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Switches FileHolder to have a usage much closer to FILE *.

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Thereby opens a route for file format implementations such as that appearing for CPC DSK that create an in-memory copy and perform a full rewrite.
This commit is contained in:
Thomas Harte
2017-11-02 22:32:00 -04:00
parent f807a6b608
commit e384c50580
28 changed files with 597 additions and 445 deletions
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Storage/Tape/Formats/CSW.cpp
+26 -27
View File
@@ -11,22 +11,21 @@
using namespace Storage::Tape;
CSW::CSW(const char *file_name) :
Storage::FileHolder(file_name),
file_(file_name),
source_data_pointer_(0) {
if(file_stats_.st_size < 0x20) throw ErrorNotCSW;
if(file_.stats().st_size < 0x20) throw ErrorNotCSW;
// Check signature.
char identifier[22];
char signature[] = "Compressed Square Wave";
fread(identifier, 1, strlen(signature), file_);
if(memcmp(identifier, signature, strlen(signature))) throw ErrorNotCSW;
if(!file_.check_signature("Compressed Square Wave")) {
throw ErrorNotCSW;
}
// Check terminating byte.
if(fgetc(file_) != 0x1a) throw ErrorNotCSW;
if(file_.get8() != 0x1a) throw ErrorNotCSW;
// Get version file number.
uint8_t major_version = static_cast<uint8_t>(fgetc(file_));
uint8_t minor_version = static_cast<uint8_t>(fgetc(file_));
uint8_t major_version = file_.get8();
uint8_t minor_version = file_.get8();
// Reject if this is an unknown version.
if(major_version > 2 || !major_version || minor_version > 1) throw ErrorNotCSW;
@@ -34,28 +33,28 @@ CSW::CSW(const char *file_name) :
// The header now diverges based on version.
uint32_t number_of_waves = 0;
if(major_version == 1) {
pulse_.length.clock_rate = fgetc16le();
pulse_.length.clock_rate = file_.get16le();
if(fgetc(file_) != 1) throw ErrorNotCSW;
if(file_.get8() != 1) throw ErrorNotCSW;
compression_type_ = RLE;
pulse_.type = (fgetc(file_) & 1) ? Pulse::High : Pulse::Low;
pulse_.type = (file_.get8() & 1) ? Pulse::High : Pulse::Low;
fseek(file_, 0x20, SEEK_SET);
file_.seek(0x20, SEEK_SET);
} else {
pulse_.length.clock_rate = fgetc32le();
number_of_waves = fgetc32le();
switch(fgetc(file_)) {
pulse_.length.clock_rate = file_.get32le();
number_of_waves = file_.get32le();
switch(file_.get8()) {
case 1: compression_type_ = RLE; break;
case 2: compression_type_ = ZRLE; break;
default: throw ErrorNotCSW;
}
pulse_.type = (fgetc(file_) & 1) ? Pulse::High : Pulse::Low;
uint8_t extension_length = static_cast<uint8_t>(fgetc(file_));
pulse_.type = (file_.get8() & 1) ? Pulse::High : Pulse::Low;
uint8_t extension_length = file_.get8();
if(file_stats_.st_size < 0x34 + extension_length) throw ErrorNotCSW;
fseek(file_, 0x34 + extension_length, SEEK_SET);
if(file_.stats().st_size < 0x34 + extension_length) throw ErrorNotCSW;
file_.seek(0x34 + extension_length, SEEK_SET);
}
if(compression_type_ == ZRLE) {
@@ -65,9 +64,9 @@ CSW::CSW(const char *file_name) :
source_data_.resize(static_cast<size_t>(number_of_waves) * 5);
std::vector<uint8_t> file_data;
size_t remaining_data = static_cast<size_t>(file_stats_.st_size) - static_cast<size_t>(ftell(file_));
size_t remaining_data = static_cast<size_t>(file_.stats().st_size) - static_cast<size_t>(file_.tell());
file_data.resize(remaining_data);
fread(file_data.data(), sizeof(uint8_t), remaining_data, file_);
file_.read(file_data.data(), remaining_data);
// uncompress will tell how many compressed bytes there actually were, so use its
// modification of output_length to throw away all the memory that isn't actually
@@ -76,7 +75,7 @@ CSW::CSW(const char *file_name) :
uncompress(source_data_.data(), &output_length, file_data.data(), file_data.size());
source_data_.resize(static_cast<size_t>(output_length));
} else {
rle_start_ = ftell(file_);
rle_start_ = file_.tell();
}
invert_pulse();
@@ -84,7 +83,7 @@ CSW::CSW(const char *file_name) :
uint8_t CSW::get_next_byte() {
switch(compression_type_) {
case RLE: return static_cast<uint8_t>(fgetc(file_));
case RLE: return file_.get8();
case ZRLE: {
if(source_data_pointer_ == source_data_.size()) return 0xff;
uint8_t result = source_data_[source_data_pointer_];
@@ -96,7 +95,7 @@ uint8_t CSW::get_next_byte() {
uint32_t CSW::get_next_int32le() {
switch(compression_type_) {
case RLE: return fgetc32le();
case RLE: return file_.get32le();
case ZRLE: {
if(source_data_pointer_ > source_data_.size() - 4) return 0xffff;
uint32_t result = (uint32_t)(
@@ -116,14 +115,14 @@ void CSW::invert_pulse() {
bool CSW::is_at_end() {
switch(compression_type_) {
case RLE: return (bool)feof(file_);
case RLE: return file_.eof();
case ZRLE: return source_data_pointer_ == source_data_.size();
}
}
void CSW::virtual_reset() {
switch(compression_type_) {
case RLE: fseek(file_, rle_start_, SEEK_SET); break;
case RLE: file_.seek(rle_start_, SEEK_SET); break;
case ZRLE: source_data_pointer_ = 0; break;
}
}