I needed an option to ignore changes in comments, so I made a patch
and it seems to work. If it's ok, please apply it to the main source.
The patch was made against diff 3.0.9-53de.
Piotr Stefaniak
diff --git a/src/diff.c b/src/diff.c
index 807d38f..341f57f 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -124,6 +124,7 @@ enum
NORMAL_OPTION,
SDIFF_MERGE_ASSIST_OPTION,
STRIP_TRAILING_CR_OPTION,
+ STRIP_ANSIC_COMMENTS_OPTION,
SUPPRESS_BLANK_EMPTY_OPTION,
SUPPRESS_COMMON_LINES_OPTION,
TABSIZE_OPTION,
@@ -202,6 +203,7 @@ static struct option const longopts[] =
{"speed-large-files", 0, 0, 'H'},
{"starting-file", 1, 0, 'S'},
{"strip-trailing-cr", 0, 0, STRIP_TRAILING_CR_OPTION},
+ {"strip-ansic-comments", 0, 0, STRIP_ANSIC_COMMENTS_OPTION},
{"suppress-blank-empty", 0, 0, SUPPRESS_BLANK_EMPTY_OPTION},
{"suppress-common-lines", 0, 0, SUPPRESS_COMMON_LINES_OPTION},
{"tabsize", 1, 0, TABSIZE_OPTION},
@@ -575,6 +577,10 @@ main (int argc, char **argv)
strip_trailing_cr = true;
break;
+ case STRIP_ANSIC_COMMENTS_OPTION:
+ strip_ansic_comments = true;
+ break;
+
case SUPPRESS_BLANK_EMPTY_OPTION:
suppress_blank_empty = true;
break;
@@ -853,6 +859,7 @@ static char const * const option_help_msgid[] = {
N_("-B --ignore-blank-lines Ignore changes whose lines are all blank."),
N_("-I RE --ignore-matching-lines=RE Ignore changes whose lines all match RE."),
N_("--strip-trailing-cr Strip trailing carriage return on input."),
+ N_("--strip-ansic-comments Strip ANSI C comments on input."),
#if O_BINARY
N_("--binary Read and write data in binary mode."),
#endif
diff --git a/src/diff.h b/src/diff.h
index 97f8d96..0e1769b 100644
--- a/src/diff.h
+++ b/src/diff.h
@@ -156,6 +156,9 @@ XTERN bool suppress_blank_empty;
/* Remove trailing carriage returns from input. */
XTERN bool strip_trailing_cr;
+/* Remove ANSI C comments from input. */
+XTERN bool strip_ansic_comments;
+
/* In directory comparison, specify file to start with (-S).
This is used for resuming an aborted comparison.
All file names less than this name are ignored. */
diff --git a/src/diff3.c b/src/diff3.c
index 0f11fdc..a445dd5 100644
--- a/src/diff3.c
+++ b/src/diff3.c
@@ -139,6 +139,9 @@ static bool text;
/* Remove trailing carriage returns from input. */
static bool strip_trailing_cr;
+/* Remove ANSI C comments from input. */
+static bool strip_ansic_comments;
+
/* If nonzero, write out an ed script instead of the standard diff3 format. */
static bool edscript;
diff --git a/src/io.c b/src/io.c
index 031be3d..63bbb67 100644
--- a/src/io.c
+++ b/src/io.c
@@ -523,6 +523,46 @@ prepare_text (struct file_data *current)
/* Don't use uninitialized storage when planting or using sentinels. */
memset (p + buffered, 0, sizeof (word));
+ if (strip_ansic_comments && (dst = memchr (p, '/', buffered)))
+ {
+ char const *src = dst;
+ char const *srclim = p + buffered;
+ int in = 0;
+
+ do
+ {
+ if (!in)
+ {
+ if (*src == '/')
+ {
+ if (++src >= srclim)
+ {
+ *dst++ = *src;
+ break;
+ }
+
+ if (*src == '*')
+ {
+ src++;
+ in = 1;
+ continue;
+ }
+ else
+ *dst++ = '/';
+ }
+ *dst++ = *src++;
+ }
+ else if (*src++ == '*' && *src == '/')
+ {
+ src++;
+ in = 0;
+ }
+ }
+ while (src < srclim);
+
+ buffered -= src - dst;
+ }
+
if (strip_trailing_cr && (dst = memchr (p, '\r', buffered)))
{
char const *src = dst;
