/*
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <string.h>
 
 #include "libavutil/avstring.h"
 
 #include "ffmpeg.h"
 
 static int nb_hw_devices;
 static HWDevice **hw_devices;
 
 static HWDevice *hw_device_get_by_type(enum AVHWDeviceType type)
 {
     HWDevice *found = NULL;
     int i;
     for (i = 0; i < nb_hw_devices; i++) {
         if (hw_devices[i]->type == type) {
             if (found)
                 return NULL;
             found = hw_devices[i];
         }
     }
     return found;
 }
 
 HWDevice *hw_device_get_by_name(const char *name)
 {
     int i;
     for (i = 0; i < nb_hw_devices; i++) {
         if (!strcmp(hw_devices[i]->name, name))
             return hw_devices[i];
     }
     return NULL;
 }
 
 static HWDevice *hw_device_add(void)
 {
     int err;
     err = av_reallocp_array(&hw_devices, nb_hw_devices + 1,
                             sizeof(*hw_devices));
     if (err) {
         nb_hw_devices = 0;
         return NULL;
     }
     hw_devices[nb_hw_devices] = av_mallocz(sizeof(HWDevice));
     if (!hw_devices[nb_hw_devices])
         return NULL;
     return hw_devices[nb_hw_devices++];
 }
 
 int hw_device_init_from_string(const char *arg, HWDevice **dev_out)
 {
     // "type=name:device,key=value,key2=value2"
     // "type:device,key=value,key2=value2"
     // -> av_hwdevice_ctx_create()
     // "type=name@name"
     // "type@name"
     // -> av_hwdevice_ctx_create_derived()
 
     AVDictionary *options = NULL;
     char *type_name = NULL, *name = NULL, *device = NULL;
     enum AVHWDeviceType type;
     HWDevice *dev, *src;

     AVBufferRef *device_ref = NULL;

     int err;
     const char *errmsg, *p, *q;
     size_t k;
 
     k = strcspn(arg, ":=@");
     p = arg + k;
 
     type_name = av_strndup(arg, k);
     if (!type_name) {
         err = AVERROR(ENOMEM);
         goto fail;
     }
     type = av_hwdevice_find_type_by_name(type_name);
     if (type == AV_HWDEVICE_TYPE_NONE) {
         errmsg = "unknown device type";
         goto invalid;
     }
 
     if (*p == '=') {
         k = strcspn(p + 1, ":@");
 
         name = av_strndup(p + 1, k);
         if (!name) {
             err = AVERROR(ENOMEM);
             goto fail;
         }
         if (hw_device_get_by_name(name)) {
             errmsg = "named device already exists";
             goto invalid;
         }
 
         p += 1 + k;
     } else {
         // Give the device an automatic name of the form "type%d".
         // We arbitrarily limit at 1000 anonymous devices of the same
         // type - there is probably something else very wrong if you
         // get to this limit.
         size_t index_pos;
         int index, index_limit = 1000;
         index_pos = strlen(type_name);
         name = av_malloc(index_pos + 4);
         if (!name) {
             err = AVERROR(ENOMEM);
             goto fail;
         }
         for (index = 0; index < index_limit; index++) {
             snprintf(name, index_pos + 4, "%s%d", type_name, index);
             if (!hw_device_get_by_name(name))
                 break;
         }
         if (index >= index_limit) {
             errmsg = "too many devices";
             goto invalid;
         }
     }
 
     if (!*p) {
         // New device with no parameters.
         err = av_hwdevice_ctx_create(&device_ref, type,
                                      NULL, NULL, 0);
         if (err < 0)
             goto fail;
 
     } else if (*p == ':') {
         // New device with some parameters.
         ++p;
         q = strchr(p, ',');
         if (q) {
             device = av_strndup(p, q - p);
             if (!device) {
                 err = AVERROR(ENOMEM);
                 goto fail;
             }
             err = av_dict_parse_string(&options, q + 1, "=", ",", 0);
             if (err < 0) {
                 errmsg = "failed to parse options";
                 goto invalid;
             }
         }
 
         err = av_hwdevice_ctx_create(&device_ref, type,
                                      device ? device : p, options, 0);
         if (err < 0)
             goto fail;
 
     } else if (*p == '@') {
         // Derive from existing device.
 
         src = hw_device_get_by_name(p + 1);
         if (!src) {
             errmsg = "invalid source device name";
             goto invalid;
         }
 
         err = av_hwdevice_ctx_create_derived(&device_ref, type,
                                              src->device_ref, 0);
         if (err < 0)
             goto fail;
     } else {
         errmsg = "parse error";
         goto invalid;
     }
 
     dev = hw_device_add();
     if (!dev) {
         err = AVERROR(ENOMEM);
         goto fail;
     }
 
     dev->name = name;
     dev->type = type;
     dev->device_ref = device_ref;
 
     if (dev_out)
         *dev_out = dev;
 
     name = NULL;
     err = 0;
 done:
     av_freep(&type_name);
     av_freep(&name);
     av_freep(&device);
     av_dict_free(&options);
     return err;
 invalid:
     av_log(NULL, AV_LOG_ERROR,
            "Invalid device specification \"%s\": %s\n", arg, errmsg);
     err = AVERROR(EINVAL);
     goto done;
 fail:
     av_log(NULL, AV_LOG_ERROR,
            "Device creation failed: %d.\n", err);

     av_buffer_unref(&device_ref);

