imstb_textedit.h 52.1 KB
Newer Older
Lionel Landwerlin's avatar
Lionel Landwerlin committed
1 2 3 4 5
// [DEAR IMGUI]
// This is a slightly modified version of stb_textedit.h 1.13.
// Those changes would need to be pushed into nothings/stb:
// - Fix in stb_textedit_discard_redo (see https://github.com/nothings/stb/issues/321)
// Grep for [DEAR IMGUI] to find the changes.
6

Lionel Landwerlin's avatar
Lionel Landwerlin committed
7
// stb_textedit.h - v1.13  - public domain - Sean Barrett
8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37
// Development of this library was sponsored by RAD Game Tools
//
// This C header file implements the guts of a multi-line text-editing
// widget; you implement display, word-wrapping, and low-level string
// insertion/deletion, and stb_textedit will map user inputs into
// insertions & deletions, plus updates to the cursor position,
// selection state, and undo state.
//
// It is intended for use in games and other systems that need to build
// their own custom widgets and which do not have heavy text-editing
// requirements (this library is not recommended for use for editing large
// texts, as its performance does not scale and it has limited undo).
//
// Non-trivial behaviors are modelled after Windows text controls.
//
//
// LICENSE
//
// See end of file for license information.
//
//
// DEPENDENCIES
//
// Uses the C runtime function 'memmove', which you can override
// by defining STB_TEXTEDIT_memmove before the implementation.
// Uses no other functions. Performs no runtime allocations.
//
//
// VERSION HISTORY
//
Lionel Landwerlin's avatar
Lionel Landwerlin committed
38
//   1.13 (2019-02-07) fix bug in undo size management
39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696
//   1.12 (2018-01-29) user can change STB_TEXTEDIT_KEYTYPE, fix redo to avoid crash
//   1.11 (2017-03-03) fix HOME on last line, dragging off single-line textfield
//   1.10 (2016-10-25) supress warnings about casting away const with -Wcast-qual
//   1.9  (2016-08-27) customizable move-by-word
//   1.8  (2016-04-02) better keyboard handling when mouse button is down
//   1.7  (2015-09-13) change y range handling in case baseline is non-0
//   1.6  (2015-04-15) allow STB_TEXTEDIT_memmove
//   1.5  (2014-09-10) add support for secondary keys for OS X
//   1.4  (2014-08-17) fix signed/unsigned warnings
//   1.3  (2014-06-19) fix mouse clicking to round to nearest char boundary
//   1.2  (2014-05-27) fix some RAD types that had crept into the new code
//   1.1  (2013-12-15) move-by-word (requires STB_TEXTEDIT_IS_SPACE )
//   1.0  (2012-07-26) improve documentation, initial public release
//   0.3  (2012-02-24) bugfixes, single-line mode; insert mode
//   0.2  (2011-11-28) fixes to undo/redo
//   0.1  (2010-07-08) initial version
//
// ADDITIONAL CONTRIBUTORS
//
//   Ulf Winklemann: move-by-word in 1.1
//   Fabian Giesen: secondary key inputs in 1.5
//   Martins Mozeiko: STB_TEXTEDIT_memmove in 1.6
//
//   Bugfixes:
//      Scott Graham
//      Daniel Keller
//      Omar Cornut
//      Dan Thompson
//
// USAGE
//
// This file behaves differently depending on what symbols you define
// before including it.
//
//
// Header-file mode:
//
//   If you do not define STB_TEXTEDIT_IMPLEMENTATION before including this,
//   it will operate in "header file" mode. In this mode, it declares a
//   single public symbol, STB_TexteditState, which encapsulates the current
//   state of a text widget (except for the string, which you will store
//   separately).
//
//   To compile in this mode, you must define STB_TEXTEDIT_CHARTYPE to a
//   primitive type that defines a single character (e.g. char, wchar_t, etc).
//
//   To save space or increase undo-ability, you can optionally define the
//   following things that are used by the undo system:
//
//      STB_TEXTEDIT_POSITIONTYPE         small int type encoding a valid cursor position
//      STB_TEXTEDIT_UNDOSTATECOUNT       the number of undo states to allow
//      STB_TEXTEDIT_UNDOCHARCOUNT        the number of characters to store in the undo buffer
//
//   If you don't define these, they are set to permissive types and
//   moderate sizes. The undo system does no memory allocations, so
//   it grows STB_TexteditState by the worst-case storage which is (in bytes):
//
//        [4 + 3 * sizeof(STB_TEXTEDIT_POSITIONTYPE)] * STB_TEXTEDIT_UNDOSTATE_COUNT
//      +          sizeof(STB_TEXTEDIT_CHARTYPE)      * STB_TEXTEDIT_UNDOCHAR_COUNT
//
//
// Implementation mode:
//
//   If you define STB_TEXTEDIT_IMPLEMENTATION before including this, it
//   will compile the implementation of the text edit widget, depending
//   on a large number of symbols which must be defined before the include.
//
//   The implementation is defined only as static functions. You will then
//   need to provide your own APIs in the same file which will access the
//   static functions.
//
//   The basic concept is that you provide a "string" object which
//   behaves like an array of characters. stb_textedit uses indices to
//   refer to positions in the string, implicitly representing positions
//   in the displayed textedit. This is true for both plain text and
//   rich text; even with rich text stb_truetype interacts with your
//   code as if there was an array of all the displayed characters.
//
// Symbols that must be the same in header-file and implementation mode:
//
//     STB_TEXTEDIT_CHARTYPE             the character type
//     STB_TEXTEDIT_POSITIONTYPE         small type that is a valid cursor position
//     STB_TEXTEDIT_UNDOSTATECOUNT       the number of undo states to allow
//     STB_TEXTEDIT_UNDOCHARCOUNT        the number of characters to store in the undo buffer
//
// Symbols you must define for implementation mode:
//
//    STB_TEXTEDIT_STRING               the type of object representing a string being edited,
//                                      typically this is a wrapper object with other data you need
//
//    STB_TEXTEDIT_STRINGLEN(obj)       the length of the string (ideally O(1))
//    STB_TEXTEDIT_LAYOUTROW(&r,obj,n)  returns the results of laying out a line of characters
//                                        starting from character #n (see discussion below)
//    STB_TEXTEDIT_GETWIDTH(obj,n,i)    returns the pixel delta from the xpos of the i'th character
//                                        to the xpos of the i+1'th char for a line of characters
//                                        starting at character #n (i.e. accounts for kerning
//                                        with previous char)
//    STB_TEXTEDIT_KEYTOTEXT(k)         maps a keyboard input to an insertable character
//                                        (return type is int, -1 means not valid to insert)
//    STB_TEXTEDIT_GETCHAR(obj,i)       returns the i'th character of obj, 0-based
//    STB_TEXTEDIT_NEWLINE              the character returned by _GETCHAR() we recognize
//                                        as manually wordwrapping for end-of-line positioning
//
//    STB_TEXTEDIT_DELETECHARS(obj,i,n)      delete n characters starting at i
//    STB_TEXTEDIT_INSERTCHARS(obj,i,c*,n)   insert n characters at i (pointed to by STB_TEXTEDIT_CHARTYPE*)
