/*

 * This file is part of mpv.

 *

 * mpv 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.

 *

 * mpv 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 mpv.  If not, see <http://www.gnu.org/licenses/>.

 */

#include <stdio.h>

#include <stdlib.h>

#include <limits.h>

#include <assert.h>

#include "osdep/io.h"

#include "mpv_talloc.h"

#include "config.h"

#include "common/common.h"

#include "common/global.h"

#include "demux/demux.h"

#include "misc/bstr.h"

#include "misc/thread_tools.h"

#include "common/msg.h"

#include "options/m_config.h"

#include "options/options.h"

#include "options/path.h"

#include "osdep/timer.h"

#include "stream.h"

#include "options/m_option.h"

#include "options/m_config.h"

extern const stream_info_t stream_info_mpv;

extern const stream_info_t stream_info_cdda;

extern const stream_info_t stream_info_dvb;

extern const stream_info_t stream_info_null;

extern const stream_info_t stream_info_memory;

extern const stream_info_t stream_info_mf;

extern const stream_info_t stream_info_ffmpeg;

extern const stream_info_t stream_info_ffmpeg_unsafe;

extern const stream_info_t stream_info_avdevice;

extern const stream_info_t stream_info_file;

extern const stream_info_t stream_info_slice;

extern const stream_info_t stream_info_fd;

extern const stream_info_t stream_info_ifo_dvdnav;

extern const stream_info_t stream_info_dvdnav;

extern const stream_info_t stream_info_bdmv_dir;

extern const stream_info_t stream_info_bluray;

extern const stream_info_t stream_info_edl;

extern const stream_info_t stream_info_libarchive;

extern const stream_info_t stream_info_cb;

extern const stream_info_t stream_info_curl;

static const stream_info_t *const stream_list[] = {

    &stream_info_mpv,

#if HAVE_CDDA

    &stream_info_cdda,

#endif

    &stream_info_avdevice,

#if HAVE_DVBIN

    &stream_info_dvb,

#endif

#if HAVE_DVDNAV

    &stream_info_ifo_dvdnav,

    &stream_info_dvdnav,

#endif

#if HAVE_LIBBLURAY

    &stream_info_bdmv_dir,

    &stream_info_bluray,

#endif

#if HAVE_LIBARCHIVE

    &stream_info_libarchive,

#endif

    &stream_info_memory,

    &stream_info_null,

    &stream_info_mf,

    &stream_info_edl,

    &stream_info_file,

    &stream_info_slice,

    &stream_info_fd,

    &stream_info_cb,

#if HAVE_LIBCURL

    &stream_info_curl,

#endif

    &stream_info_ffmpeg,

    &stream_info_ffmpeg_unsafe,

};

// Because of guarantees documented on STREAM_BUFFER_SIZE.

// Half the buffer is used as forward buffer, the other for seek-back.

#define STREAM_MIN_BUFFER_SIZE (STREAM_BUFFER_SIZE * 2)

// Sort of arbitrary; keep *2 of it comfortably within integer limits.

// Must be power of 2.

#define STREAM_MAX_BUFFER_SIZE (512 * 1024 * 1024)

struct stream_opts {

    int64_t buffer_size;

    bool load_unsafe_playlists;

};

#define OPT_BASE_STRUCT struct stream_opts

const struct m_sub_options stream_conf = {

    .opts = (const struct m_option[]){

        {"stream-buffer-size", OPT_BYTE_SIZE(buffer_size),

            M_RANGE(STREAM_MIN_BUFFER_SIZE, STREAM_MAX_BUFFER_SIZE)},

        {"load-unsafe-playlists", OPT_BOOL(load_unsafe_playlists)},

        {0}

    },

    .size = sizeof(struct stream_opts),

    .defaults = &(const struct stream_opts){

        .buffer_size = 128 * 1024,

    },

};

// return -1 if not hex char

static int hex2dec(char c)

