lavu/dict: add av_dict_get_string

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>

doc/APIchanges

@@ -15,6 +15,9 @@ libavutil:     2014-08-09
 
 API changes, most recent first:
 
+2014-11-21 - xxxxxxx - lavu 54.15.100 - dict.h
+   Add av_dict_get_string().
+
 2014-11-18 - xxxxxxx - lavu 54.14.100 - float_dsp.h
   Add avpriv_float_dsp_alloc().
 

libavutil/Makefile

@@ -157,6 +157,7 @@ TESTPROGS = adler32                                                     \
             cpu                                                         \
             crc                                                         \
             des                                                         \
+            dict                                                        \
             error                                                       \
             eval                                                        \
             file                                                        \

libavutil/dict.c

@@ -24,6 +24,7 @@
 #include "dict.h"
 #include "internal.h"
 #include "mem.h"
+#include "bprint.h"
 
 struct AVDictionary {
     int count;
@@ -207,3 +208,92 @@ void av_dict_copy(AVDictionary **dst, FF_CONST_AVUTIL53 AVDictionary *src, int f
     while ((t = av_dict_get(src, "", t, AV_DICT_IGNORE_SUFFIX)))
         av_dict_set(dst, t->key, t->value, flags);
 }
+
+int av_dict_get_string(const AVDictionary *m, char **buffer,
+                       const char key_val_sep, const char pairs_sep)
+{
+    AVDictionaryEntry *t = NULL;
+    AVBPrint bprint;
+    int cnt = 0;
+    char special_chars[] = {pairs_sep, key_val_sep, '\0'};
+
+    if (!buffer || pairs_sep == '\0' || key_val_sep == '\0' || pairs_sep == key_val_sep ||
+        pairs_sep == '\\' || key_val_sep == '\\')
+        return AVERROR(EINVAL);
+
+    if (!av_dict_count(m)) {
+        *buffer = av_strdup("");
+        return *buffer ? 0 : AVERROR(ENOMEM);
+    }
+
+    av_bprint_init(&bprint, 64, AV_BPRINT_SIZE_UNLIMITED);
+    while ((t = av_dict_get(m, "", t, AV_DICT_IGNORE_SUFFIX))) {
+        if (cnt++)
+            av_bprint_append_data(&bprint, &pairs_sep, 1);
+        av_bprint_escape(&bprint, t->key, special_chars, AV_ESCAPE_MODE_BACKSLASH, 0);
+        av_bprint_append_data(&bprint, &key_val_sep, 1);
+        av_bprint_escape(&bprint, t->value, special_chars, AV_ESCAPE_MODE_BACKSLASH, 0);
+    }
+    return av_bprint_finalize(&bprint, buffer);
+}
+
+#ifdef TEST
+static void print_dict(const AVDictionary *m)
+{
+    AVDictionaryEntry *t = NULL;
+    while ((t = av_dict_get(m, "", t, AV_DICT_IGNORE_SUFFIX)))
+        printf("%s %s   ", t->key, t->value);
+    printf("\n");
+}
+
+static void test_separators(const AVDictionary *m, const char pair, const char val)
+{
+    AVDictionary *dict = NULL;
+    char pairs[] = {pair , '\0'};
+    char vals[]  = {val, '\0'};
+
+    char *buffer = NULL;
+    av_dict_copy(&dict, m, 0);
+    print_dict(dict);
+    av_dict_get_string(dict, &buffer, val, pair);
+    printf("%s\n", buffer);
+    av_dict_free(&dict);
+    av_dict_parse_string(&dict, buffer, vals, pairs, 0);
+    av_freep(&buffer);
+    print_dict(dict);
+    av_dict_free(&dict);
+}
+
+int main(void)
+{
+    AVDictionary *dict = NULL;
+    char *buffer = NULL;
+
+    printf("Testing av_dict_get_string() and av_dict_parse_string()\n");
+    av_dict_get_string(dict, &buffer, '=', ',');
+    printf("%s\n", buffer);
+    av_freep(&buffer);
+    av_dict_set(&dict, "aaa", "aaa", 0);
+    av_dict_set(&dict, "b,b", "bbb", 0);
+    av_dict_set(&dict, "c=c", "ccc", 0);
+    av_dict_set(&dict, "ddd", "d,d", 0);
+    av_dict_set(&dict, "eee", "e=e", 0);
+    av_dict_set(&dict, "f,f", "f=f", 0);
+    av_dict_set(&dict, "g=g", "g,g", 0);
+    test_separators(dict, ',', '=');
+    av_dict_free(&dict);
+    av_dict_set(&dict, "aaa", "aaa", 0);
+    av_dict_set(&dict, "bbb", "bbb", 0);
+    av_dict_set(&dict, "ccc", "ccc", 0);
+    av_dict_set(&dict, "\\,=\'\"", "\\,=\'\"", 0);
+    test_separators(dict, '"',  '=');
+    test_separators(dict, '\'', '=');
+    test_separators(dict, ',', '"');
+    test_separators(dict, ',', '\'');
+    test_separators(dict, '\'', '"');
+    test_separators(dict, '"', '\'');
+    av_dict_free(&dict);
+
+    return 0;
+}
+#endif

libavutil/dict.h

@@ -171,6 +171,24 @@ void av_dict_copy(AVDictionary **dst, FF_CONST_AVUTIL53 AVDictionary *src, int f
  */
 void av_dict_free(AVDictionary **m);
 
+/**
+ * Get dictionary entries as a string.
+ *
+ * Create a string containing dictionary's entries.
+ * Such string may be passed back to av_dict_parse_string().
+ * @note String is escaped with backslashes ('\').
+ *
+ * @param[in]  m             dictionary
+ * @param[out] buffer        Pointer to buffer that will be allocated with string containg entries.
+ *                           Buffer must be freed by the caller when is no longer needed.
+ * @param[in]  key_val_sep   character used to separate key from value
+ * @param[in]  pairs_sep     character used to separate two pairs from each other
+ * @return                   >= 0 on success, negative on error
+ * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same.
+ */
+int av_dict_get_string(const AVDictionary *m, char **buffer,
+                       const char key_val_sep, const char pairs_sep);
+
 /**
  * @}
  */

libavutil/version.h

@@ -56,7 +56,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  54
-#define LIBAVUTIL_VERSION_MINOR  14
+#define LIBAVUTIL_VERSION_MINOR  15
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \