/* * Concat URL protocol * Copyright (c) 2006 Steve Lhomme * Copyright (c) 2007 Wolfram Gloger * Copyright (c) 2010 Michele Orrù * * 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 "libavutil/avstring.h"#include "libavutil/mem.h" #include "avformat.h"#include "url.h" #define AV_CAT_SEPARATOR "|" struct concat_nodes {    URLContext *uc;                ///< node's URLContext    int64_t     size;              ///< url filesize}; struct concat_data {    struct concat_nodes *nodes;    ///< list of nodes to concat    size_t               length;   ///< number of cat'ed nodes    size_t               current;  ///< index of currently read node}; static av_cold int concat_close(URLContext *h){    int err = 0;    size_t i;    struct concat_data  *data  = h->priv_data;    struct concat_nodes *nodes = data->nodes;     for (i = 0; i != data->length; i++)        err |= ffurl_close(nodes[i].uc);     av_freep(&data->nodes);     return err < 0 ? -1 : 0;} static av_cold int concat_open(URLContext *h, const char *uri, int flags){    char *node_uri = NULL;    int err = 0;    int64_t size;    size_t len, i;    URLContext *uc;    struct concat_data  *data = h->priv_data;    struct concat_nodes *nodes;     if (!av_strstart(uri, "concat:", &uri)) {        av_log(h, AV_LOG_ERROR, "URL %s lacks prefix\n", uri);        return AVERROR(EINVAL);    }     for (i = 0, len = 1; uri[i]; i++) {        if (uri[i] == *AV_CAT_SEPARATOR) {            /* integer overflow */            if (++len == UINT_MAX / sizeof(*nodes)) {                av_freep(&h->priv_data);                return AVERROR(ENAMETOOLONG);            }        }    }     if (!(nodes = av_realloc(NULL, sizeof(*nodes) * len)))        return AVERROR(ENOMEM);    else        data->nodes = nodes;     /* handle input */    if (!*uri)        err = AVERROR(ENOENT);    for (i = 0; *uri; i++) {        /* parsing uri */        len = strcspn(uri, AV_CAT_SEPARATOR);        if ((err = av_reallocp(&node_uri, len + 1)) < 0)            break;        av_strlcpy(node_uri, uri, len + 1);        uri += len + strspn(uri + len, AV_CAT_SEPARATOR);         /* creating URLContext */        err = ffurl_open_whitelist(&uc, node_uri, flags,                                   &h->interrupt_callback, NULL, h->protocol_whitelist, h->protocol_blacklist, h);        if (err < 0)            break;         /* creating size */        if ((size = ffurl_size(uc)) < 0) {            ffurl_close(uc);            err = AVERROR(ENOSYS);            break;        }         /* assembling */        nodes[i].uc   = uc;        nodes[i].size = size;    }    av_free(node_uri);    data->length = i;     if (err < 0)        concat_close(h);    else if (!(nodes = av_realloc(nodes, data->length * sizeof(*nodes)))) {        concat_close(h);        err = AVERROR(ENOMEM);    } else        data->nodes = nodes;    return err;} static int concat_read(URLContext *h, unsigned char *buf, int size){    int result, total = 0;    struct concat_data  *data  = h->priv_data;    struct concat_nodes *nodes = data->nodes;    size_t i                   = data->current;     while (size > 0) {        result = ffurl_read(nodes[i].uc, buf, size);        if (result < 0)            return total ? total : result;        if (!result) {            if (i + 1 == data->length ||                ffurl_seek(nodes[++i].uc, 0, SEEK_SET) < 0)                break;        }        total += result;        buf   += result;        size  -= result;    }    data->current = i;    return total;} static int64_t concat_seek(URLContext *h, int64_t pos, int whence){    int64_t result;    struct concat_data  *data  = h->priv_data;    struct concat_nodes *nodes = data->nodes;    size_t i;     switch (whence) {    case SEEK_END:        for (i = data->length - 1; i && pos < -nodes[i].size; i--)            pos += nodes[i].size;        break;    case SEEK_CUR:        /* get the absolute position */        for (i = 0; i != data->current; i++)            pos += nodes[i].size;        pos += ffurl_seek(nodes[i].uc, 0, SEEK_CUR);        whence = SEEK_SET;        /* fall through with the absolute position */    case SEEK_SET:        for (i = 0; i != data->length - 1 && pos >= nodes[i].size; i++)            pos -= nodes[i].size;        break;    default:        return AVERROR(EINVAL);    }     result = ffurl_seek(nodes[i].uc, pos, whence);    if (result >= 0) {        data->current = i;        while (i)            result += nodes[--i].size;    }    return result;} const URLProtocol ff_concat_protocol = {    .name           = "concat",    .url_open       = concat_open,    .url_read       = concat_read,    .url_seek       = concat_seek,    .url_close      = concat_close,    .priv_data_size = sizeof(struct concat_data),    .default_whitelist = "concat,file,subfile",};