aboutsummaryrefslogtreecommitdiffstats
path: root/src/libs/3rdparty/winpty/src/agent/DefaultInputMap.cc
blob: 5e29d98e4ec5a5e85daef66a63134ef31af88a66 (plain)
1
2
3
4
5
6
7
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
38
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
// Copyright (c) 2015 Ryan Prichard
//
// 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.

#include "DefaultInputMap.h"

#include <windows.h>
#include <string.h>

#include <algorithm>

#include "../shared/StringBuilder.h"
#include "../shared/WinptyAssert.h"
#include "InputMap.h"

#define ESC "\x1B"
#define DIM(x) (sizeof(x) / sizeof((x)[0]))

namespace {

struct EscapeEncoding {
    bool alt_prefix_allowed;
    char prefix;
    char id;
    int modifiers;
    InputMap::Key key;
};

// Modifiers.  A "modifier" is an integer from 2 to 8 that conveys the status
// of Shift(1), Alt(2), and Ctrl(4).  The value is constructed by OR'ing the
// appropriate value for each active modifier, then adding 1.
//
// Details:
//  - kBare:    expands to: ESC <prefix> <suffix>
//  - kSemiMod: expands to: ESC <prefix> <numid> ; <mod> <suffix>
//  - kBareMod: expands to: ESC <prefix> <mod> <suffix>
const int kBare        = 0x01;
const int kSemiMod     = 0x02;
const int kBareMod     = 0x04;

// Numeric escape sequences suffixes:
//  - with no flag: accept: ~
//  - kSuffixCtrl:  accept: ~ ^
//  - kSuffixShift: accept: ~ $
//  - kSuffixBoth:  accept: ~ ^ $ @
const int kSuffixCtrl  = 0x08;
const int kSuffixShift = 0x10;
const int kSuffixBoth  = kSuffixCtrl | kSuffixShift;

static const EscapeEncoding escapeLetterEncodings[] = {
    // Conventional arrow keys
    // kBareMod: Ubuntu /etc/inputrc and IntelliJ/JediTerm use escapes like: ESC [ n ABCD
    { true,  '[', 'A', kBare | kBareMod | kSemiMod, { VK_UP,      '\0', 0             } },
    { true,  '[', 'B', kBare | kBareMod | kSemiMod, { VK_DOWN,    '\0', 0             } },
    { true,  '[', 'C', kBare | kBareMod | kSemiMod, { VK_RIGHT,   '\0', 0             } },
    { true,  '[', 'D', kBare | kBareMod | kSemiMod, { VK_LEFT,    '\0', 0             } },

    // putty.  putty uses this sequence for Ctrl-Arrow, Shift-Arrow, and
    // Ctrl-Shift-Arrow, but I can only decode to one choice, so I'm just
    // leaving the modifier off altogether.
    { true,  'O', 'A', kBare,                       { VK_UP,      '\0', 0             } },
    { true,  'O', 'B', kBare,                       { VK_DOWN,    '\0', 0             } },
    { true,  'O', 'C', kBare,                       { VK_RIGHT,   '\0', 0             } },
    { true,  'O', 'D', kBare,                       { VK_LEFT,    '\0', 0             } },

    // rxvt, rxvt-unicode
    // Shift-Ctrl-Arrow can't be identified.  It's the same as Shift-Arrow.
    { true,  '[', 'a', kBare,                       { VK_UP,      '\0', SHIFT_PRESSED       } },
    { true,  '[', 'b', kBare,                       { VK_DOWN,    '\0', SHIFT_PRESSED       } },
    { true,  '[', 'c', kBare,                       { VK_RIGHT,   '\0', SHIFT_PRESSED       } },
    { true,  '[', 'd', kBare,                       { VK_LEFT,    '\0', SHIFT_PRESSED       } },
    { true,  'O', 'a', kBare,                       { VK_UP,      '\0', LEFT_CTRL_PRESSED   } },
    { true,  'O', 'b', kBare,                       { VK_DOWN,    '\0', LEFT_CTRL_PRESSED   } },
    { true,  'O', 'c', kBare,                       { VK_RIGHT,   '\0', LEFT_CTRL_PRESSED   } },
    { true,  'O', 'd', kBare,                       { VK_LEFT,    '\0', LEFT_CTRL_PRESSED   } },

