queue->pos, queue->count); |
| 771 | } |
| 772 | else |
| 773 | { |
| 774 | for (j = queue->window - 1; j >= queue->pos; --j) |
| 775 | { |
| 776 | while (retained_p[++next]) |
| 777 | ; |
| 778 | copy_from[j] = next; |
| 779 | } |
| 780 | } |
| 781 | } |
| 782 | while (queue > queue_start); |
| 783 | } |
| 784 | |
| 785 | /* Now, for each row I in the range of rows we are working on, |
| 786 | copy_from[i] gives the original line to copy to I, and |
| 787 | retained_p[copy_from[i]] is zero if line I in the new display is |
| 788 | empty. */ |
| 789 | mirrored_line_dance (current_matrix, unchanged_at_top, window_size, |
| 790 | copy_from, retained_p); |
| 791 | |
| 792 | if (terminal_window_p) |
| 793 | set_terminal_window (frame, 0); |
| 794 | } |
| 795 | |
| 796 | |
| 797 | \f |
| 798 | void |
| 799 | scrolling_1 (FRAME_PTR frame, int window_size, int unchanged_at_top, |
| 800 | int unchanged_at_bottom, int *draw_cost, int *old_draw_cost, |
| 801 | int *old_hash, int *new_hash, int free_at_end) |
| 802 | { |
| 803 | struct matrix_elt *matrix; |
| 804 | matrix = ((struct matrix_elt *) |
| 805 | alloca ((window_size + 1) * (window_size + 1) * sizeof *matrix)); |
| 806 | |
| 807 | if (FRAME_SCROLL_REGION_OK (frame)) |
| 808 | { |
| 809 | calculate_direct_scrolling (frame, matrix, window_size, |
| 810 | unchanged_at_bottom, |
| 811 | draw_cost, old_draw_cost, |
| 812 | old_hash, new_hash, free_at_end); |
| 813 | do_direct_scrolling (frame, frame->current_matrix, |
| 814 | matrix, window_size, unchanged_at_top); |
| 815 | } |
| 816 | else |
| 817 | { |
| 818 | calculate_scrolling (frame, matrix, window_size, unchanged_at_bottom, |
| 819 | draw_cost, old_hash, new_hash, |
| 820 | free_at_end); |
| 821 | do_scrolling (frame, |
| 822 | frame->current_matrix, matrix, window_size, |
| 823 | unchanged_at_top); |
| 824 | } |
| 825 | } |
| 826 | |
| 827 | |
| 828 | \f |
| 829 | /* Return number of lines in common between current and desired frame |
| 830 | contents described to us only as vectors of hash codes OLDHASH and |
| 831 | NEWHASH. Consider only vpos range START to END (not including |
| 832 | END). Ignore short lines on the assumption that avoiding redrawing |
| 833 | such a line will have little weight. */ |
| 834 | |
| 835 | int |
| 836 | scrolling_max_lines_saved (int start, int end, |
| 837 | int *oldhash, int *newhash, |
| 838 | int *cost) |
| 839 | { |
| 840 | struct { int hash; int count; } lines[01000]; |
| 841 | register int i, h; |
| 842 | register int matchcount = 0; |
| 843 | int avg_length = 0; |
| 844 | int threshold; |
| 845 | |
| 846 | /* Compute a threshold which is 1/4 of average length of these lines. */ |
| 847 | |
| 848 | for (i = start; i < end; i++) |
| 849 | avg_length += cost[i]; |
| 850 | |
| 851 | avg_length /= end - start; |
| 852 | threshold = avg_length / 4; |
| 853 | |
| 854 | memset (lines, 0, sizeof lines); |
| 855 | |
| 856 | /* Put new lines' hash codes in hash table. Ignore lines shorter |
| 857 | than the threshold. Thus, if the lines that are in common are |
| 858 | mainly the ones that are short, they won't count. */ |
| 859 | for (i = start; i < end; i++) |
| 860 | { |
| 861 | if (cost[i] > threshold) |
| 862 | { |
| 863 | h = newhash[i] & 0777; |
| 864 | lines[h].hash = newhash[i]; |
| 865 | lines[h].count++; |
| 866 | } |
| 867 | } |
| 868 | |
| 869 | /* Look up old line hash codes in the hash table. Count number of |
| 870 | matches between old lines and new. */ |
| 871 | for (i = start; i < end; i++) |
| 872 | { |
| 873 | h = oldhash[i] & 0777; |
| 874 | if (oldhash[i] == lines[h].hash) |
| 875 | { |
| 876 | matchcount++; |
| 877 | if (--lines[h].count == 0) |
| 878 | lines[h].hash = 0; |
| 879 | } |
| 880 | } |
| 881 | |
| 882 | return matchcount; |
| 883 | } |
| 884 | \f |
| 885 | /* Calculate the line insertion/deletion |
| 886 | overhead and multiply factor values */ |
| 887 | |
| 888 | static void |
| 889 | line_ins_del (FRAME_PTR frame, int ov1, int pf1, int ovn, int pfn, |
| 890 | register int *ov, register int *mf) |
| 891 | { |
| 892 | register int i; |
| 893 | register int frame_lines = FRAME_LINES (frame); |
| 894 | register int insert_overhead = ov1 * 10; |
| 895 | register int next_insert_cost = ovn * 10; |
