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Extract length validation and conversion function into a templated function

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Since there's no reasonable way for us to figure out what the type of
stat::st_size is on Android NDK without resorting to C++11 auto /
non-standard decltype extensions, we're going to resort to a templated
function that can deduce the length type. The rest of the validation and
conversion logic is preserved as is.
This commit is contained in:
Arseny Kapoulkine 2023-12-23 09:30:57 -08:00
parent 8fef4591be
commit 86591a97c3
1 changed files with 25 additions and 24 deletions
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49
src/pugixml.cpp
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@ -4790,6 +4790,20 @@ PUGI_IMPL_NS_BEGIN
return res; return res;
} }
template <typename T> PUGI_IMPL_FN xml_parse_status convert_file_size(T length, size_t& out_result)
{
// check for I/O errors
if (length < 0) return status_io_error;
// check for overflow
size_t result = static_cast<size_t>(length);
if (static_cast<T>(result) != length) return status_out_of_memory;
out_result = result;
return status_ok;
}
// we need to get length of entire file to load it in memory; the only (relatively) sane way to do it is via seek/tell trick // we need to get length of entire file to load it in memory; the only (relatively) sane way to do it is via seek/tell trick
PUGI_IMPL_FN xml_parse_status get_file_size(FILE* file, size_t& out_result) PUGI_IMPL_FN xml_parse_status get_file_size(FILE* file, size_t& out_result)
{ {
@ -4801,44 +4815,31 @@ PUGI_IMPL_NS_BEGIN
// anything that's not a regular file doesn't have a coherent length // anything that's not a regular file doesn't have a coherent length
if (!S_ISREG(st.st_mode)) return status_io_error; if (!S_ISREG(st.st_mode)) return status_io_error;
// normally st_size is off_t, but Android NDK defines off_t as long (which is 32-bit when targeting x86 on Android) and st_size as long long xml_parse_status status = convert_file_size(st.st_size, out_result);
typedef long long length_type;
length_type length = st.st_size;
#elif defined(PUGI_IMPL_MSVC_CRT_VERSION) && PUGI_IMPL_MSVC_CRT_VERSION >= 1400 #elif defined(PUGI_IMPL_MSVC_CRT_VERSION) && PUGI_IMPL_MSVC_CRT_VERSION >= 1400
// there are 64-bit versions of fseek/ftell, let's use them // there are 64-bit versions of fseek/ftell, let's use them
typedef __int64 length_type;
_fseeki64(file, 0, SEEK_END); _fseeki64(file, 0, SEEK_END);
length_type length = _ftelli64(file); __int64 length = _ftelli64(file);
_fseeki64(file, 0, SEEK_SET); _fseeki64(file, 0, SEEK_SET);
xml_parse_status status = convert_file_size(length, out_result);
#elif defined(__MINGW32__) && !defined(__NO_MINGW_LFS) && (!defined(__STRICT_ANSI__) || defined(__MINGW64_VERSION_MAJOR)) #elif defined(__MINGW32__) && !defined(__NO_MINGW_LFS) && (!defined(__STRICT_ANSI__) || defined(__MINGW64_VERSION_MAJOR))
// there are 64-bit versions of fseek/ftell, let's use them // there are 64-bit versions of fseek/ftell, let's use them
typedef off64_t length_type;
fseeko64(file, 0, SEEK_END); fseeko64(file, 0, SEEK_END);
length_type length = ftello64(file); off64_t length = ftello64(file);
fseeko64(file, 0, SEEK_SET); fseeko64(file, 0, SEEK_SET);
xml_parse_status status = convert_file_size(length, out_result);
#else #else
// if this is a 32-bit OS, long is enough; if this is a unix system, long is 64-bit, which is enough; otherwise we can't do anything anyway. // if this is a 32-bit OS, long is enough; if this is a unix system, long is 64-bit, which is enough; otherwise we can't do anything anyway.
typedef long length_type;
fseek(file, 0, SEEK_END); fseek(file, 0, SEEK_END);
length_type length = ftell(file); long length = ftell(file);
fseek(file, 0, SEEK_SET); fseek(file, 0, SEEK_SET);
xml_parse_status status = convert_file_size(length, out_result);
#endif #endif
// check for I/O errors return status;
if (length < 0) return status_io_error;
// check for overflow
size_t result = static_cast<size_t>(length);
if (static_cast<length_type>(result) != length) return status_out_of_memory;
// finalize
out_result = result;
return status_ok;
} }
// This function assumes that buffer has extra sizeof(char_t) writable bytes after size // This function assumes that buffer has extra sizeof(char_t) writable bytes after size