    // Numpad 5 with NumLock off
    //  * xterm, mintty, and gnome-terminal use `ESC [ E`.
    //  * putty, TERM=cygwin, TERM=linux all use `ESC [ G` for 5
    //  * putty uses `ESC O G` for Ctrl-5 and Shift-5.  Omit the modifier
    //    as with putty's arrow keys.
    //  * I never saw modifiers inserted into these escapes, but I think
    //    it should be completely OK with the CSI escapes.
    { true,  '[', 'E', kBare | kSemiMod,            { VK_CLEAR,   '\0', 0             } },
    { true,  '[', 'G', kBare | kSemiMod,            { VK_CLEAR,   '\0', 0             } },
    { true,  'O', 'G', kBare,                       { VK_CLEAR,   '\0', 0             } },

    // Home/End, letter version
    //  * gnome-terminal uses `ESC O [HF]`.  I never saw it modified.
    // kBareMod: IntelliJ/JediTerm uses escapes like: ESC [ n HF
    { true,  '[', 'H', kBare | kBareMod | kSemiMod, { VK_HOME,    '\0', 0             } },
    { true,  '[', 'F', kBare | kBareMod | kSemiMod, { VK_END,     '\0', 0             } },
    { true,  'O', 'H', kBare,                       { VK_HOME,    '\0', 0             } },
    { true,  'O', 'F', kBare,                       { VK_END,     '\0', 0             } },

    // F1-F4, letter version (xterm, VTE, konsole)
    { true,  '[', 'P', kSemiMod,                    { VK_F1,      '\0', 0             } },
    { true,  '[', 'Q', kSemiMod,                    { VK_F2,      '\0', 0             } },
    { true,  '[', 'R', kSemiMod,                    { VK_F3,      '\0', 0             } },
    { true,  '[', 'S', kSemiMod,                    { VK_F4,      '\0', 0             } },

    // GNOME VTE and Konsole have special encodings for modified F1-F4:
    //  * [VTE]     ESC O 1 ; n [PQRS]
    //  * [Konsole] ESC O     n [PQRS]
    { false, 'O', 'P', kBare | kBareMod | kSemiMod, { VK_F1,      '\0', 0             } },
    { false, 'O', 'Q', kBare | kBareMod | kSemiMod, { VK_F2,      '\0', 0             } },
    { false, 'O', 'R', kBare | kBareMod | kSemiMod, { VK_F3,      '\0', 0             } },
    { false, 'O', 'S', kBare | kBareMod | kSemiMod, { VK_F4,      '\0', 0             } },

    // Handle the "application numpad" escape sequences.
    //
    // Terminals output these codes under various circumstances:
    //  * rxvt-unicode: numpad, hold down SHIFT
    //  * rxvt: numpad, by default
    //  * xterm: numpad, after enabling app-mode using DECPAM (`ESC =`).  xterm
    //    generates `ESC O <mod> <letter>` for modified numpad presses,
    //    necessitating kBareMod.
    //  * mintty: by combining Ctrl with various keys such as '1' or ','.
    //    Handling those keys is difficult, because mintty is generating the
    //    same sequence for Ctrl-1 and Ctrl-NumPadEnd -- should the virtualKey
    //    be '1' or VK_HOME?

