Quoting Mark Thompson (2017-03-05 00:57:29)
> Adds functions to convert to/from strings and a function to iterate
> over all supported device types. Also adds a new invalid type
> AV_HWDEVICE_TYPE_NONE, which acts as a sentinel value.
> ---
> libavutil/hwcontext.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
> libavutil/hwcontext.h | 28 ++++++++++++++++++++++++++++
> 2 files changed, 74 insertions(+)
>
> diff --git a/libavutil/hwcontext.c b/libavutil/hwcontext.c
> index 252dd32e3..8195a7245 100644
> --- a/libavutil/hwcontext.c
> +++ b/libavutil/hwcontext.c
> @@ -47,6 +47,52 @@ static const HWContextType * const hw_table[] = {
> NULL,
> };
>
> +static const struct {
> + enum AVHWDeviceType type;
> + const char *name;
> +} hw_type_map[] = {
> + { AV_HWDEVICE_TYPE_CUDA, "cuda" },
> + { AV_HWDEVICE_TYPE_DXVA2, "dxva2" },
> + { AV_HWDEVICE_TYPE_QSV, "qsv" },
> + { AV_HWDEVICE_TYPE_VAAPI, "vaapi" },
> + { AV_HWDEVICE_TYPE_VDPAU, "vdpau" },
> +};
> +
> +enum AVHWDeviceType av_hwdevice_find_type_by_name(const char *name)
> +{
> + int i;
> + for (i = 0; i < FF_ARRAY_ELEMS(hw_type_map); i++) {
> + if (!strcmp(hw_type_map[i].name, name))
> + return hw_type_map[i].type;
> + }
> + return AV_HWDEVICE_TYPE_NONE;
> +}
> +
> +const char *av_hwdevice_get_type_name(enum AVHWDeviceType type)
> +{
> + int i;
> + for (i = 0; i < FF_ARRAY_ELEMS(hw_type_map); i++) {
> + if (hw_type_map[i].type == type)
> + return hw_type_map[i].name;
> + }
> + return NULL;
> +}
> +
> +enum AVHWDeviceType av_hwdevice_iterate_types(enum AVHWDeviceType prev)
> +{
> + enum AVHWDeviceType next;
> + int i, set = 0;
> + for (i = 0; hw_table[i]; i++) {
> + if (prev != AV_HWDEVICE_TYPE_NONE && hw_table[i]->type <= prev)
> + continue;
> + if (!set || hw_table[i]->type < next) {
> + next = hw_table[i]->type;
> + set = 1;
> + }
> + }
> + return set ? next : AV_HWDEVICE_TYPE_NONE;
> +}
> +
> static const AVClass hwdevice_ctx_class = {
> .class_name = "AVHWDeviceContext",
> .item_name = av_default_item_name,
> diff --git a/libavutil/hwcontext.h b/libavutil/hwcontext.h
> index 49c7a21c1..cce7cdc7e 100644
> --- a/libavutil/hwcontext.h
> +++ b/libavutil/hwcontext.h
> @@ -30,6 +30,8 @@ enum AVHWDeviceType {
> AV_HWDEVICE_TYPE_VAAPI,
> AV_HWDEVICE_TYPE_DXVA2,
> AV_HWDEVICE_TYPE_QSV,
> +
> + AV_HWDEVICE_TYPE_NONE
> };
>
> typedef struct AVHWDeviceInternal AVHWDeviceInternal;
> @@ -223,6 +225,32 @@ typedef struct AVHWFramesContext {
> } AVHWFramesContext;
>
> /**
> + * Look up an AVHWDeviceType by name.
> + *
> + * @param name String name of the device type (case-insensitive).
> + * @return The type from enum AVHWDeviceType, or AV_HWDEVICE_TYPE_NONE if
> + * not found.
> + */
> +enum AVHWDeviceType av_hwdevice_find_type_by_name(const char *name);
> +
> +/** Get the string name of an AVHWDeviceType.
> + *
> + * @param type Type from enum AVHWDeviceType.
> + * @return Pointer to a static string containing the name, or NULL if the
> type
> + * is not valid.
> + */
> +const char *av_hwdevice_get_type_name(enum AVHWDeviceType type);
> +
> +/**
> + * Iterate over supported device types.
> + *
> + * @param type AV_HWDEVICE_TYPE_NONE initially, then the previous type
> + * returned by this function in subsequent iterations.
> + * @return The next usable device type from enum AVHWDeviceType.
> + */
Better mention explicitly that TYPE_NONE is returned at the end.
--
Anton Khirnov
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