demux_mkv: use new EBML parser for file header

3 files changed, 29 insertions, 79 deletions

diff --git a/libmpdemux/demux_mkv.c b/libmpdemux/demux_mkv.c
index 99e3302c1d..203523ff62 100644
--- a/libmpdemux/demux_mkv.c
+++ b/libmpdemux/demux_mkv.c
@@ -2018,16 +2018,40 @@ static int demux_mkv_open(demuxer_t *demuxer)
     stream_t *s = demuxer->stream;
     mkv_demuxer_t *mkv_d;
     mkv_track_t *track;
-    int i, version, cont = 0;
-    char *str;
+    int i, cont = 0;
 
     stream_seek(s, s->start_pos);
-    str = ebml_read_header(s, &version);
-    if (str == NULL || strcmp(str, "matroska") || version > 2) {
+    if (ebml_read_id(s, NULL) != EBML_ID_EBML)
+        return 0;
+    struct ebml_ebml ebml_master = {};
+    struct ebml_parse_ctx parse_ctx = { .no_error_messages = true };
+    if (ebml_read_element(s, &parse_ctx, &ebml_master, &ebml_ebml_desc) < 0)
+        return 0;
+    if (ebml_master.doc_type.len != 8 || strncmp(ebml_master.doc_type.start,
+                                                 "matroska", 8)) {
         mp_msg(MSGT_DEMUX, MSGL_DBG2, "[mkv] no head found\n");
+        talloc_free(parse_ctx.talloc_ctx);
+        return 0;
+    }
+    if (ebml_master.doc_type_read_version > 2) {
+        mp_msg(MSGT_DEMUX, MSGL_WARN, "[mkv] This looks like a Matroska file, "
+               "but we don't support format version %"PRIu64"\n",
+               ebml_master.doc_type_read_version);
+        talloc_free(parse_ctx.talloc_ctx);
+        return 0;
+    }
+    if ((ebml_master.n_ebml_read_version
+         && ebml_master.ebml_read_version != EBML_VERSION)
+        || (ebml_master.n_ebml_max_size_length
+            && ebml_master.ebml_max_size_length > 8)
+        || (ebml_master.n_ebml_max_id_length
+            && ebml_master.ebml_max_id_length != 4)) {
+        mp_msg(MSGT_DEMUX, MSGL_WARN, "[mkv] This looks like a Matroska file, "
+               "but the header has bad parameters\n");
+        talloc_free(parse_ctx.talloc_ctx);
         return 0;
     }
-    free(str);
+    talloc_free(parse_ctx.talloc_ctx);
 
     mp_msg(MSGT_DEMUX, MSGL_V, "[mkv] Found the head...\n");
 
diff --git a/libmpdemux/ebml.c b/libmpdemux/ebml.c
index 37e2fe0ffb..6eae1ef2c1 100644
--- a/libmpdemux/ebml.c
+++ b/libmpdemux/ebml.c
@@ -285,79 +285,6 @@ uint32_t ebml_read_master(stream_t *s, uint64_t *length)
 }
 
 
-/*
- * Read an EBML header.
- */
-char *ebml_read_header(stream_t *s, int *version)
-{
-    uint64_t length, l, num;
-    uint32_t id;
-    char *str = NULL;
-
-    if (ebml_read_master(s, &length) != EBML_ID_EBML)
-        return 0;
-
-    if (version)
-        *version = 1;
-
-    while (length > 0) {
-        id = ebml_read_id(s, NULL);
-        if (id == EBML_ID_INVALID)
-            return NULL;
-        length -= 2;
-
-        switch (id) {
-            /* is our read version uptodate? */
-        case EBML_ID_EBMLREADVERSION:
-            num = ebml_read_uint(s, &l);
-            if (num != EBML_VERSION)
-                return NULL;
-            break;
-
-            /* we only handle 8 byte lengths at max */
-        case EBML_ID_EBMLMAXSIZELENGTH:
-            num = ebml_read_uint(s, &l);
-            if (num != sizeof(uint64_t))
-                return NULL;
-            break;
-
-            /* we handle 4 byte IDs at max */
-        case EBML_ID_EBMLMAXIDLENGTH:
-            num = ebml_read_uint(s, &l);
-            if (num != sizeof(uint32_t))
-                return NULL;
-            break;
-
-        case EBML_ID_DOCTYPE:
-            str = ebml_read_ascii(s, &l);
-            if (str == NULL)
-                return NULL;
-            break;
-
-        case EBML_ID_DOCTYPEREADVERSION:
-            num = ebml_read_uint(s, &l);
-            if (num == EBML_UINT_INVALID)
-                return NULL;
-            if (version)
-                *version = num;
-            break;
-
-            /* we ignore these two, they don't tell us anything we care about */
-        case EBML_ID_VOID:
-        case EBML_ID_EBMLVERSION:
-        case EBML_ID_DOCTYPEVERSION:
-        default:
-            if (ebml_read_skip(s, &l))
-                return NULL;
-            break;
-        }
-        length -= l;
-    }
-
-    return str;
-}
-
-
 
 #define EVALARGS(F, ...) F(__VA_ARGS__)
 #define E(str, N, type) const struct ebml_elem_desc ebml_ ## N ## _desc = { str, type };
diff --git a/libmpdemux/ebml.h b/libmpdemux/ebml.h
index fc6a0ddbac..0398b1813a 100644
--- a/libmpdemux/ebml.h
+++ b/libmpdemux/ebml.h
@@ -109,7 +109,6 @@ char *ebml_read_ascii (stream_t *s, uint64_t *length);
 char *ebml_read_utf8 (stream_t *s, uint64_t *length);
 int ebml_read_skip (stream_t *s, uint64_t *length);
 uint32_t ebml_read_master (stream_t *s, uint64_t *length);
-char *ebml_read_header (stream_t *s, int *version);
 
 int ebml_read_element(struct stream *s, struct ebml_parse_ctx *ctx,
                       void *target, const struct ebml_elem_desc *desc);