{

    if (c >= '0' && c <= '9')

        return c - '0';

    if (c >= 'A' && c <= 'F')

        return 10 + c - 'A';

    if (c >= 'a' && c <= 'f')

        return 10 + c - 'a';

    return -1;

}

// Replace escape sequences in an URL (or a part of an URL)

void mp_url_unescape_inplace(char *url)

{

    for (int len = strlen(url), i = 0, o = 0; i <= len;) {

        if ((url[i] != '%') || (i > len - 3)) {  // %NN can't start after len-3

            url[o++] = url[i++];

            continue;

        }

        int msd = hex2dec(url[i + 1]),

            lsd = hex2dec(url[i + 2]);

        if (msd >= 0 && lsd >= 0) {

            url[o++] = 16 * msd + lsd;

            i += 3;

        } else {

            url[o++] = url[i++];

            url[o++] = url[i++];

            url[o++] = url[i++];

        }

    }

}

char *mp_url_unescape(void *talloc_ctx, const char *url)

{

    char *unescaped = talloc_strdup(talloc_ctx, url);

    mp_url_unescape_inplace(unescaped);

    return unescaped;

}

static const char hex_digits[] = "0123456789ABCDEF";

static const char url_default_ok[] = "abcdefghijklmnopqrstuvwxyz"

                                     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

                                     "0123456789"

                                     "-._~";

// Escape according to http://tools.ietf.org/html/rfc3986#section-2.1

// Only unreserved characters are not escaped.

// The argument ok (if not NULL) is as follows:

//      ok[0] != '~': additional characters that are not escaped

//      ok[0] == '~': do not escape anything but these characters

//                    (can't override the unreserved characters, which are

//                     never escaped)

char *mp_url_escape(void *talloc_ctx, const char *url, const char *ok)

{

    char *rv = talloc_size(talloc_ctx, strlen(url) * 3 + 1);

    char *out = rv;

    bool negate = ok && ok[0] == '~';

    for (char c; (c = *url); url++) {

        bool as_is = negate ? !strchr(ok + 1, c)

                            : (strchr(url_default_ok, c) || (ok && strchr(ok, c)));

        if (as_is) {

            *out++ = c;

        } else {

            unsigned char v = c;

            *out++ = '%';

            *out++ = hex_digits[v / 16];

            *out++ = hex_digits[v % 16];

        }

    }

    *out = 0;

    return rv;

}

static const char *match_proto(const char *url, const char *proto)

{

    int l = strlen(proto);

    if (l > 0) {

        if (strncasecmp(url, proto, l) == 0 && strncmp("://", url + l, 3) == 0)

            return url + l + 3;

    } else if (!mp_is_url(bstr0(url))) {

        return url; // pure filenames

    }

    return NULL;

}

// src and new are both STREAM_ORIGIN_* values. This checks whether a stream

// with flags "new" can be opened from the "src". On success, return

// new origin, on incompatibility return 0.

static int check_origin(int src, int new)

{

    switch (src) {

    case STREAM_ORIGIN_DIRECT:

    case STREAM_ORIGIN_UNSAFE:

        // Allow anything, but constrain it to the new origin.

        return new;

    case STREAM_ORIGIN_FS:

        // From unix FS, allow all but unsafe.

        if (new == STREAM_ORIGIN_FS || new == STREAM_ORIGIN_NET)

            return new;

        break;

    case STREAM_ORIGIN_NET:

        // Allow only other network links.

        if (new == STREAM_ORIGIN_NET)

            return new;

        break;

    }

    return 0;

}

// Read len bytes from the start position, and wrap around as needed. Limit the

// actually read data to the size of the buffer. Return amount of copied bytes.