    { true,  'O', 'M', kBare | kBareMod,            { VK_RETURN,   '\r',   0 } },
    { true,  'O', 'j', kBare | kBareMod,            { VK_MULTIPLY, '*',    0 } },
    { true,  'O', 'k', kBare | kBareMod,            { VK_ADD,      '+',    0 } },
    { true,  'O', 'm', kBare | kBareMod,            { VK_SUBTRACT, '-',    0 } },
    { true,  'O', 'n', kBare | kBareMod,            { VK_DELETE,   '\0',   0 } },
    { true,  'O', 'o', kBare | kBareMod,            { VK_DIVIDE,   '/',    0 } },
    { true,  'O', 'p', kBare | kBareMod,            { VK_INSERT,   '\0',   0 } },
    { true,  'O', 'q', kBare | kBareMod,            { VK_END,      '\0',   0 } },
    { true,  'O', 'r', kBare | kBareMod,            { VK_DOWN,     '\0',   0 } },
    { true,  'O', 's', kBare | kBareMod,            { VK_NEXT,     '\0',   0 } },
    { true,  'O', 't', kBare | kBareMod,            { VK_LEFT,     '\0',   0 } },
    { true,  'O', 'u', kBare | kBareMod,            { VK_CLEAR,    '\0',   0 } },
    { true,  'O', 'v', kBare | kBareMod,            { VK_RIGHT,    '\0',   0 } },
    { true,  'O', 'w', kBare | kBareMod,            { VK_HOME,     '\0',   0 } },
    { true,  'O', 'x', kBare | kBareMod,            { VK_UP,       '\0',   0 } },
    { true,  'O', 'y', kBare | kBareMod,            { VK_PRIOR,    '\0',   0 } },

    { true,  '[', 'M', kBare | kSemiMod,            { VK_RETURN,   '\r',   0 } },
    { true,  '[', 'j', kBare | kSemiMod,            { VK_MULTIPLY, '*',    0 } },
    { true,  '[', 'k', kBare | kSemiMod,            { VK_ADD,      '+',    0 } },
    { true,  '[', 'm', kBare | kSemiMod,            { VK_SUBTRACT, '-',    0 } },
    { true,  '[', 'n', kBare | kSemiMod,            { VK_DELETE,   '\0',   0 } },
    { true,  '[', 'o', kBare | kSemiMod,            { VK_DIVIDE,   '/',    0 } },
    { true,  '[', 'p', kBare | kSemiMod,            { VK_INSERT,   '\0',   0 } },
    { true,  '[', 'q', kBare | kSemiMod,            { VK_END,      '\0',   0 } },
    { true,  '[', 'r', kBare | kSemiMod,            { VK_DOWN,     '\0',   0 } },
    { true,  '[', 's', kBare | kSemiMod,            { VK_NEXT,     '\0',   0 } },
    { true,  '[', 't', kBare | kSemiMod,            { VK_LEFT,     '\0',   0 } },
    { true,  '[', 'u', kBare | kSemiMod,            { VK_CLEAR,    '\0',   0 } },
    { true,  '[', 'v', kBare | kSemiMod,            { VK_RIGHT,    '\0',   0 } },
    { true,  '[', 'w', kBare | kSemiMod,            { VK_HOME,     '\0',   0 } },
    { true,  '[', 'x', kBare | kSemiMod,            { VK_UP,       '\0',   0 } },
    { true,  '[', 'y', kBare | kSemiMod,            { VK_PRIOR,    '\0',   0 } },

    { false, '[', 'Z', kBare,                       { VK_TAB,     '\t', SHIFT_PRESSED } },
};

