lavu/opt: add av_opt_ accessors for pixel/format/image size options

The interface is implemented against the style of the other options
accessors. Possibly simplify programmatic setting of options.

doc/APIchanges

@@ -15,6 +15,15 @@ libavutil:     2012-10-22
 
 API changes, most recent first:
 
+2012-11-25 - xxxxxxx - lavu 52.9.100 - opt.h
+  Add the following convenience functions to opt.h:
+   av_opt_get_image_size
+   av_opt_get_pixel_fmt
+   av_opt_get_sample_fmt
+   av_opt_set_image_size
+   av_opt_set_pixel_fmt
+   av_opt_set_sample_fmt
+
 2012-11-17 - xxxxxxx - lavu 52.8.100 - bprint.h
   Add av_bprint_strftime().
 

libavutil/opt.c

@@ -402,6 +402,62 @@ int av_opt_set_bin(void *obj, const char *name, const uint8_t *val, int len, int
     return 0;
 }
 
+int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags)
+{
+    void *target_obj;
+    const AVOption *o = av_opt_find2(obj, name, NULL, 0, search_flags, &target_obj);
+
+    if (!o || !target_obj)
+        return AVERROR_OPTION_NOT_FOUND;
+    if (o->type != AV_OPT_TYPE_IMAGE_SIZE) {
+        av_log(obj, AV_LOG_ERROR,
+               "The value set by option '%s' is not an image size.\n", o->name);
+        return AVERROR(EINVAL);
+    }
+    if (w<0 || h<0) {
+        av_log(obj, AV_LOG_ERROR,
+               "Invalid negative size value %dx%d for size '%s'\n", w, h, o->name);
+        return AVERROR(EINVAL);
+    }
+    *(int *)(((uint8_t *)target_obj)             + o->offset) = w;
+    *(int *)(((uint8_t *)target_obj+sizeof(int)) + o->offset) = h;
+    return 0;
+}
+
+static int set_format(void *obj, const char *name, int fmt, int search_flags,
+                      enum AVOptionType type, const char *desc, int max)
+{
+    void *target_obj;
+    const AVOption *o = av_opt_find2(obj, name, NULL, 0,
+                                     search_flags, &target_obj);
+    if (!o || !target_obj)
+        return AVERROR_OPTION_NOT_FOUND;
+    if (o->type != type) {
+        av_log(obj, AV_LOG_ERROR,
+               "The value set by option '%s' is not a %s format", name, desc);
+        return AVERROR(EINVAL);
+    }
+
+    if (fmt < -1 || fmt > max) {
+        av_log(obj, AV_LOG_ERROR,
+               "Value %d for parameter '%s' out of %s format range [0 - %d]\n",
+               fmt, name, desc, max);
+        return AVERROR(ERANGE);
+    }
+    *(int *)(((uint8_t *)target_obj) + o->offset) = fmt;
+    return 0;
+}
+
+int av_opt_set_pixel_fmt(void *obj, const char *name, enum AVPixelFormat fmt, int search_flags)
+{
+    return set_format(obj, name, fmt, search_flags, AV_OPT_TYPE_PIXEL_FMT, "pixel", AV_PIX_FMT_NB-1);
+}
+
+int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags)
+{
+    return set_format(obj, name, fmt, search_flags, AV_OPT_TYPE_SAMPLE_FMT, "sample", AV_SAMPLE_FMT_NB-1);
+}
+
 #if FF_API_OLD_AVOPTIONS
 /**
  *
@@ -596,6 +652,52 @@ int av_opt_get_q(void *obj, const char *name, int search_flags, AVRational *out_
     return 0;
 }
 
+int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out)
+{
+    void *dst, *target_obj;
+    const AVOption *o = av_opt_find2(obj, name, NULL, 0, search_flags, &target_obj);
+    if (!o || !target_obj)
+        return AVERROR_OPTION_NOT_FOUND;
+    if (o->type != AV_OPT_TYPE_IMAGE_SIZE) {
+        av_log(obj, AV_LOG_ERROR,
+               "The value for option '%s' is not an image size.\n", name);
+        return AVERROR(EINVAL);
+    }
+
+    dst = ((uint8_t*)target_obj) + o->offset;
+    if (w_out) *w_out = *(int *)dst;
+    if (h_out) *h_out = *((int *)dst+1);
+    return 0;
+}
+
+static int get_format(void *obj, const char *name, int search_flags, int *out_fmt,
+                      enum AVOptionType type, const char *desc)
+{
+    void *dst, *target_obj;
+    const AVOption *o = av_opt_find2(obj, name, NULL, 0, search_flags, &target_obj);
+    if (!o || !target_obj)
+        return AVERROR_OPTION_NOT_FOUND;
+    if (o->type != type) {
+        av_log(obj, AV_LOG_ERROR,
+               "The value for option '%s' is not a %s format.\n", desc, name);
+        return AVERROR(EINVAL);
+    }
+
+    dst = ((uint8_t*)target_obj) + o->offset;
+    *out_fmt = *(int *)dst;
+    return 0;
+}
+
+int av_opt_get_pixel_fmt(void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt)
+{
+    return get_format(obj, name, search_flags, out_fmt, AV_OPT_TYPE_PIXEL_FMT, "pixel");
+}
+
+int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt)
+{
+    return get_format(obj, name, search_flags, out_fmt, AV_OPT_TYPE_SAMPLE_FMT, "sample");
+}
+
 int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name)
 {
     const AVOption *field = av_opt_find(obj, field_name, NULL, 0, 0);

libavutil/opt.h

@@ -31,6 +31,8 @@
 #include "avutil.h"
 #include "dict.h"
 #include "log.h"
+#include "pixfmt.h"
+#include "samplefmt.h"
 
 /**
  * @defgroup avoptions AVOptions
@@ -629,6 +631,9 @@ int av_opt_set_int   (void *obj, const char *name, int64_t     val, int search_f
 int av_opt_set_double(void *obj, const char *name, double      val, int search_flags);
 int av_opt_set_q     (void *obj, const char *name, AVRational  val, int search_flags);
 int av_opt_set_bin   (void *obj, const char *name, const uint8_t *val, int size, int search_flags);
+int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags);
+int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags);
+int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags);
 /**
  * @}
  */
@@ -652,6 +657,9 @@ int av_opt_get       (void *obj, const char *name, int search_flags, uint8_t   *
 int av_opt_get_int   (void *obj, const char *name, int search_flags, int64_t    *out_val);
 int av_opt_get_double(void *obj, const char *name, int search_flags, double     *out_val);
 int av_opt_get_q     (void *obj, const char *name, int search_flags, AVRational *out_val);
+int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out);
+int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt);
+int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt);
 /**
  * @}
  */

libavutil/version.h

@@ -75,7 +75,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  52
-#define LIBAVUTIL_VERSION_MINOR   8
+#define LIBAVUTIL_VERSION_MINOR   9
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \