ascii.c - ascii-table

(482 lines)
   1 /**
   2   ASCII Table Utility by Bruce Hill
   3 
   4   A simple utility that uses ncurses to display the ASCII table and lets you
   5   manually output ASCII characters one byte at a time. Use arrow keys or
   6   h/j/k/l to move, 'enter' to add a character to the output, '/' to search,
   7   and 'q' or escape to quit and print the output.
   8 
   9   Licensed under the MIT License (see LICENSE file for details)
  10 */
  11 
  12 #include <curses.h>
  13 #include <ncurses.h>
  14 #include <poll.h>
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <unistd.h>
  19 
  20 typedef enum {BROWSE_MODE, INSERT_MODE, SEARCH_MODE} Mode;
  21 
  22 #define DELETE_KEY 127
  23 #define ESCAPE_KEY 27
  24 
  25 // The descriptive names of the ASCII characters
  26 const char *NAMES[128][2] = {
  27     {"NUL", "null"}, // 0
  28     {"SOH", "start of heading"}, // 1
  29     {"STX", "start of text"}, // 2
  30     {"ETX", "end of text"}, // 3
  31     {"EOT", "end of transmission"}, // 4
  32     {"ENQ", "enquiry"}, // 5
  33     {"ACK", "acknowledge"}, // 6
  34     {"BEL", "bell"}, // 7
  35     {"BS", "backspace"}, // 8
  36     {"TAB", "horizontal tab"}, // 9
  37     {"LF", "NL line feed, new line"}, // 10
  38     {"VT", "vertical tab"}, // 11
  39     {"FF", "NP form feed, new page"}, // 12
  40     {"CR", "carriage return"}, // 13
  41     {"SO", "shift out"}, // 14
  42     {"SI", "shift in"}, // 15
  43     {"DLE", "data link escape"}, // 16
  44     {"DC1", "device control 1"}, // 17
  45     {"DC2", "device control 2"}, // 18
  46     {"DC3", "device control 3"}, // 19
  47     {"DC4", "device control 4"}, // 20
  48     {"NAK", "negative acknowledge"}, // 21
  49     {"SYN", "synchonous idle"}, // 22
  50     {"ETB", "end of transmission block"}, // 23
  51     {"CAN", "cancel"}, // 24
  52     {"EM", "end of medium"}, // 25
  53     {"SUB", "substitute"}, // 26
  54     {"ESC", "escape"}, // 27
  55     {"FS", "file separator"}, // 28
  56     {"GS", "group separator"}, // 29
  57     {"RS", "record separator"}, // 30
  58     {"US", "unit separator"}, // 31
  59     {" ", "space"}, // 32
  60     [127] = {"DEL", "delete"}
  61 };
  62 
  63 static int new_colorpair(int fg, int bg)
  64 {
  65     static int next_colornum = 1;
  66     init_pair(next_colornum, fg, bg);
  67     return COLOR_PAIR(next_colornum++);
  68 }
  69 
  70 int DECIMAL_COLORS, HEX_COLORS, CHAR_COLORS, DESCRIPTION_SPECIAL_COLORS,
  71     DESCRIPTION_LETTER_COLORS, DESCRIPTION_NUMBER_COLORS, DESCRIPTION_SYMBOL_COLORS,
  72     OUTPUT_CHAR_COLORS, OUTPUT_ESCAPE_COLORS, OUTPUT_LABEL_COLORS, BROWSE_MODE_COLORS,
  73     INSERT_MODE_COLORS, SEARCH_MODE_COLORS;
  74 
  75 const int COL_WIDTH = 42;
  76 int W = 0;
  77 int H = 0;
  78 
  79 static inline int min(int a, int b) {
  80     return a < b ? a : b;
  81 }
  82 
  83 static inline int max(int a, int b) {
  84     return a >= b ? a : b;
  85 }
  86 
  87 // Shift the cursor
  88 static inline void shift(int dy, int dx) {
  89     int x, y;
  90     getyx(stdscr, y, x);
  91     move(y+dy, x+dx);
  92 }
  93 
  94 // Same as printw, except it doesn't do text wrapping, and it sets attributes
  95 #define printwattrs(_attrs, ...) \
  96     { char _buf[W+1];\
  97     chtype _bufch[W+1];\
  98     sprintf(_buf, __VA_ARGS__);\
  99     for (int i = 0; i == 0 || _buf[i-1]; i++) _bufch[i] = _buf[i] | _attrs;\
 100     addchstr(_bufch);\
 101     shift(0, strlen(_buf));}
 102 
 103 
 104 // Draw the information for one character
 105 static inline void draw_entry(int i, int scrollx, int attrs)
 106 {