static const EscapeEncoding escapeNumericEncodings[] = {
    { true,  '[',  1,  kBare | kSemiMod | kSuffixBoth,      { VK_HOME,    '\0', 0             } },
    { true,  '[',  2,  kBare | kSemiMod | kSuffixBoth,      { VK_INSERT,  '\0', 0             } },
    { true,  '[',  3,  kBare | kSemiMod | kSuffixBoth,      { VK_DELETE,  '\0', 0             } },
    { true,  '[',  4,  kBare | kSemiMod | kSuffixBoth,      { VK_END,     '\0', 0             } },
    { true,  '[',  5,  kBare | kSemiMod | kSuffixBoth,      { VK_PRIOR,   '\0', 0             } },
    { true,  '[',  6,  kBare | kSemiMod | kSuffixBoth,      { VK_NEXT,    '\0', 0             } },
    { true,  '[',  7,  kBare | kSemiMod | kSuffixBoth,      { VK_HOME,    '\0', 0             } },
    { true,  '[',  8,  kBare | kSemiMod | kSuffixBoth,      { VK_END,     '\0', 0             } },
    { true,  '[', 11,  kBare | kSemiMod | kSuffixBoth,      { VK_F1,      '\0', 0             } },
    { true,  '[', 12,  kBare | kSemiMod | kSuffixBoth,      { VK_F2,      '\0', 0             } },
    { true,  '[', 13,  kBare | kSemiMod | kSuffixBoth,      { VK_F3,      '\0', 0             } },
    { true,  '[', 14,  kBare | kSemiMod | kSuffixBoth,      { VK_F4,      '\0', 0             } },
    { true,  '[', 15,  kBare | kSemiMod | kSuffixBoth,      { VK_F5,      '\0', 0             } },
    { true,  '[', 17,  kBare | kSemiMod | kSuffixBoth,      { VK_F6,      '\0', 0             } },
    { true,  '[', 18,  kBare | kSemiMod | kSuffixBoth,      { VK_F7,      '\0', 0             } },
    { true,  '[', 19,  kBare | kSemiMod | kSuffixBoth,      { VK_F8,      '\0', 0             } },
    { true,  '[', 20,  kBare | kSemiMod | kSuffixBoth,      { VK_F9,      '\0', 0             } },
    { true,  '[', 21,  kBare | kSemiMod | kSuffixBoth,      { VK_F10,     '\0', 0             } },
    { true,  '[', 23,  kBare | kSemiMod | kSuffixBoth,      { VK_F11,     '\0', 0             } },
    { true,  '[', 24,  kBare | kSemiMod | kSuffixBoth,      { VK_F12,     '\0', 0             } },
    { true,  '[', 25,  kBare | kSemiMod | kSuffixBoth,      { VK_F3,      '\0', SHIFT_PRESSED } },
    { true,  '[', 26,  kBare | kSemiMod | kSuffixBoth,      { VK_F4,      '\0', SHIFT_PRESSED } },
    { true,  '[', 28,  kBare | kSemiMod | kSuffixBoth,      { VK_F5,      '\0', SHIFT_PRESSED } },
    { true,  '[', 29,  kBare | kSemiMod | kSuffixBoth,      { VK_F6,      '\0', SHIFT_PRESSED } },
    { true,  '[', 31,  kBare | kSemiMod | kSuffixBoth,      { VK_F7,      '\0', SHIFT_PRESSED } },
    { true,  '[', 32,  kBare | kSemiMod | kSuffixBoth,      { VK_F8,      '\0', SHIFT_PRESSED } },
    { true,  '[', 33,  kBare | kSemiMod | kSuffixBoth,      { VK_F9,      '\0', SHIFT_PRESSED } },
    { true,  '[', 34,  kBare | kSemiMod | kSuffixBoth,      { VK_F10,     '\0', SHIFT_PRESSED } },
};

const int kCsiShiftModifier = 1;
const int kCsiAltModifier   = 2;
const int kCsiCtrlModifier  = 4;

static inline bool useEnhancedForVirtualKey(uint16_t vk) {
    switch (vk) {
        case VK_UP:
        case VK_DOWN:
        case VK_LEFT:
        case VK_RIGHT:
        case VK_INSERT:
        case VK_DELETE:
        case VK_HOME:
        case VK_END:
        case VK_PRIOR:
        case VK_NEXT:
            return true;
        default:
            return false;
    }
}

static void addSimpleEntries(InputMap &inputMap) {
    struct SimpleEncoding {
        const char *encoding;
        InputMap::Key key;
    };

    static const SimpleEncoding simpleEncodings[] = {
        // Ctrl-<letter/digit> seems to be handled OK by the default code path.

