1/* hexedit.c - Hexadecimal file editor
2 *
3 * Copyright 2015 Rob Landley <rob@landley.net>
4 *
5 * No standard
6
7USE_HEXEDIT(NEWTOY(hexedit, "<1>1r", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_LOCALE))
8
9config HEXEDIT
10  bool "hexedit"
11  default y
12  help
13    usage: hexedit FILENAME
14
15    Hexadecimal file editor. All changes are written to disk immediately.
16
17    -r	Read only (display but don't edit)
18
19    Keys:
20    Arrows        Move left/right/up/down by one line/column
21    Pg Up/Pg Dn   Move up/down by one page
22    0-9, a-f      Change current half-byte to hexadecimal value
23    u             Undo
24    q/^c/^d/<esc> Quit
25*/
26
27#define FOR_hexedit
28#include "toys.h"
29
30GLOBALS(
31  char *data;
32  long long len, base;
33  int numlen, undo, undolen;
34  unsigned height;
35)
36
37#define UNDO_LEN (sizeof(toybuf)/(sizeof(long long)+1))
38
39// Render all characters printable, using color to distinguish.
40static int draw_char(FILE *fp, wchar_t broiled)
41{
42  if (fp) {
43    if (broiled<32 || broiled>=127) {
44      if (broiled>127) {
45        tty_esc("2m");
46        broiled &= 127;
47      }
48      if (broiled<32 || broiled==127) {
49        tty_esc("7m");
50        if (broiled==127) broiled = 32;
51        else broiled += 64;
52      }
53      printf("%c", broiled);
54      tty_esc("0m");
55    } else printf("%c", broiled);
56  }
57
58  return 1;
59}
60
61static void draw_tail(void)
62{
63  tty_jump(0, TT.height);
64  tty_esc("K");
65
66  draw_trim(*toys.optargs, -1, 71);
67}
68
69static void draw_line(long long yy)
70{
71  int x, xx = 16;
72
73  yy = (TT.base+yy)*16;
74  if (yy+xx>=TT.len) xx = TT.len-yy;
75
76  if (yy<TT.len) {
77    printf("\r%0*llX ", TT.numlen, yy);
78    for (x=0; x<xx; x++) printf(" %02X", TT.data[yy+x]);
79    printf("%*s", 2+3*(16-xx), "");
80    for (x=0; x<xx; x++) draw_char(stdout, TT.data[yy+x]);
81    printf("%*s", 16-xx, "");
82  }
83  tty_esc("K");
84}
85
86static void draw_page(void)
87{
88  int y;
89
90  tty_jump(0, 0);
91  for (y = 0; y<TT.height; y++) {
92    if (y) printf("\r\n");
93    draw_line(y);
94  }
95  draw_tail();
96}
97
98// side: 0 = editing left, 1 = editing right, 2 = clear, 3 = read only
99static void highlight(int xx, int yy, int side)
100{
101  char cc = TT.data[16*(TT.base+yy)+xx];
102  int i;
103
104  // Display cursor
105  tty_jump(2+TT.numlen+3*xx, yy);
106  tty_esc("0m");
107  if (side!=2) tty_esc("7m");
108  if (side>1) printf("%02X", cc);
109  else for (i=0; i<2;) {
110    if (side==i) tty_esc("32m");
111    printf("%X", (cc>>(4*(1&++i)))&15);
112  }
113  tty_esc("0m");
114  tty_jump(TT.numlen+17*3+xx, yy);
115  draw_char(stdout, cc);
116}
117
118void hexedit_main(void)
119{
120  long long pos = 0, y;
121  int x, i, side = 0, key, ro = toys.optflags&FLAG_r,
122      fd = xopen(*toys.optargs, ro ? O_RDONLY : O_RDWR);
123  char keybuf[16];
124
125  *keybuf = 0;
126
127  // Terminal setup
128  TT.height = 25;
129  terminal_size(0, &TT.height);
130  if (TT.height) TT.height--;
131  sigatexit(tty_sigreset);
132  tty_esc("0m");
133  tty_esc("?25l");