 107     int x = (i / (H-2)) * COL_WIDTH - scrollx;
 108     if (x > W || x < 0) return;
 109     int y = (i % (H-2)) + 1;
 110     move(y, x);
 111     printwattrs(DECIMAL_COLORS | attrs, "%3d ", i);
 112     printwattrs(HEX_COLORS | attrs, " 0x%02X ", i);
 113     if (NAMES[i][0]) {
 114         printwattrs(CHAR_COLORS | attrs, " %-3s ", NAMES[i][0]);
 115     } else {
 116         printwattrs(CHAR_COLORS | attrs, " %c   ", i);
 117     }
 118     if (NAMES[i][1]) {
 119         printwattrs(DESCRIPTION_SPECIAL_COLORS | attrs, " %-25s", NAMES[i][1]);
 120     } else if (('a' <= i && i <= 'z') || ('A' <= i && i <= 'Z')) {
 121         printwattrs(DESCRIPTION_LETTER_COLORS | attrs, " the letter %c             ", i);
 122     } else if ('0' <= i && i <= '9') {
 123         printwattrs(DESCRIPTION_NUMBER_COLORS | attrs, " the number %c             ", i);
 124     } else {
 125         printwattrs(DESCRIPTION_SYMBOL_COLORS | A_BOLD | attrs, " the %c symbol             ", i);
 126     }
 127 }
 128 
 129 // Redraw the parts of the ASCII table necessary for the selected item
 130 static void redraw(int selected)
 131 {
 132     static int last_selected = -1, last_scrollx = -1, last_W = -1, last_H = -1;
 133     int selectedx = (selected / (H-2)) * COL_WIDTH;
 134     int scrollx = (selectedx + COL_WIDTH < W) ? 0 : (((selectedx + COL_WIDTH) - W)/COL_WIDTH+1)*COL_WIDTH;
 135     if (last_selected == -1 || last_scrollx != scrollx || last_W != W || last_H != H) {
 136         // Redraw all the entries
 137         erase();
 138         for (int i = 0; i < 128; i++) {
 139             draw_entry(i, scrollx, i == selected ? A_REVERSE : 0);
 140         }
 141         last_scrollx = scrollx;
 142         last_H = H;
 143         last_W = W;
 144     } else if (selected != last_selected) {
 145         // Otherwise, we can lazily just redraw 2 entries
 146         draw_entry(selected, scrollx, A_REVERSE);
 147         draw_entry(last_selected, scrollx, 0);
 148     }
 149     last_selected = selected;
 150 }
 151 
 152 // Find the ascii character starting at `start`, going in `direction`, matching
 153 // `searchbuff`, and return `fallback` if nothing matches.
 154 static int find_ascii_match(int start, int fallback, int direction, char *searchbuf)
 155 {
 156     if (searchbuf[0] == '\0') return fallback;
 157     char tmp[COL_WIDTH+6];
 158     for (int i = 0; i <= 127; i++) {
 159         int c = (start + i*direction) % 128; // relative to starting point
 160         if (searchbuf[0] == c && searchbuf[1] == '\0')
 161             return c;
 162         // Only do full match for search strings longer than 1
 163         if (searchbuf[1]) {
 164             if (NAMES[c][1]) {
 165                 sprintf(tmp, "%d 0x%02X 0x%02x %s %s", c, c, c, NAMES[c][0] ? NAMES[c][0] : "", NAMES[c][1]);
 166             } else if (('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z')) {
 167                 sprintf(tmp, "%d 0x%02X 0x%02x %s the letter %c", c, c, c, NAMES[c][0] ? NAMES[c][0] : "", c);
 168             } else if ('0' <= c && c <= '9') {
 169                 sprintf(tmp, "%d 0x%02X 0x%02x %s the number %c", c, c, c, NAMES[c][0] ? NAMES[c][0] : "", c);
 170             } else {
 171                 sprintf(tmp, "%d 0x%02X 0x%02x %s the %c character", c, c, c, NAMES[c][0] ? NAMES[c][0] : "", c);
 172             }
 173             if (strstr(tmp, searchbuf) != NULL)
 174                 return c;
 175         }
 176     }
 177     return fallback;
 178 }
 179 
 180 // To prevent wasted work, wait until 200ms has elapsed with no additional
 181 // resizes before doing anything, then set the correct W/H values.
