CDImage: Handle cue sheets where pregap is in file

src/common/cd_image.cpp

@@ -95,7 +95,7 @@ bool CDImage::Seek(const Position& pos)
 
 u32 CDImage::Read(ReadMode read_mode, u32 sector_count, void* buffer)
 {
-  char* buffer_ptr = static_cast<char*>(buffer);
+  u8* buffer_ptr = static_cast<u8*>(buffer);
   u32 sectors_read = 0;
   for (; sectors_read < sector_count; sectors_read++)
   {
@@ -105,16 +105,22 @@ u32 CDImage::Read(ReadMode read_mode, u32 sector_count, void* buffer)
         break;
     }
 
-    Assert(m_current_index->file);
-
     // get raw sector
-    char raw_sector[RAW_SECTOR_SIZE];
+    u8 raw_sector[RAW_SECTOR_SIZE];
+    if (m_current_index->file)
+    {
       if (std::fread(raw_sector, RAW_SECTOR_SIZE, 1, m_current_index->file) != 1)
       {
         Log_ErrorPrintf("Read of LBA %u failed", m_position_on_disc);
         Seek(m_position_on_disc);
         return false;
       }
+    }
+    else
+    {
+      // This in an implicit pregap. Return silence.
+      std::fill(raw_sector, raw_sector + RAW_SECTOR_SIZE, u8(0));
+    }
 
     switch (read_mode)
     {
@@ -155,15 +161,20 @@ bool CDImage::ReadRawSector(void* buffer)
       return false;
   }
 
-  Assert(m_current_index->file);
+  if (m_current_index->file)
-
+  {
-  // get raw sector
     if (std::fread(buffer, RAW_SECTOR_SIZE, 1, m_current_index->file) != 1)
     {
       Log_ErrorPrintf("Read of LBA %u failed", m_position_on_disc);
       Seek(m_position_on_disc);
       return false;
     }
+  }
+  else
+  {
+    // This in an implicit pregap. Return silence.
+    std::fill(static_cast<u8*>(buffer), static_cast<u8*>(buffer) + RAW_SECTOR_SIZE, u8(0));
+  }
 
   m_position_on_disc++;
   m_position_in_index++;

src/common/cd_image_cue.cpp

@@ -107,10 +107,12 @@ bool CDImageCueSheet::OpenAndParse(const char* filename)
 
     // two seconds pregap for track 1 is assumed if not specified
     long pregap_frames = track_get_zero_pre(track);
+    bool pregap_in_file = pregap_frames > 0;
     if (pregap_frames < 0 && track_num == 1)
       pregap_frames = 2 * FRAMES_PER_SECOND;
 
     // create the index for the pregap
+    u64 file_offset = static_cast<u64>(static_cast<s64>(track_start)) * track_sector_size;
     if (pregap_frames > 0)
     {
       Index pregap_index = {};
@@ -120,6 +122,14 @@ bool CDImageCueSheet::OpenAndParse(const char* filename)
       pregap_index.track_number = track_num;
       pregap_index.index_number = 0;
       pregap_index.is_pregap = true;
+      if (pregap_in_file)
+      {
+        pregap_index.file = it->second;
+        pregap_index.file_offset = file_offset;
+        pregap_index.file_sector_size = track_sector_size;
+        file_offset += static_cast<u64>(pregap_index.length) * track_sector_size;
+      }
+
       m_indices.push_back(pregap_index);
 
       disc_lba += pregap_index.length;
@@ -137,7 +147,7 @@ bool CDImageCueSheet::OpenAndParse(const char* filename)
     last_index.index_number = 1;
     last_index.file = it->second;
     last_index.file_sector_size = track_sector_size;
-    last_index.file_offset = 0;
+    last_index.file_offset = file_offset;
     last_index.is_pregap = false;
 
     long last_index_offset = track_start;