//
//    STB_TEXTEDIT_K_SHIFT       a power of two that is or'd in to a keyboard input to represent the shift key
//
//    STB_TEXTEDIT_K_LEFT        keyboard input to move cursor left
//    STB_TEXTEDIT_K_RIGHT       keyboard input to move cursor right
//    STB_TEXTEDIT_K_UP          keyboard input to move cursor up
//    STB_TEXTEDIT_K_DOWN        keyboard input to move cursor down
//    STB_TEXTEDIT_K_LINESTART   keyboard input to move cursor to start of line  // e.g. HOME
//    STB_TEXTEDIT_K_LINEEND     keyboard input to move cursor to end of line    // e.g. END
//    STB_TEXTEDIT_K_TEXTSTART   keyboard input to move cursor to start of text  // e.g. ctrl-HOME
//    STB_TEXTEDIT_K_TEXTEND     keyboard input to move cursor to end of text    // e.g. ctrl-END
//    STB_TEXTEDIT_K_DELETE      keyboard input to delete selection or character under cursor
//    STB_TEXTEDIT_K_BACKSPACE   keyboard input to delete selection or character left of cursor
//    STB_TEXTEDIT_K_UNDO        keyboard input to perform undo
//    STB_TEXTEDIT_K_REDO        keyboard input to perform redo
//
// Optional:
//    STB_TEXTEDIT_K_INSERT              keyboard input to toggle insert mode
//    STB_TEXTEDIT_IS_SPACE(ch)          true if character is whitespace (e.g. 'isspace'),
//                                          required for default WORDLEFT/WORDRIGHT handlers
//    STB_TEXTEDIT_MOVEWORDLEFT(obj,i)   custom handler for WORDLEFT, returns index to move cursor to
//    STB_TEXTEDIT_MOVEWORDRIGHT(obj,i)  custom handler for WORDRIGHT, returns index to move cursor to
//    STB_TEXTEDIT_K_WORDLEFT            keyboard input to move cursor left one word // e.g. ctrl-LEFT
//    STB_TEXTEDIT_K_WORDRIGHT           keyboard input to move cursor right one word // e.g. ctrl-RIGHT
//    STB_TEXTEDIT_K_LINESTART2          secondary keyboard input to move cursor to start of line
//    STB_TEXTEDIT_K_LINEEND2            secondary keyboard input to move cursor to end of line
//    STB_TEXTEDIT_K_TEXTSTART2          secondary keyboard input to move cursor to start of text
//    STB_TEXTEDIT_K_TEXTEND2            secondary keyboard input to move cursor to end of text
//
// Todo:
//    STB_TEXTEDIT_K_PGUP        keyboard input to move cursor up a page
//    STB_TEXTEDIT_K_PGDOWN      keyboard input to move cursor down a page
//
// Keyboard input must be encoded as a single integer value; e.g. a character code
// and some bitflags that represent shift states. to simplify the interface, SHIFT must
// be a bitflag, so we can test the shifted state of cursor movements to allow selection,
// i.e. (STB_TEXTED_K_RIGHT|STB_TEXTEDIT_K_SHIFT) should be shifted right-arrow.
//
// You can encode other things, such as CONTROL or ALT, in additional bits, and
// then test for their presence in e.g. STB_TEXTEDIT_K_WORDLEFT. For example,
// my Windows implementations add an additional CONTROL bit, and an additional KEYDOWN
// bit. Then all of the STB_TEXTEDIT_K_ values bitwise-or in the KEYDOWN bit,
// and I pass both WM_KEYDOWN and WM_CHAR events to the "key" function in the
// API below. The control keys will only match WM_KEYDOWN events because of the
// keydown bit I add, and STB_TEXTEDIT_KEYTOTEXT only tests for the KEYDOWN
// bit so it only decodes WM_CHAR events.
//
// STB_TEXTEDIT_LAYOUTROW returns information about the shape of one displayed
// row of characters assuming they start on the i'th character--the width and
// the height and the number of characters consumed. This allows this library
// to traverse the entire layout incrementally. You need to compute word-wrapping
// here.
//
// Each textfield keeps its own insert mode state, which is not how normal
// applications work. To keep an app-wide insert mode, update/copy the
// "insert_mode" field of STB_TexteditState before/after calling API functions.
//
// API
//
//    void stb_textedit_initialize_state(STB_TexteditState *state, int is_single_line)
//
//    void stb_textedit_click(STB_TEXTEDIT_STRING *str, STB_TexteditState *state, float x, float y)
//    void stb_textedit_drag(STB_TEXTEDIT_STRING *str, STB_TexteditState *state, float x, float y)
//    int  stb_textedit_cut(STB_TEXTEDIT_STRING *str, STB_TexteditState *state)
//    int  stb_textedit_paste(STB_TEXTEDIT_STRING *str, STB_TexteditState *state, STB_TEXTEDIT_CHARTYPE *text, int len)
//    void stb_textedit_key(STB_TEXTEDIT_STRING *str, STB_TexteditState *state, STB_TEXEDIT_KEYTYPE key)
//
//    Each of these functions potentially updates the string and updates the
//    state.
//
//      initialize_state:
//          set the textedit state to a known good default state when initially
//          constructing the textedit.
//
//      click:
//          call this with the mouse x,y on a mouse down; it will update the cursor
//          and reset the selection start/end to the cursor point. the x,y must
//          be relative to the text widget, with (0,0) being the top left.
//
//      drag:
//          call this with the mouse x,y on a mouse drag/up; it will update the
//          cursor and the selection end point
//
//      cut:
//          call this to delete the current selection; returns true if there was
//          one. you should FIRST copy the current selection to the system paste buffer.
//          (To copy, just copy the current selection out of the string yourself.)
//
//      paste:
//          call this to paste text at the current cursor point or over the current
//          selection if there is one.
//
//      key:
//          call this for keyboard inputs sent to the textfield. you can use it
//          for "key down" events or for "translated" key events. if you need to
//          do both (as in Win32), or distinguish Unicode characters from control
//          inputs, set a high bit to distinguish the two; then you can define the
//          various definitions like STB_TEXTEDIT_K_LEFT have the is-key-event bit
//          set, and make STB_TEXTEDIT_KEYTOCHAR check that the is-key-event bit is
//          clear. STB_TEXTEDIT_KEYTYPE defaults to int, but you can #define it to
//          anything other type you wante before including.
//
//
//   When rendering, you can read the cursor position and selection state from
//   the STB_TexteditState.
//
//
// Notes:
//
// This is designed to be usable in IMGUI, so it allows for the possibility of
// running in an IMGUI that has NOT cached the multi-line layout. For this
// reason, it provides an interface that is compatible with computing the
// layout incrementally--we try to make sure we make as few passes through
// as possible. (For example, to locate the mouse pointer in the text, we
// could define functions that return the X and Y positions of characters
// and binary search Y and then X, but if we're doing dynamic layout this
// will run the layout algorithm many times, so instead we manually search
// forward in one pass. Similar logic applies to e.g. up-arrow and
// down-arrow movement.)
//
// If it's run in a widget that *has* cached the layout, then this is less
// efficient, but it's not horrible on modern computers. But you wouldn't
// want to edit million-line files with it.


