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author AJR <ariedlmayer@gmail.com>2024-12-24 09:24:28 -0500
committer AJR <ariedlmayer@gmail.com>2024-12-24 09:26:11 -0500
commite097571653f6aabe3b7a34d025fde58bef340fc4 (patch)
treeabd88f4d21a90441a3e9efca295d928c54c12bec
parente3ba3354926cb7090ec155128f071fa9f9c36aef (diff)
formats/fs_vtech.cpp: Fix off-by-one error: end address is exclusive, not inclusive
-rw-r--r--src/lib/formats/fs_vtech.cpp12
1 files changed, 6 insertions, 6 deletions
diff --git a/src/lib/formats/fs_vtech.cpp b/src/lib/formats/fs_vtech.cpp
index 03ceffbab5b..6b414518437 100644
--- a/src/lib/formats/fs_vtech.cpp
+++ b/src/lib/formats/fs_vtech.cpp
@@ -19,7 +19,7 @@ namespace fs { const vtech_image VTECH; }
// Filesystem has no subdirectories.
//
// Track 0 sectors 0-14 have the file names. 16 bytes/entry
-// offset 0 : File type 'T' (basic) or 'B' (binary)
+// offset 0 : File type 'T' (basic), 'B' (binary), or some other letter (application-specific)
// offset 1 : 0x3a
// offset 2-9: File name
// offset a : Track number of first file sector
@@ -147,7 +147,7 @@ meta_data vtech_impl::file_metadata(const u8 *entry)
res.set(meta_name::name, trim_end_spaces(rstr(entry+2, 8)));
res.set(meta_name::file_type, std::string{ char(entry[0]) });
res.set(meta_name::loading_address, get_u16le(entry + 0xc));
- res.set(meta_name::length, ((get_u16le(entry + 0xe) - get_u16le(entry + 0xc) + 1) & 0xffff));
+ res.set(meta_name::length, (get_u16le(entry + 0xe) - get_u16le(entry + 0xc)) & 0xffff);
return res;
}
@@ -280,7 +280,7 @@ err_t vtech_impl::file_create(const std::vector<std::string> &path, const meta_d
bdir.w8 (off+0xa, 0x00);
bdir.w8 (off+0xb, 0x00);
bdir.w16l(off+0xc, meta.get_number(meta_name::loading_address, 0x7ae9));
- bdir.w16l(off+0xe, bdir.r16l(off+0xc) - 1); // Size 0 initially
+ bdir.w16l(off+0xe, bdir.r16l(off+0xc)); // Size 0 initially
return ERR_OK;
}
}
@@ -303,7 +303,7 @@ std::pair<err_t, std::vector<u8>> vtech_impl::file_read(const std::vector<std::s
u8 track = entry[0xa];
u8 sector = entry[0xb];
- int len = ((get_u16le(entry + 0xe) - get_u16le(entry + 0xc)) & 0xffff) + 1;
+ int len = (get_u16le(entry + 0xe) - get_u16le(entry + 0xc)) & 0xffff;
data.resize(len, 0);
int pos = 0;
@@ -333,7 +333,7 @@ err_t vtech_impl::file_write(const std::vector<std::string> &path, const std::ve
u8 *entry = bdir.data() + off;
- u32 cur_len = ((get_u16le(entry + 0xe) - get_u16le(entry + 0xc) + 1) & 0xffff);
+ u32 cur_len = (get_u16le(entry + 0xe) - get_u16le(entry + 0xc)) & 0xffff;
u32 new_len = data.size();
if(new_len > 65535)
new_len = 65535;
@@ -372,7 +372,7 @@ err_t vtech_impl::file_write(const std::vector<std::string> &path, const std::ve
dblk.w16l(126, 0);
}
- u16 end_address = (get_u16le(entry + 0xc) + data.size() - 1) & 0xffff;
+ u16 end_address = (get_u16le(entry + 0xc) + data.size()) & 0xffff;
put_u16le(entry + 0xe, end_address);
if(need_ns) {
entry[0xa] = blocks[0].first;