//  len: max bytes to copy to dst

//  pos: index into s->buffer[], e.g. s->buf_start is byte 0

//  returns: bytes copied to dst (limited by len and available buffered data)

static int ring_copy(struct stream *s, void *dst, int len, int pos)

{

    mp_assert(len >= 0);

    if (pos < s->buf_start || pos > s->buf_end)

        return 0;

    int copied = 0;

    len = MPMIN(len, s->buf_end - pos);

    if (len && pos <= s->buffer_mask) {

        int copy = MPMIN(len, s->buffer_mask + 1 - pos);

        memcpy(dst, &s->buffer[pos], copy);

        copied += copy;

        len -= copy;

        pos += copy;

    }

    if (len) {

        memcpy((char *)dst + copied, &s->buffer[pos & s->buffer_mask], len);

        copied += len;

    }

    return copied;

}

// Resize the current stream buffer. Uses a larger size if needed to keep data.

// Does nothing if the size is adequate. Calling this with 0 ensures it uses the

// default buffer size if possible.

// The caller must check whether enough data was really allocated.

//  keep: keep at least [buf_end-keep, buf_end] (used for mp_assert()s only)

//  new: new total size of buffer

//  returns: false if buffer allocation failed, true if reallocated or size ok

static bool stream_resize_buffer(struct stream *s, int keep, int new)

{

    mp_assert(keep >= s->buf_end - s->buf_cur);

    mp_assert(keep <= new);

    new = MPMAX(new, s->requested_buffer_size);

    new = MPMIN(new, STREAM_MAX_BUFFER_SIZE);

    new = mp_round_next_power_of_2(new);

    mp_assert(keep <= new); // can't fail (if old buffer size was valid)

    if (new == s->buffer_mask + 1)

        return true;

    int old_pos = s->buf_cur - s->buf_start;

    int old_used_len = s->buf_end - s->buf_start;

    int skip = old_used_len > new ? old_used_len - new : 0;

    MP_DBG(s, "resize stream to %d bytes, drop %d bytes\n", new, skip);

    void *nbuf = ta_alloc_size(s, new);

    if (!nbuf)

        return false; // oom; tolerate it, caller needs to check if required

    int new_len = 0;

    if (s->buffer)

        new_len = ring_copy(s, nbuf, new, s->buf_start + skip);

    mp_assert(new_len == old_used_len - skip);

    mp_assert(old_pos >= skip); // "keep" too low

    mp_assert(old_pos - skip <= new_len);

    s->buf_start = 0;

    s->buf_cur = old_pos - skip;

    s->buf_end = new_len;

    ta_free(s->buffer);

    s->buffer = nbuf;

    s->buffer_mask = new - 1;

    return true;

}

static int stream_create_instance(const stream_info_t *sinfo,

                                  struct stream_open_args *args,

                                  struct stream **ret)

{

    const char *url = args->url;

    int flags = args->flags;

    *ret = NULL;

    const char *path = url;

    if (flags & STREAM_LOCAL_FS_ONLY) {

        if (!sinfo->local_fs)

            return STREAM_NO_MATCH;

    } else {

        char **get_protocols = sinfo->get_protocols ? sinfo->get_protocols() : NULL;

        char **protocols = get_protocols ? get_protocols : (char **)sinfo->protocols;

        for (int n = 0; protocols && protocols[n]; n++) {

            path = match_proto(url, protocols[n]);

            if (path)

                break;

        }

        talloc_free(get_protocols);

        if (!path)

            return STREAM_NO_MATCH;

    }

    stream_t *s = talloc_zero(NULL, stream_t);

    s->global = args->global;

    struct stream_opts *opts = mp_get_config_group(s, s->global, &stream_conf);

    if (flags & STREAM_SILENT) {

        s->log = mp_null_log;

    } else {

        s->log = mp_log_new(s, s->global->log, sinfo->name);