////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////
////
////   Header-file mode
////
////

#ifndef INCLUDE_STB_TEXTEDIT_H
#define INCLUDE_STB_TEXTEDIT_H

////////////////////////////////////////////////////////////////////////
//
//     STB_TexteditState
//
// Definition of STB_TexteditState which you should store
// per-textfield; it includes cursor position, selection state,
// and undo state.
//

#ifndef STB_TEXTEDIT_UNDOSTATECOUNT
#define STB_TEXTEDIT_UNDOSTATECOUNT   99
#endif
#ifndef STB_TEXTEDIT_UNDOCHARCOUNT
#define STB_TEXTEDIT_UNDOCHARCOUNT   999
#endif
#ifndef STB_TEXTEDIT_CHARTYPE
#define STB_TEXTEDIT_CHARTYPE        int
#endif
#ifndef STB_TEXTEDIT_POSITIONTYPE
#define STB_TEXTEDIT_POSITIONTYPE    int
#endif

typedef struct
{
   // private data
   STB_TEXTEDIT_POSITIONTYPE  where;
   STB_TEXTEDIT_POSITIONTYPE  insert_length;
   STB_TEXTEDIT_POSITIONTYPE  delete_length;
   int                        char_storage;
} StbUndoRecord;

typedef struct
{
   // private data
   StbUndoRecord          undo_rec [STB_TEXTEDIT_UNDOSTATECOUNT];
   STB_TEXTEDIT_CHARTYPE  undo_char[STB_TEXTEDIT_UNDOCHARCOUNT];
   short undo_point, redo_point;
   int undo_char_point, redo_char_point;
} StbUndoState;

typedef struct
{
   /////////////////////
   //
   // public data
   //

   int cursor;
   // position of the text cursor within the string

   int select_start;          // selection start point
   int select_end;
   // selection start and end point in characters; if equal, no selection.
   // note that start may be less than or greater than end (e.g. when
   // dragging the mouse, start is where the initial click was, and you
   // can drag in either direction)

   unsigned char insert_mode;
   // each textfield keeps its own insert mode state. to keep an app-wide
   // insert mode, copy this value in/out of the app state

   /////////////////////
   //
   // private data
   //
   unsigned char cursor_at_end_of_line; // not implemented yet
   unsigned char initialized;
   unsigned char has_preferred_x;
   unsigned char single_line;
   unsigned char padding1, padding2, padding3;
   float preferred_x; // this determines where the cursor up/down tries to seek to along x
   StbUndoState undostate;
} STB_TexteditState;


////////////////////////////////////////////////////////////////////////
//
//     StbTexteditRow
//
// Result of layout query, used by stb_textedit to determine where
// the text in each row is.

// result of layout query
typedef struct
{
   float x0,x1;             // starting x location, end x location (allows for align=right, etc)
   float baseline_y_delta;  // position of baseline relative to previous row's baseline
   float ymin,ymax;         // height of row above and below baseline
   int num_chars;
} StbTexteditRow;
#endif //INCLUDE_STB_TEXTEDIT_H


////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////
////
////   Implementation mode
////
////


// implementation isn't include-guarded, since it might have indirectly
// included just the "header" portion
#ifdef STB_TEXTEDIT_IMPLEMENTATION

#ifndef STB_TEXTEDIT_memmove
#include <string.h>
#define STB_TEXTEDIT_memmove memmove
#endif


/////////////////////////////////////////////////////////////////////////////
//
//      Mouse input handling
//

// traverse the layout to locate the nearest character to a display position
static int stb_text_locate_coord(STB_TEXTEDIT_STRING *str, float x, float y)
{
   StbTexteditRow r;
   int n = STB_TEXTEDIT_STRINGLEN(str);
   float base_y = 0, prev_x;
   int i=0, k;

   r.x0 = r.x1 = 0;
   r.ymin = r.ymax = 0;
   r.num_chars = 0;

   // search rows to find one that straddles 'y'
   while (i < n) {
      STB_TEXTEDIT_LAYOUTROW(&r, str, i);
      if (r.num_chars <= 0)
         return n;

      if (i==0 && y < base_y + r.ymin)
         return 0;

      if (y < base_y + r.ymax)
         break;

      i += r.num_chars;
      base_y += r.baseline_y_delta;
   }

   // below all text, return 'after' last character
   if (i >= n)
      return n;

   // check if it's before the beginning of the line
   if (x < r.x0)
      return i;

   // check if it's before the end of the line
   if (x < r.x1) {
      // search characters in row for one that straddles 'x'
      prev_x = r.x0;
      for (k=0; k < r.num_chars; ++k) {
         float w = STB_TEXTEDIT_GETWIDTH(str, i, k);
         if (x < prev_x+w) {
            if (x < prev_x+w/2)
               return k+i;
            else
               return k+i+1;
         }
         prev_x += w;
      }
      // shouldn't happen, but if it does, fall through to end-of-line case
   }

   // if the last character is a newline, return that. otherwise return 'after' the last character
   if (STB_TEXTEDIT_GETCHAR(str, i+r.num_chars-1) == STB_TEXTEDIT_NEWLINE)
      return i+r.num_chars-1;
   else
      return i+r.num_chars;
}

// API click: on mouse down, move the cursor to the clicked location, and reset the selection
static void stb_textedit_click(STB_TEXTEDIT_STRING *str, STB_TexteditState *state, float x, float y)
{
   // In single-line mode, just always make y = 0. This lets the drag keep working if the mouse
   // goes off the top or bottom of the text
   if( state->single_line )
   {
      StbTexteditRow r;
      STB_TEXTEDIT_LAYOUTROW(&r, str, 0);
      y = r.ymin;
   }

   state->cursor = stb_text_locate_coord(str, x, y);
   state->select_start = state->cursor;
   state->select_end = state->cursor;
   state->has_preferred_x = 0;
}

// API drag: on mouse drag, move the cursor and selection endpoint to the clicked location
static void stb_textedit_drag(STB_TEXTEDIT_STRING *str, STB_TexteditState *state, float x, float y)
{
   int p = 0;

   // In single-line mode, just always make y = 0. This lets the drag keep working if the mouse
   // goes off the top or bottom of the text
   if( state->single_line )
   {
      StbTexteditRow r;
      STB_TEXTEDIT_LAYOUTROW(&r, str, 0);
      y = r.ymin;
   }

   if (state->select_start == state->select_end)
      state->select_start = state->cursor;

   p = stb_text_locate_coord(str, x, y);
   state->cursor = state->select_end = p;
}