 182 static void handle_resize()
 183 {
 184     timeout(0);
 185     do {
 186         // Wait 200ms
 187         usleep(2e5);
 188         // Peek if there's another resize event
 189         int k = getch();
 190         if (k == KEY_RESIZE) continue;
 191         if (k > 0) ungetch(k);
 192     } while (0);
 193     // Back to blocking input
 194     timeout(-1);
 195     W = getmaxx(stdscr);
 196     H = getmaxy(stdscr);
 197 }
 198 
 199 int main(int argc, char *argv[])
 200 {	
 201     if (argc > 1 && (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-h") == 0)) {
 202         printf("ASCII table viewer/editor, Usage: ascii [N...]\n");
 203         return 0;
 204     }
 205 
 206     // Instead of initscr(), set up the terminal this way to play nicely with
 207     // the unix pipeline:
 208     {
 209         char* term_type = getenv("TERM");
 210         if (term_type == NULL || *term_type == '\0') {
 211           term_type = "unknown";
 212         }
 213         FILE* term_in = fopen("/dev/tty", "r");
 214         if (term_in == NULL) {
 215             perror("fopen(/dev/tty)");
 216             exit(EXIT_FAILURE);
 217         }
 218         SCREEN *screen = newterm(term_type, stderr, term_in);
 219         set_term(screen);
 220     }
 221 
 222     W = getmaxx(stdscr);
 223     H = getmaxy(stdscr);
 224     noecho();
 225     set_escdelay(5);
 226     keypad(stdscr, 1);
 227     curs_set(2);
 228     start_color();
 229 
 230 	DECIMAL_COLORS = new_colorpair(COLOR_YELLOW, COLOR_BLACK) | A_BOLD;
 231 	HEX_COLORS = new_colorpair(COLOR_GREEN, COLOR_BLACK) | A_BOLD;
 232 	CHAR_COLORS = new_colorpair(COLOR_MAGENTA, COLOR_BLACK) | A_BOLD;
 233 	DESCRIPTION_SPECIAL_COLORS = new_colorpair(COLOR_RED, COLOR_BLACK) | A_BOLD;
 234 	DESCRIPTION_LETTER_COLORS = new_colorpair(COLOR_BLUE, COLOR_BLACK) | A_BOLD;
 235 	DESCRIPTION_NUMBER_COLORS = new_colorpair(COLOR_CYAN, COLOR_BLACK) | A_BOLD;
 236 	DESCRIPTION_SYMBOL_COLORS = new_colorpair(COLOR_WHITE, COLOR_BLACK) | A_BOLD;
 237 	OUTPUT_CHAR_COLORS = new_colorpair(COLOR_BLACK, COLOR_WHITE) | A_BOLD;
 238 	OUTPUT_ESCAPE_COLORS = new_colorpair(COLOR_RED, COLOR_WHITE) | A_BOLD;
 239     OUTPUT_LABEL_COLORS = new_colorpair(COLOR_BLACK, COLOR_YELLOW);
 240     BROWSE_MODE_COLORS = new_colorpair(COLOR_BLACK, COLOR_YELLOW);
 241     INSERT_MODE_COLORS = new_colorpair(COLOR_WHITE, COLOR_RED) | A_BOLD;
 242     SEARCH_MODE_COLORS = new_colorpair(COLOR_BLACK, COLOR_BLUE);
 243 
 244     size_t buf_chunk = 1024;
 245     size_t buf_size = buf_chunk, buf_i = 0;
 246     char *outbuf = calloc(buf_size, sizeof(char));
 247 
 248     { // Read stdin if anything was piped in
 249         struct pollfd desc;
 250         desc.fd = STDIN_FILENO;
 251         desc.events = POLLIN;
 252         int ret = poll(&desc, 1, 50);
 253         if (ret > 0) {
 254             size_t consumed;
 255             while ((consumed = fread(&outbuf[buf_i], 1, buf_chunk, stdin))) {
 256                 buf_i += consumed;
 257                 if (consumed == buf_chunk) {
 258                     buf_chunk *= 2;
 259                     buf_size += buf_chunk;
 260                     outbuf = realloc(outbuf, buf_size);
 261                 }
 262             }
 263         }
 264     }
 265 
 266     char searchbuf[1024] = {'\0'};
 267     size_t searchlen = 0;
 268 
 269     // If any command line args, treat them as bytes to append to
 270     // the output buffer
 271     for (int i = 1; i < argc; i++) {
 272         long c = strtol(argv[i], NULL, 0);
 273         outbuf[buf_i++] = (char)c;
 274         if (buf_i >= buf_size) {
 275             buf_size *= 2;
 276             outbuf = realloc(outbuf, buf_size);
 277         }
 278     }
 279 
 280     Mode mode = BROWSE_MODE;
 281     int prev_selected = 0, selected = 0;
 282     while (1) {
 283         redraw(selected);
 284         // Title bar
 285         move(0,0);
 286         char *title;
 287         int title_colors;
