1 /*
2  * Copyright (c) 2020 Neels Hofmeyr <neels@hofmeyr.de>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #define DEBUG 0
18 
19 #if DEBUG
20 #include <stdio.h>
21 #include <unistd.h>
22 #define print(args...) fprintf(stderr, ##args)
23 #define debug print
24 #define debug_dump dump
25 #define debug_dump_atom dump_atom
26 #define debug_dump_atoms dump_atoms
27 
28 static inline void
29 print_atom_byte(unsigned char c) {
30 	if (c == '\r')
31 		print("\\r");
32 	else if (c == '\n')
33 		print("\\n");
34 	else if ((c < 32 || c >= 127) && (c != '\t'))
35 		print("\\x%02x", c);
36 	else
37 		print("%c", c);
38 }
39 
40 static inline void
41 dump_atom(const struct diff_data *left, const struct diff_data *right,
42 	  const struct diff_atom *atom)
43 {
44 	if (!atom) {
45 		print("NULL atom\n");
46 		return;
47 	}
48 	if (left)
49 		print(" %3u", diff_atom_root_idx(left, atom));
50 	if (right && atom->patience.pos_in_other)
51 		print(" %3u",
52 		      diff_atom_root_idx(right, atom->patience.pos_in_other));
53 
54 	print(" %s%s '",
55 	      atom->patience.unique_here ? "u" : " ",
56 	      atom->patience.unique_in_both ? "c" : " ");
57 	if (atom->at == NULL) {
58 		off_t remain = atom->len;
59 		if (fseek(atom->d->root->f, atom->pos, SEEK_SET) == -1)
60 			abort(); /* cannot return error */
61 		while (remain > 0) {
62 			char buf[16];
63 			size_t r;
64 			int i;
65 			r = fread(buf, 1, MIN(remain, sizeof(buf)),
66 			    atom->d->root->f);
67 			if (r == -1)
68 				abort(); /* cannot return error */
69 			if (r == 0)
70 				break;
71 			remain -= r;
72 			for (i = 0; i < r; i++)
73 				print_atom_byte(buf[i]);
74 		}
75 	} else {
76 		const char *s;
77 		for (s = atom->at; s < (const char*)(atom->at + atom->len); s++)
78 			print_atom_byte(*s);
79 	}
80 	print("'\n");
81 }
82 
83 static inline void
84 dump_atoms(const struct diff_data *d, struct diff_atom *atom,
85 	   unsigned int count)
86 {
87 	if (count > 42) {
88 		dump_atoms(d, atom, 20);
89 		print("[%u lines skipped]\n", count - 20 - 20);
90 		dump_atoms(d, atom + count - 20, 20);
91 		return;
92 	} else {
93 		struct diff_atom *i;
94 		foreach_diff_atom(i, atom, count) {
95 			dump_atom(d, NULL, i);
96 		}
97 	}
98 }
99 
100 static inline void
101 dump(struct diff_data *d)
102 {
103 	dump_atoms(d, d->atoms.head, d->atoms.len);
104 }
105 
106 /* kd is a quadratic space myers matrix from the original Myers algorithm.
107  * kd_forward and kd_backward are linear slices of a myers matrix from the Myers
108  * Divide algorithm.
109  */
110 static inline void
111 dump_myers_graph(const struct diff_data *l, const struct diff_data *r,
112 		 int *kd, int *kd_forward, int kd_forward_d,
113 		 int *kd_backward, int kd_backward_d)
114 {
115 	#define COLOR_YELLOW "\033[1;33m"
116 	#define COLOR_GREEN "\033[1;32m"
117 	#define COLOR_BLUE "\033[1;34m"
118 	#define COLOR_RED "\033[1;31m"
119 	#define COLOR_END "\033[0;m"
120 	int x;
121 	int y;
122 	print("   ");
123 	for (x = 0; x <= l->atoms.len; x++)
124 		print("%2d", x % 100);
125 	print("\n");
126 
127 	for (y = 0; y <= r->atoms.len; y++) {
128 		print("%3d ", y);
129 		for (x = 0; x <= l->atoms.len; x++) {
130 
131 			/* print d advancements from kd, if any. */
132 			char label = 'o';
133 			char *color = NULL;
134 			if (kd) {
135 				int max = l->atoms.len + r->atoms.len;
136 				size_t kd_len = max + 1 + max;
137 				int *kd_pos = kd;
138 				int di;
139 #define xk_to_y(X, K) ((X) - (K))
140 				for (di = 0; di < max; di++) {
141 					int ki;
142 					for (ki = di; ki >= -di; ki -= 2) {
143 						if (x != kd_pos[ki]
144 						    || y != xk_to_y(x, ki))
145 							continue;
146 						label = '0' + (di % 10);
147 						color = COLOR_YELLOW;
148 						break;
149 					}
150 					if (label != 'o')
151 						break;
152 					kd_pos += kd_len;
153 				}
154 			}
155 			if (kd_forward && kd_forward_d >= 0) {
156 #define xc_to_y(X, C, DELTA) ((X) - (C) + (DELTA))
157 				int ki;
158 				for (ki = kd_forward_d;
159 				     ki >= -kd_forward_d;
160 				     ki -= 2) {
161 					if (x != kd_forward[ki])
162 						continue;
163 					if (y != xk_to_y(x, ki))
164 						continue;
165 					label = 'F';
166 					color = COLOR_GREEN;
167 					break;
168 				}
169 			}
170 			if (kd_backward && kd_backward_d >= 0) {
171 				int delta = (int)r->atoms.len
172 					    - (int)l->atoms.len;
173 				int ki;
174 				for (ki = kd_backward_d;
175 				     ki >= -kd_backward_d;
176 				     ki -= 2) {
177 					if (x != kd_backward[ki])
178 						continue;
179 					if (y != xc_to_y(x, ki, delta))
180 						continue;
181 					if (label == 'o') {
182 						label = 'B';
183 						color = COLOR_BLUE;
184 					} else {
185 						label = 'X';
186 						color = COLOR_RED;
187 					}
188 					break;
189 				}
190 			}
191 			if (color)
192 				print("%s", color);
193 			print("%c", label);
194 			if (color)
195 				print("%s", COLOR_END);
196 			if (x < l->atoms.len)
197 				print("-");
198 		}
199 		print("\n");
200 		if (y == r->atoms.len)
201 			break;
202 
203 		print("    ");
204 		for (x = 0; x < l->atoms.len; x++) {
205 			bool same;
206 			diff_atom_same(&same, &l->atoms.head[x],
207 			    &r->atoms.head[y]);
208 			if (same)
209 				print("|\\");
210 			else
211 				print("| ");
212 		}
213 		print("|\n");
214 	}
215 }
216 
217 static inline void
218 debug_dump_myers_graph(const struct diff_data *l, const struct diff_data *r,
219 		       int *kd, int *kd_forward, int kd_forward_d,
220 		       int *kd_backward, int kd_backward_d)
221 {
222 	if (l->atoms.len > 99 || r->atoms.len > 99)
223 		return;
224 	dump_myers_graph(l, r, kd, kd_forward, kd_forward_d,
225 			 kd_backward, kd_backward_d);
226 }
227 
228 #else
229 #define debug(args...)
230 #define debug_dump(args...)
231 #define debug_dump_atom(args...)
232 #define debug_dump_atoms(args...)
233 #define debug_dump_myers_graph(args...)
234 #endif