    }

    s->info = sinfo;

    s->cancel = args->cancel;

    s->url = talloc_strdup(s, url);

    s->path = talloc_strdup(s, path);

    s->mode = flags & (STREAM_READ | STREAM_WRITE);

    s->requested_buffer_size = opts->buffer_size;

    s->allow_partial_read = flags & STREAM_ALLOW_PARTIAL_READ;

    if (flags & STREAM_LESS_NOISE)

        mp_msg_set_max_level(s->log, MSGL_WARN);

    struct demux_opts *demux_opts = mp_get_config_group(s, s->global, &demux_conf);

    s->access_references = demux_opts->access_references;

    talloc_free(demux_opts);

    MP_VERBOSE(s, "Opening %s\n", url);

    if (strlen(url) > INT_MAX / 8) {

        MP_ERR(s, "URL too large.\n");

        talloc_free(s);

        return STREAM_ERROR;

    }

    if ((s->mode & STREAM_WRITE) && !sinfo->can_write) {

        MP_DBG(s, "No write access implemented.\n");

        talloc_free(s);

        return STREAM_NO_MATCH;

    }

    s->stream_origin = flags & STREAM_ORIGIN_MASK; // pass through by default

    if (opts->load_unsafe_playlists) {

        s->stream_origin = STREAM_ORIGIN_DIRECT;

    } else if (sinfo->stream_origin) {

        s->stream_origin = check_origin(s->stream_origin, sinfo->stream_origin);

    }

    if (!s->stream_origin) {

        talloc_free(s);

        return STREAM_UNSAFE;

    }

    int r = STREAM_UNSUPPORTED;

    if (sinfo->open2) {

        r = sinfo->open2(s, args);

    } else if (!args->special_arg) {

        r = (sinfo->open)(s);

    }

    if (r != STREAM_OK) {

        talloc_free(s);

        return r;

    }

    if (!stream_resize_buffer(s, 0, 0)) {

        free_stream(s);

        return STREAM_ERROR;

    }

    mp_assert(s->seekable == !!s->seek);

    if (s->mime_type)

        MP_VERBOSE(s, "Mime-type: '%s'\n", s->mime_type);

    MP_DBG(s, "Stream opened successfully.\n");

    *ret = s;

    return STREAM_OK;

}

int stream_create_with_args(struct stream_open_args *args, struct stream **ret)

{

    mp_assert(args->url);

    int r = STREAM_NO_MATCH;

    *ret = NULL;

    // Open stream proper

    if (args->sinfo) {

        r = stream_create_instance(args->sinfo, args, ret);

    } else {

        for (int i = 0; i < MP_ARRAY_SIZE(stream_list); i++) {

            r = stream_create_instance(stream_list[i], args, ret);

            if (r == STREAM_OK)

                break;

            if (r == STREAM_NO_MATCH || r == STREAM_UNSUPPORTED)

                continue;

            if (r == STREAM_UNSAFE)

                continue;

            break;

        }

    }

    if (!*ret && !(args->flags & STREAM_SILENT) && !mp_cancel_test(args->cancel))

    {

        struct mp_log *log = mp_log_new(NULL, args->global->log, "!stream");

        if (r == STREAM_UNSAFE) {

            mp_err(log, "\nRefusing to load potentially unsafe URL from a playlist.\n"

                   "Use the --load-unsafe-playlists option to load it anyway.\n\n");

        } else if (r == STREAM_NO_MATCH || r == STREAM_UNSUPPORTED) {

            mp_err(log, "No protocol handler found to open URL %s\n", args->url);

            mp_err(log, "The protocol is either unsupported, or was disabled "

                        "at compile-time.\n");

        } else {

            mp_err(log, "Failed to open %s.\n", args->url);

        }

        talloc_free(log);

    }

    return r;

}

struct stream *stream_create(const char *url, int flags,

                             struct mp_cancel *c, struct mpv_global *global)

{

    struct stream_open_args args = {

        .global = global,

        .cancel = c,

        .flags = flags,

        .url = url,

    };

    struct stream *s;

    stream_create_with_args(&args, &s);

    return s;

}

stream_t *open_output_stream(const char *filename, struct mpv_global *global)

{

    struct stream *s = stream_create(filename, STREAM_ORIGIN_DIRECT | STREAM_WRITE,

                                     NULL, global);

    if (s && s->is_directory) {

        free_stream(s);

        s = NULL;

    }

    return s;

}

// Read function bypassing the local stream buffer. This will not write into

// s->buffer, but into buf[0..len] instead.