 288         switch (mode) {
 289             case INSERT_MODE:
 290                 title = "ASCII TABLE (typing, 'esc' to browse)";
 291                 title_colors = INSERT_MODE_COLORS;
 292                 break;
 293             case SEARCH_MODE:
 294                 title = "ASCII TABLE (searching, 'esc' to browse)";
 295                 title_colors = SEARCH_MODE_COLORS;
 296                 break;
 297             case BROWSE_MODE:
 298                 title = "ASCII TABLE (browsing, 'esc' to exit)";
 299                 title_colors = BROWSE_MODE_COLORS;
 300                 break;
 301         }
 302         int spacer = W/2-strlen(title)/2;
 303         printwattrs(title_colors, "%*s%s%*s", spacer, "", title, spacer+1, "");
 304 
 305         if (mode == SEARCH_MODE) {
 306             attron(SEARCH_MODE_COLORS);
 307             mvprintw(H-1, 0, " Search:");
 308             attroff(SEARCH_MODE_COLORS);
 309             addch(' ');
 310             printwattrs(OUTPUT_CHAR_COLORS, "%s", searchbuf);
 311         } else {
 312             // Bar at the bottom of the screen showing the output text:
 313             // left-truncate output so the end of it fits on screen:
 314             char *visible = &outbuf[buf_i];
 315             for (int space = W-strlen(" Output: ")-1-5; space > 0 && visible > outbuf; visible--) {
 316                 int chlen = (' ' <= *visible && *visible <= '~') ? 1 : 4; // printable range
 317                 if (chlen > space) break;
 318                 else space -= chlen;
 319             }
 320             attron(mode == INSERT_MODE ? INSERT_MODE_COLORS : OUTPUT_LABEL_COLORS);
 321             mvprintw(H-1, 0, " Output:");
 322             attroff(mode == INSERT_MODE ? INSERT_MODE_COLORS : OUTPUT_LABEL_COLORS);
 323             addch(' ');
 324             for (char *c = visible; c < &outbuf[buf_i]; c++) {
 325                 if (' ' <= *c && *c <= '~') { // printable range
 326                     printwattrs(OUTPUT_CHAR_COLORS, "%c", *c);
 327                 } else {
 328                     printwattrs(OUTPUT_ESCAPE_COLORS, "\\x%02X", *c);
 329                 }
 330             }
 331         }
 332         int y, x;
 333         getyx(stdscr, y, x);
 334         // Clear to end of line
 335         for (int x2 = x; x2 < W; x2++) mvaddch(y, x2, ' ');
 336         move(y, x);
 337 
 338         refresh();
 339 
 340         int key;
 341       next_input:
 342         key = getch();
 343         switch (mode) {
 344             case INSERT_MODE:
 345                 switch (key) {
 346                     case ESCAPE_KEY:
 347                         mode = BROWSE_MODE;
 348                         break;
 349                     case DELETE_KEY:
 350                         if (buf_i > 0) buf_i--;
 351                         break;
 352                     case KEY_RESIZE:
 353                         handle_resize();
 354                         break;
 355                     default:
 356                         if (0 <= key && key < 127) {
 357                             outbuf[buf_i++] = (char)key;
 358                             if (buf_i >= buf_size) {
 359                                 buf_size *= 2;
 360                                 outbuf = realloc(outbuf, buf_size);
 361                             }
 362                             break;
 363                         } else goto next_input; // skip redraw
 364                 }
 365                 break;
 366 
 367 
 368             case SEARCH_MODE:
 369                 switch (key) {
 370                     case ESCAPE_KEY: // Escape
 371                         selected = prev_selected;
 372                         searchbuf[0] = '\0';
 373                         searchlen = 0;
 374                         mode = BROWSE_MODE;
 375                         break;
 376 
 377                     case KEY_ENTER: case '\n':
 378                         mode = BROWSE_MODE;
 379                         break;