134  fflush(0);
135  xset_terminal(1, 1, 0);
136
137  if ((TT.len = fdlength(fd))<1) error_exit("bad length");
138  if (sizeof(long)==32 && TT.len>SIZE_MAX) TT.len = SIZE_MAX;
139  // count file length hex in digits, rounded up to multiple of 4
140  for (pos = TT.len, TT.numlen = 0; pos; pos >>= 4, TT.numlen++);
141  TT.numlen += (4-TT.numlen)&3;
142
143  TT.data = mmap(0, TT.len, PROT_READ|(PROT_WRITE*!ro), MAP_SHARED, fd, 0);
144  draw_page();
145
146  for (;;) {
147    // Scroll display if necessary
148    if (pos<0) pos = 0;
149    if (pos>=TT.len) pos = TT.len-1;
150    x = pos&15;
151    y = pos/16;
152
153    i = 0;
154    while (y<TT.base) {
155      if (TT.base-y>(TT.height/2)) {
156        TT.base = y;
157        draw_page();
158      } else {
159        TT.base--;
160        i++;
161        tty_esc("1T");
162        tty_jump(0, 0);
163        draw_line(0);
164      }
165    }
166    while (y>=TT.base+TT.height) {
167      if (y-(TT.base+TT.height)>(TT.height/2)) {
168        TT.base = y-TT.height-1;
169        draw_page();
170      } else {
171        TT.base++;
172        i++;
173        tty_esc("1S");
174        tty_jump(0, TT.height-1);
175        draw_line(TT.height-1);
176      }
177    }
178    if (i) draw_tail();
179    y -= TT.base;
180
181    // Display cursor and flush output
182    highlight(x, y, ro ? 3 : side);
183    xflush();
184
185    // Wait for next key
186    key = scan_key(keybuf, -1);
187    // Exit for q, ctrl-c, ctrl-d, escape, or EOF
188    if (key==-1 || key==3 || key==4 || key==27 || key=='q') break;
189    highlight(x, y, 2);
190
191    // Hex digit?
192    if (key>='a' && key<='f') key-=32;
193    if (!ro && ((key>='0' && key<='9') || (key>='A' && key<='F'))) {
194      if (!side) {
195        long long *ll = (long long *)toybuf;
196
197        ll[TT.undo] = pos;
198        toybuf[(sizeof(long long)*UNDO_LEN)+TT.undo++] = TT.data[pos];
199        if (TT.undolen < UNDO_LEN) TT.undolen++;
200        TT.undo %= UNDO_LEN;
201      }
202
203      i = key - '0';
204      if (i>9) i -= 7;
205      TT.data[pos] &= 15<<(4*side);
206      TT.data[pos] |= i<<(4*!side);
207
208      if (++side==2) {
209        highlight(x, y, side);
210        side = 0;
211        ++pos;
212      }
213    } else side = 0;
214    if (key=='u') {
215      if (TT.undolen) {
216        long long *ll = (long long *)toybuf;
217
218        TT.undolen--;
219        if (!TT.undo) TT.undo = UNDO_LEN;
220        pos = ll[--TT.undo];
221        TT.data[pos] = toybuf[sizeof(long long)*UNDO_LEN+TT.undo];
222      }
223    }
224    if (key>=256) {
225      key -= 256;
226
227      if (key==KEY_UP) pos -= 16;
228      else if (key==KEY_DOWN) pos += 16;
229      else if (key==KEY_RIGHT) {
230        if (x<15) pos++;
231      } else if (key==KEY_LEFT) {
232        if (x) pos--;
233      } else if (key==KEY_PGUP) pos -= 16*TT.height;
234      else if (key==KEY_PGDN) pos += 16*TT.height;
235      else if (key==KEY_HOME) pos = 0;
236      else if (key==KEY_END) pos = TT.len-1;
237    }
238  }
239  munmap(TT.data, TT.len);
240  close(fd);
241  tty_reset();
242}
243