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-rw-r--r--lib/diff_debug.h226
1 files changed, 226 insertions, 0 deletions
diff --git a/lib/diff_debug.h b/lib/diff_debug.h
new file mode 100644
index 000000000000..4b7ec8090638
--- /dev/null
+++ b/lib/diff_debug.h
@@ -0,0 +1,226 @@
+/*
+ * Copyright (c) 2020 Neels Hofmeyr <neels@hofmeyr.de>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#define DEBUG 0
+
+#if DEBUG
+#include <stdio.h>
+#include <unistd.h>
+#define print(args...) fprintf(stderr, ##args)
+#define debug print
+#define debug_dump dump
+#define debug_dump_atom dump_atom
+#define debug_dump_atoms dump_atoms
+
+static inline void
+print_atom_byte(unsigned char c) {
+ if (c == '\r')
+ print("\\r");
+ else if (c == '\n')
+ print("\\n");
+ else if ((c < 32 || c >= 127) && (c != '\t'))
+ print("\\x%02x", c);
+ else
+ print("%c", c);
+}
+
+static inline void
+dump_atom(const struct diff_data *left, const struct diff_data *right,
+ const struct diff_atom *atom)
+{
+ if (!atom) {
+ print("NULL atom\n");
+ return;
+ }
+ if (left)
+ print(" %3u '", diff_atom_root_idx(left, atom));
+
+ if (atom->at == NULL) {
+ off_t remain = atom->len;
+ if (fseek(atom->root->f, atom->pos, SEEK_SET) == -1)
+ abort(); /* cannot return error */
+ while (remain > 0) {
+ char buf[16];
+ size_t r;
+ int i;
+ r = fread(buf, 1, MIN(remain, sizeof(buf)),
+ atom->root->f);
+ if (r == 0)
+ break;
+ remain -= r;
+ for (i = 0; i < r; i++)
+ print_atom_byte(buf[i]);
+ }
+ } else {
+ const char *s;
+ for (s = atom->at; s < (const char*)(atom->at + atom->len); s++)
+ print_atom_byte(*s);
+ }
+ print("'\n");
+}
+
+static inline void
+dump_atoms(const struct diff_data *d, struct diff_atom *atom,
+ unsigned int count)
+{
+ if (count > 42) {
+ dump_atoms(d, atom, 20);
+ print("[%u lines skipped]\n", count - 20 - 20);
+ dump_atoms(d, atom + count - 20, 20);
+ return;
+ } else {
+ struct diff_atom *i;
+ foreach_diff_atom(i, atom, count) {
+ dump_atom(d, NULL, i);
+ }
+ }
+}
+
+static inline void
+dump(struct diff_data *d)
+{
+ dump_atoms(d, d->atoms.head, d->atoms.len);
+}
+
+/* kd is a quadratic space myers matrix from the original Myers algorithm.
+ * kd_forward and kd_backward are linear slices of a myers matrix from the Myers
+ * Divide algorithm.
+ */
+static inline void
+dump_myers_graph(const struct diff_data *l, const struct diff_data *r,
+ int *kd, int *kd_forward, int kd_forward_d,
+ int *kd_backward, int kd_backward_d)
+{
+ #define COLOR_YELLOW "\033[1;33m"
+ #define COLOR_GREEN "\033[1;32m"
+ #define COLOR_BLUE "\033[1;34m"
+ #define COLOR_RED "\033[1;31m"
+ #define COLOR_END "\033[0;m"
+ int x;
+ int y;
+ print(" ");
+ for (x = 0; x <= l->atoms.len; x++)
+ print("%2d", x % 100);
+ print("\n");
+
+ for (y = 0; y <= r->atoms.len; y++) {
+ print("%3d ", y);
+ for (x = 0; x <= l->atoms.len; x++) {
+
+ /* print d advancements from kd, if any. */
+ char label = 'o';
+ char *color = NULL;
+ if (kd) {
+ int max = l->atoms.len + r->atoms.len;
+ size_t kd_len = max + 1 + max;
+ int *kd_pos = kd;
+ int di;
+#define xk_to_y(X, K) ((X) - (K))
+ for (di = 0; di < max; di++) {
+ int ki;
+ for (ki = di; ki >= -di; ki -= 2) {
+ if (x != kd_pos[ki]
+ || y != xk_to_y(x, ki))
+ continue;
+ label = '0' + (di % 10);
+ color = COLOR_YELLOW;
+ break;
+ }
+ if (label != 'o')
+ break;
+ kd_pos += kd_len;
+ }
+ }
+ if (kd_forward && kd_forward_d >= 0) {
+#define xc_to_y(X, C, DELTA) ((X) - (C) + (DELTA))
+ int ki;
+ for (ki = kd_forward_d;
+ ki >= -kd_forward_d;
+ ki -= 2) {
+ if (x != kd_forward[ki])
+ continue;
+ if (y != xk_to_y(x, ki))
+ continue;
+ label = 'F';
+ color = COLOR_GREEN;
+ break;
+ }
+ }
+ if (kd_backward && kd_backward_d >= 0) {
+ int delta = (int)r->atoms.len
+ - (int)l->atoms.len;
+ int ki;
+ for (ki = kd_backward_d;
+ ki >= -kd_backward_d;
+ ki -= 2) {
+ if (x != kd_backward[ki])
+ continue;
+ if (y != xc_to_y(x, ki, delta))
+ continue;
+ if (label == 'o') {
+ label = 'B';
+ color = COLOR_BLUE;
+ } else {
+ label = 'X';
+ color = COLOR_RED;
+ }
+ break;
+ }
+ }
+ if (color)
+ print("%s", color);
+ print("%c", label);
+ if (color)
+ print("%s", COLOR_END);
+ if (x < l->atoms.len)
+ print("-");
+ }
+ print("\n");
+ if (y == r->atoms.len)
+ break;
+
+ print(" ");
+ for (x = 0; x < l->atoms.len; x++) {
+ bool same;
+ diff_atom_same(&same, &l->atoms.head[x],
+ &r->atoms.head[y]);
+ if (same)
+ print("|\\");
+ else
+ print("| ");
+ }
+ print("|\n");
+ }
+}
+
+static inline void
+debug_dump_myers_graph(const struct diff_data *l, const struct diff_data *r,
+ int *kd, int *kd_forward, int kd_forward_d,
+ int *kd_backward, int kd_backward_d)
+{
+ if (l->atoms.len > 99 || r->atoms.len > 99)
+ return;
+ dump_myers_graph(l, r, kd, kd_forward, kd_forward_d,
+ kd_backward, kd_backward_d);
+}
+
+#else
+#define debug(args...)
+#define debug_dump(args...)
+#define debug_dump_atom(args...)
+#define debug_dump_atoms(args...)
+#define debug_dump_myers_graph(args...)
+#endif
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