/////////////////////////////////////////////////////////////////////////////
//
//      Keyboard input handling
//

// forward declarations
static void stb_text_undo(STB_TEXTEDIT_STRING *str, STB_TexteditState *state);
static void stb_text_redo(STB_TEXTEDIT_STRING *str, STB_TexteditState *state);
static void stb_text_makeundo_delete(STB_TEXTEDIT_STRING *str, STB_TexteditState *state, int where, int length);
static void stb_text_makeundo_insert(STB_TexteditState *state, int where, int length);
static void stb_text_makeundo_replace(STB_TEXTEDIT_STRING *str, STB_TexteditState *state, int where, int old_length, int new_length);

typedef struct
{
   float x,y;    // position of n'th character
   float height; // height of line
   int first_char, length; // first char of row, and length
   int prev_first;  // first char of previous row
} StbFindState;

// find the x/y location of a character, and remember info about the previous row in
// case we get a move-up event (for page up, we'll have to rescan)
static void stb_textedit_find_charpos(StbFindState *find, STB_TEXTEDIT_STRING *str, int n, int single_line)
{
   StbTexteditRow r;
   int prev_start = 0;
   int z = STB_TEXTEDIT_STRINGLEN(str);
   int i=0, first;

   if (n == z) {
      // if it's at the end, then find the last line -- simpler than trying to
      // explicitly handle this case in the regular code
      if (single_line) {
         STB_TEXTEDIT_LAYOUTROW(&r, str, 0);
         find->y = 0;
         find->first_char = 0;
         find->length = z;
         find->height = r.ymax - r.ymin;
         find->x = r.x1;
      } else {
         find->y = 0;
         find->x = 0;
         find->height = 1;
         while (i < z) {
            STB_TEXTEDIT_LAYOUTROW(&r, str, i);
            prev_start = i;
            i += r.num_chars;
         }
         find->first_char = i;
         find->length = 0;
         find->prev_first = prev_start;
      }
      return;
   }

   // search rows to find the one that straddles character n
   find->y = 0;

   for(;;) {
      STB_TEXTEDIT_LAYOUTROW(&r, str, i);
      if (n < i + r.num_chars)
         break;
      prev_start = i;
      i += r.num_chars;
      find->y += r.baseline_y_delta;
   }

   find->first_char = first = i;
   find->length = r.num_chars;
   find->height = r.ymax - r.ymin;
   find->prev_first = prev_start;

   // now scan to find xpos
   find->x = r.x0;
   for (i=0; first+i < n; ++i)
      find->x += STB_TEXTEDIT_GETWIDTH(str, first, i);
}

#define STB_TEXT_HAS_SELECTION(s)   ((s)->select_start != (s)->select_end)

// make the selection/cursor state valid if client altered the string
static void stb_textedit_clamp(STB_TEXTEDIT_STRING *str, STB_TexteditState *state)
{
   int n = STB_TEXTEDIT_STRINGLEN(str);
   if (STB_TEXT_HAS_SELECTION(state)) {
      if (state->select_start > n) state->select_start = n;
      if (state->select_end   > n) state->select_end = n;
      // if clamping forced them to be equal, move the cursor to match
      if (state->select_start == state->select_end)
         state->cursor = state->select_start;
   }
   if (state->cursor > n) state->cursor = n;
}

// delete characters while updating undo
static void stb_textedit_delete(STB_TEXTEDIT_STRING *str, STB_TexteditState *state, int where, int len)
{
   stb_text_makeundo_delete(str, state, where, len);
   STB_TEXTEDIT_DELETECHARS(str, where, len);
   state->has_preferred_x = 0;
}

// delete the section
static void stb_textedit_delete_selection(STB_TEXTEDIT_STRING *str, STB_TexteditState *state)
{
   stb_textedit_clamp(str, state);
   if (STB_TEXT_HAS_SELECTION(state)) {
      if (state->select_start < state->select_end) {
         stb_textedit_delete(str, state, state->select_start, state->select_end - state->select_start);
         state->select_end = state->cursor = state->select_start;
      } else {
         stb_textedit_delete(str, state, state->select_end, state->select_start - state->select_end);
         state->select_start = state->cursor = state->select_end;
      }
      state->has_preferred_x = 0;
   }
}

// canoncialize the selection so start <= end
static void stb_textedit_sortselection(STB_TexteditState *state)
{
   if (state->select_end < state->select_start) {
      int temp = state->select_end;
      state->select_end = state->select_start;
      state->select_start = temp;
   }
}

// move cursor to first character of selection
static void stb_textedit_move_to_first(STB_TexteditState *state)
{
   if (STB_TEXT_HAS_SELECTION(state)) {
      stb_textedit_sortselection(state);
      state->cursor = state->select_start;
      state->select_end = state->select_start;
      state->has_preferred_x = 0;
   }
}

// move cursor to last character of selection
static void stb_textedit_move_to_last(STB_TEXTEDIT_STRING *str, STB_TexteditState *state)
{
   if (STB_TEXT_HAS_SELECTION(state)) {
      stb_textedit_sortselection(state);
      stb_textedit_clamp(str, state);
      state->cursor = state->select_end;
      state->select_start = state->select_end;
      state->has_preferred_x = 0;
   }
}

#ifdef STB_TEXTEDIT_IS_SPACE
static int is_word_boundary( STB_TEXTEDIT_STRING *str, int idx )
{
   return idx > 0 ? (STB_TEXTEDIT_IS_SPACE( STB_TEXTEDIT_GETCHAR(str,idx-1) ) && !STB_TEXTEDIT_IS_SPACE( STB_TEXTEDIT_GETCHAR(str, idx) ) ) : 1;
}

#ifndef STB_TEXTEDIT_MOVEWORDLEFT
static int stb_textedit_move_to_word_previous( STB_TEXTEDIT_STRING *str, int c )
{
   --c; // always move at least one character
   while( c >= 0 && !is_word_boundary( str, c ) )
      --c;

   if( c < 0 )
      c = 0;

   return c;
}
#define STB_TEXTEDIT_MOVEWORDLEFT stb_textedit_move_to_word_previous
#endif

#ifndef STB_TEXTEDIT_MOVEWORDRIGHT
static int stb_textedit_move_to_word_next( STB_TEXTEDIT_STRING *str, int c )
{
   const int len = STB_TEXTEDIT_STRINGLEN(str);
   ++c; // always move at least one character
   while( c < len && !is_word_boundary( str, c ) )
      ++c;

   if( c > len )
      c = len;

   return c;
}
#define STB_TEXTEDIT_MOVEWORDRIGHT stb_textedit_move_to_word_next
#endif

#endif

// update selection and cursor to match each other
static void stb_textedit_prep_selection_at_cursor(STB_TexteditState *state)
{
   if (!STB_TEXT_HAS_SELECTION(state))
      state->select_start = state->select_end = state->cursor;
   else
      state->cursor = state->select_end;
}

