File diff3-style-merges-locate-merge.diff of Package patch

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File diff3-style-merges-locate-merge.diff of Package patch (Revision 76adc40b1b455416b40416052aa2d017)

Currently displaying revision 76adc40b1b455416b40416052aa2d017 , Show latest

---
 patch.c |   78 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 72 insertions(+), 6 deletions(-)

Index: b/patch.c
===================================================================
--- a/patch.c
+++ b/patch.c
@@ -62,6 +62,8 @@ static FILE *create_output_file (char co
 static LINENUM locate_hunk (LINENUM);
 static bool apply_hunk (struct outstate *, LINENUM);
 static bool common_context(LINENUM, LINENUM, LINENUM);
+static LINENUM min_mismatches(LINENUM, LINENUM);
+static LINENUM locate_merge (void);
 static bool merge_hunk (struct outstate *, LINENUM, LINENUM);
 static void merge_ends_here(struct outstate *outstate);
 static bool copy_till (struct outstate *, LINENUM);
@@ -304,15 +306,11 @@ main (int argc, char **argv)
 		goto skip_hunk;
 	    } else if (!where) {
 		if (mergetype & MERGE_REJECTS) {
-		    LINENUM guess = pch_first () + last_offset;
-
-		    if (merge_hunk(&outstate, guess, -1)) {
+		    if (merge_hunk(&outstate, locate_merge(), -1)) {
 			merged++;
 			mismatch = 1;
-		    } else {
-			/* FIXME: guess harder! */
+		    } else
 			goto skip_hunk;
-		    }
 		} else
 		    goto skip_hunk;
 	    } else {
@@ -1356,6 +1354,74 @@ static bool common_context(LINENUM where
 	     memcmp(line, pfetch(new), size) == 0));
 }
 
+static LINENUM min_mismatches(LINENUM where, LINENUM lowest)
+{
+    register LINENUM ptrn_lines = pch_ptrn_lines();
+    register LINENUM old, mismatched = 0;
+
+    for (old = 1; old <= ptrn_lines; old++, where++) {
+	size_t size;
+	const char *line;
+
+	line = ifetch (where, false, &size);
+	if (!size ||
+	    !(canonicalize ?
+	      similar(pfetch(old), pch_line_len(old), line, size) :
+	     (size == pch_line_len(old) &&
+	      memcmp(line, pfetch(old), size) == 0))) {
+	    mismatched++;
+	    if (mismatched >= lowest)
+		break;
+	}
+    }
+    return mismatched;
+}
+
+static LINENUM locate_merge ()
+{
+    register LINENUM first_guess = pch_first () + last_offset;
+    register LINENUM lowest = input_lines, where = first_guess;
+    register LINENUM offset;
+    LINENUM pat_lines = pch_ptrn_lines();
+    LINENUM suffix_context = pch_suffix_context ();
+    LINENUM max_where = input_lines - (pat_lines - suffix_context) + 1;
+    LINENUM min_where = last_frozen_line + 1;
+    LINENUM max_pos_offset = max_where - first_guess;
+    LINENUM max_neg_offset = first_guess - min_where;
+    LINENUM max_offset = (max_pos_offset < max_neg_offset
+			  ? max_neg_offset : max_pos_offset);
+
+    /* Do not try lines <= 0.  */
+    if (first_guess <= max_neg_offset)
+	max_neg_offset = first_guess - 1;
+
+    for (offset = 0;  offset <= max_offset;  offset++) {
+	if (offset <= max_pos_offset) {
+	    register LINENUM mismatched;
+
+	    mismatched = min_mismatches(first_guess - offset, lowest);
+	    if (mismatched < lowest) {
+		lowest = mismatched;
+		where = first_guess - offset;
+		if (lowest == 1)
+			break;
+	    }
+	}
+	if (0 < offset && offset <= max_neg_offset) {
+	    register LINENUM mismatched;
+
+	    mismatched = min_mismatches(first_guess + offset, lowest);
+	    if (mismatched < lowest) {
+		lowest = mismatched;
+		where = first_guess + offset;
+		if (lowest == 1)
+			break;
+	    }
+	}
+    }
+    return where;
+}
+
 /* A FUZZ value of -1 indicates that the hunk could not be applied. */
 
 static bool merge_hunk (struct outstate *outstate, LINENUM where, LINENUM fuzz)

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File diff3-style-merges-locate-merge.diff of Package patch (Revision 76adc40b1b455416b40416052aa2d017)

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