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mirror of synced 2026-01-22 02:04:49 +00:00
2020-09-09 15:11:45 -07:00

225 lines
6.6 KiB
C++

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include "utils.h"
#include <iostream>
#include <fstream>
#include <boost/filesystem.hpp>
#include <boost/crc.hpp>
/*
Tape Dump format:
- Each file on the tape is set up of a set of records
- Each record contains a header and an optional footer, both of which are 4 bytes long.
- The header and the footer contains the length of the record
- The footer doesn't exist if length is set to 0, which marks the end of file
*/
// This CRC is documented in http://bitsavers.trailing-edge.com/pdf/ibm/24xx/A22-6862-4_2400_Series_Magnetic_Tape_Units_OEM.pdf
// page 8
class MyCrc_c {
public:
explicit MyCrc_c(uint8_t aInitValue = 0, bool aOddParity = false) : mAccumulator(aInitValue), mOddParity(aOddParity), mAccumulatorOddParity(true) {}
void process_byte(uint8_t aByte) {
// Calculate parity first...
uint8_t Parity = 0;
uint16_t Data = aByte;
for (int i = 0; i < 7; ++i) {
Parity ^= Data & 1;
Data >>= 1;
}
CRAY_ASSERT(Parity <= 1);
if (mOddParity) {
Parity = 1 - Parity;
}
Data = (Parity << 8) | aByte;
mAccumulator ^= Data;
// Rotate by 1
uint8_t Msb = (mAccumulator & 256) >> 8;
if (Msb == 1) {
mAccumulator ^= (1 << 2 | 1 << 3 | 1 << 4 | 1 << 5);
}
mAccumulator = ((mAccumulator & 255) << 1) | Msb;
}
void process_bytes(void *aData, size_t aDataSize) {
uint8_t *Data = (uint8_t*)aData;
for (size_t i = 0; i < aDataSize; ++i) {
process_byte(Data[i]);
}
}
uint16_t checksum() const {
uint16_t RetVal = mAccumulator ^ ((~(1 << 2 | 1 << 4) & 511));
if (!mAccumulatorOddParity) {
RetVal ^= 1;
}
return RetVal;
}
protected:
bool mOddParity;
bool mAccumulatorOddParity;
uint16_t mAccumulator;
};
bool IsPowerOf2(uint32_t aVal) {
if (aVal == 0) return false;
return (aVal & (aVal - 1)) == 0;
}
uint32_t ReadRecord(std::istream &aFile, std::vector<uint8_t> &aData, bool aCorrectRecordSize, size_t aExpectedRecordSize, bool &aHasChecksum, int aRecordIdx) {
uint32_t RecordSize;
if (aFile.eof()) {
aData.resize(0);
return 0;
}
aFile.read((char*)(&RecordSize), 4);
if (aFile.eof()) {
aData.resize(0);
return 0;
}
// Test to see if record size is 2^n+2 format. If it is, it's likely the record has a checksum and CRC at the end
bool LikelyHasChecksum = IsPowerOf2(RecordSize - 2);
bool LikelyCorruptedRecord = false;
if (aRecordIdx > 0) {
if (LikelyHasChecksum || aHasChecksum) {
LikelyCorruptedRecord = RecordSize - 2 != aExpectedRecordSize;
}
else {
LikelyCorruptedRecord = RecordSize != aExpectedRecordSize;
}
}
if (RecordSize > 0x00100000) {
throw Generic_x("Record size is suspicicously large. Aborting...");
}
uint32_t ReadSize = RecordSize;
aData.resize(ReadSize);
if (RecordSize > 0) {
aFile.read((char*)(&(aData[0])), ReadSize);
uint8_t LRC = 0;
for (uint32_t i = 0; i < ReadSize; ++i) {
LRC ^= aData[i];
}
if (LikelyHasChecksum || aHasChecksum) {
aData.resize(aData.size() - 2); // Remove checksum from record
}
if (LRC != 0) {
if (LikelyHasChecksum || aHasChecksum) {
std::cout << "LRC error in record " << DecPrinter(aRecordIdx+1) << std::endl;
}
}
else {
if (aRecordIdx == 0) aHasChecksum = true;
}
uint32_t EndRecordSize;