| 896 | |
| 897 | for (i = frame_lines-1; i >= 0; i--) |
| 898 | { |
| 899 | mf[i] = next_insert_cost / 10; |
| 900 | next_insert_cost += pfn; |
| 901 | ov[i] = (insert_overhead + next_insert_cost) / 10; |
| 902 | insert_overhead += pf1; |
| 903 | } |
| 904 | } |
| 905 | |
| 906 | static void |
| 907 | ins_del_costs (FRAME_PTR frame, |
| 908 | const char *one_line_string, const char *multi_string, |
| 909 | const char *setup_string, const char *cleanup_string, |
| 910 | int *costvec, int *ncostvec, |
| 911 | int coefficient) |
| 912 | { |
| 913 | if (multi_string) |
| 914 | line_ins_del (frame, |
| 915 | string_cost (multi_string) * coefficient, |
| 916 | per_line_cost (multi_string) * coefficient, |
| 917 | 0, 0, costvec, ncostvec); |
| 918 | else if (one_line_string) |
| 919 | line_ins_del (frame, |
| 920 | string_cost (setup_string) + string_cost (cleanup_string), 0, |
| 921 | string_cost (one_line_string), |
| 922 | per_line_cost (one_line_string), |
| 923 | costvec, ncostvec); |
| 924 | else |
| 925 | line_ins_del (frame, |
| 926 | 9999, 0, 9999, 0, |
| 927 | costvec, ncostvec); |
| 928 | } |
| 929 | |
| 930 | /* Calculate the insert and delete line costs. |
| 931 | Note that this is done even when running with a window system |
| 932 | because we want to know how long scrolling takes (and avoid it). |
| 933 | This must be redone whenever the frame height changes. |
| 934 | |
| 935 | We keep the ID costs in a precomputed array based on the position |
| 936 | at which the I or D is performed. Also, there are two kinds of ID |
| 937 | costs: the "once-only" and the "repeated". This is to handle both |
| 938 | those terminals that are able to insert N lines at a time (once- |
| 939 | only) and those that must repeatedly insert one line. |
| 940 | |
| 941 | The cost to insert N lines at line L is |
| 942 | [tt.t_ILov + (frame_lines + 1 - L) * tt.t_ILpf] + |
| 943 | N * [tt.t_ILnov + (frame_lines + 1 - L) * tt.t_ILnpf] |
| 944 | |
| 945 | ILov represents the basic insert line overhead. ILpf is the padding |
| 946 | required to allow the terminal time to move a line: insertion at line |
| 947 | L changes (frame_lines + 1 - L) lines. |
| 948 | |
| 949 | The first bracketed expression above is the overhead; the second is |
| 950 | the multiply factor. Both are dependent only on the position at |
| 951 | which the insert is performed. We store the overhead in |
| 952 | FRAME_INSERT_COST (frame) and the multiply factor in |
| 953 | FRAME_INSERTN_COST (frame). Note however that any insertion |
| 954 | must include at least one multiply factor. Rather than compute this |
| 955 | as FRAME_INSERT_COST (frame)[line]+FRAME_INSERTN_COST (frame)[line], |
| 956 | we add FRAME_INSERTN_COST (frame) into FRAME_INSERT_COST (frame). |
| 957 | This is reasonable because of the particular algorithm used in calcM. |
| 958 | |
| 959 | Deletion is essentially the same as insertion. |
| 960 | */ |
| 961 | |
| 962 | void |
| 963 | do_line_insertion_deletion_costs (FRAME_PTR frame, |
| 964 | const char *ins_line_string, |
| 965 | const char *multi_ins_string, |
| 966 | const char *del_line_string, |
| 967 | const char *multi_del_string, |
| 968 | const char *setup_string, |
| 969 | const char *cleanup_string, |
| 970 | int coefficient) |
| 971 | { |
| 972 | FRAME_INSERT_COST (frame) = |
| 973 | xnrealloc (FRAME_INSERT_COST (frame), FRAME_LINES (frame), sizeof (int)); |
| 974 | FRAME_DELETEN_COST (frame) = |
| 975 | xnrealloc (FRAME_DELETEN_COST (frame), FRAME_LINES (frame), sizeof (int)); |
| 976 | FRAME_INSERTN_COST (frame) = |
| 977 | xnrealloc (FRAME_INSERTN_COST (frame), FRAME_LINES (frame), sizeof (int)); |
| 978 | FRAME_DELETE_COST (frame) = |
| 979 | xnrealloc (FRAME_DELETE_COST (frame), FRAME_LINES (frame), sizeof (int)); |
| 980 | |
| 981 | ins_del_costs (frame, |
| 982 | ins_line_string, multi_ins_string, |
| 983 | setup_string, cleanup_string, |
| 984 | FRAME_INSERT_COST (frame), FRAME_INSERTN_COST (frame), |
| 985 | coefficient); |
| 986 | ins_del_costs (frame, |
| 987 | del_line_string, multi_del_string, |
| 988 | setup_string, cleanup_string, |
| 989 | FRAME_DELETE_COST (frame), FRAME_DELETEN_COST (frame), |
| 990 | coefficient); |
| 991 | } |