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Clean up floppy signature detection code. #157

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Merged
dingusdev merged 1 commit into from
Dec 6, 2025
Merged

Clean up floppy signature detection code. #157

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29 changes: 16 additions & 13 deletions devices/floppy/floppyimg.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -34,8 +34,8 @@ along with this program. If not, see <https://www.gnu.org/licenses/>.
static FlopImgType identify_image(ImgFile& img_file)
{
// WOZ images identification strings
static uint8_t WOZ1_SIG[] = {0x57, 0x4F, 0x5A, 0x31, 0xFF, 0x0A, 0x0D, 0x0A};
static uint8_t WOZ2_SIG[] = {0x57, 0x4F, 0x5A, 0x32, 0xFF, 0x0A, 0x0D, 0x0A};
static const uint8_t WOZ1_SIG[] = {0x57, 0x4F, 0x5A, 0x31, 0xFF, 0x0A, 0x0D, 0x0A};
static const uint8_t WOZ2_SIG[] = {0x57, 0x4F, 0x5A, 0x32, 0xFF, 0x0A, 0x0D, 0x0A};

uint8_t buf[8] = { 0 };

Expand All @@ -47,20 +47,23 @@ static FlopImgType identify_image(ImgFile& img_file)
} else if (!std::memcmp(buf, WOZ2_SIG, sizeof(buf))) {
return FlopImgType::WOZ2;
} else {
for (int offset = 0; offset <=84; offset += 84) {
auto check_hfs_mfs = [](ImgFile& img, std::size_t offset) -> bool {
/* 2 bytes needed for MFS/HFS signature */
unsigned char buf[2];

// rewind to logical block 2
img_file.read((char *)buf, 2*BLOCK_SIZE + offset, sizeof(buf));
img.read((char *)buf, 2*BLOCK_SIZE + offset, sizeof(buf));

// check for HFS/MFS signature at the start of the logical block 2
if ((buf[0] == 0x42 && buf[1] == 0x44) ||
(buf[0] == 0xD2 && buf[1] == 0xD7)) {
if (offset) {
return FlopImgType::DC42;
} else {
return FlopImgType::RAW;
}
}
}
return ((buf[0] == 0x42 && buf[1] == 0x44)
|| (buf[0] == 0xD2 && buf[1] == 0xD7));
};

if (check_hfs_mfs(img_file, 84))
return FlopImgType::DC42;

if (check_hfs_mfs(img_file, 0))
return FlopImgType::RAW;
}

return FlopImgType::UNKNOWN;
Expand Down