hacking. Add value_compare, value_union, and value_intersect functions

Original commit message from CVS:
hacking.  Add value_compare, value_union, and value_intersect functions

gst/gststructure.c

@@ -565,6 +565,28 @@ gst_structure_n_fields(GstStructure *structure)
   return structure->fields->len;
 }
 
+/**
+ * gst_structure_field_foreach:
+ * @structure: a #GstStructure
+ * @func: a function to call for each field
+ * @user_data: private data
+ *
+ * Calls the provided function once for each field in the #GstStructure.
+ */
+void
+gst_structure_field_foreach (GstStructure *structure,
+    GstStructureForeachFunc func, gpointer user_data)
+{
+  int i;
+  GstStructureField *field;
+
+  for(i=0;i<structure->fields->len;i++){
+    field = GST_STRUCTURE_FIELD(structure, i);
+
+    func (structure, field->name, &field->value, user_data);
+  }
+}
+
 /**
  * gst_structure_has_field:
  * @structure: a #GstStructure

gst/gststructure.h

@@ -28,6 +28,9 @@ G_BEGIN_DECLS
 typedef struct _GstStructure GstStructure;
 typedef struct _GstStructureField GstStructureField;
 
+typedef void (*GstStructureForeachFunc) (GstStructure *structure,
+    GQuark field_id, GValue *value, gpointer user_data);
+
 struct _GstStructure {
   int len;
 
@@ -76,6 +79,8 @@ void gst_structure_remove_field(GstStructure *structure, const gchar *field);
 
 GType gst_structure_get_field_type(GstStructure *structure,
     const gchar *field);
+void gst_structure_field_foreach (GstStructure *structure,
+    GstStructureForeachFunc func, gpointer user_data);
 gint gst_structure_n_fields(GstStructure *structure);
 gboolean gst_structure_has_field(GstStructure *structure, const gchar *field);
 gboolean gst_structure_has_field_typed(GstStructure *structure,

gst/gstvalue.c

@@ -20,15 +20,40 @@
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
+#include <string.h>
 
 #include <gst/gst.h>
 #include <gobject/gvaluecollector.h>
 
+typedef struct _GstValueCompareInfo GstValueCompareInfo;
+struct _GstValueCompareInfo {
+  GType type;
+  GstValueCompareFunc func;
+};
+
+typedef struct _GstValueUnionInfo GstValueUnionInfo;
+struct _GstValueUnionInfo {
+  GType type1;
+  GType type2;
+  GstValueUnionFunc func;
+};
+
+typedef struct _GstValueIntersectInfo GstValueIntersectInfo;
+struct _GstValueIntersectInfo {
+  GType type1;
+  GType type2;
+  GstValueIntersectFunc func;
+};
 
 GType gst_type_fourcc;
 GType gst_type_int_range;
 GType gst_type_double_range;
 
+GArray *gst_value_compare_funcs;
+GArray *gst_value_union_funcs;
+GArray *gst_value_intersect_funcs;
+
+
 static void 
 gst_value_init_fourcc (GValue *value)
 {
@@ -129,7 +154,7 @@ gst_value_set_int_range (GValue *value, int start, int end)
 }
 
 int
-gst_value_get_int_range_start (const GValue *value)
+gst_value_get_int_range_min (const GValue *value)
 {
   g_return_val_if_fail (GST_VALUE_HOLDS_FOURCC (value), 0);
 
@@ -137,7 +162,7 @@ gst_value_get_int_range_start (const GValue *value)
 }
 
 int
-gst_value_get_int_range_end (const GValue *value)
+gst_value_get_int_range_max (const GValue *value)
 {
   g_return_val_if_fail (GST_VALUE_HOLDS_FOURCC (value), 0);
 
@@ -160,6 +185,214 @@ gst_value_transform_int_range_string (const GValue *src_value,
       (int)src_value->data[0].v_long, (int)src_value->data[1].v_long);
 }
 
