4 * Copyright 2004 Develer S.r.l. (http://www.develer.com/)
5 * Copyright 2004 Giovanni Bajo
9 * \brief Line editing support with history
11 * Rationale for basic implementation choices:
13 * \li The history is implemented storing consecutive ASCIIZ strings within an array of memory. When
14 * the history is full, the first (oldest) line is cancelled and the whole buffer is memmoved to
15 * overwrite it and make room. while this is is obviously not the fastest algorithm (which would
16 * require the use of a circular buffer) it is surely good enough for this module, which does not
17 * aim at fast performances (line editing does not require to be blazingly fast).
19 * \li The first character in the history is always \c \\0, and it is used as a guard. By 'wasting' it
20 * in this way, the code actually gets much simpler in that we remove many checks when moving
21 * backward (\c i>0 and similar).
23 * \li While editing, the current index points to the position of the buffer which contains the
24 * last character typed in (exactly like a stack pointer). This also allows to simplify calculations
25 * and to make easier using the last byte of history.
27 * \li While editing, the current line is always kept null-terminated. This is important because
28 * if the user press ENTER, we must have room to add a \c \\0 to terminate the line. If the line
29 * is as long as the whole history buffer, there would not be space for it. By always keeping the
30 * \c \\0 at the end, we properly ensure this without making index checks harder.
32 * \li When removing a line from the history (see \c pop_history()), instead of updating all the
33 * indices we have around, we move backward the pointer to the history we use. This way, we don't
34 * have to update anything. This means that we keep two pointers to the history: \c real_history
35 * always points to the physical start, while \c history is the adjusted pointer (that is
36 * dereference to read/write to it).
38 * \todo Use up/down to move through history The history line will be copied to the current line,
39 * making sure there is room for it.
43 * \author Giovanni Bajo <rasky@develer.com>
48 *#* Revision 1.2 2006/07/19 12:56:28 bernie
49 *#* Convert to new Doxygen style.
51 *#* Revision 1.1 2006/06/01 12:27:39 marco
52 *#* Added utilities for protocols
58 #include <cfg/compiler.h>
59 #include <cfg/debug.h>
64 /// Enable compilation of the unit test code
65 #define DEBUG_UNIT_TEST 0
67 /// Enable dump of the history after each line
68 #define DEBUG_DUMP_HISTORY 0
71 /** Special keys (escape sequences converted to a single code) */
73 SPECIAL_KEYS = 0x1000,
78 * UpArrow: 0x1B 0x5B 0X41
79 * DownArrow: 0x1B 0x5B 0X42
80 * RightArrow: 0x1B 0x5B 0x43
81 * LeftArrow: 0x1b 0x5B 0x44
82 * Beak(Pause): 0x1b 0x5B 0x50
93 * F1: 0x1b 0x5B 0x5B 0x41
94 * F2: 0x1b 0x5B 0x5B 0x42
95 * F3: 0x1b 0x5B 0x5B 0x43
96 * F4: 0x1b 0x5B 0x5B 0x44
97 * F5: 0x1b 0x5B 0x5B 0x45
98 * Ins: 0x1b 0x5B 0x32 0x7E
99 * Home: 0x1b 0x5B 0x31 0x7E
100 * PgUp: 0x1b 0x5B 0x35 0x7E
101 * Del: 0x1b 0x5B 0x33 0x7E
102 * End: 0x1b 0x5B 0x34 0x7E
103 * PgDn: 0x1b 0x5B 0x36 0x7E
105 KEY_F1, KEY_F2, KEY_F3, KEY_F4, KEY_F5,
106 KEY_INS, KEY_HOME, KEY_PGUP, KEY_DEL, KEY_END, KEY_PGDN,
111 * F6: 0x1b 0x5B 0x31 0x37 0x7E
112 * F7: 0x1b 0x5B 0x31 0x38 0x7E
113 * F8: 0x1b 0x5B 0x31 0x39 0x7E
114 * F9: 0x1b 0x5B 0x32 0x30 0x7E
115 * F10: 0x1b 0x5B 0x32 0x31 0x7E
116 * F11: 0x1b 0x5B 0x32 0x33 0x7E
117 * F12: 0x1b 0x5B 0x32 0x34 0x7E
119 KEY_F6, KEY_F7, KEY_F8, KEY_F9,
120 KEY_F10, KEY_F11, KEY_F12,
123 /** Check if \a c is a separator between words.
124 * \note Parameter \a c is evaluated multiple times
126 #define IS_WORD_SEPARATOR(c) ((c) == ' ' || (c) == '\0')
128 /// Write the string \a txt to the IO output (without any kind of termination)
129 INLINE void rl_puts(const struct RLContext* ctx, const char* txt)
135 ctx->put(*txt++, ctx->put_param);
138 /// Write character \a ch to the IO output.
139 INLINE void rl_putc(const struct RLContext* ctx, char ch)
142 ctx->put(ch, ctx->put_param);
145 /** Read a character from the IO into \a ch. This function also takes
146 * care of converting the ANSI escape sequences into one of the codes
147 * defined in \c RL_KEYS.
149 static bool rl_getc(const struct RLContext* ctx, int* ch)
151 int c = ctx->get(ctx->get_param);
157 // Unknown ESC sequence. Ignore it and read
158 // return next character.
159 if (ctx->get(ctx->get_param) != 0x5B)
160 return rl_getc(ctx, ch);
163 * Home: 0x1b 0x5B 0x31 0x7E
164 * F6: 0x1b 0x5B 0x31 0x37 0x7E
165 * F7: 0x1b 0x5B 0x31 0x38 0x7E
166 * F8: 0x1b 0x5B 0x31 0x39 0x7E
167 * Ins: 0x1b 0x5B 0x32 0x7E
168 * F9: 0x1b 0x5B 0x32 0x30 0x7E
169 * F10: 0x1b 0x5B 0x32 0x31 0x7E
170 * F11: 0x1b 0x5B 0x32 0x33 0x7E
171 * F12: 0x1b 0x5B 0x32 0x34 0x7E
172 * Del: 0x1b 0x5B 0x33 0x7E
173 * End: 0x1b 0x5B 0x34 0x7E
174 * PgUp: 0x1b 0x5B 0x35 0x7E
175 * PgDn: 0x1b 0x5B 0x36 0x7E
178 c = ctx->get(ctx->get_param);
181 case 0x41: c = KEY_UP_ARROW; break;
182 case 0x42: c = KEY_DOWN_ARROW; break;
183 case 0x43: c = KEY_RIGHT_ARROW; break;
184 case 0x44: c = KEY_LEFT_ARROW; break;
185 case 0x50: c = KEY_PAUSE; break;
187 c = ctx->get(ctx->get_param);
190 case 0x41: c = KEY_F1; break;
191 case 0x42: c = KEY_F2; break;
192 case 0x43: c = KEY_F3; break;
193 case 0x44: c = KEY_F4; break;
194 case 0x45: c = KEY_F5; break;
195 default: return rl_getc(ctx, ch);
198 default: return rl_getc(ctx, ch);
206 INLINE void beep(struct RLContext* ctx)
211 static bool pop_history(struct RLContext* ctx, int total_len)
213 // Compute the length of the first command (including terminator).
214 int len = strlen(ctx->real_history+1)+1;
216 // (the first byte of the history should always be 0)
217 ASSERT(ctx->real_history[0] == '\0');
219 // If it is the only one in the history, do nothing
220 if (len == total_len)
223 // Overwrite the first command with the second one
224 memmove(ctx->real_history, ctx->real_history+len, HISTORY_SIZE-len);
226 // Move back the ctx->buffer pointer so that all the indices are still valid
232 /// Check if index \a i points to the begin of the history.
233 INLINE bool is_history_begin(struct RLContext* ctx, int i)
234 { return ctx->history + i == ctx->real_history; }
236 /// Check if index \a i points to the (exclusive) end of history
237 INLINE bool is_history_end(struct RLContext* ctx, int i)
238 { return ctx->history + i == ctx->real_history + HISTORY_SIZE; }
240 /// Check if index \a i points to the (exclusive) end of history, or somewhere past the end.
241 INLINE bool is_history_past_end(struct RLContext* ctx, int i)
242 { return ctx->history + i >= ctx->real_history + HISTORY_SIZE; }
244 /** Insert \a num_chars characters from \a ch into the history buffer at the
245 * position indicated by \a curpos. If needed, remove old history to make room.
246 * Returns true if everything was successful, false if there was no room to
247 * add the characters.
248 * \note \a num_chars can be 0, in which case we just make sure the line is
249 * correctly zero-terminated (ASCIIZ format).
251 static bool insert_chars(struct RLContext* ctx, size_t *curpos, const char* ch, int num_chars)
253 ASSERT(!is_history_past_end(ctx, *curpos));
255 while (is_history_past_end(ctx, *curpos+num_chars+1))
257 if (!pop_history(ctx, *curpos))
262 ctx->history[++(*curpos)] = *ch++;
264 ASSERT(!is_history_past_end(ctx, *curpos + 1));
265 ctx->history[*curpos+1] = '\0';
269 /// Insert a single character \a ch into the buffer (with the same semantic of \c insert_chars())
270 static bool insert_char(struct RLContext* ctx, size_t *curpos, char ch)
272 return insert_chars(ctx, curpos, &ch, 1);
275 #if DEBUG_DUMP_HISTORY
276 /// Dump the internal history of a context (used only for debug purposes)
277 static void dump_history(struct RLContext* ctx)
281 ASSERT(ctx->real_history[0] == '\0');
282 rl_puts(ctx, "History dump:");
283 rl_puts(ctx, "\r\n");
285 ctx->real_history + k != ctx->history + ctx->history_pos + 1;
286 k += strlen(&ctx->real_history[k]) + 1)
288 rl_puts(ctx, &ctx->real_history[k]);
289 rl_puts(ctx, "\r\n");
292 sprintf(buf, "%d\r\n", ctx->history_pos + (ctx->history - ctx->real_history));
295 #endif /* DEBUG_DUMP_HISTORY */
297 /// Complete the current word. Return false if no unambiguous completion was found
298 static bool complete_word(struct RLContext *ctx, size_t *curpos)
300 const char* completed_word;
303 // If the current character is a separator,
304 // there is nothing to complete
306 if (IS_WORD_SEPARATOR(ctx->history[wstart]))
312 // Find the separator before the current word
315 while (!IS_WORD_SEPARATOR(ctx->history[wstart]));
317 // Complete the word through the hook
318 completed_word = ctx->match(ctx->match_param, ctx->history + wstart + 1, *curpos - wstart);
322 // Move back the terminal cursor to the separator
323 while (*curpos != wstart)
329 // Insert the completed command
330 insert_chars(ctx, curpos, completed_word, strlen(completed_word));
331 rl_puts(ctx, completed_word);
332 insert_char(ctx, curpos, ' ');
338 void rl_refresh(struct RLContext* ctx)
340 rl_puts(ctx, "\r\n");
342 rl_puts(ctx, ctx->prompt);
343 rl_puts(ctx, ctx->history + ctx->history_pos + 1);
346 const char* rl_readline(struct RLContext* ctx)
348 size_t i = ctx->history_pos;
351 rl_puts(ctx, ctx->prompt);
353 insert_chars(ctx, &i, NULL, 0);
360 ASSERT(ctx->history - ctx->real_history + i < HISTORY_SIZE);
362 if (!rl_getc(ctx, &c))
365 // Just ignore special keys for now
366 if (c > SPECIAL_KEYS)
371 // Ask the match hook if available
375 complete_word(ctx, &i);
379 if (c == '\r' || c == '\n')
381 rl_puts(ctx, "\r\n");
385 // Backspace cancels a character, or it is ignored if at
386 // the start of the line
389 if (ctx->history[i] != '\0')
392 rl_puts(ctx, "\b \b");
397 // Add a character to the buffer, if possible
399 ASSERT2(ch == c, "a special key was not properly handled");
400 if (insert_chars(ctx, &i, &ch, 1))
406 ctx->history_pos = i+1;
407 while (ctx->history[i] != '\0')
410 // Do not store empty lines in the history
411 if (i == ctx->history_pos - 1)
412 ctx->history_pos -= 1;
414 #if DEBUG_DUMP_HISTORY
418 // Since the current pointer now points to the separator, we need
419 // to return the first character
420 return &ctx->history[i+1];
426 /** Perform the unit test for the readline library */
429 #if HISTORY_SIZE != 32
430 #error This test needs HISTORY_SIZE to be set at 32
433 static struct RLContext test_ctx;
435 static char* test_getc_ptr;
436 static int test_getc(void* data)
438 return *test_getc_ptr++;
441 /** Perform a readline test. The function pipes the characters from \a input_buffer
442 * through the I/O to \c rl_readline(). After the whole string is sent, \c do_test()
443 * checks if the current history within the context match \a expected_history.
445 static bool do_test(char* input_buffer, char* expected_history)
447 rl_init_ctx(&test_ctx);
448 rl_sethook_get(&test_ctx, test_getc, NULL);
450 test_getc_ptr = input_buffer;
451 while (*test_getc_ptr)
452 rl_readline(&test_ctx);
454 if (memcmp(test_ctx.real_history, expected_history, HISTORY_SIZE) != 0)
456 ASSERT2(0, "history compare failed");
465 char* test1_in = "a\nb\nc\nd\ne\nf\ng\nh\ni\nj\nk\nl\nm\nn\no\np\nq\nr\ns\nt\nu\nv\nw\nx\ny\nz\n";
466 char test1_hist[HISTORY_SIZE] = "\0l\0m\0n\0o\0p\0q\0r\0s\0t\0u\0v\0w\0x\0y\0z";
468 if (!do_test(test1_in, test1_hist))
471 kprintf("rl_test successful\n");
474 #endif /* DEBUG_UNIT_TEST */