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lib: Win32 port of MemoryMappedFile 

lib/memory_mapped_file.cc used POSIX open/fstat/mmap, which does not
exist under mingw-w64, blocking a native Windows build of the prjxray
tools. Add an #ifdef _WIN32 branch using
CreateFileA/CreateFileMappingA/MapViewOfFile; the POSIX path is
byte-for-byte unchanged.

One behavioural note: a zero-length file cannot be mapped on Windows,
so that case returns an object with nullptr data and zero size to
preserve the "file exists" contract of InitWithFile.
This commit is contained in:
Carlos Venegas Arrabé 2026-07-30 16:18:36 +02:00
parent 132342f7a2
commit a2c712e588
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1 changed files with 46 additions and 0 deletions
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46
lib/memory_mapped_file.cc
View File

@ -9,16 +9,56 @@
*/
#include <prjxray/memory_mapped_file.h>
#ifdef _WIN32
#include <windows.h>
#else
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#endif
namespace prjxray {
std::unique_ptr<MemoryMappedFile> MemoryMappedFile::InitWithFile(
const std::string& path) {
#ifdef _WIN32
HANDLE file = CreateFileA(path.c_str(), GENERIC_READ, FILE_SHARE_READ,
NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL,
NULL);
if (file == INVALID_HANDLE_VALUE)
return nullptr;
LARGE_INTEGER file_size;
if (!GetFileSizeEx(file, &file_size)) {
CloseHandle(file);
return nullptr;
}
// A zero-length file cannot be mapped; return an object (to indicate
// the file exists) with a nullptr and zero length.
if (file_size.QuadPart == 0) {
CloseHandle(file);
return std::unique_ptr<MemoryMappedFile>(
new MemoryMappedFile(nullptr, 0));
}
HANDLE mapping =
CreateFileMappingA(file, NULL, PAGE_READONLY, 0, 0, NULL);
// The view keeps the file/mapping alive, so the handles can be closed.
CloseHandle(file);
if (mapping == NULL)
return nullptr;
void* file_map = MapViewOfFile(mapping, FILE_MAP_READ, 0, 0, 0);
CloseHandle(mapping);
if (file_map == NULL)
return nullptr;
return std::unique_ptr<MemoryMappedFile>(new MemoryMappedFile(
file_map, static_cast<size_t>(file_size.QuadPart)));
#else
int fd = open(path.c_str(), O_RDONLY, 0);
if (fd == -1)
return nullptr;
@ -51,10 +91,16 @@ std::unique_ptr<MemoryMappedFile> MemoryMappedFile::InitWithFile(
return std::unique_ptr<MemoryMappedFile>(
new MemoryMappedFile(file_map, statbuf.st_size));
#endif
}
MemoryMappedFile::~MemoryMappedFile() {
#ifdef _WIN32
if (data_)
UnmapViewOfFile(data_);
#else
munmap(data_, size_);
#endif
}
} // namespace prjxray