int
G64Archive::getStartOfItem(int n)
{
if (n < 0 || n >= 84)
return -1;
int offset = 0x00C + (4 * n);
return LO_LO_HI_HI(data[offset], data[offset+1], data[offset+2], data[offset+3]);
}
void
T64File::seekItem(long offset)
{
size_t i = 0x48 + (selectedItem * 0x20);
// Move file pointer the the start of the selected item + offset
iFp = LO_LO_HI_HI(data[i], data[i+1], data[i+2], data[i+3]) + offset;
// Invalidate file pointer if it is out of range
if (iFp > size)
iFp = -1;
}
bool
TAPFile::readFromBuffer(const uint8_t *buffer, size_t length)
{
if (!AnyC64File::readFromBuffer(buffer, length))
return false;
int l = LO_LO_HI_HI(data[0x10], data[0x11], data[0x12], data[0x13]);
if (l + 0x14 /* Header */ != size) {
warn("Size mismatch! Archive should have %d data bytes, found %d\n", l, size - 0x14);
}
return true;
}
void
T64Archive::selectItem(int n)
{
unsigned i;
if (n < getNumberOfItems()) {
// Compute start address in container
i = 0x48 + (n * 0x20);
if ((fp = LO_LO_HI_HI(data[i], data[i+1], data[i+2], data[i+3])) >= size)
fprintf(stderr, "PANIC! fp is out of bounds!\n");
// Compute start address in memory
i = 0x42 + (n * 0x20);
uint16_t startAddrInMemory = LO_HI(data[i], data[i+1]);
// Compute end address in memory
i = 0x44 + (n * 0x20);
uint16_t endAddrInMemory = LO_HI(data[i], data[i+1]);
if (endAddrInMemory == 0xC3C6) {
fprintf(stderr, "WARNING: Corrupted archive. Mostly likely created with CONV64!\n");
// WHAT DO WE DO ABOUT IT?
}
// Compute size of item
uint16_t length = endAddrInMemory - startAddrInMemory;
// fprintf(stderr, "start = %d end = %d diff = %d\n", startAddrInMemory, endAddrInMemory, length);
// fprintf(stderr, "fp = %d fp_eof = %d\n", fp, fp_eof);
// Store largest offset that belongs to the file
if ((fp_eof = fp + length) > size)
fprintf(stderr, "PANIC! fp_eof is out of bounds!\n");
// Return if offset values are safe
if (fp < size && fp_eof <= size)
return; // success
}
fp = fp_eof = -1; // fail
return;
}
int
Datasette::pulseLength(int *skip)
{
assert(head < size);
if (data[head] != 0) {
// Pulse lengths between 1 * 8 and 255 * 8
if (skip) *skip = 1;
return 8 * data[head];
}
if (type == 0) {
// Pulse lengths greater than 8 * 255 (TAP V0 files)
if (skip) *skip = 1;
return 8 * 256;
} else {
// Pulse lengths greater than 8 * 255 (TAP V1 files)
if (skip) *skip = 4;
return LO_LO_HI_HI(data[head+1], data[head+2], data[head+3], 0);
}
}
void
T64File::selectItem(unsigned item)
{
// Invalidate the file pointer if a non-existing item is requested.
if (item >= numberOfItems()) {
iFp = -1;
return;
}
// Remember the selection
selectedItem = item;
// Set file pointer and end of file index
unsigned i = 0x48 + (item * 0x20);
iFp = LO_LO_HI_HI(data[i], data[i+1], data[i+2], data[i+3]);
iEof = iFp + getSizeOfItem();
// Check for inconsistent values. As all inconsistencies should have
// been ruled out by repair(), the if condition should never hit.
if (iFp > size || iEof > size) {
assert(false);
}
}
bool
T64File::repair()
{
unsigned i, n;
uint16_t noOfItems = numberOfItems();
//
// 1. Repair number of items, if this value is zero
//
if (noOfItems == 0) {
while (directoryItemIsPresent(noOfItems))
noOfItems++;
uint16_t noOfItemsStatedInHeader = numberOfItems();
if (noOfItems != noOfItemsStatedInHeader) {
debug(1, "Repairing corrupted T64 archive: Changing number of items from %d to %d.\n",
noOfItemsStatedInHeader, noOfItems);
data[0x24] = LO_BYTE(noOfItems);
data[0x25] = HI_BYTE(noOfItems);
}
assert(noOfItems == numberOfItems());
}
for (i = 0; i < noOfItems; i++) {
//
// 2. Check relative offset information for each item
//
// Compute start address in file
n = 0x48 + (i * 0x20);
uint16_t startAddrInContainer = LO_LO_HI_HI(data[n], data[n+1], data[n+2], data[n+3]);
if (startAddrInContainer >= size) {
warn("T64 archive is corrupt (offset mismatch). Sorry, can't repair.\n");
return false;
}
//
// 3. Check for file end address mismatches (as created by CONVC64)
//
// Compute start address in memory
n = 0x42 + (i * 0x20);
uint16_t startAddrInMemory = LO_HI(data[n], data[n+1]);
// Compute end address in memory
n = 0x44 + (i * 0x20);
uint16_t endAddrInMemory = LO_HI(data[n], data[n+1]);
if (endAddrInMemory == 0xC3C6) {
// Let's assume that the rest of the file data belongs to this file ...
uint16_t fixedEndAddrInMemory = startAddrInMemory + (size - startAddrInContainer);
debug(1, "Repairing corrupted T64 archive: Changing end address of item %d from %04X to %04X.\n",
i, endAddrInMemory, fixedEndAddrInMemory);
data[n] = LO_BYTE(fixedEndAddrInMemory);
data[n+1] = HI_BYTE(fixedEndAddrInMemory);
}
}
return 1; // Archive repaired successfully
}