PeerStreamer

/*

 * Unbuffered io for ffmpeg system

 * Copyright (c) 2001 Fabrice Bellard

 *

 * 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

 */

/* needed for usleep() */

#define _XOPEN_SOURCE 600

#include <unistd.h>

#include "libavutil/avstring.h"

#include "libavcodec/opt.h"

#include "os_support.h"

#include "avformat.h"

#if LIBAVFORMAT_VERSION_MAJOR >= 53

/** @name Logging context. */

/*@{*/

static const char *urlcontext_to_name(void *ptr)

{

    URLContext *h = (URLContext *)ptr;

    if(h->prot) return h->prot->name;

    else        return "NULL";

}

static const AVOption options[] = {{NULL}};

static const AVClass urlcontext_class =

        { "URLContext", urlcontext_to_name, options };

/*@}*/

#endif

static int default_interrupt_cb(void);

URLProtocol *first_protocol = NULL;

URLInterruptCB *url_interrupt_cb = default_interrupt_cb;

URLProtocol *av_protocol_next(URLProtocol *p)

{

    if(p) return p->next;

    else  return first_protocol;

}

int av_register_protocol(URLProtocol *protocol)

{

    URLProtocol **p;

    p = &first_protocol;

    while (*p != NULL) p = &(*p)->next;

    *p = protocol;

    protocol->next = NULL;

    return 0;

}

#if LIBAVFORMAT_VERSION_MAJOR < 53

int register_protocol(URLProtocol *protocol)

{

    return av_register_protocol(protocol);

}

#endif

int url_open_protocol (URLContext **puc, struct URLProtocol *up,

                       const char *filename, int flags)

{

    URLContext *uc;

    int err;

    uc = av_malloc(sizeof(URLContext) + strlen(filename) + 1);

    if (!uc) {

        err = AVERROR(ENOMEM);

        goto fail;

    }

#if LIBAVFORMAT_VERSION_MAJOR >= 53

    uc->av_class = &urlcontext_class;

#endif

    uc->filename = (char *) &uc[1];

    strcpy(uc->filename, filename);

    uc->prot = up;

    uc->flags = flags;

    uc->is_streamed = 0; /* default = not streamed */

    uc->max_packet_size = 0; /* default: stream file */

    err = up->url_open(uc, filename, flags);

    if (err < 0) {

        av_free(uc);

        *puc = NULL;

        return err;

    }

    //We must be careful here as url_seek() could be slow, for example for http

    if(   (flags & (URL_WRONLY | URL_RDWR))

       || !strcmp(up->name, "file"))

        if(!uc->is_streamed && url_seek(uc, 0, SEEK_SET) < 0)

            uc->is_streamed= 1;

    *puc = uc;

    return 0;

 fail:

    *puc = NULL;

    return err;

}

int url_open(URLContext **puc, const char *filename, int flags)

{

    URLProtocol *up;

    const char *p;

    char proto_str[128], *q;

    p = filename;

    q = proto_str;

    while (*p != '\0' && *p != ':') {

        /* protocols can only contain alphabetic chars */

        if (!isalpha(*p))

            goto file_proto;

        if ((q - proto_str) < sizeof(proto_str) - 1)

            *q++ = *p;

        p++;

    }

    /* if the protocol has length 1, we consider it is a dos drive */

    if (*p == '\0' || is_dos_path(filename)) {

    file_proto:

        strcpy(proto_str, "file");

    } else {

        *q = '\0';

    }

    up = first_protocol;

    while (up != NULL) {

        if (!strcmp(proto_str, up->name))

            return url_open_protocol (puc, up, filename, flags);

        up = up->next;

    }

    *puc = NULL;

    return AVERROR(ENOENT);

}

int url_read(URLContext *h, unsigned char *buf, int size)

{

    int ret;

    if (h->flags & URL_WRONLY)

        return AVERROR(EIO);

    ret = h->prot->url_read(h, buf, size);

    return ret;

}

int url_read_complete(URLContext *h, unsigned char *buf, int size)

{

    int ret, len;

    int fast_retries = 5;

    len = 0;

    while (len < size) {

        ret = url_read(h, buf+len, size-len);

        if (ret == AVERROR(EAGAIN)) {

            ret = 0;

            if (fast_retries)

                fast_retries--;

            else

                usleep(1000);

        } else if (ret < 1)

            return ret < 0 ? ret : len;

        if (ret)

           fast_retries = FFMAX(fast_retries, 2);

        len += ret;

    }

    return len;

}

int url_write(URLContext *h, unsigned char *buf, int size)

{

    int ret;

    if (!(h->flags & (URL_WRONLY | URL_RDWR)))

        return AVERROR(EIO);

    /* avoid sending too big packets */

    if (h->max_packet_size && size > h->max_packet_size)

        return AVERROR(EIO);

    ret = h->prot->url_write(h, buf, size);

    return ret;

}

int64_t url_seek(URLContext *h, int64_t pos, int whence)

{

    int64_t ret;

    if (!h->prot->url_seek)

        return AVERROR(EPIPE);

    ret = h->prot->url_seek(h, pos, whence);

    return ret;

}

int url_close(URLContext *h)

{

    int ret = 0;

    if (!h) return 0; /* can happen when url_open fails */

    if (h->prot->url_close)

        ret = h->prot->url_close(h);

    av_free(h);

    return ret;

}

int url_exist(const char *filename)

{

    URLContext *h;

    if (url_open(&h, filename, URL_RDONLY) < 0)

        return 0;

    url_close(h);

    return 1;

}

int64_t url_filesize(URLContext *h)

{

    int64_t pos, size;

    size= url_seek(h, 0, AVSEEK_SIZE);

    if(size<0){

        pos = url_seek(h, 0, SEEK_CUR);

        if ((size = url_seek(h, -1, SEEK_END)) < 0)

            return size;

        size++;

        url_seek(h, pos, SEEK_SET);

    }

    return size;

}

int url_get_file_handle(URLContext *h)

{

    if (!h->prot->url_get_file_handle)

        return -1;

    return h->prot->url_get_file_handle(h);

}

int url_get_max_packet_size(URLContext *h)

{

    return h->max_packet_size;

}

void url_get_filename(URLContext *h, char *buf, int buf_size)

{

    av_strlcpy(buf, h->filename, buf_size);

}

static int default_interrupt_cb(void)

{

    return 0;

}

void url_set_interrupt_cb(URLInterruptCB *interrupt_cb)

{

    if (!interrupt_cb)

        interrupt_cb = default_interrupt_cb;

    url_interrupt_cb = interrupt_cb;

}

int av_url_read_pause(URLContext *h, int pause)

{

    if (!h->prot->url_read_pause)

        return AVERROR(ENOSYS);

    return h->prot->url_read_pause(h, pause);

}

int64_t av_url_read_seek(URLContext *h,

        int stream_index, int64_t timestamp, int flags)

{

    if (!h->prot->url_read_seek)

        return AVERROR(ENOSYS);

    return h->prot->url_read_seek(h, stream_index, timestamp, flags);

}