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Ensures that segments are written in a properly-circular fashion.

This commit is contained in:
Thomas Harte 2018-07-02 19:35:49 -04:00
parent abca38a548
commit 1fcb461c42
2 changed files with 37 additions and 16 deletions

View File

@ -71,7 +71,6 @@
buildConfiguration = "Debug"
selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
enableAddressSanitizer = "YES"
enableASanStackUseAfterReturn = "YES"
disableMainThreadChecker = "YES"
launchStyle = "0"

View File

@ -157,22 +157,44 @@ void PCMTrack::add_segment(const Time &start_time, const PCMSegment &segment, bo
const size_t start_bit = start_time.length * destination.data.size() / start_time.clock_rate;
const size_t end_bit = end_time.length * destination.data.size() / end_time.clock_rate;
const size_t target_width = end_bit - start_bit;
// If clamping is applied, just put a hard cut-off at the index hole.
// if(clamp_to_index_hole) {
// end_bit = std::min(end_bit, destination.data.size());
// }
// !!TODO!! Deal with wrapping and clamping.
// Reset the destination.
std::fill(destination.data.begin() + static_cast<off_t>(start_bit), destination.data.begin() + static_cast<off_t>(end_bit), false);
// Step through the source data, and for each true map to a location in the destination and set it.
const size_t half_offset = target_width / (2 * segment.data.size());
for(size_t bit = 0; bit < segment.data.size(); ++bit) {
if(segment.data[bit]) {
const size_t output_bit = start_bit + half_offset + (bit * target_width) / segment.data.size();
destination.data[output_bit] = true;
if(clamp_to_index_hole || end_bit <= destination.data.size()) {
// If clamping is applied, just write a single segment, from the start_bit to whichever is
// closer of the end of track and the end_bit.
const size_t selected_end_bit = std::min(end_bit, destination.data.size());
// Reset the destination.
std::fill(destination.data.begin() + static_cast<off_t>(start_bit), destination.data.begin() + static_cast<off_t>(selected_end_bit), false);
// Step through the source data from start to finish, stopping early if it goes out of bounds.
for(size_t bit = 0; bit < segment.data.size(); ++bit) {
if(segment.data[bit]) {
const size_t output_bit = start_bit + half_offset + (bit * target_width) / segment.data.size();
if(output_bit >= destination.data.size()) return;
destination.data[output_bit] = true;
}
}
} else {
// Clamping is not enabled, so the supplied segment loops over the index hole, arbitrarily many times.
// So work backwards unless or until the original start position is reached, then stop.
// This definitely runs over the index hole; check whether the whole track needs clearing, or whether
// a centre segment is untouched.
if(target_width >= destination.data.size()) {
std::fill(destination.data.begin(), destination.data.end(), false);
} else {
std::fill(destination.data.begin(), destination.data.begin() + static_cast<off_t>(end_bit % destination.data.size()), false);
std::fill(destination.data.begin() + static_cast<off_t>(start_bit), destination.data.end(), false);
}
// Run backwards from final bit back to first, stopping early if overlapping the beginning.
for(off_t bit = static_cast<off_t>(segment.data.size()-1); bit >= 0; --bit) {
if(segment.data[static_cast<size_t>(bit)]) {
const size_t output_bit = start_bit + half_offset + (static_cast<size_t>(bit) * target_width) / segment.data.size();
if(output_bit <= end_bit - destination.data.size()) return;
destination.data[output_bit % destination.data.size()] = true;
}
}
}
}