core: add new support for reading .cue files

Playing a .cue file directly will now parse the .cue file, and load and
play the file(s) referenced in the cue. If multiple files are referenced,
a timeline including all files will be created to create the impression
of a single, flat audio file containing all the tracks.

For each track, a chapter is created. The chapter navigation commands can
be used to jump between tracks. The chapter titles will use the string
provided by the track's TITLE cue command. (The -identify command can be
used to print all chapters in a not so user friendly way.)

Other than the chapter names, there is no attempt at displaying or exposing
any other meta data contained in the cue files yet.

The handling (or lack of thereof) of gaps (track pregaps and postgaps) is
probably not correct yet. In general, mplayer's mapping of tracks to the
source audio files can be verified by examining the timeline, which will
be printed when passing the -v switch.

Note that this has nothing to do with the old cue:// support. The old code
isn't touched, and is still only able to play .cue/.bin pairs. Prefixing a
.cue file with cue:// will always invoke the old code, while playing a .cue
file directly (i.e. "mplayer file.cue") will always use the new code.

Playing audio images (.cue/.bin pairs of files) doesn't work yet.

1 files changed, 422 insertions, 0 deletions

diff --git a/timeline/tl_cue.c b/timeline/tl_cue.c
new file mode 100644
index 0000000000..e3fcbb56df
--- /dev/null
+++ b/timeline/tl_cue.c
@@ -0,0 +1,422 @@
+/*
+ * This file is part of mplayer2.
+ *
+ * mplayer2 is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * mplayer2 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with mplayer2; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <dirent.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <inttypes.h>
+#include <ctype.h>
+
+#include "talloc.h"
+
+#include "mp_core.h"
+#include "mp_msg.h"
+#include "libmpdemux/demuxer.h"
+#include "path.h"
+#include "bstr.h"
+#include "mpcommon.h"
+#include "stream/stream.h"
+
+// used by demuxer_cue.c
+bool mp_probe_cue(struct bstr data);
+
+#define SECS_PER_CUE_FRAME (1.0/75.0)
+
+enum cue_command {
+    CUE_ERROR = -1,     // not a valid CUE command, or an unknown extension
+    CUE_EMPTY,          // line with whitespace only
+    CUE_UNUSED,         // valid CUE command, but ignored by this code
+    CUE_FILE,
+    CUE_TRACK,
+    CUE_INDEX,
+    CUE_TITLE,
+};
+
+static const struct {
+    enum cue_command command;
+    const char *text;
+} cue_command_strings[] = {
+    { CUE_FILE, "FILE" },
+    { CUE_TRACK, "TRACK" },
+    { CUE_INDEX, "INDEX" },
+    { CUE_TITLE, "TITLE" },
+    { CUE_UNUSED, "CATALOG" },
+    { CUE_UNUSED, "CDTEXTFILE" },
+    { CUE_UNUSED, "FLAGS" },
+    { CUE_UNUSED, "ISRC" },
+    { CUE_UNUSED, "PERFORMER" },
+    { CUE_UNUSED, "POSTGAP" },
+    { CUE_UNUSED, "PREGAP" },
+    { CUE_UNUSED, "REM" },
+    { CUE_UNUSED, "SONGWRITER" },
+    { CUE_UNUSED, "MESSAGE" },
+    { -1 },
+};
+
+struct cue_track {
+    double pregap_start;        // corresponds to INDEX 00
+    double start;               // corresponds to INDEX 01
+    struct bstr filename;
+    int source;
+    struct bstr title;
+};
+
+static enum cue_command read_cmd(struct bstr *data, struct bstr *out_params)
+{
+    struct bstr line = bstr_getline(*data, data);
+    line = bstr_lstrip(line);
+    if (line.len == 0)
+        return CUE_EMPTY;
+    for (int n = 0; cue_command_strings[n].command != -1; n++) {
+        struct bstr name = bstr(cue_command_strings[n].text);
+        if (bstr_startswith(line, name)) {