     goto done;
 }
 
 void hw_device_free_all(void)
 {
     int i;
     for (i = 0; i < nb_hw_devices; i++) {
         av_freep(&hw_devices[i]->name);
         av_buffer_unref(&hw_devices[i]->device_ref);
         av_freep(&hw_devices[i]);
     }
     av_freep(&hw_devices);
     nb_hw_devices = 0;
 }
 
 static enum AVHWDeviceType hw_device_match_type_by_hwaccel(enum HWAccelID hwaccel_id)
 {
     int i;
     if (hwaccel_id == HWACCEL_NONE)
         return AV_HWDEVICE_TYPE_NONE;
     for (i = 0; hwaccels[i].name; i++) {
         if (hwaccels[i].id == hwaccel_id)
             return hwaccels[i].device_type;
     }
     return AV_HWDEVICE_TYPE_NONE;
 }
 
 static enum AVHWDeviceType hw_device_match_type_in_name(const char *codec_name)
 {
     const char *type_name;
     enum AVHWDeviceType type;
     for (type = av_hwdevice_iterate_types(AV_HWDEVICE_TYPE_NONE);
          type != AV_HWDEVICE_TYPE_NONE;
          type = av_hwdevice_iterate_types(type)) {
         type_name = av_hwdevice_get_type_name(type);
         if (strstr(codec_name, type_name))
             return type;
     }
     return AV_HWDEVICE_TYPE_NONE;
 }
 
 int hw_device_setup_for_decode(InputStream *ist)
 {
     enum AVHWDeviceType type;
     HWDevice *dev;
     int err;
 
     if (ist->hwaccel_device) {
         dev = hw_device_get_by_name(ist->hwaccel_device);
         if (!dev) {
             char *tmp;
             type = hw_device_match_type_by_hwaccel(ist->hwaccel_id);
             if (type == AV_HWDEVICE_TYPE_NONE) {
                 // No match - this isn't necessarily invalid, though,
                 // because an explicit device might not be needed or
                 // the hwaccel setup could be handled elsewhere.
                 return 0;
             }
             tmp = av_asprintf("%s:%s", av_hwdevice_get_type_name(type),
                               ist->hwaccel_device);
             if (!tmp)
                 return AVERROR(ENOMEM);
             err = hw_device_init_from_string(tmp, &dev);
             av_free(tmp);
             if (err < 0)
                 return err;
         }
     } else {
         if (ist->hwaccel_id != HWACCEL_NONE)
             type = hw_device_match_type_by_hwaccel(ist->hwaccel_id);
         else
             type = hw_device_match_type_in_name(ist->dec->name);
         if (type != AV_HWDEVICE_TYPE_NONE) {
             dev = hw_device_get_by_type(type);
             if (!dev) {
                 hw_device_init_from_string(av_hwdevice_get_type_name(type),
                                            &dev);
             }
         } else {
             // No device required.
             return 0;
         }
     }
 
     if (!dev) {
         av_log(ist->dec_ctx, AV_LOG_WARNING, "No device available "
                "for decoder (device type %s for codec %s).\n",
                av_hwdevice_get_type_name(type), ist->dec->name);
         return 0;
     }
 
     ist->dec_ctx->hw_device_ctx = av_buffer_ref(dev->device_ref);
     if (!ist->dec_ctx->hw_device_ctx)
         return AVERROR(ENOMEM);
 
     return 0;
 }
 
 int hw_device_setup_for_encode(OutputStream *ost)
 {
     enum AVHWDeviceType type;
     HWDevice *dev;
 
     type = hw_device_match_type_in_name(ost->enc->name);
     if (type != AV_HWDEVICE_TYPE_NONE) {
         dev = hw_device_get_by_type(type);
         if (!dev) {
             av_log(ost->enc_ctx, AV_LOG_WARNING, "No device available "
                    "for encoder (device type %s for codec %s).\n",
                    av_hwdevice_get_type_name(type), ost->enc->name);
             return 0;
         }
         ost->enc_ctx->hw_device_ctx = av_buffer_ref(dev->device_ref);
         if (!ost->enc_ctx->hw_device_ctx)
             return AVERROR(ENOMEM);
         return 0;
     } else {
         // No device required.
         return 0;
     }
 }
 
 static int hwaccel_retrieve_data(AVCodecContext *avctx, AVFrame *input)
 {
     InputStream *ist = avctx->opaque;
     AVFrame *output = NULL;
     enum AVPixelFormat output_format = ist->hwaccel_output_format;
     int err;
 
     if (input->format == output_format) {
         // Nothing to do.
         return 0;
     }
 
     output = av_frame_alloc();
     if (!output)
         return AVERROR(ENOMEM);
 
     output->format = output_format;
 
     err = av_hwframe_transfer_data(output, input, 0);
     if (err < 0) {
         av_log(avctx, AV_LOG_ERROR, "Failed to transfer data to "
                "output frame: %d.\n", err);
         goto fail;
     }
 
     err = av_frame_copy_props(output, input);
     if (err < 0) {
         av_frame_unref(output);
         goto fail;
     }
 
     av_frame_unref(input);
     av_frame_move_ref(input, output);
     av_frame_free(&output);
 
     return 0;
 
 fail:
     av_frame_free(&output);
     return err;
 }
 
 int hwaccel_decode_init(AVCodecContext *avctx)
 {
     InputStream *ist = avctx->opaque;
 
     ist->hwaccel_retrieve_data = &hwaccel_retrieve_data;
 
     return 0;
 }