aFile.read((char*)(&EndRecordSize), 4);
if (EndRecordSize != RecordSize) throw Generic_x("Record size mismatch at end");
if (LikelyCorruptedRecord) {
// Peek into the stream to see if this is the last record
uint32_t NextRecordSize;
aFile.read((char*)(&NextRecordSize), 4);
if (NextRecordSize != 0 && aCorrectRecordSize) {
std::cout << "Incorrect record size " << DecPrinter(aData.size()) << " detected in record " << DecPrinter(aRecordIdx+1) << ". Correcting to " << DecPrinter(aExpectedRecordSize) << std::endl;
aData.resize(aExpectedRecordSize);
}
aFile.seekg(-4, std::ios_base::cur);
}
}
return RecordSize;
}
int PrintUsage(const char *aExecName, const char *ErrorStr = nullptr) {
std::cout << "Usage: " << aExecName << " <image file> -c <output base file name>" << std::endl;
std::cout << " -c: assume all records in the file are the same length. Correct if not." << std::endl;
return 1;
}
int main(int argc, const char* argv[])
{
CommandLine_c CommandLine(argc, argv);
std::string OutputBaseFileName;
std::string InFileName;
bool CorrectRecordSize = false;
try {
while (CommandLine.HasMoreParams()) {
std::string CurParam = CommandLine.GetNextParam();
if (CurParam.length() == 0) continue;
if (CurParam == "-c") {
CorrectRecordSize = true;
} else if (InFileName.empty()) {
InFileName = CurParam;
}
else if (OutputBaseFileName.length() == 0) {
OutputBaseFileName = CurParam;
} else {
throw Generic_x("Unkown command line parameter");
}
}
if (InFileName.empty()) throw Generic_x("Input file name must be specified");
}
catch (std::exception &Ex) {
return PrintUsage(argv[0], Ex.what());
}
if (OutputBaseFileName.length() == 0) {
//Figure out base-name from input
OutputBaseFileName = boost::filesystem::basename(InFileName);
}
errno = 0;
std::ifstream InStrm;
try {
InStrm.open(InFileName, std::ios_base::in | std::ios_base::binary);
}
catch (std::exception &e) {
std::cout << "Can't open input file: " << InFileName << " - " << e.what() << std::endl;
return 1;
}
size_t EOTCount = 0;
try {
size_t FileIdx = 1;
while (!InStrm.eof()) {
std::vector<uint8_t> Record;
int RecordIdx = 0;
std::ofstream OutStrm;
size_t ExpectedRecordSize = 0;
bool HasChecksum = false;
while (ReadRecord(InStrm, Record, CorrectRecordSize, ExpectedRecordSize, HasChecksum, RecordIdx) > 0) { // Read till EOF marker
if (ExpectedRecordSize == 0) ExpectedRecordSize = Record.size();
if (RecordIdx == 0) {
if (EOTCount > 0) {
std::cout << "Warning: non-0 file after EOT" << std::endl;
}
std::stringstream OutFileName;
OutFileName << OutputBaseFileName << "." << std::setw(3) << std::setfill('0') << FileIdx;
OutStrm.open(OutFileName.str(), std::ios_base::out | std::ios_base::binary);
if (!OutStrm.good()) throw Generic_x("Can't create file");
}
OutStrm.write((char*)(&(Record[0])), Record.size());
RecordIdx++;
}
OutStrm.close();
if ((RecordIdx == 0) && !InStrm.eof()) { ++EOTCount; }
if (RecordIdx > 0) ++FileIdx; // Only increment file name if it was in fact created
}
}
catch (std::exception &e) {
std::cout << e.what() << std::endl;
return 1;
}
if (EOTCount == 0) {
std::cout << "Warning: no EOT marker found" << std::endl;
}
if (EOTCount != 1) {
std::cout << "Warning: " << EOTCount << " of EOT markers found" << std::endl;
}
return 0;
}