+/* comparison functions */
+
+static int
+gst_value_compare_int (const GValue *value1, const GValue *value2)
+{
+  return value2->data[0].v_int - value1->data[0].v_int;
+}
+
+static int
+gst_value_compare_double (const GValue *value1, const GValue *value2)
+{
+  return (value2->data[0].v_double > value1->data[0].v_double) -
+    (value2->data[0].v_double < value1->data[0].v_double);
+}
+
+static int
+gst_value_compare_string (const GValue *value1, const GValue *value2)
+{
+  return strcmp(value1->data[0].v_pointer, value2->data[0].v_pointer);
+}
+
+static int
+gst_value_compare_fourcc (const GValue *value1, const GValue *value2)
+{
+  return value2->data[0].v_int - value1->data[0].v_int;
+}
+
+gboolean
+gst_value_can_compare (const GValue *value1, const GValue *value2)
+{
+  GstValueCompareInfo *compare_info;
+  int i;
+
+  if(G_VALUE_TYPE(value1) != G_VALUE_TYPE(value2))return FALSE;
+  for(i=0;i<gst_value_compare_funcs->len;i++){
+    compare_info = &g_array_index(gst_value_compare_funcs,
+	GstValueCompareInfo, i);
+    if(compare_info->type == G_VALUE_TYPE(value1)) return TRUE;
+  }
+
+  return FALSE;
+}
+
+int
+gst_value_compare (const GValue *value1, const GValue *value2)
+{
+  GstValueCompareInfo *compare_info;
+  int i;
+
+  g_return_val_if_fail(G_VALUE_TYPE(value1) == G_VALUE_TYPE(value2), 0);
+  for(i=0;i<gst_value_compare_funcs->len;i++){
+    compare_info = &g_array_index(gst_value_compare_funcs,
+	GstValueCompareInfo, i);
+    if(compare_info->type != G_VALUE_TYPE(value1)) continue;
+
+    return compare_info->func(value1, value2);
+  }
+
+  g_return_val_if_fail(0 /* type not found */, 0);
+  return 0;
+}
+
+void
+gst_value_register_compare_func (GType type, GstValueCompareFunc func)
+{
+  GstValueCompareInfo compare_info;
+
+  compare_info.type = type;
+  compare_info.func = func;
+
+  g_array_append_val(gst_value_compare_funcs, compare_info);
+}
+
+/* union */
+
+gboolean
+gst_value_can_union (const GValue *value1, const GValue *value2)
+{
+  GstValueUnionInfo *union_info;
+  int i;
+
+  for(i=0;i<gst_value_union_funcs->len;i++){
+    union_info = &g_array_index(gst_value_union_funcs, GstValueUnionInfo, i);
+    if(union_info->type1 == G_VALUE_TYPE(value1) &&
+	union_info->type2 == G_VALUE_TYPE(value2)) return TRUE;
+  }
+
+  return FALSE;
+}
+
+void
+gst_value_union (GValue *dest, const GValue *value1, const GValue *value2)
+{
+  GstValueUnionInfo *union_info;
+  int i;
+
+  for(i=0;i<gst_value_union_funcs->len;i++){
+    union_info = &g_array_index(gst_value_union_funcs, GstValueUnionInfo, i);
+    if(union_info->type1 == G_VALUE_TYPE(value1) &&
+	union_info->type2 == G_VALUE_TYPE(value2)) {
+      union_info->func(dest, value1, value2);
+      return;
+    }
+  }
+}
+
+void
+gst_value_register_union_func (GType type1, GType type2, GstValueUnionFunc func)
+{
+  GstValueUnionInfo union_info;
+
+  union_info.type1 = type1;
+  union_info.type2 = type2;
+  union_info.func = func;
+
+  g_array_append_val(gst_value_union_funcs, union_info);
+}
+
+/* intersection */
+
+static gboolean
+gst_value_intersect_int_int_range (GValue *dest, const GValue *src1,
+    const GValue *src2)
+{
+  g_return_val_if_fail(G_VALUE_TYPE(src1) == G_TYPE_INT, FALSE);
+  g_return_val_if_fail(G_VALUE_TYPE(src2) == GST_TYPE_INT_RANGE, FALSE);
+
+  if (src2->data[0].v_long <= src1->data[0].v_int &&
+      src2->data[1].v_long >= src1->data[0].v_int){
+    g_value_copy(src1, dest);
+    return TRUE;
+  }
+
+  return FALSE;
+}
+
+static gboolean
+gst_value_intersect_int_range_int_range (GValue *dest, const GValue *src1,
+    const GValue *src2)
+{
+  int min;
+  int max;
+
+  g_return_val_if_fail(G_VALUE_TYPE(src1) == GST_TYPE_INT_RANGE, FALSE);
+  g_return_val_if_fail(G_VALUE_TYPE(src2) == GST_TYPE_INT_RANGE, FALSE);
+
+  min = MAX(src1->data[0].v_long, src2->data[0].v_long);
+  max = MIN(src1->data[1].v_long, src2->data[1].v_long);
+
+  if(min < max){
+    g_value_init(dest, GST_TYPE_INT_RANGE);
+    gst_value_set_int_range(dest, min, max);
+    return TRUE;
+  }
+  if(min == max){
+    g_value_init(dest, G_TYPE_INT);
+    g_value_set_int(dest, min);
+    return TRUE;
+  }
+
+  return FALSE;
+}
+
+gboolean
+gst_value_can_intersect (const GValue *value1, const GValue *value2)
+{
+  GstValueIntersectInfo *intersect_info;
+  int i;
+
+  for(i=0;i<gst_value_intersect_funcs->len;i++){
+    intersect_info = &g_array_index(gst_value_intersect_funcs,
+	GstValueIntersectInfo, i);
+    if(intersect_info->type1 == G_VALUE_TYPE(value1) &&
+	intersect_info->type2 == G_VALUE_TYPE(value2)) return TRUE;
+  }
+
+  return FALSE;
+}
+
+void
+gst_value_intersect (GValue *dest, const GValue *value1, const GValue *value2)
+{
+  GstValueIntersectInfo *intersect_info;
+  int i;
+
+  for(i=0;i<gst_value_intersect_funcs->len;i++){
+    intersect_info = &g_array_index(gst_value_intersect_funcs,
+	GstValueIntersectInfo, i);
+    if(intersect_info->type1 == G_VALUE_TYPE(value1) &&
+	intersect_info->type2 == G_VALUE_TYPE(value2)) {
+      intersect_info->func(dest, value1, value2);
+      return;
+    }
+  }
+}
+
+void
+gst_value_register_intersect_func (GType type1, GType type2,
+    GstValueIntersectFunc func)
+{
+  GstValueIntersectInfo intersect_info;
+
+  intersect_info.type1 = type1;
+  intersect_info.type2 = type2;
+  intersect_info.func = func;
+
+  g_array_append_val(gst_value_intersect_funcs, intersect_info);
+}
 