        {   "\x7F",         { VK_BACK,  '\x08', 0,                                  } },
        {   ESC "\x7F",     { VK_BACK,  '\x08', LEFT_ALT_PRESSED,                   } },
        {   "\x03",         { 'C',      '\x03', LEFT_CTRL_PRESSED,                  } },

        // Handle special F1-F5 for TERM=linux and TERM=cygwin.
        {   ESC "[[A",      { VK_F1,    '\0',   0                                   } },
        {   ESC "[[B",      { VK_F2,    '\0',   0                                   } },
        {   ESC "[[C",      { VK_F3,    '\0',   0                                   } },
        {   ESC "[[D",      { VK_F4,    '\0',   0                                   } },
        {   ESC "[[E",      { VK_F5,    '\0',   0                                   } },

        {   ESC ESC "[[A",  { VK_F1,    '\0',   LEFT_ALT_PRESSED                    } },
        {   ESC ESC "[[B",  { VK_F2,    '\0',   LEFT_ALT_PRESSED                    } },
        {   ESC ESC "[[C",  { VK_F3,    '\0',   LEFT_ALT_PRESSED                    } },
        {   ESC ESC "[[D",  { VK_F4,    '\0',   LEFT_ALT_PRESSED                    } },
        {   ESC ESC "[[E",  { VK_F5,    '\0',   LEFT_ALT_PRESSED                    } },
    };

    for (size_t i = 0; i < DIM(simpleEncodings); ++i) {
        auto k = simpleEncodings[i].key;
        if (useEnhancedForVirtualKey(k.virtualKey)) {
            k.keyState |= ENHANCED_KEY;
        }
        inputMap.set(simpleEncodings[i].encoding,
                     strlen(simpleEncodings[i].encoding),
                     k);
    }
}

struct ExpandContext {
    InputMap &inputMap;
    const EscapeEncoding &e;
    char *buffer;
    char *bufferEnd;
};

static inline void setEncoding(const ExpandContext &ctx, char *end,
                               uint16_t extraKeyState) {
    InputMap::Key k = ctx.e.key;
    k.keyState |= extraKeyState;
    if (k.keyState & LEFT_CTRL_PRESSED) {
        switch (k.virtualKey) {
            case VK_ADD:
            case VK_DIVIDE:
            case VK_MULTIPLY:
            case VK_SUBTRACT:
                k.unicodeChar = '\0';
                break;
            case VK_RETURN:
                k.unicodeChar = '\n';
                break;
        }
    }
    if (useEnhancedForVirtualKey(k.virtualKey)) {
        k.keyState |= ENHANCED_KEY;
    }
    ctx.inputMap.set(ctx.buffer, end - ctx.buffer, k);
}

static inline uint16_t keyStateForMod(int mod) {
    int ret = 0;
    if ((mod - 1) & kCsiShiftModifier)  ret |= SHIFT_PRESSED;
    if ((mod - 1) & kCsiAltModifier)    ret |= LEFT_ALT_PRESSED;
    if ((mod - 1) & kCsiCtrlModifier)   ret |= LEFT_CTRL_PRESSED;
    return ret;
}

static void expandNumericEncodingSuffix(const ExpandContext &ctx, char *p,
        uint16_t extraKeyState) {
    ASSERT(p <= ctx.bufferEnd - 1);
    {
        char *q = p;
        *q++ = '~';
        setEncoding(ctx, q, extraKeyState);
    }
    if (ctx.e.modifiers & kSuffixShift) {
        char *q = p;
        *q++ = '$';
        setEncoding(ctx, q, extraKeyState | SHIFT_PRESSED);
    }
    if (ctx.e.modifiers & kSuffixCtrl) {
        char *q = p;
        *q++ = '^';
        setEncoding(ctx, q, extraKeyState | LEFT_CTRL_PRESSED);
    }
    if (ctx.e.modifiers & (kSuffixCtrl | kSuffixShift)) {
        char *q = p;
        *q++ = '@';
        setEncoding(ctx, q, extraKeyState | SHIFT_PRESSED | LEFT_CTRL_PRESSED);
    }
}

template <bool is_numeric>
static inline void expandEncodingAfterAltPrefix(
        const ExpandContext &ctx, char *p, uint16_t extraKeyState) {
    auto appendId = [&](char *&ptr) {
        const auto idstr = decOfInt(ctx.e.id);
        ASSERT(ptr <= ctx.bufferEnd - idstr.size());
        std::copy(idstr.data(), idstr.data() + idstr.size(), ptr);
        ptr += idstr.size();
    };
    ASSERT(p <= ctx.bufferEnd - 2);
    *p++ = '\x1b';
    *p++ = ctx.e.prefix;
    if (ctx.e.modifiers & kBare) {
        char *q = p;
        if (is_numeric) {
            appendId(q);
            expandNumericEncodingSuffix(ctx, q, extraKeyState);
        } else {
            ASSERT(q <= ctx.bufferEnd - 1);
            *q++ = ctx.e.id;
            setEncoding(ctx, q, extraKeyState);
        }
    }
    if (ctx.e.modifiers & kBareMod) {
        ASSERT(!is_numeric && "kBareMod is invalid with numeric sequences");
        for (int mod = 2; mod <= 8; ++mod) {
            char *q = p;
            ASSERT(q <= ctx.bufferEnd - 2);
            *q++ = '0' + mod;
            *q++ = ctx.e.id;
            setEncoding(ctx, q, extraKeyState | keyStateForMod(mod));
        }
    }
    if (ctx.e.modifiers & kSemiMod) {
        for (int mod = 2; mod <= 8; ++mod) {
            char *q = p;
            if (is_numeric) {
                appendId(q);
                ASSERT(q <= ctx.bufferEnd - 2);
                *q++ = ';';
                *q++ = '0' + mod;
                expandNumericEncodingSuffix(
                    ctx, q, extraKeyState | keyStateForMod(mod));
            } else {
                ASSERT(q <= ctx.bufferEnd - 4);
                *q++ = '1';
                *q++ = ';';
                *q++ = '0' + mod;
                *q++ = ctx.e.id;
                setEncoding(ctx, q, extraKeyState | keyStateForMod(mod));
            }
        }
    }
}

template <bool is_numeric>
static inline void expandEncoding(const ExpandContext &ctx) {
    if (ctx.e.alt_prefix_allowed) {
        // For better or for worse, this code expands all of:
        //  *     ESC [       <key>     -- <key>
        //  * ESC ESC [       <key>     -- Alt-<key>
        //  *     ESC [ 1 ; 3 <key>     -- Alt-<key>
        //  * ESC ESC [ 1 ; 3 <key>     -- Alt-<key> specified twice
        // I suspect no terminal actually emits the last one (i.e. specifying
        // the Alt modifier using both methods), but I have seen a terminal
        // that emitted a prefix ESC for Alt and a non-Alt modifier.
        char *p = ctx.buffer;
        ASSERT(p <= ctx.bufferEnd - 1);
        *p++ = '\x1b';
        expandEncodingAfterAltPrefix<is_numeric>(ctx, p, LEFT_ALT_PRESSED);
    }
    expandEncodingAfterAltPrefix<is_numeric>(ctx, ctx.buffer, 0);
}

template <bool is_numeric, size_t N>
static void addEscapes(InputMap &inputMap, const EscapeEncoding (&encodings)[N]) {
    char buffer[32];
    for (size_t i = 0; i < DIM(encodings); ++i) {
        ExpandContext ctx = {
            inputMap, encodings[i],
            buffer, buffer + sizeof(buffer)
        };
        expandEncoding<is_numeric>(ctx);
    }
}

} // anonymous namespace

void addDefaultEntriesToInputMap(InputMap &inputMap) {
    addEscapes<false>(inputMap, escapeLetterEncodings);
    addEscapes<true>(inputMap, escapeNumericEncodings);
    addSimpleEntries(inputMap);
}