// API cut: delete selection
static int stb_textedit_cut(STB_TEXTEDIT_STRING *str, STB_TexteditState *state)
{
   if (STB_TEXT_HAS_SELECTION(state)) {
Lionel Landwerlin's avatar
Lionel Landwerlin committed
697
      stb_textedit_delete_selection(str,state); // implicitly clamps
698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748
      state->has_preferred_x = 0;
      return 1;
   }
   return 0;
}

// API paste: replace existing selection with passed-in text
static int stb_textedit_paste_internal(STB_TEXTEDIT_STRING *str, STB_TexteditState *state, STB_TEXTEDIT_CHARTYPE *text, int len)
{
   // if there's a selection, the paste should delete it
   stb_textedit_clamp(str, state);
   stb_textedit_delete_selection(str,state);
   // try to insert the characters
   if (STB_TEXTEDIT_INSERTCHARS(str, state->cursor, text, len)) {
      stb_text_makeundo_insert(state, state->cursor, len);
      state->cursor += len;
      state->has_preferred_x = 0;
      return 1;
   }
   // remove the undo since we didn't actually insert the characters
   if (state->undostate.undo_point)
      --state->undostate.undo_point;
   return 0;
}

#ifndef STB_TEXTEDIT_KEYTYPE
#define STB_TEXTEDIT_KEYTYPE int
#endif

// API key: process a keyboard input
static void stb_textedit_key(STB_TEXTEDIT_STRING *str, STB_TexteditState *state, STB_TEXTEDIT_KEYTYPE key)
{
retry:
   switch (key) {
      default: {
         int c = STB_TEXTEDIT_KEYTOTEXT(key);
         if (c > 0) {
            STB_TEXTEDIT_CHARTYPE ch = (STB_TEXTEDIT_CHARTYPE) c;

            // can't add newline in single-line mode
            if (c == '\n' && state->single_line)
               break;

            if (state->insert_mode && !STB_TEXT_HAS_SELECTION(state) && state->cursor < STB_TEXTEDIT_STRINGLEN(str)) {
               stb_text_makeundo_replace(str, state, state->cursor, 1, 1);
               STB_TEXTEDIT_DELETECHARS(str, state->cursor, 1);
               if (STB_TEXTEDIT_INSERTCHARS(str, state->cursor, &ch, 1)) {
                  ++state->cursor;
                  state->has_preferred_x = 0;
               }
            } else {
Lionel Landwerlin's avatar
Lionel Landwerlin committed
749
               stb_textedit_delete_selection(str,state); // implicitly clamps
750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136
               if (STB_TEXTEDIT_INSERTCHARS(str, state->cursor, &ch, 1)) {
                  stb_text_makeundo_insert(state, state->cursor, 1);
                  ++state->cursor;
                  state->has_preferred_x = 0;
               }
            }
         }
         break;
      }

#ifdef STB_TEXTEDIT_K_INSERT
      case STB_TEXTEDIT_K_INSERT:
         state->insert_mode = !state->insert_mode;
         break;
#endif

      case STB_TEXTEDIT_K_UNDO:
         stb_text_undo(str, state);
         state->has_preferred_x = 0;
         break;

      case STB_TEXTEDIT_K_REDO:
         stb_text_redo(str, state);
         state->has_preferred_x = 0;
         break;

      case STB_TEXTEDIT_K_LEFT:
         // if currently there's a selection, move cursor to start of selection
         if (STB_TEXT_HAS_SELECTION(state))
            stb_textedit_move_to_first(state);
         else
            if (state->cursor > 0)
               --state->cursor;
         state->has_preferred_x = 0;
         break;

      case STB_TEXTEDIT_K_RIGHT:
         // if currently there's a selection, move cursor to end of selection
         if (STB_TEXT_HAS_SELECTION(state))
            stb_textedit_move_to_last(str, state);
         else
            ++state->cursor;
         stb_textedit_clamp(str, state);
         state->has_preferred_x = 0;
         break;

      case STB_TEXTEDIT_K_LEFT | STB_TEXTEDIT_K_SHIFT:
         stb_textedit_clamp(str, state);
         stb_textedit_prep_selection_at_cursor(state);
         // move selection left
         if (state->select_end > 0)
            --state->select_end;
         state->cursor = state->select_end;
         state->has_preferred_x = 0;
         break;

#ifdef STB_TEXTEDIT_MOVEWORDLEFT
      case STB_TEXTEDIT_K_WORDLEFT:
         if (STB_TEXT_HAS_SELECTION(state))
            stb_textedit_move_to_first(state);
         else {
            state->cursor = STB_TEXTEDIT_MOVEWORDLEFT(str, state->cursor);
            stb_textedit_clamp( str, state );
         }
         break;

      case STB_TEXTEDIT_K_WORDLEFT | STB_TEXTEDIT_K_SHIFT:
         if( !STB_TEXT_HAS_SELECTION( state ) )
            stb_textedit_prep_selection_at_cursor(state);

         state->cursor = STB_TEXTEDIT_MOVEWORDLEFT(str, state->cursor);
         state->select_end = state->cursor;

         stb_textedit_clamp( str, state );
         break;
#endif

#ifdef STB_TEXTEDIT_MOVEWORDRIGHT
      case STB_TEXTEDIT_K_WORDRIGHT:
         if (STB_TEXT_HAS_SELECTION(state))
            stb_textedit_move_to_last(str, state);
         else {
            state->cursor = STB_TEXTEDIT_MOVEWORDRIGHT(str, state->cursor);
            stb_textedit_clamp( str, state );
         }
         break;

      case STB_TEXTEDIT_K_WORDRIGHT | STB_TEXTEDIT_K_SHIFT:
         if( !STB_TEXT_HAS_SELECTION( state ) )
            stb_textedit_prep_selection_at_cursor(state);

         state->cursor = STB_TEXTEDIT_MOVEWORDRIGHT(str, state->cursor);
         state->select_end = state->cursor;

         stb_textedit_clamp( str, state );
         break;
#endif

      case STB_TEXTEDIT_K_RIGHT | STB_TEXTEDIT_K_SHIFT:
         stb_textedit_prep_selection_at_cursor(state);
         // move selection right
         ++state->select_end;
         stb_textedit_clamp(str, state);
         state->cursor = state->select_end;
         state->has_preferred_x = 0;
         break;

      case STB_TEXTEDIT_K_DOWN:
      case STB_TEXTEDIT_K_DOWN | STB_TEXTEDIT_K_SHIFT: {
         StbFindState find;
         StbTexteditRow row;
         int i, sel = (key & STB_TEXTEDIT_K_SHIFT) != 0;

         if (state->single_line) {
            // on windows, up&down in single-line behave like left&right
            key = STB_TEXTEDIT_K_RIGHT | (key & STB_TEXTEDIT_K_SHIFT);
            goto retry;
         }

         if (sel)
            stb_textedit_prep_selection_at_cursor(state);
         else if (STB_TEXT_HAS_SELECTION(state))
            stb_textedit_move_to_last(str,state);

