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Attempted a full implementation of CSW. All in memory for now.

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This commit is contained in:
Thomas Harte 2017-07-12 21:23:59 -04:00
parent 33eadb5549
commit f09fe30af5
2 changed files with 51 additions and 20 deletions
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59
Storage/Tape/Formats/CSW.cpp
View File

@ -11,7 +11,8 @@
using namespace Storage::Tape;
CSW::CSW(const char *file_name) :
Storage::FileHolder(file_name) {
Storage::FileHolder(file_name),
source_data_pointer_(0) {
if(file_stats_.st_size < 0x20) throw ErrorNotCSW;
// Check signature.
@ -31,6 +32,7 @@ CSW::CSW(const char *file_name) :
if(major_version > 2 || !major_version || minor_version > 1) throw ErrorNotCSW;
// The header now diverges based on version.
uint32_t number_of_waves = 0;
if(major_version == 1) {
pulse_.length.clock_rate = fgetc16le();
@ -42,7 +44,7 @@ CSW::CSW(const char *file_name) :
fseek(file_, 0x20, SEEK_SET);
} else {
pulse_.length.clock_rate = fgetc32le();
number_of_waves_ = fgetc32le();
number_of_waves = fgetc32le();
switch(fgetc(file_)) {
case 1: compression_type_ = RLE; break;
case 2: compression_type_ = ZRLE; break;
@ -57,31 +59,54 @@ CSW::CSW(const char *file_name) :
}
if(compression_type_ == ZRLE) {
inflation_stream_.zalloc = Z_NULL;
inflation_stream_.zfree = Z_NULL;
inflation_stream_.opaque = Z_NULL;
inflation_stream_.avail_in = 0;
inflation_stream_.next_in = Z_NULL;
int result = inflateInit(&inflation_stream_);
if(result != Z_OK) throw ErrorNotCSW;
source_data_.resize((size_t)number_of_waves);
std::vector<uint8_t> file_data;
size_t remaining_data = (size_t)file_stats_.st_size - (size_t)ftell(file_);
file_data.resize(remaining_data);
fread(file_data.data(), sizeof(uint8_t), remaining_data, file_);
uLongf output_length = (uLongf)remaining_data;
uncompress(source_data_.data(), &output_length, file_data.data(), file_data.size());
} else {
rle_start_ = ftell(file_);
}
invert_pulse();
}
uint8_t CSW::get_next_byte() {
switch(compression_type_) {
case RLE: return (uint8_t)fgetc(file_);
case ZRLE: {
if(source_data_pointer_ == source_data_.size()) return 0xff;
uint8_t result = source_data_[source_data_pointer_];
source_data_pointer_++;
return result;
}
}
}
CSW::~CSW() {
if(compression_type_ == ZRLE) {
inflateEnd(&inflation_stream_);
}
void CSW::invert_pulse() {
pulse_.type = (pulse_.type == Pulse::High) ? Pulse::Low : Pulse::High;
}
bool CSW::is_at_end() {
return true;
switch(compression_type_) {
case RLE: return (bool)feof(file_);
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 ZRLE: source_data_pointer_ = 0; break;
}
}
Tape::Pulse CSW::virtual_get_next_pulse() {
Tape::Pulse pulse;
return pulse;
invert_pulse();
pulse_.length.length = get_next_byte();
return pulse_;
}

12
Storage/Tape/Formats/CSW.hpp
View File

@ -13,6 +13,7 @@
#include "../../FileHolder.hpp"
#include <zlib.h>
#include <vector>
namespace Storage {
namespace Tape {
@ -28,7 +29,6 @@ class CSW: public Tape, public Storage::FileHolder {
@throws ErrorNotCSW if this file could not be opened and recognised as a valid CSW file.
*/
CSW(const char *file_name);
~CSW();
enum {
ErrorNotCSW
@ -46,8 +46,14 @@ class CSW: public Tape, public Storage::FileHolder {
RLE,
ZRLE
} compression_type_;
uint32_t number_of_waves_;
z_stream inflation_stream_;
uint8_t get_next_byte();
void invert_pulse();
std::vector<uint8_t> source_data_;
size_t source_data_pointer_;
long rle_start_;
};
}