 void
 _gst_value_initialize (void)
@@ -212,6 +445,25 @@ _gst_value_initialize (void)
       gst_value_transform_fourcc_string);
   g_value_register_transform_func (GST_TYPE_INT_RANGE, G_TYPE_STRING,
       gst_value_transform_int_range_string);
+
+  gst_value_compare_funcs = g_array_new(FALSE, FALSE,
+      sizeof(GstValueCompareInfo));
+
+  gst_value_register_compare_func (G_TYPE_INT, gst_value_compare_int);
+  gst_value_register_compare_func (G_TYPE_DOUBLE, gst_value_compare_double);
+  gst_value_register_compare_func (G_TYPE_STRING, gst_value_compare_string);
+  gst_value_register_compare_func (GST_TYPE_FOURCC, gst_value_compare_fourcc);
+
+  gst_value_union_funcs = g_array_new(FALSE, FALSE,
+      sizeof(GstValueUnionInfo));
+
+  gst_value_intersect_funcs = g_array_new(FALSE, FALSE,
+      sizeof(GstValueIntersectInfo));
+
+  gst_value_register_intersect_func (G_TYPE_INT, GST_TYPE_INT_RANGE,
+      gst_value_intersect_int_int_range);
+  gst_value_register_intersect_func (GST_TYPE_INT_RANGE, GST_TYPE_INT_RANGE,
+      gst_value_intersect_int_range_int_range);
 }
 
 

gst/gstvalue.h

@@ -24,6 +24,13 @@
 
 G_BEGIN_DECLS
 
+typedef int (* GstValueCompareFunc) (const GValue *value1,
+    const GValue *value2);
+typedef int (* GstValueUnionFunc) (GValue *dest, const GValue *value1,
+    const GValue *value2);
+typedef int (* GstValueIntersectFunc) (GValue *dest, const GValue *value1,
+    const GValue *value2);
+
 #define GST_VALUE_HOLDS_FOURCC(x) TRUE
 
 #define GST_TYPE_FOURCC gst_type_fourcc
@@ -38,8 +45,8 @@ void gst_value_set_fourcc (GValue *value, guint32 fourcc);
 guint32 gst_value_get_fourcc (const GValue *value);
 
 void gst_value_set_int_range (GValue *value, int start, int end);
-int gst_value_get_int_range_start (const GValue *value);
-int gst_value_get_int_range_end (const GValue *value);
+int gst_value_get_int_range_min (const GValue *value);
+int gst_value_get_int_range_max (const GValue *value);
 
 void gst_value_set_double_range (GValue *value, double start, double end);
 double gst_value_get_double_range_start (const GValue *value);