lavu/opt: extend AVOptionRange by extra values

AVOptionRange is not flexible enough to store AV_OPT_TYPE_IMAGE_SIZE
ranges. Current implementation can only store pixel count.
This patch aims to keep backward compatibility and extend
AVOptionRange with possibility to store width/height ranges.
Signed-off-by: Lukasz Marek <lukasz.m.luki@gmail.com>

doc/APIchanges

@@ -15,6 +15,10 @@ libavutil:     2012-10-22
 
 API changes, most recent first:
 
+2014-04-xx - xxxxxxx - lavu 52.72.100 - opt.h
+  Add AV_OPT_MULTI_COMPONENT_RANGE define to allow return 
+  multi-component option ranges.
+
 2014-03-xx - xxxxxxx - lavu 52.70.100 - mem.h
   Add av_dynarray_add_nofree() function.
 

libavutil/opt.c

@@ -1514,6 +1514,7 @@ void *av_opt_ptr(const AVClass *class, void *obj, const char *name)
 
 int av_opt_query_ranges(AVOptionRanges **ranges_arg, void *obj, const char *key, int flags)
 {
+    int ret;
     const AVClass *c = *(AVClass**)obj;
     int (*callback)(AVOptionRanges **, void *obj, const char *key, int flags) = NULL;
 
@@ -1523,7 +1524,13 @@ int av_opt_query_ranges(AVOptionRanges **ranges_arg, void *obj, const char *key,
     if (!callback)
         callback = av_opt_query_ranges_default;
 
-    return callback(ranges_arg, obj, key, flags);
+    ret = callback(ranges_arg, obj, key, flags);
+    if (ret >= 0) {
+        if (!(flags & AV_OPT_MULTI_COMPONENT_RANGE))
+            ret = 1;
+        (*ranges_arg)->nb_components = ret;
+    }
+    return ret;
 }
 
 int av_opt_query_ranges_default(AVOptionRanges **ranges_arg, void *obj, const char *key, int flags)
@@ -1544,6 +1551,7 @@ int av_opt_query_ranges_default(AVOptionRanges **ranges_arg, void *obj, const ch
     ranges->range = range_array;
     ranges->range[0] = range;
     ranges->nb_ranges = 1;
+    ranges->nb_components = 1;
     range->is_range = 1;
     range->value_min = field->min;
     range->value_max = field->max;
@@ -1587,7 +1595,7 @@ int av_opt_query_ranges_default(AVOptionRanges **ranges_arg, void *obj, const ch
     }
 
     *ranges_arg = ranges;
-    return 0;
+    return 1;
 fail:
     av_free(ranges);
     av_free(range);
@@ -1600,7 +1608,7 @@ void av_opt_freep_ranges(AVOptionRanges **rangesp)
     int i;
     AVOptionRanges *ranges = *rangesp;
 
-    for (i = 0; i < ranges->nb_ranges; i++) {
+    for (i = 0; i < ranges->nb_ranges * ranges->nb_components; i++) {
         AVOptionRange *range = ranges->range[i];
         av_freep(&range->str);
         av_freep(&ranges->range[i]);

libavutil/opt.h

@@ -313,17 +313,67 @@ typedef struct AVOption {
  */
 typedef struct AVOptionRange {
     const char *str;
-    double value_min, value_max;             ///< For string ranges this represents the min/max length, for dimensions this represents the min/max pixel count
-    double component_min, component_max;     ///< For string this represents the unicode range for chars, 0-127 limits to ASCII
-    int is_range;                            ///< if set to 1 the struct encodes a range, if set to 0 a single value
+    /**
+     * Value range.
+     * For string ranges this represents the min/max length.
+     * For dimensions this represents the min/max pixel count or width/height in multi-component case.
+     */
+    double value_min, value_max;
+    /**
+     * Value's component range.
+     * For string this represents the unicode range for chars, 0-127 limits to ASCII.
+     */
+    double component_min, component_max;
+    /**
+     * Range flag.
+     * If set to 1 the struct encodes a range, if set to 0 a single value.
+     */
+    int is_range;
 } AVOptionRange;
 
 /**
- * List of AVOptionRange structs
+ * List of AVOptionRange structs.
  */
 typedef struct AVOptionRanges {
+    /**
+     * Array of option ranges.
+     *
+     * Most of option types use just one component.
+     * Following describes multi-component option types:
+     *
+     * AV_OPT_TYPE_IMAGE_SIZE:
+     * component index 0: range of pixel count (width * height).
+     * component index 1: range of width.
+     * component index 2: range of height.
+     *
+     * @note To obtain multi-component version of this structure, user must
+     *       provide AV_OPT_MULTI_COMPONENT_RANGE to av_opt_query_ranges or
+     *       av_opt_query_ranges_default function.
+     *
+     * Multi-component range can be read as in following example:
+     *
+     * @code
+     * int range_index, component_index;
+     * AVOptionRanges *ranges;
+     * AVOptionRange *range[3]; //may require more than 3 in the future.
+     * av_opt_query_ranges(&ranges, obj, key, AV_OPT_MULTI_COMPONENT_RANGE);
+     * for (range_index = 0; range_index < ranges->nb_ranges; range_index++) {
+     *     for (component_index = 0; component_index < ranges->nb_components; component_index++)
+     *         range[component_index] = ranges->range[ranges->nb_ranges * component_index + range_index];
+     *     //do something with range here.
+     * }
+     * av_opt_freep_ranges(&ranges);
+     * @endcode
+     */
     AVOptionRange **range;
+    /**
+     * Number of ranges per component.
+     */
     int nb_ranges;
+    /**
+     * Number of componentes.
+     */
+    int nb_components;
 } AVOptionRanges;
 
 
@@ -558,6 +608,13 @@ int av_opt_eval_q     (void *obj, const AVOption *o, const char *val, AVRational
  */
 #define AV_OPT_SEARCH_FAKE_OBJ   0x0002
 
+/**
+ *  Allows av_opt_query_ranges and av_opt_query_ranges_default to return more than
+ *  one component for certain option types.
+ *  @see AVOptionRanges for details.
+ */
+#define AV_OPT_MULTI_COMPONENT_RANGE 0x1000
+
 /**
  * Look for an option in an object. Consider only options which
  * have all the specified flags set.
@@ -739,10 +796,11 @@ void av_opt_freep_ranges(AVOptionRanges **ranges);
  *
  * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
  *              AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
+ *              AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
  *
  * The result must be freed with av_opt_freep_ranges.
  *
- * @return >= 0 on success, a negative errro code otherwise
+ * @return number of compontents returned on success, a negative errro code otherwise
  */
 int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags);
 
@@ -754,10 +812,11 @@ int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags
  *
  * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
  *              AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
+ *              AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
  *
  * The result must be freed with av_opt_free_ranges.
  *
- * @return >= 0 on success, a negative errro code otherwise
+ * @return number of compontents returned on success, a negative errro code otherwise
  */
 int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags);
 

libavutil/version.h

@@ -56,7 +56,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  52
-#define LIBAVUTIL_VERSION_MINOR  71
+#define LIBAVUTIL_VERSION_MINOR  72
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \