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Workaround for a weird bug that suddenly appears to manifest: gzgetc is returning the file name, not bytes from the file. Seems to be related to improper initialisation of the next field within the gzFile header. I can't immediately see where ZLib intends to do that so it's a bit mysterious. But the larger-than-8 readers could probably save time by reading in blocks anyway.

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This commit is contained in:
Thomas Harte 2016-09-17 22:01:25 -04:00
parent 14a9edcf5d
commit dbb758aaf1
1 changed files with 31 additions and 27 deletions
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58
Storage/Tape/Formats/TapeUEF.cpp
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@ -17,10 +17,7 @@
static float gzgetfloat(gzFile file)
{
uint8_t bytes[4];
bytes[0] = (uint8_t)gzgetc(file);
bytes[1] = (uint8_t)gzgetc(file);
bytes[2] = (uint8_t)gzgetc(file);
bytes[3] = (uint8_t)gzgetc(file);
gzread(file, bytes, 4);
/* assume a four byte array named Float exists, where Float[0]
was the first byte read from the UEF, Float[1] the second, etc */
@ -45,25 +42,33 @@ static float gzgetfloat(gzFile file)
return result;
}
static uint8_t gzget8(gzFile file)
{
// This is a workaround for gzgetc, which seems to be broken in ZLib 1.2.8.
uint8_t result;
gzread(file, &result, 1);
return result;
}
static int gzget16(gzFile file)
{
int result = gzgetc(file);
result |= (gzgetc(file) << 8);
return result;
uint8_t bytes[2];
gzread(file, bytes, 2);
return bytes[0] | (bytes[1] << 8);
}
static int gzget24(gzFile file)
{
int result = gzget16(file);
result |= (gzgetc(file) << 16);
return result;
uint8_t bytes[3];
gzread(file, bytes, 3);
return bytes[0] | (bytes[1] << 8) | (bytes[2] << 16);
}
static int gzget32(gzFile file)
{
int result = gzget16(file);
result |= (gzget16(file) << 16);
return result;
uint8_t bytes[4];
gzread(file, bytes, 4);
return bytes[0] | (bytes[1] << 8) | (bytes[2] << 16) | (bytes[3] << 24);
}
using namespace Storage::Tape;
@ -83,11 +88,10 @@ UEF::UEF(const char *file_name) :
throw ErrorNotUEF;
}
int minor, major;
minor = gzgetc(_file);
major = gzgetc(_file);
uint8_t version[2];
gzread(_file, version, 2);
if(major > 0 || minor > 10 || major < 0 || minor < 0)
if(version[1] > 0 || version[0] > 10)
{
throw ErrorNotUEF;
}
@ -199,17 +203,17 @@ void UEF::queue_implicit_bit_pattern(uint32_t length)
{
while(length--)
{
queue_implicit_byte((uint8_t)gzgetc(_file));
queue_implicit_byte(gzget8(_file));
}
}
void UEF::queue_explicit_bit_pattern(uint32_t length)
{
size_t length_in_bits = (length << 3) - (size_t)gzgetc(_file);
size_t length_in_bits = (length << 3) - (size_t)gzget8(_file);
uint8_t current_byte = 0;
for(size_t bit = 0; bit < length_in_bits; bit++)
{
if(!(bit&7)) current_byte = (uint8_t)gzgetc(_file);
if(!(bit&7)) current_byte = gzget8(_file);
queue_bit(current_byte&1);
current_byte >>= 1;
}
@ -250,13 +254,13 @@ void UEF::queue_carrier_tone_with_dummy()
void UEF::queue_security_cycles()
{
int number_of_cycles = gzget24(_file);
bool first_is_pulse = gzgetc(_file) == 'P';
bool last_is_pulse = gzgetc(_file) == 'P';
bool first_is_pulse = gzget8(_file) == 'P';
bool last_is_pulse = gzget8(_file) == 'P';
uint8_t current_byte = 0;
for(int cycle = 0; cycle < number_of_cycles; cycle++)
{
if(!(cycle&7)) current_byte = (uint8_t)gzgetc(_file);
if(!(cycle&7)) current_byte = gzget8(_file);
int bit = (current_byte >> 7);
current_byte <<= 1;
@ -284,9 +288,9 @@ void UEF::queue_defined_data(uint32_t length)
{
if(length < 3) return;
int bits_per_packet = gzgetc(_file);
char parity_type = (char)gzgetc(_file);
int number_of_stop_bits = gzgetc(_file);
int bits_per_packet = gzget8(_file);
char parity_type = (char)gzget8(_file);
int number_of_stop_bits = gzget8(_file);
bool has_extra_stop_wave = (number_of_stop_bits < 0);
number_of_stop_bits = abs(number_of_stop_bits);
@ -294,7 +298,7 @@ void UEF::queue_defined_data(uint32_t length)
length -= 3;
while(length--)
{
uint8_t byte = (uint8_t)gzgetc(_file);
uint8_t byte = gzget8(_file);
uint8_t parity_value = byte;
parity_value ^= (parity_value >> 4);