// Returns 0 on error or EOF, and length of bytes read on success.

// Partial reads are possible, even if EOF is not reached.

static int stream_read_unbuffered(stream_t *s, void *buf, int len)

{

    mp_assert(len >= 0);

    if (len <= 0)

        return 0;

    int res = 0;

    // we will retry even if we already reached EOF previously.

    if (s->fill_buffer && !mp_cancel_test(s->cancel))

        res = s->fill_buffer(s, buf, len);

    if (res <= 0) {

        s->eof = 1;

        return 0;

    }

    mp_assert(res <= len);

    // When reading succeeded we are obviously not at eof.

    s->eof = 0;

    s->pos += res;

    s->total_unbuffered_read_bytes += res;

    return res;

}

// Ask for having at most "forward" bytes ready to read in the buffer.

// To read everything, you may have to call this in a loop.

//  forward: desired amount of bytes in buffer after s->cur_pos

//  returns: progress (false on EOF or on OOM or if enough data was available)

static bool stream_read_more(struct stream *s, int forward)

{

    mp_assert(forward >= 0);

    int forward_avail = s->buf_end - s->buf_cur;

    if (forward_avail >= forward)

        return false;

    // Avoid that many small reads will lead to many low-level read calls.

    forward = MPMAX(forward, s->requested_buffer_size / 2);

    mp_assert(forward_avail < forward);

    // Keep guaranteed seek-back.

    int buf_old = MPMIN(s->buf_cur - s->buf_start, s->requested_buffer_size / 2);

    // Never shrink the buffer here. That's stream_drop_buffers()'s job. Otherwise

    // data fetched by earlier larger reads (e.g. demuxer probing) would be

    // discarded, forcing redundant re-reads on backward seeks.

    int new_size = MPMAX(buf_old + forward, s->buffer_mask + 1);

    if (!stream_resize_buffer(s, buf_old + forward_avail, new_size))

        return false;

    int buf_alloc = s->buffer_mask + 1;

    mp_assert(s->buf_start <= s->buf_cur);

    mp_assert(s->buf_cur <= s->buf_end);

    mp_assert(s->buf_cur < buf_alloc * 2);

    mp_assert(s->buf_end < buf_alloc * 2);

    mp_assert(s->buf_start < buf_alloc);

    // Note: read as much as possible, even if forward is much smaller. Do

    // this because the stream buffer is supposed to set an approx. minimum

    // read size on it.

    int read = buf_alloc - (buf_old + forward_avail); // free buffer past end

    int pos = s->buf_end & s->buffer_mask;

    read = MPMIN(read, buf_alloc - pos);

    // Note: if wrap-around happens, we need to make two calls. This may

    // affect latency (e.g. waiting for new data on a socket), so do only

    // 1 read call always.

    read = stream_read_unbuffered(s, &s->buffer[pos], read);

    s->buf_end += read;

    // May have overwritten old data.

    if (s->buf_end - s->buf_start >= buf_alloc) {

        mp_assert(s->buf_end >= buf_alloc);

        s->buf_start = s->buf_end - buf_alloc;

        mp_assert(s->buf_start <= s->buf_cur);

        mp_assert(s->buf_cur <= s->buf_end);

        if (s->buf_start >= buf_alloc) {

            s->buf_start -= buf_alloc;

            s->buf_cur -= buf_alloc;

            s->buf_end -= buf_alloc;

        }

    }

    // Must not have overwritten guaranteed old data.

    mp_assert(s->buf_cur - s->buf_start >= buf_old);

    if (s->buf_cur < s->buf_end)

        s->eof = 0;

    return !!read;

}

// Read between 1..buf_size bytes of data, return how much data has been read.

