[FFmpeg-devel,v6,1/4] avutil/{avstring, bprint}: add XML escaping from ffprobe to avutil

diff --git a/libavutil/avstring.h b/libavutil/avstring.h
index ee225585b3..fae446c302 100644
--- a/libavutil/avstring.h
+++ b/libavutil/avstring.h
@@ -324,6 +324,7 @@  enum AVEscapeMode {
     AV_ESCAPE_MODE_AUTO,      ///< Use auto-selected escaping mode.
     AV_ESCAPE_MODE_BACKSLASH, ///< Use backslash escaping.
     AV_ESCAPE_MODE_QUOTE,     ///< Use single-quote escaping.
+    AV_ESCAPE_MODE_XML,       ///< Use XML non-markup character data escaping.
 };
 
 /**
@@ -343,6 +344,19 @@  enum AVEscapeMode {
  */
 #define AV_ESCAPE_FLAG_STRICT (1 << 1)
 
+/**
+ * Within AV_ESCAPE_MODE_XML, additionally escape single quotes for single
+ * quoted attributes.
+ */
+#define AV_ESCAPE_FLAG_XML_SINGLE_QUOTES (1 << 2)
+
+/**
+ * Within AV_ESCAPE_MODE_XML, additionally escape double quotes for double
+ * quoted attributes.
+ */
+#define AV_ESCAPE_FLAG_XML_DOUBLE_QUOTES (1 << 3)
+
+
 /**
  * Escape string in src, and put the escaped string in an allocated
  * string in *dst, which must be freed with av_free().
diff --git a/libavutil/bprint.c b/libavutil/bprint.c
index 2f059c5ba6..e12fb263fe 100644
--- a/libavutil/bprint.c
+++ b/libavutil/bprint.c
@@ -283,6 +283,35 @@  void av_bprint_escape(AVBPrint *dstbuf, const char *src, const char *special_cha
         av_bprint_chars(dstbuf, '\'', 1);
         break;
 
+    case AV_ESCAPE_MODE_XML:
+        /* escape XML non-markup character data as per 2.4 by default: */
+        /*  [^<&]* - ([^<&]* ']]>' [^<&]*) */
+
+        /* additionally, given one of the AV_ESCAPE_FLAG_XML_* flags, */
+        /* escape those specific characters as required. */
+        for (; *src; src++) {
+            switch (*src) {
+            case '&' : av_bprintf(dstbuf, "%s", "&amp;");  break;
+            case '<' : av_bprintf(dstbuf, "%s", "&lt;");   break;
+            case '>' : av_bprintf(dstbuf, "%s", "&gt;");   break;
+            case '\'':
+                if (!(flags & AV_ESCAPE_FLAG_XML_SINGLE_QUOTES))
+                    goto XML_DEFAULT_HANDLING;
+
+                av_bprintf(dstbuf, "%s", "&apos;");
+                break;
+            case '"' :
+                if (!(flags & AV_ESCAPE_FLAG_XML_DOUBLE_QUOTES))
+                    goto XML_DEFAULT_HANDLING;
+
+                av_bprintf(dstbuf, "%s", "&quot;");
+                break;
+XML_DEFAULT_HANDLING:
+            default: av_bprint_chars(dstbuf, *src, 1);
+            }
+        }
+        break;
+
     /* case AV_ESCAPE_MODE_BACKSLASH or unknown mode */
     default:
         /* \-escape characters */
diff --git a/libavutil/version.h b/libavutil/version.h
index b7c5892a37..356c54d633 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -79,7 +79,7 @@ 
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  56
-#define LIBAVUTIL_VERSION_MINOR  66
+#define LIBAVUTIL_VERSION_MINOR  67
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
diff --git a/tools/ffescape.c b/tools/ffescape.c
index 0530d28c6d..1ed8daa801 100644
--- a/tools/ffescape.c
+++ b/tools/ffescape.c
@@ -78,8 +78,10 @@  int main(int argc, char **argv)
             infilename = optarg;
             break;
         case 'f':
-            if      (!strcmp(optarg, "whitespace")) escape_flags |= AV_ESCAPE_FLAG_WHITESPACE;
-            else if (!strcmp(optarg, "strict"))     escape_flags |= AV_ESCAPE_FLAG_STRICT;
+            if      (!strcmp(optarg, "whitespace"))        escape_flags |= AV_ESCAPE_FLAG_WHITESPACE;
+            else if (!strcmp(optarg, "strict"))            escape_flags |= AV_ESCAPE_FLAG_STRICT;
+            else if (!strcmp(optarg, "xml_single_quotes")) escape_flags |= AV_ESCAPE_FLAG_XML_SINGLE_QUOTES;
+            else if (!strcmp(optarg, "xml_double_quotes")) escape_flags |= AV_ESCAPE_FLAG_XML_DOUBLE_QUOTES;
             else {
                 av_log(NULL, AV_LOG_ERROR,
                        "Invalid value '%s' for option -f, "
@@ -104,6 +106,7 @@  int main(int argc, char **argv)
             if      (!strcmp(optarg, "auto"))      escape_mode = AV_ESCAPE_MODE_AUTO;
             else if (!strcmp(optarg, "backslash")) escape_mode = AV_ESCAPE_MODE_BACKSLASH;
             else if (!strcmp(optarg, "quote"))     escape_mode = AV_ESCAPE_MODE_QUOTE;
+            else if (!strcmp(optarg, "xml"))       escape_mode = AV_ESCAPE_MODE_XML;
             else {
                 av_log(NULL, AV_LOG_ERROR,
                        "Invalid value '%s' for option -m, "