+            struct bstr rest = bstr_cut(line, name.len);
+            if (rest.len && !strchr(WHITESPACE, rest.start[0]))
+                continue;
+            if (out_params)
+                *out_params = rest;
+            return cue_command_strings[n].command;
+        }
+    }
+    return CUE_ERROR;
+}
+
+static bool eat_char(struct bstr *data, char ch)
+{
+    if (data->len && data->start[0] == ch) {
+        *data = bstr_cut(*data, 1);
+        return true;
+    } else {
+        return false;
+    }
+}
+
+static struct bstr read_quoted(struct bstr *data)
+{
+    *data = bstr_lstrip(*data);
+    if (!eat_char(data, '"'))
+        return (struct bstr) {0};
+    int end = bstrchr(*data, '"');
+    if (end < 0)
+        return (struct bstr) {0};
+    struct bstr res = bstr_splice(*data, 0, end);
+    *data = bstr_cut(*data, end + 1);
+    return res;
+}
+
+// Read a 2 digit unsigned decimal integer.
+// Return -1 on failure.
+static int read_int_2(struct bstr *data)
+{
+    *data = bstr_lstrip(*data);
+    if (data->len && data->start[0] == '-')
+        return -1;
+    struct bstr s = *data;
+    int res = (int)bstrtoll(s, &s, 10);
+    if (data->len == s.len || data->len - s.len > 2)
+        return -1;
+    *data = s;
+    return res;
+}
+
+static double read_time(struct bstr *data)
+{
+    struct bstr s = *data;
+    bool ok = true;
+    double t1 = read_int_2(&s);
+    ok = eat_char(&s, ':') && ok;
+    double t2 = read_int_2(&s);
+    ok = eat_char(&s, ':') && ok;
+    double t3 = read_int_2(&s);
+    ok = ok && t1 >= 0 && t2 >= 0 && t3 >= 0;
+    return ok ? t1 * 60.0 + t2 + t3 * SECS_PER_CUE_FRAME : 0;
+}
+
+static struct bstr skip_utf8_bom(struct bstr data)
+{
+    return bstr_startswith0(data, "\xEF\xBB\xBF") ? bstr_cut(data, 3) : data;
+}
+
+// Check if the text in data is most likely CUE data. This is used by the
+// demuxer code to check the file type.
+// data is the start of the probed file, possibly cut off at a random point.
+bool mp_probe_cue(struct bstr data)
+{
+    bool valid = false;
+    data = skip_utf8_bom(data);
+    for (;;) {
+        enum cue_command cmd = read_cmd(&data, NULL);
+        // End reached. Since the line was most likely cut off, don't use the
+        // result of the last parsing call.
+        if (data.len == 0)
+            break;
+        if (cmd == CUE_ERROR)
+            return false;
+        if (cmd != CUE_EMPTY)
+            valid = true;
+    }
+    return valid;
+}
+
+static void add_source(struct MPContext *mpctx, struct stream *s,
+                       struct demuxer *d)
+{
+    mpctx->num_sources++;
+    mpctx->sources = talloc_realloc(NULL, mpctx->sources, struct content_source,
+                                    mpctx->num_sources);
+    mpctx->sources[mpctx->num_sources - 1] = (struct content_source) {
+        .stream = s,
+        .demuxer = d,
+    };
+}
+
+static bool try_open(struct MPContext *mpctx, char *filename)
+{
+    struct bstr bfilename = bstr(filename);
+    // Avoid trying to open itself or another .cue file. Best would be
+    // to check the result of demuxer auto-detection, but the demuxer
+    // API doesn't allow this without opening a full demuxer.
+    if (bstr_case_endswith(bfilename, bstr(".cue"))
+        || bstrcasecmp(bstr(mpctx->demuxer->filename), bfilename) == 0)
+        return false;
+
+    int format = 0;
+    struct stream *s = open_stream(filename, &mpctx->opts, &format);
+    if (!s)
+        return false;
+    struct demuxer *d = demux_open(&mpctx->opts, s, format,
+                                    mpctx->opts.audio_id,
+                                    mpctx->opts.video_id,
+                                    mpctx->opts.sub_id,