// Return 0 on EOF, error, or if buf_size was 0.

int stream_read_partial(stream_t *s, void *buf, int buf_size)

{

    mp_assert(s->buf_cur <= s->buf_end);

    mp_assert(buf_size >= 0);

    if (s->buf_cur == s->buf_end && buf_size > 0) {

        if (buf_size > (s->buffer_mask + 1) / 2) {

            // Direct read if the buffer is too small anyway.

            stream_drop_buffers(s);

            return stream_read_unbuffered(s, buf, buf_size);

        }

        stream_read_more(s, 1);

    }

    int res = ring_copy(s, buf, buf_size, s->buf_cur);

    s->buf_cur += res;

    return res;

}

// Slow version of stream_read_char(); called by it if the buffer is empty.

int stream_read_char_fallback(stream_t *s)

{

    uint8_t c;

    return stream_read_partial(s, &c, 1) ? c : STREAM_EOF;

}

int stream_read(stream_t *s, void *mem, int total)

{

    int len = total;

    while (len > 0) {

        int read = stream_read_partial(s, mem, len);

        if (read <= 0)

            break; // EOF

        mem = (char *)mem + read;

        len -= read;

    }

    total -= len;

    return total;

}

// Read ahead so that at least forward_size bytes are readable ahead. Returns

// the actual forward amount available (restricted by EOF or buffer limits).

int stream_peek(stream_t *s, int forward_size)

{

    while (stream_read_more(s, forward_size)) {}

    return s->buf_end - s->buf_cur;

}

// Like stream_read(), but do not advance the current position. This may resize

// the buffer to satisfy the read request.

int stream_read_peek(stream_t *s, void *buf, int buf_size)

{

    stream_peek(s, buf_size);

    return ring_copy(s, buf, buf_size, s->buf_cur);

}

int stream_write_buffer(stream_t *s, void *buf, int len)

{

    if (!s->write_buffer)

        return -1;

    int orig_len = len;

    while (len) {

        int w = s->write_buffer(s, buf, len);

        if (w <= 0)

            return -1;

        s->pos += w;

        buf = (char *)buf + w;

        len -= w;

    }

    return orig_len;

}

// Drop len bytes form input, possibly reading more until all is skipped. If

// EOF or an error was encountered before all could be skipped, return false,

// otherwise return true.

static bool stream_skip_read(struct stream *s, int64_t len)

{

    while (len > 0) {

        unsigned int left = s->buf_end - s->buf_cur;

        if (!left) {

            if (!stream_read_more(s, 1))

                return false;

            continue;

        }

        unsigned skip = MPMIN(len, left);

        s->buf_cur += skip;

        len -= skip;

    }

    return true;

}

// Drop the internal buffer. Note that this will advance the stream position

// (as seen by stream_tell()), because the real stream position is ahead of the

// logical stream position by the amount of buffered but not yet read data.

void stream_drop_buffers(stream_t *s)

{

    s->pos = stream_tell(s);

    s->buf_start = s->buf_cur = s->buf_end = 0;

    s->eof = 0;

    stream_resize_buffer(s, 0, 0);

}

// Seek function bypassing the local stream buffer.

static bool stream_seek_unbuffered(stream_t *s, int64_t newpos)

{

    if (newpos != s->pos) {

        MP_VERBOSE(s, "stream level seek from %" PRId64 " to %" PRId64 "\n",

                   s->pos, newpos);

        s->total_stream_seeks++;

        if (newpos > s->pos && !s->seekable) {

            MP_ERR(s, "Cannot seek forward in this stream\n");

            return false;

        }

        if (newpos < s->pos && !s->seekable) {

            MP_ERR(s, "Cannot seek backward in linear streams!\n");

            return false;