         // compute current position of cursor point
         stb_textedit_clamp(str, state);
         stb_textedit_find_charpos(&find, str, state->cursor, state->single_line);

         // now find character position down a row
         if (find.length) {
            float goal_x = state->has_preferred_x ? state->preferred_x : find.x;
            float x;
            int start = find.first_char + find.length;
            state->cursor = start;
            STB_TEXTEDIT_LAYOUTROW(&row, str, state->cursor);
            x = row.x0;
            for (i=0; i < row.num_chars; ++i) {
               float dx = STB_TEXTEDIT_GETWIDTH(str, start, i);
               #ifdef STB_TEXTEDIT_GETWIDTH_NEWLINE
               if (dx == STB_TEXTEDIT_GETWIDTH_NEWLINE)
                  break;
               #endif
               x += dx;
               if (x > goal_x)
                  break;
               ++state->cursor;
            }
            stb_textedit_clamp(str, state);

            state->has_preferred_x = 1;
            state->preferred_x = goal_x;

            if (sel)
               state->select_end = state->cursor;
         }
         break;
      }

      case STB_TEXTEDIT_K_UP:
      case STB_TEXTEDIT_K_UP | STB_TEXTEDIT_K_SHIFT: {
         StbFindState find;
         StbTexteditRow row;
         int i, sel = (key & STB_TEXTEDIT_K_SHIFT) != 0;

         if (state->single_line) {
            // on windows, up&down become left&right
            key = STB_TEXTEDIT_K_LEFT | (key & STB_TEXTEDIT_K_SHIFT);
            goto retry;
         }

         if (sel)
            stb_textedit_prep_selection_at_cursor(state);
         else if (STB_TEXT_HAS_SELECTION(state))
            stb_textedit_move_to_first(state);

         // compute current position of cursor point
         stb_textedit_clamp(str, state);
         stb_textedit_find_charpos(&find, str, state->cursor, state->single_line);

         // can only go up if there's a previous row
         if (find.prev_first != find.first_char) {
            // now find character position up a row
            float goal_x = state->has_preferred_x ? state->preferred_x : find.x;
            float x;
            state->cursor = find.prev_first;
            STB_TEXTEDIT_LAYOUTROW(&row, str, state->cursor);
            x = row.x0;
            for (i=0; i < row.num_chars; ++i) {
               float dx = STB_TEXTEDIT_GETWIDTH(str, find.prev_first, i);
               #ifdef STB_TEXTEDIT_GETWIDTH_NEWLINE
               if (dx == STB_TEXTEDIT_GETWIDTH_NEWLINE)
                  break;
               #endif
               x += dx;
               if (x > goal_x)
                  break;
               ++state->cursor;
            }
            stb_textedit_clamp(str, state);

            state->has_preferred_x = 1;
            state->preferred_x = goal_x;

            if (sel)
               state->select_end = state->cursor;
         }
         break;
      }

      case STB_TEXTEDIT_K_DELETE:
      case STB_TEXTEDIT_K_DELETE | STB_TEXTEDIT_K_SHIFT:
         if (STB_TEXT_HAS_SELECTION(state))
            stb_textedit_delete_selection(str, state);
         else {
            int n = STB_TEXTEDIT_STRINGLEN(str);
            if (state->cursor < n)
               stb_textedit_delete(str, state, state->cursor, 1);
         }
         state->has_preferred_x = 0;
         break;

      case STB_TEXTEDIT_K_BACKSPACE:
      case STB_TEXTEDIT_K_BACKSPACE | STB_TEXTEDIT_K_SHIFT:
         if (STB_TEXT_HAS_SELECTION(state))
            stb_textedit_delete_selection(str, state);
         else {
            stb_textedit_clamp(str, state);
            if (state->cursor > 0) {
               stb_textedit_delete(str, state, state->cursor-1, 1);
               --state->cursor;
            }
         }
         state->has_preferred_x = 0;
         break;

#ifdef STB_TEXTEDIT_K_TEXTSTART2
      case STB_TEXTEDIT_K_TEXTSTART2:
#endif
      case STB_TEXTEDIT_K_TEXTSTART:
         state->cursor = state->select_start = state->select_end = 0;
         state->has_preferred_x = 0;
         break;

#ifdef STB_TEXTEDIT_K_TEXTEND2
      case STB_TEXTEDIT_K_TEXTEND2:
#endif
      case STB_TEXTEDIT_K_TEXTEND:
         state->cursor = STB_TEXTEDIT_STRINGLEN(str);
         state->select_start = state->select_end = 0;
         state->has_preferred_x = 0;
         break;

#ifdef STB_TEXTEDIT_K_TEXTSTART2
      case STB_TEXTEDIT_K_TEXTSTART2 | STB_TEXTEDIT_K_SHIFT:
#endif
      case STB_TEXTEDIT_K_TEXTSTART | STB_TEXTEDIT_K_SHIFT:
         stb_textedit_prep_selection_at_cursor(state);
         state->cursor = state->select_end = 0;
         state->has_preferred_x = 0;
         break;

#ifdef STB_TEXTEDIT_K_TEXTEND2
      case STB_TEXTEDIT_K_TEXTEND2 | STB_TEXTEDIT_K_SHIFT:
#endif
      case STB_TEXTEDIT_K_TEXTEND | STB_TEXTEDIT_K_SHIFT:
         stb_textedit_prep_selection_at_cursor(state);
         state->cursor = state->select_end = STB_TEXTEDIT_STRINGLEN(str);
         state->has_preferred_x = 0;
         break;


#ifdef STB_TEXTEDIT_K_LINESTART2
      case STB_TEXTEDIT_K_LINESTART2:
#endif
      case STB_TEXTEDIT_K_LINESTART:
         stb_textedit_clamp(str, state);
         stb_textedit_move_to_first(state);
         if (state->single_line)
            state->cursor = 0;
         else while (state->cursor > 0 && STB_TEXTEDIT_GETCHAR(str, state->cursor-1) != STB_TEXTEDIT_NEWLINE)
            --state->cursor;
         state->has_preferred_x = 0;
         break;

#ifdef STB_TEXTEDIT_K_LINEEND2
      case STB_TEXTEDIT_K_LINEEND2:
#endif
      case STB_TEXTEDIT_K_LINEEND: {
         int n = STB_TEXTEDIT_STRINGLEN(str);
         stb_textedit_clamp(str, state);
         stb_textedit_move_to_first(state);
         if (state->single_line)
             state->cursor = n;
         else while (state->cursor < n && STB_TEXTEDIT_GETCHAR(str, state->cursor) != STB_TEXTEDIT_NEWLINE)
             ++state->cursor;
         state->has_preferred_x = 0;
         break;
      }

