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Speed up cimg::fsize #484

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Merged
dtschump merged 1 commit into from
Jul 1, 2026
Merged

Speed up cimg::fsize #484

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46 changes: 35 additions & 11 deletions CImg.h
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Original file line number Diff line number Diff line change
Expand Up @@ -5735,6 +5735,7 @@ namespace cimg_library {
// Get the file or directory attributes with support for UTF-8 paths (Windows only).
#if cimg_OS==2
inline DWORD win_getfileattributes(const char *const path);
inline BOOL win_getfileattributesEx(const char* const path, WIN32_FILE_ATTRIBUTE_DATA* attr);
#endif

//! Check if a path is a directory.
Expand Down Expand Up @@ -67570,24 +67571,24 @@ namespace cimg_library {
\return File size or '-1' if file does not exist.
**/
inline cimg_int64 fsize(std::FILE *const file) {
if (!file) return (cimg_int64)-1;
cimg_int64 siz = -1;
if (!file) return siz;

#if cimg_OS==1 // Optimized for POSIX Environments (Linux, macOS, BSD, etc.)
const int fd = fileno(file);
struct stat st;
if (fd>=0 && !fstat(fd,&st)) return (cimg_int64)st.st_size;
#elif cimg_OS==2 // Optimized for Windows Environments (MSVC, MinGW)
if (!fstat(fd,&st)) siz = (cimg_int64)st.st_size;
#elif cimg_OS==2 // Optimized for Windows Environements (MSVC, MinGW)
const int fd = _fileno(file);
if (fd>=0) {
const cimg_int64 siz = (cimg_int64)_filelengthi64(fd);
if (siz>=0) return siz;
}
siz = (cimg_int64)_filelengthi64(fd);
#endif
// Fallback, used for non-POSIX systems or if fstat failed (pipes or sockets).
const cimg_long pos = cimg::ftell(file);
cimg::fseek(file,0,SEEK_END);
const cimg_int64 siz = (cimg_int64)cimg::ftell(file);
cimg::fseek(file,pos,SEEK_SET);
if (siz < 0) {
const cimg_long pos = cimg::ftell(file);
cimg::fseek(file, 0, SEEK_END);
siz = (cimg_int64)cimg::ftell(file);
cimg::fseek(file, pos, SEEK_SET);
}
return siz;
}

Expand All @@ -67602,6 +67603,16 @@ namespace cimg_library {
#if cimg_OS==1 // Optimized for POSIX Environments (Linux, macOS, BSD, etc.)
struct stat st;
if (!stat(filename,&st)) return (cimg_int64)st.st_size;
#elif cimg_OS==2
WIN32_FILE_ATTRIBUTE_DATA attr;
if (win_getfileattributesEx(filename, &attr)) {
if (!(attr.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)) {
LARGE_INTEGER size;
size.HighPart = attr.nFileSizeHigh;
size.LowPart = attr.nFileSizeLow;
return (cimg_int64)size.QuadPart;
}
}
#endif
// Fallback for other systems.
std::FILE *const file = cimg::std_fopen(filename, "rb");
Expand Down Expand Up @@ -67694,6 +67705,19 @@ namespace cimg_library {
}
return res;
}

inline BOOL win_getfileattributesEx(const char* const path, WIN32_FILE_ATTRIBUTE_DATA* attr) {
BOOL res = GetFileAttributesExA(path, GetFileExInfoStandard, attr);
if (!res) {
// Try alternative method, with wide-character string.
int err = MultiByteToWideChar(CP_UTF8, 0, path, -1, 0, 0);
if (err) {
CImg<wchar_t> wpath((unsigned int)err);
if (MultiByteToWideChar(CP_UTF8, 0, path, -1, wpath, err)) res = GetFileAttributesExW(wpath, GetFileExInfoStandard, attr);
}
}
return res;
}
#endif

//! Get/set path to the <i>Program Files/</i> directory (Windows only).
Expand Down