[FFmpeg-devel] [PATCH 1/5] lavu/bprint: add XML escaping

[Rodger Combs]

---
 libavutil/avstring.h |  7 +++++++
 libavutil/bprint.c   | 30 ++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/libavutil/avstring.h b/libavutil/avstring.h
index 466edaf..4d809d9 100644
--- a/libavutil/avstring.h
+++ b/libavutil/avstring.h
@@ -290,6 +290,7 @@ 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 ampersand-escaping.
 };
 
 /**
@@ -310,6 +311,12 @@ enum AVEscapeMode {
 #define AV_ESCAPE_FLAG_STRICT 0x02
 
 /**
+ * In addition to the provided list, escape all characters outside the range of
+ * U+0020 to U+007E. This only applies to XML-escaping.
+ */
+#define AV_ESCAPE_FLAG_NON_ASCII 0x04
+
+/**
  * 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 0a0d078..64d2ab1 100644
--- a/libavutil/bprint.c
+++ b/libavutil/bprint.c
@@ -261,6 +261,7 @@ int av_bprint_finalize(AVBPrint *buf, char **ret_str)
 }
 
 #define WHITESPACES " \n\t"
+#define XML_ESCAPES "&<>\"'"
 
 void av_bprint_escape(AVBPrint *dstbuf, const char *src, const char *special_chars,
                       enum AVEscapeMode mode, int flags)
@@ -271,6 +272,35 @@ void av_bprint_escape(AVBPrint *dstbuf, const char *src, const char *special_cha
         mode = AV_ESCAPE_MODE_BACKSLASH; /* TODO: implement a heuristic */
 
     switch (mode) {
+    case AV_ESCAPE_MODE_XML:
+        /* &;-escape characters */
+        if (!special_chars)
+            special_chars = XML_ESCAPES;
+
+        while (*src) {
+            uint8_t tmp;
+            uint32_t cp;
+            GET_UTF8(cp, (uint8_t)*src++, goto err;);
+
+            if ((cp < 0xFF && strchr(special_chars, cp)) ||
+                ((flags & AV_ESCAPE_FLAG_NON_ASCII) && (cp < 0x20 || cp > 0x7e))) {
+                switch (cp) {
+                case '&' : av_bprintf(dstbuf, "&");  break;
+                case '<' : av_bprintf(dstbuf, "<");   break;
+                case '>' : av_bprintf(dstbuf, ">");   break;
+                case '"' : av_bprintf(dstbuf, """); break;
+                case '\'': av_bprintf(dstbuf, "'"); break;
+                default:   av_bprintf(dstbuf, "&#%"PRIu32";", cp); break;
+                }
+            } else {
+                PUT_UTF8(cp, tmp, av_bprint_chars(dstbuf, tmp, 1);)
+            }
+            continue;
+        err:
+            av_bprint_chars(dstbuf, '?', 1);
+        }
+        break;
+
     case AV_ESCAPE_MODE_QUOTE:
         /* enclose the string between '' */
         av_bprint_chars(dstbuf, '\'', 1);
-- 
2.4.1