+                                    filename);
+    if (d) {
+        add_source(mpctx, s, d);
+        return true;
+    }
+    mp_msg(MSGT_CPLAYER, MSGL_ERR, "Could not open source '%s'!\n", filename);
+    free_stream(s);
+    return false;
+}
+
+static bool open_source(struct MPContext *mpctx, struct bstr filename)
+{
+    void *ctx = talloc_new(NULL);
+    bool res = false;
+
+    struct bstr dirname = mp_dirname(mpctx->demuxer->filename);
+
+    struct bstr base_filename = bstr(mp_basename(bstrdup0(ctx, filename)));
+    if (!base_filename.len) {
+        mp_msg(MSGT_CPLAYER, MSGL_WARN,
+               "CUE: Invalid audio filename in .cue file!\n");
+    } else {
+        char *fullname = mp_path_join(ctx, dirname, base_filename);
+        if (try_open(mpctx, fullname)) {
+            res = true;
+            goto out;
+        }
+    }
+
+    // Try an audio file with the same name as the .cue file (but different
+    // extension).
+    // Rationale: this situation happens easily if the audio file or both files
+    // are renamed.
+
+    struct bstr cuefile =
+        bstr_strip_ext(bstr(mp_basename(mpctx->demuxer->filename)));
+
+    DIR *d = opendir(bstrdup0(ctx, dirname));
+    if (!d)
+        goto out;
+    struct dirent *de;
+    while ((de = readdir(d))) {
+        char *dename0 = de->d_name;
+        struct bstr dename = bstr(dename0);
+        if (bstr_case_startswith(dename, cuefile)) {
+            mp_msg(MSGT_CPLAYER, MSGL_WARN, "CUE: No useful audio filename "
+                    "in .cue file found, trying with '%s' instead!\n",
+                    dename0);
+            if (try_open(mpctx, mp_path_join(ctx, dirname, dename))) {
+                res = true;
+                break;
+            }
+        }
+    }
+    closedir(d);
+
+out:
+    talloc_free(ctx);
+    if (!res)
+        mp_msg(MSGT_CPLAYER, MSGL_ERR, "CUE: Could not open audio file!\n");
+    return res;
+}
+
+// return length of the source in seconds, or -1 if unknown
+static double source_get_length(struct content_source *source)
+{
+    struct demuxer *demuxer = source->demuxer;
+    double get_time_ans;
+    // <= 0 means DEMUXER_CTRL_NOTIMPL or DEMUXER_CTRL_DONTKNOW
+    if (demuxer && demux_control(demuxer, DEMUXER_CTRL_GET_TIME_LENGTH,
+                                 (void *) &get_time_ans) > 0)
+    {
+        return get_time_ans;
+    } else {
+        return -1;
+    }
+}
+
+void build_cue_timeline(struct MPContext *mpctx)
+{
+    void *ctx = talloc_new(NULL);
+
+    struct bstr data = mpctx->demuxer->file_contents;
+    data = skip_utf8_bom(data);
+
+    struct cue_track *tracks = NULL;
+    size_t track_count = 0;
+
+    struct bstr filename = {0};
+    // Global metadata, and copied into new tracks.
+    struct cue_track proto_track = {0};
+    struct cue_track *cur_track = &proto_track;
+
+    while (data.len) {
+        struct bstr param;
+        switch (read_cmd(&data, &param)) {
+        case CUE_ERROR:
+            mp_msg(MSGT_CPLAYER, MSGL_ERR, "CUE: error parsing input file!\n");
+            goto out;
+        case CUE_TRACK: {
+            track_count++;
+            tracks = talloc_realloc(ctx, tracks, struct cue_track, track_count);
+            cur_track = &tracks[track_count - 1];
+            *cur_track = proto_track;
+            break;
+        }
+        case CUE_TITLE:
+            cur_track->title = read_quoted(&param);
+            break;
+        case CUE_INDEX: {
+            int type = read_int_2(&param);
+            double time = read_time(&param);
+            if (type == 1) {
+                cur_track->start = time;
+                cur_track->filename = filename;