 380 
 381                     case DELETE_KEY:
 382                         if (searchlen > 0) {
 383                             searchbuf[searchlen--] = '\0';
 384                             selected = find_ascii_match(prev_selected, prev_selected, 1, searchbuf);
 385                         }
 386                         break;
 387 
 388                     case KEY_RESIZE:
 389                         handle_resize();
 390                         break;
 391 
 392                     default:
 393                         if (0 <= key && key < 127) {
 394                             if (searchlen < sizeof(searchbuf)-1) {
 395                                 searchbuf[searchlen++] = (char)key;
 396                                 searchbuf[searchlen] = '\0';
 397                             }
 398                             selected = find_ascii_match(prev_selected, prev_selected, 1, searchbuf);
 399                             break;
 400                         } else goto next_input; // skip redraw
 401                 }
 402                 break;
 403 
 404 
 405             case BROWSE_MODE:
 406                 switch (key) {
 407                     case 'j': case KEY_DOWN:
 408                         selected++;
 409                         break;
 410 
 411                     case 'J':
 412                         selected += 10;
 413                         break;
 414 
 415                     case 'k': case KEY_UP:
 416                         selected--;
 417                         break;
 418 
 419                     case 'K':
 420                         selected -= 10;
 421                         break;
 422 
 423                     case 'l': case 'L': case KEY_RIGHT: case KEY_SRIGHT:
 424                         selected += H-2;
 425                         break;
 426 
 427                     case 'h': case 'H': case KEY_LEFT: case KEY_SLEFT:
 428                         selected -= H-2;
 429                         break;
 430 
 431                     case 'i': case 'a':
 432                         mode = INSERT_MODE;
 433                         break;
 434 
 435                     case '/':
 436                         mode = SEARCH_MODE;
 437                         prev_selected = selected;
 438                         searchbuf[0] = '\0';
 439                         searchlen = 0;
 440                         break;
 441 
 442                     case 'n':
 443                         selected = find_ascii_match(selected+1, selected, 1, searchbuf);
 444                         break;
 445 
 446                     case 'N':
 447                         selected = find_ascii_match(selected-1, selected, -1, searchbuf);
 448                         break;
 449 
 450                     case KEY_RESIZE:
 451                         handle_resize();
 452                         break;
 453 
 454                     case KEY_ENTER: case '\n':
 455                         outbuf[buf_i++] = (char)selected;
 456                         if (buf_i >= buf_size) {
 457                             buf_size *= 2;
 458                             outbuf = realloc(outbuf, buf_size);
 459                         }
 460                         break;
 461 
 462                     case KEY_BACKSPACE: case KEY_DC: case DELETE_KEY:
 463                         if (buf_i > 0) buf_i--;
 464                         break;
 465 
 466                     case 'q': case 'Q': case KEY_CANCEL: case KEY_CLOSE: case KEY_EXIT: case ESCAPE_KEY:
 467                         endwin();
 468                         write(STDOUT_FILENO, outbuf, buf_i);
 469                         return 0;
 470 
 471                     default:
 472                         goto next_input; // skip redraw
 473                 }
 474                 break;
 475         }
 476         if (selected < 0) selected = 0;
 477         if (selected > 127) selected = 127;
 478     }
 479 
 480 	endwin();
 481 	return 0;
 482 }