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-rw-r--r--editors/diff.c94
-rwxr-xr-xtestsuite/diff.tests31
2 files changed, 71 insertions, 54 deletions
diff --git a/editors/diff.c b/editors/diff.c
index 2e3a455..e4d74ab 100644
--- a/editors/diff.c
+++ b/editors/diff.c
@@ -368,16 +368,6 @@ static int line_compar(const void *a, const void *b)
#undef l1
}
-static void uni_range(int a, int b)
-{
- if (a < b)
- printf("%d,%d", a, b - a + 1);
- else if (a == b)
- printf("%d", b);
- else
- printf("%d,0", b);
-}
-
static void fetch(FILE_and_pos_t *ft, const off_t *ix, int a, int b, int ch)
{
for (int i = a; i <= b; i++) {
@@ -561,17 +551,6 @@ start:
return J;
}
-/*
- * The following struct is used to record change information
- * doing a "context" or "unified" diff.
- */
-struct context_vec {
- int a; /* start line in old file */
- int b; /* end line in old file */
- int c; /* start line in new file */
- int d; /* end line in new file */
-};
-
static bool diff(FILE* fp[2], char *file[2])
{
int nlen[2];
@@ -580,22 +559,23 @@ static bool diff(FILE* fp[2], char *file[2])
int *J = create_J(ft, nlen, ix);
bool anychange = false;
- struct context_vec *vec = NULL;
- int idx = -1, i = 1;
+ typedef struct { int a, b; } vec_t[2];
+ vec_t *vec = NULL;
+ int i = 1, idx = -1;
do {
bool nonempty = false;
while (1) {
- struct context_vec v;
+ vec_t v;
- for (v.a = i; v.a <= nlen[0] && J[v.a] == J[v.a - 1] + 1; v.a++)
+ for (v[0].a = i; v[0].a <= nlen[0] && J[v[0].a] == J[v[0].a - 1] + 1; v[0].a++)
continue;
- v.c = J[v.a - 1] + 1;
+ v[1].a = J[v[0].a - 1] + 1;
- for (v.b = v.a - 1; v.b < nlen[0] && !J[v.b + 1]; v.b++)
+ for (v[0].b = v[0].a - 1; v[0].b < nlen[0] && !J[v[0].b + 1]; v[0].b++)
continue;
- v.d = J[v.b + 1] - 1;
+ v[1].b = J[v[0].b + 1] - 1;
/*
* Indicate that there is a difference between lines a and b of the 'from' file
* to get to lines c to d of the 'to' file. If a is greater than b then there
@@ -603,35 +583,36 @@ static bool diff(FILE* fp[2], char *file[2])
* lines appended (beginning at b). If c is greater than d then there are
* lines missing from the 'to' file.
*/
- if (v.a <= v.b || v.c <= v.d) {
+ if (v[0].a <= v[0].b || v[1].a <= v[1].b) {
/*
* If this change is more than 'context' lines from the
* previous change, dump the record and reset it.
