Add scanner support for Philips CD-i disc images (#18424)

CD-i discs have a unique quirk: they store data in tracks labeled as
AUDIO in both CUE and CHD formats. The scanner normally skips AUDIO
tracks when looking for data, causing CD-i games to never match the
database.

Author: warmenhoven

tasks/task_database.c

@@ -384,14 +384,50 @@ static int task_database_gdi_get_serial(const char *name, char *s, size_t len, u
    return intfstream_file_get_serial(track_path, 0, INT64_MAX, s, len, filesize);
 }
 
+/* Helper function to detect if a CHD file is a CD-i disc
+ * CD-i discs store data in AUDIO-labeled tracks, so we need
+ * to explicitly open track 1 for scanning */
+static bool is_chd_file_cdi(const char *path)
+{
+   intfstream_t *fd;
+   uint8_t magic[12];
+   bool is_cdi = false;
+   const uint8_t cdi_magic[] = {0x00, 0xff, 0xff, 0xff, 0xff, 0xff,
+                                 0xff, 0xff, 0xff, 0xff, 0xff, 0x00};
+
+   /* Try to open track 1 explicitly */
+   fd = intfstream_open_chd_track(path,
+         RETRO_VFS_FILE_ACCESS_READ,
+         RETRO_VFS_FILE_ACCESS_HINT_NONE,
+         1);  /* Explicit track number, not CHDSTREAM_TRACK_FIRST_DATA */
+
+   if (!fd)
+      return false;
+
+   /* Read and check CD-i magic bytes at offset 0 */
+   if (intfstream_read(fd, magic, sizeof(magic)) == sizeof(magic))
+      is_cdi = (memcmp(magic, cdi_magic, sizeof(cdi_magic)) == 0);
+
+   intfstream_close(fd);
+   free(fd);
+   return is_cdi;
+}
+
 static int task_database_chd_get_serial(const char *name, char *serial, size_t len, uint64_t *filesize)
 {
    int result;
-   intfstream_t *fd = intfstream_open_chd_track(
+   int32_t track;
+   intfstream_t *fd;
+
+   /* CD-i discs store data in AUDIO-labeled tracks, so we must
+    * explicitly open track 1 instead of using CHDSTREAM_TRACK_FIRST_DATA */
+   track = is_chd_file_cdi(name) ? 1 : CHDSTREAM_TRACK_FIRST_DATA;
+
+   fd = intfstream_open_chd_track(
          name,
          RETRO_VFS_FILE_ACCESS_READ,
          RETRO_VFS_FILE_ACCESS_HINT_NONE,
-         CHDSTREAM_TRACK_FIRST_DATA);
+         track);
    if (!fd)
       return 0;
 
@@ -503,11 +539,18 @@ static int task_database_gdi_get_crc_and_size(const char *name, uint32_t *crc, u
 static bool task_database_chd_get_crc_and_size(const char *name, uint32_t *crc, uint64_t *size)
 {
    bool found_crc   = false;
-   intfstream_t *fd = intfstream_open_chd_track(
+   int32_t track;
+   intfstream_t *fd;
+
+   /* CD-i discs store data in AUDIO-labeled tracks, so we must
+    * explicitly open track 1 instead of using CHDSTREAM_TRACK_PRIMARY */
+   track = is_chd_file_cdi(name) ? 1 : CHDSTREAM_TRACK_PRIMARY;
+
+   fd = intfstream_open_chd_track(
          name,
          RETRO_VFS_FILE_ACCESS_READ,
          RETRO_VFS_FILE_ACCESS_HINT_NONE,
-         CHDSTREAM_TRACK_PRIMARY);
+         track);
    if (!fd)
       return 0;
 

tasks/task_database_cue.c

@@ -62,6 +62,7 @@ static struct magic_entry MAGIC_NUMBERS[] = {
    { "Sony - PlayStation 2",        "PLAYSTATION",      0x008008}, /* PS2 DVD */
    { "Sony - PlayStation 2",        "           ",      0x008008}, /* PS2 DVD */
    { "Sony - PlayStation Portable", "PSP GAME",         0x008008},
+   { "Philips - CD-i",              "\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\x00", 0x000000},
    { NULL,                          NULL,               0}
 };
 
@@ -1165,6 +1166,37 @@ int cue_find_track(const char *cue_path, bool first,
          task_database_cue_get_token(fd, tmp_token, sizeof(tmp_token));
          is_data = !string_is_equal_noncase(tmp_token, "AUDIO");
          ++track;
+
+         /* Special case: CD-i stores data in AUDIO-labeled tracks */
+         /* Check if track 1 is AUDIO but contains CD-i magic bytes */
+         if (!is_data && track == 1 && last_file[0] != '\0')
+         {
+            intfstream_t *track_fd = NULL;
+            intfstream_info_t track_info;
+            uint8_t magic_buf[12];
+            const uint8_t cdi_magic[] = {0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00};
+
+            track_info.type = INTFSTREAM_FILE;
+            if ((track_fd = (intfstream_t*)intfstream_init(&track_info)))
+            {
+               if (intfstream_open(track_fd, last_file,
+                     RETRO_VFS_FILE_ACCESS_READ, RETRO_VFS_FILE_ACCESS_HINT_NONE))
+               {
+                  if (intfstream_read(track_fd, magic_buf, sizeof(magic_buf)) == sizeof(magic_buf))
+                  {
+                     if (memcmp(magic_buf, cdi_magic, sizeof(cdi_magic)) == 0)
+                     {
+                        is_data = true;  /* CD-i AUDIO track contains data */
+#ifdef DEBUG
+                        RARCH_LOG("[Scanner] Detected CD-i data in AUDIO track 1\n");
+#endif
+                     }
+                  }
+                  intfstream_close(track_fd);
+               }
+               free(track_fd);
+            }
+         }
       }
       else if (string_is_equal_noncase(tmp_token, "INDEX"))
       {