#ifdef STB_TEXTEDIT_K_LINESTART2
      case STB_TEXTEDIT_K_LINESTART2 | STB_TEXTEDIT_K_SHIFT:
#endif
      case STB_TEXTEDIT_K_LINESTART | STB_TEXTEDIT_K_SHIFT:
         stb_textedit_clamp(str, state);
         stb_textedit_prep_selection_at_cursor(state);
         if (state->single_line)
            state->cursor = 0;
         else while (state->cursor > 0 && STB_TEXTEDIT_GETCHAR(str, state->cursor-1) != STB_TEXTEDIT_NEWLINE)
            --state->cursor;
         state->select_end = state->cursor;
         state->has_preferred_x = 0;
         break;

#ifdef STB_TEXTEDIT_K_LINEEND2
      case STB_TEXTEDIT_K_LINEEND2 | STB_TEXTEDIT_K_SHIFT:
#endif
      case STB_TEXTEDIT_K_LINEEND | STB_TEXTEDIT_K_SHIFT: {
         int n = STB_TEXTEDIT_STRINGLEN(str);
         stb_textedit_clamp(str, state);
         stb_textedit_prep_selection_at_cursor(state);
         if (state->single_line)
             state->cursor = n;
         else while (state->cursor < n && STB_TEXTEDIT_GETCHAR(str, state->cursor) != STB_TEXTEDIT_NEWLINE)
            ++state->cursor;
         state->select_end = state->cursor;
         state->has_preferred_x = 0;
         break;
      }

// @TODO:
//    STB_TEXTEDIT_K_PGUP      - move cursor up a page
//    STB_TEXTEDIT_K_PGDOWN    - move cursor down a page
   }
}

/////////////////////////////////////////////////////////////////////////////
//
//      Undo processing
//
// @OPTIMIZE: the undo/redo buffer should be circular

static void stb_textedit_flush_redo(StbUndoState *state)
{
   state->redo_point = STB_TEXTEDIT_UNDOSTATECOUNT;
   state->redo_char_point = STB_TEXTEDIT_UNDOCHARCOUNT;
}

// discard the oldest entry in the undo list
static void stb_textedit_discard_undo(StbUndoState *state)
{
   if (state->undo_point > 0) {
      // if the 0th undo state has characters, clean those up
      if (state->undo_rec[0].char_storage >= 0) {
         int n = state->undo_rec[0].insert_length, i;
         // delete n characters from all other records
         state->undo_char_point -= n;
         STB_TEXTEDIT_memmove(state->undo_char, state->undo_char + n, (size_t) (state->undo_char_point*sizeof(STB_TEXTEDIT_CHARTYPE)));
         for (i=0; i < state->undo_point; ++i)
            if (state->undo_rec[i].char_storage >= 0)
               state->undo_rec[i].char_storage -= n; // @OPTIMIZE: get rid of char_storage and infer it
      }
      --state->undo_point;
      STB_TEXTEDIT_memmove(state->undo_rec, state->undo_rec+1, (size_t) (state->undo_point*sizeof(state->undo_rec[0])));
   }
}

// discard the oldest entry in the redo list--it's bad if this
// ever happens, but because undo & redo have to store the actual
// characters in different cases, the redo character buffer can
// fill up even though the undo buffer didn't
static void stb_textedit_discard_redo(StbUndoState *state)
{
   int k = STB_TEXTEDIT_UNDOSTATECOUNT-1;

   if (state->redo_point <= k) {
      // if the k'th undo state has characters, clean those up
      if (state->undo_rec[k].char_storage >= 0) {
         int n = state->undo_rec[k].insert_length, i;
         // move the remaining redo character data to the end of the buffer
         state->redo_char_point += n;
         STB_TEXTEDIT_memmove(state->undo_char + state->redo_char_point, state->undo_char + state->redo_char_point-n, (size_t) ((STB_TEXTEDIT_UNDOCHARCOUNT - state->redo_char_point)*sizeof(STB_TEXTEDIT_CHARTYPE)));
         // adjust the position of all the other records to account for above memmove
         for (i=state->redo_point; i < k; ++i)
            if (state->undo_rec[i].char_storage >= 0)
               state->undo_rec[i].char_storage += n;
      }
      // now move all the redo records towards the end of the buffer; the first one is at 'redo_point'
Lionel Landwerlin's avatar
Lionel Landwerlin committed
1137 1138 1139 1140 1141 1142 1143 1144
      // {DEAR IMGUI]
      size_t move_size = (size_t)((STB_TEXTEDIT_UNDOSTATECOUNT - state->redo_point - 1) * sizeof(state->undo_rec[0]));
      const char* buf_begin = (char*)state->undo_rec; (void)buf_begin;
      const char* buf_end   = (char*)state->undo_rec + sizeof(state->undo_rec); (void)buf_end;
      IM_ASSERT(((char*)(state->undo_rec + state->redo_point)) >= buf_begin);
      IM_ASSERT(((char*)(state->undo_rec + state->redo_point + 1) + move_size) <= buf_end);
      STB_TEXTEDIT_memmove(state->undo_rec + state->redo_point+1, state->undo_rec + state->redo_point, move_size);

1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417
      // now move redo_point to point to the new one
      ++state->redo_point;
   }
}

static StbUndoRecord *stb_text_create_undo_record(StbUndoState *state, int numchars)
{
   // any time we create a new undo record, we discard redo
   stb_textedit_flush_redo(state);

   // if we have no free records, we have to make room, by sliding the
   // existing records down
   if (state->undo_point == STB_TEXTEDIT_UNDOSTATECOUNT)
      stb_textedit_discard_undo(state);

   // if the characters to store won't possibly fit in the buffer, we can't undo
   if (numchars > STB_TEXTEDIT_UNDOCHARCOUNT) {
      state->undo_point = 0;
      state->undo_char_point = 0;
      return NULL;
   }

   // if we don't have enough free characters in the buffer, we have to make room
   while (state->undo_char_point + numchars > STB_TEXTEDIT_UNDOCHARCOUNT)
      stb_textedit_discard_undo(state);

   return &state->undo_rec[state->undo_point++];
}

static STB_TEXTEDIT_CHARTYPE *stb_text_createundo(StbUndoState *state, int pos, int insert_len, int delete_len)
{
   StbUndoRecord *r = stb_text_create_undo_record(state, insert_len);
   if (r == NULL)
      return NULL;

   r->where = pos;
   r->insert_length = (STB_TEXTEDIT_POSITIONTYPE) insert_len;
   r->delete_length = (STB_TEXTEDIT_POSITIONTYPE) delete_len;

   if (insert_len == 0) {
      r->char_storage = -1;
      return NULL;
   } else {
      r->char_storage = state->undo_char_point;
      state->undo_char_point += insert_len;
      return &state->undo_char[r->char_storage];
   }
}

static void stb_text_undo(STB_TEXTEDIT_STRING *str, STB_TexteditState *state)
{
   StbUndoState *s = &state->undostate;
   StbUndoRecord u, *r;
   if (s->undo_point == 0)
      return;

   // we need to do two things: apply the undo record, and create a redo record
   u = s->undo_rec[s->undo_point-1];
   r = &s->undo_rec[s->redo_point-1];
   r->char_storage = -1;

   r->insert_length = u.delete_length;
   r->delete_length = u.insert_length;
   r->where = u.where;

   if (u.delete_length) {
      // if the undo record says to delete characters, then the redo record will
      // need to re-insert the characters that get deleted, so we need to store
      // them.