*/
+ int ct = (2 * opt_U_context) + 1;
if (idx >= 0
- && v.a > vec[idx].b + (2 * opt_U_context) + 1
- && v.c > vec[idx].d + (2 * opt_U_context) + 1
+ && v[0].a > vec[idx][0].b + ct
+ && v[1].a > vec[idx][1].b + ct
) {
break;
}
- nonempty |= (v.a >= v.b) && (v.c >= v.d);
+
+ for (int j = 0; j < 2; j++)
+ for (int k = v[j].a; k < v[j].b; k++)
+ nonempty |= (ix[j][k+1] - ix[j][k] != 1);
+
vec = xrealloc_vector(vec, 6, ++idx);
- vec[idx] = v;
+ memcpy(vec[idx], v, sizeof(v));
}
- i = v.b + 1;
+ i = v[0].b + 1;
if (i > nlen[0])
break;
- J[v.b] = v.d;
+ J[v[0].b] = v[1].b;
}
- if (idx < 0)
- continue;
- if (!(option_mask32 & (FLAG(q)+FLAG(B))) && !nonempty) {
- struct context_vec *cvp = vec;
- int lowa = MAX(1, cvp->a - opt_U_context);
- int upb = MIN(nlen[0], vec[idx].b + opt_U_context);
- int lowc = MAX(1, cvp->c - opt_U_context);
- int upd = MIN(nlen[1], vec[idx].d + opt_U_context);
+ if (idx < 0 || ((option_mask32 & FLAG(B)) && !nonempty))
+ goto cont;
+ if (!(option_mask32 & FLAG(q))) {
+ vec_t span, *cvp = vec;
if (!anychange) {
/* Print the context/unidiff header first time through */
@@ -639,28 +620,33 @@ static bool diff(FILE* fp[2], char *file[2])
printf("+++ %s\n", label[1] ? label[1] : file[1]);
}
- printf("@@ -");
- uni_range(lowa, upb);
- printf(" +");
- uni_range(lowc, upd);
- printf(" @@\n");
+ printf("@@");
+ for (int j = 0; j < 2; j++) {
+ int a = span[j].a = MAX(1, (*cvp)[j].a - opt_U_context);
+ int b = span[j].b = MIN(nlen[j], vec[idx][j].b + opt_U_context);
+ printf(" %c%d", j ? '+' : '-', MIN(a, b));
+ if (a == b)
+ continue;
+ printf(",%d", (a < b) ? b - a + 1 : 0);
+ }
+ printf(" @@\n");
/*
* Output changes in "unified" diff format--the old and new lines
* are printed together.
*/
- while (1) {
+ for (int lowa = span[0].a; ; lowa = (*cvp++)[0].b + 1) {
bool end = cvp > &vec[idx];
- fetch(&ft[0], ix[0], lowa, end ? upb : cvp->a - 1, ' ');
+ fetch(&ft[0], ix[0], lowa, end ? span[0].b : (*cvp)[0].a - 1, ' ');
if (end)
break;
- fetch(&ft[0], ix[0], cvp->a, cvp->b, '-');
- fetch(&ft[1], ix[1], cvp->c, cvp->d, '+');
- lowa = cvp++->b + 1;
+ for (int j = 0; j < 2; j++)
+ fetch(&ft[j], ix[j], (*cvp)[j].a, (*cvp)[j].b, j ? '+' : '-');
}
}
- idx = -1;
anychange = true;
+ cont:
+ idx = -1;
} while (i <= nlen[0]);
free(vec);
diff --git a/testsuite/diff.tests b/testsuite/diff.tests
index f7bde2f..72ebb6c 100755
--- a/testsuite/diff.tests
+++ b/testsuite/diff.tests
@@ -44,6 +44,17 @@ testing "diff of stdin, twice" \
"" \
"stdin"
+testing "diff of empty file against nonempty one" \
+ "diff -u - input | $TRIM_TAB" \
+"\
+--- -
++++ input
+@@ -0,0 +1 @@
++a
+" \
+ "a\n" \
+ ""
+
testing "diff -b treats EOF as whitespace" \
'diff -ub - input; echo $?' \
"0\n" \
@@ -56,6 +67,26 @@ testing "diff -b treats all spaces as equal" \
"a \t c\n" \
"a\t \tc\n"
+testing "diff -B ignores changes whose lines are all blank" \
+ 'diff -uB - input; echo $?' \
+ "0\n" \
+ "a\n" \
+ "\na\n\n"
+
+testing "diff -B does not ignore changes whose lines are not all blank" \
+ "diff -uB - input | $TRIM_TAB" \
+"\
+--- -
++++ input
+@@ -1,3 +1 @@
+-
+-b
+-
++a
+" \
+ "a\n" \
+ "\nb\n\n"
+
testing "diff always takes context from old file" \
"diff -ub - input | $TRIM_TAB" \
"\