        }

        if (s->seek(s, newpos) <= 0) {

            int level = mp_cancel_test(s->cancel) ? MSGL_V : MSGL_ERR;

            MP_MSG(s, level, "Seek failed (to %lld, size %lld)\n",

                   (long long)newpos, (long long)stream_get_size(s));

            return false;

        }

        stream_drop_buffers(s);

        s->pos = newpos;

    }

    return true;

}

bool stream_seek(stream_t *s, int64_t pos)

{

    MP_TRACE(s, "seek request from %" PRId64 " to %" PRId64 "\n",

             stream_tell(s), pos);

    s->eof = 0; // eof should be set only on read; seeking always clears it

    if (pos < 0) {

        MP_ERR(s, "Invalid seek to negative position %lld!\n", (long long)pos);

        pos = 0;

    }

    if (pos <= s->pos) {

        int64_t x = pos - (s->pos - (int)s->buf_end);

        if (x >= (int)s->buf_start) {

            s->buf_cur = x;

            mp_assert(s->buf_cur >= s->buf_start);

            mp_assert(s->buf_cur <= s->buf_end);

            return true;

        }

    }

    if (s->mode == STREAM_WRITE)

        return s->seekable && s->seek(s, pos);

    // Skip data instead of performing a seek in some cases.

    if (pos >= s->pos &&

        ((!s->seekable && s->fast_skip) ||

         pos - s->pos <= s->requested_buffer_size))

    {

        return stream_skip_read(s, pos - stream_tell(s));

    }

    return stream_seek_unbuffered(s, pos);

}

// Like stream_seek(), but strictly prefer skipping data instead of failing, if

// it's a forward-seek.

bool stream_seek_skip(stream_t *s, int64_t pos)

{

    uint64_t cur_pos = stream_tell(s);

    if (cur_pos == pos)

        return true;

    return !s->seekable && pos > cur_pos

        ? stream_skip_read(s, pos - cur_pos)

        : stream_seek(s, pos);

}

int stream_control(stream_t *s, int cmd, void *arg)

{

    return s->control ? s->control(s, cmd, arg) : STREAM_UNSUPPORTED;

}

// Return the current size of the stream, or a negative value if unknown.

int64_t stream_get_size(stream_t *s)

{

    return s->get_size ? s->get_size(s) : -1;

}

void free_stream(stream_t *s)

{

    if (!s)

        return;

    if (s->close)

        s->close(s);

    talloc_free(s);

}

static const char *const bom[3] = {"\xEF\xBB\xBF", "\xFF\xFE", "\xFE\xFF"};

// Return utf16 argument for stream_read_line

int stream_skip_bom(struct stream *s)

{

    char buf[4];

    int len = stream_read_peek(s, buf, sizeof(buf));

    bstr data = {buf, len};

    for (int n = 0; n < 3; n++) {

        if (bstr_startswith0(data, bom[n])) {

            stream_seek_skip(s, stream_tell(s) + strlen(bom[n]));

            return n;

        }

    }

    return -1; // default to 8 bit codepages

}

// Read the rest of the stream into memory (current pos to EOF), and return it.

//  talloc_ctx: used as talloc parent for the returned allocation

//  max_size: must be set to >=0. If the file is larger than that, it is treated

//            as error. This is a minor robustness measure. If the stream is

//            created with STREAM_ALLOW_PARTIAL_READ flag, partial result up to

//            max_size is returned instead.

//  returns: stream contents, or .start/.len set to NULL on error

// If the file was empty, but no error happened, .start will be non-NULL and

// .len will be 0.