      // there are three cases:
      //    there's enough room to store the characters
      //    characters stored for *redoing* don't leave room for redo
      //    characters stored for *undoing* don't leave room for redo
      // if the last is true, we have to bail

      if (s->undo_char_point + u.delete_length >= STB_TEXTEDIT_UNDOCHARCOUNT) {
         // the undo records take up too much character space; there's no space to store the redo characters
         r->insert_length = 0;
      } else {
         int i;

         // there's definitely room to store the characters eventually
         while (s->undo_char_point + u.delete_length > s->redo_char_point) {
            // should never happen:
            if (s->redo_point == STB_TEXTEDIT_UNDOSTATECOUNT)
               return;
            // there's currently not enough room, so discard a redo record
            stb_textedit_discard_redo(s);
         }
         r = &s->undo_rec[s->redo_point-1];

         r->char_storage = s->redo_char_point - u.delete_length;
         s->redo_char_point = s->redo_char_point - u.delete_length;

         // now save the characters
         for (i=0; i < u.delete_length; ++i)
            s->undo_char[r->char_storage + i] = STB_TEXTEDIT_GETCHAR(str, u.where + i);
      }

      // now we can carry out the deletion
      STB_TEXTEDIT_DELETECHARS(str, u.where, u.delete_length);
   }

   // check type of recorded action:
   if (u.insert_length) {
      // easy case: was a deletion, so we need to insert n characters
      STB_TEXTEDIT_INSERTCHARS(str, u.where, &s->undo_char[u.char_storage], u.insert_length);
      s->undo_char_point -= u.insert_length;
   }

   state->cursor = u.where + u.insert_length;

   s->undo_point--;
   s->redo_point--;
}

static void stb_text_redo(STB_TEXTEDIT_STRING *str, STB_TexteditState *state)
{
   StbUndoState *s = &state->undostate;
   StbUndoRecord *u, r;
   if (s->redo_point == STB_TEXTEDIT_UNDOSTATECOUNT)
      return;

   // we need to do two things: apply the redo record, and create an undo record
   u = &s->undo_rec[s->undo_point];
   r = s->undo_rec[s->redo_point];

   // we KNOW there must be room for the undo record, because the redo record
   // was derived from an undo record

   u->delete_length = r.insert_length;
   u->insert_length = r.delete_length;
   u->where = r.where;
   u->char_storage = -1;

   if (r.delete_length) {
      // the redo record requires us to delete characters, so the undo record
      // needs to store the characters

      if (s->undo_char_point + u->insert_length > s->redo_char_point) {
         u->insert_length = 0;
         u->delete_length = 0;
      } else {
         int i;
         u->char_storage = s->undo_char_point;
         s->undo_char_point = s->undo_char_point + u->insert_length;

         // now save the characters
         for (i=0; i < u->insert_length; ++i)
            s->undo_char[u->char_storage + i] = STB_TEXTEDIT_GETCHAR(str, u->where + i);
      }

      STB_TEXTEDIT_DELETECHARS(str, r.where, r.delete_length);
   }

   if (r.insert_length) {
      // easy case: need to insert n characters
      STB_TEXTEDIT_INSERTCHARS(str, r.where, &s->undo_char[r.char_storage], r.insert_length);
      s->redo_char_point += r.insert_length;
   }

   state->cursor = r.where + r.insert_length;

   s->undo_point++;
   s->redo_point++;
}

static void stb_text_makeundo_insert(STB_TexteditState *state, int where, int length)
{
   stb_text_createundo(&state->undostate, where, 0, length);
}

static void stb_text_makeundo_delete(STB_TEXTEDIT_STRING *str, STB_TexteditState *state, int where, int length)
{
   int i;
   STB_TEXTEDIT_CHARTYPE *p = stb_text_createundo(&state->undostate, where, length, 0);
   if (p) {
      for (i=0; i < length; ++i)
         p[i] = STB_TEXTEDIT_GETCHAR(str, where+i);
   }
}

static void stb_text_makeundo_replace(STB_TEXTEDIT_STRING *str, STB_TexteditState *state, int where, int old_length, int new_length)
{
   int i;
   STB_TEXTEDIT_CHARTYPE *p = stb_text_createundo(&state->undostate, where, old_length, new_length);
   if (p) {
      for (i=0; i < old_length; ++i)
         p[i] = STB_TEXTEDIT_GETCHAR(str, where+i);
   }
}

// reset the state to default
static void stb_textedit_clear_state(STB_TexteditState *state, int is_single_line)
{
   state->undostate.undo_point = 0;
   state->undostate.undo_char_point = 0;
   state->undostate.redo_point = STB_TEXTEDIT_UNDOSTATECOUNT;
   state->undostate.redo_char_point = STB_TEXTEDIT_UNDOCHARCOUNT;
   state->select_end = state->select_start = 0;
   state->cursor = 0;
   state->has_preferred_x = 0;
   state->preferred_x = 0;
   state->cursor_at_end_of_line = 0;
   state->initialized = 1;
   state->single_line = (unsigned char) is_single_line;
   state->insert_mode = 0;
}

// API initialize
static void stb_textedit_initialize_state(STB_TexteditState *state, int is_single_line)
{
   stb_textedit_clear_state(state, is_single_line);
}

#if defined(__GNUC__) || defined(__clang__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-qual"
#endif

static int stb_textedit_paste(STB_TEXTEDIT_STRING *str, STB_TexteditState *state, STB_TEXTEDIT_CHARTYPE const *ctext, int len)
{
   return stb_textedit_paste_internal(str, state, (STB_TEXTEDIT_CHARTYPE *) ctext, len);
}

#if defined(__GNUC__) || defined(__clang__)
#pragma GCC diagnostic pop
#endif

#endif//STB_TEXTEDIT_IMPLEMENTATION

/*
------------------------------------------------------------------------------
This software is available under 2 licenses -- choose whichever you prefer.
------------------------------------------------------------------------------
ALTERNATIVE A - MIT License
Copyright (c) 2017 Sean Barrett
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, 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
AUTHORS OR 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.
------------------------------------------------------------------------------
ALTERNATIVE B - Public Domain (www.unlicense.org)
This is free and unencumbered software released into the public domain.
Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
software, either in source code form or as a compiled binary, for any purpose,
commercial or non-commercial, and by any means.
In jurisdictions that recognize copyright laws, the author or authors of this
software dedicate any and all copyright interest in the software to the public
domain. We make this dedication for the benefit of the public at large and to
the detriment of our heirs and successors. We intend this dedication to be an
overt act of relinquishment in perpetuity of all present and future rights to
this software under copyright law.
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
AUTHORS 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.
------------------------------------------------------------------------------
*/