+            } else if (type == 0) {
+                cur_track->pregap_start = time;
+            }
+            break;
+        }
+        case CUE_FILE:
+            // NOTE: FILE comes before TRACK, so don't use cur_track->filename
+            filename = read_quoted(&param);
+            break;
+        }
+    }
+
+    if (track_count == 0) {
+        mp_msg(MSGT_CPLAYER, MSGL_ERR, "CUE: no tracks found!\n");
+        goto out;
+    }
+
+    // Remove duplicate file entries. This might be too sophisticated, since
+    // CUE files usually use either separate files for every single track, or
+    // only one file for all tracks.
+
+    struct bstr *files = 0;
+    size_t file_count = 0;
+
+    for (size_t n = 0; n < track_count; n++) {
+        struct cue_track *track = &tracks[n];
+        track->source = -1;
+        for (size_t file = 0; file < file_count; file++) {
+            if (bstrcmp(files[file], track->filename) == 0) {
+                track->source = file;
+                break;
+            }
+        }
+        if (track->source == -1) {
+            file_count++;
+            files = talloc_realloc(ctx, files, struct bstr, file_count);
+            files[file_count - 1] = track->filename;
+            track->source = file_count - 1;
+        }
+    }
+
+    add_source(mpctx, mpctx->stream, mpctx->demuxer);
+
+    for (size_t i = 0; i < file_count; i++) {
+        if (!open_source(mpctx, files[i]))
+            goto out;
+    }
+
+    struct timeline_part *timeline = talloc_array_ptrtype(NULL, timeline,
+                                                          track_count + 1);
+    struct chapter *chapters = talloc_array_ptrtype(NULL, chapters,
+                                                    track_count);
+    double starttime = 0;
+    for (int i = 0; i < track_count; i++) {
+        struct content_source *source = mpctx->sources + 1 + tracks[i].source;
+        double duration;
+        if (i + 1 < track_count && tracks[i].source == tracks[i + 1].source) {
+            duration = tracks[i + 1].start - tracks[i].start;
+        } else {
+            duration = source_get_length(source);
+            // Two cases: 1) last track of a single-file cue, or 2) any track of
+            // a multi-file cue. We need to do this for 1) only because the
+            // timeline needs to be terminated with the length of the last
+            // track.
+            duration -= tracks[i].start;
+        }
+        if (duration < 0) {
+            mp_msg(MSGT_CPLAYER, MSGL_WARN,
+                   "CUE: Can't get duration of source file!\n");
+            // xxx: do something more reasonable
+            duration = 0.0;
+        }
+        timeline[i] = (struct timeline_part) {
+            .start = starttime,
+            .source_start = tracks[i].start,
+            .source = source,
+        };
+        chapters[i] = (struct chapter) {
+            .start = timeline[i].start,
+            // might want to include other metadata here
+            .name = bstrdup0(chapters, tracks[i].title),
+        };
+        starttime += duration;
+    }
+
+    // apparently we need this to give the last part a non-zero length
+    timeline[track_count] = (struct timeline_part) {
+        .start = starttime,
+        // perhaps unused by the timeline code
+        .source_start = 0,
+        .source = timeline[0].source,
+    };
+
+    mpctx->timeline = timeline;
+    // the last part is not included it in the count
+    mpctx->num_timeline_parts = track_count + 1 - 1;
+    mpctx->chapters = chapters;
+    mpctx->num_chapters = track_count;
+
+out:
+    talloc_free(ctx);
+}