// For convenience, the returned buffer is padded with a 0 byte. The padding

// is not included in the returned length.

struct bstr stream_read_complete(struct stream *s, void *talloc_ctx,

                                 int max_size)

{

    if (max_size < 0 || max_size > STREAM_MAX_READ_SIZE)

        abort();

    if (s->is_directory)

        return (struct bstr){NULL, 0};

    int bufsize;

    int total_read = 0;

    int padding = 1;

    char *buf = NULL;

    int64_t size = stream_get_size(s) - stream_tell(s);

    if (size > max_size && !s->allow_partial_read)

        return (struct bstr){NULL, 0};

    if (size > 0)

        bufsize = size + padding;

    else

        bufsize = 1000;

    if (s->allow_partial_read)

        bufsize = MPMIN(bufsize, max_size + padding);

    while (1) {

        buf = talloc_realloc_size(talloc_ctx, buf, bufsize);

        int readsize = stream_read(s, buf + total_read, bufsize - total_read);

        total_read += readsize;

        if (total_read >= max_size && s->allow_partial_read) {

            total_read = max_size;

            break;

        }

        if (total_read < bufsize)

            break;

        if (bufsize > max_size) {

            talloc_free(buf);

            return (struct bstr){NULL, 0};

        }

        bufsize = MPMIN(bufsize + (bufsize >> 1), max_size + padding);

    }

    buf = talloc_realloc_size(talloc_ctx, buf, total_read + padding);

    memset(&buf[total_read], 0, padding);

    return (struct bstr){buf, total_read};

}

struct bstr stream_read_file(const char *filename, void *talloc_ctx,

                             struct mpv_global *global, int max_size)

{

    return stream_read_file2(filename, talloc_ctx, STREAM_READ_FILE_FLAGS_DEFAULT,

                             global, max_size);

}

struct bstr stream_read_file2(const char *filename, void *talloc_ctx,

                              int flags, struct mpv_global *global, int max_size)

{

    struct bstr res = {0};

    stream_t *s = stream_create(filename, flags, NULL, global);

    if (s) {

        if (s->is_directory)

            mp_err(s->log, "Failed to open %s (not a file).\n", filename);

        else

            res = stream_read_complete(s, talloc_ctx, max_size);

    }

    free_stream(s);

    return res;

}

char **stream_get_proto_list(bool safe_only)

{

    char **list = NULL;

    int num = 0;

    for (int i = 0; i < MP_ARRAY_SIZE(stream_list); i++) {

        const stream_info_t *stream_info = stream_list[i];

        if (safe_only && (stream_info->stream_origin & STREAM_ORIGIN_UNSAFE))

            continue;

        char **get_protocols = stream_info->get_protocols ? stream_info->get_protocols() : NULL;

        char **protocols = get_protocols ? get_protocols : (char **)stream_info->protocols;

        for (int j = 0; protocols && protocols[j]; j++) {

            if (*protocols[j] == '\0')

                continue;

            MP_TARRAY_APPEND(NULL, list, num, talloc_strdup(list, protocols[j]));

        }

        talloc_free(get_protocols);

    }

    MP_TARRAY_APPEND(NULL, list, num, NULL);

    return list;

}

void stream_print_proto_list(struct mp_log *log)

{

    int count = 0;

    mp_info(log, "Protocols:\n\n");

    char **list = stream_get_proto_list(false);

    for (int i = 0; list[i]; i++) {

        mp_info(log, " %s://\n", list[i]);

        count++;

    }

    talloc_free(list);

    mp_info(log, "\nTotal: %d protocols\n", count);

}

bool stream_has_proto(const char *proto)

{

    for (int i = 0; i < MP_ARRAY_SIZE(stream_list); i++) {

        const stream_info_t *stream_info = stream_list[i];

        bool match = false;

        char **get_protocols = stream_info->get_protocols ? stream_info->get_protocols() : NULL;

        char **protocols = get_protocols ? get_protocols : (char **)stream_info->protocols;

        for (int j = 0; protocols && protocols[j]; j++) {

            if (strcmp(protocols[j], proto) == 0) {

                match = true;

                break;

            }

        }

        talloc_free(get_protocols);

        if (match)

            return match;

    }

    return false;

}