ref: ea90460a261fb602af273041f3b226f2b723ebd2
dir: /src/w_file_posix.c/
// Emacs style mode select -*- C++ -*- //----------------------------------------------------------------------------- // // Copyright(C) 1993-1996 Id Software, Inc. // Copyright(C) 2008 Simon Howard // // This program is free software; you can redistribute it and/or // modify it under the terms of the GNU General Public License // as published by the Free Software Foundation; either version 2 // of the License, or (at your option) any later version. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA // 02111-1307, USA. // // DESCRIPTION: // WAD I/O functions. // //----------------------------------------------------------------------------- #include "config.h" #ifdef HAVE_MMAP #include <errno.h> #include <fcntl.h> #include <unistd.h> #include <sys/mman.h> #include <string.h> #include "w_file.h" #include "z_zone.h" typedef struct { wad_file_t wad; int handle; } posix_wad_file_t; extern wad_file_class_t posix_wad_file; static void MapFile(posix_wad_file_t *wad, char *filename) { void *result; int protection; int flags; // Mapped area can be read and written to. Ideally // this should be read-only, as none of the Doom code should // change the WAD files after being read. However, there may // be code lurking in the source that does. protection = PROT_READ|PROT_WRITE; // Writes to the mapped area result in private changes that are // *not* written to disk. flags = MAP_PRIVATE; result = mmap(NULL, wad->wad.length, protection, flags, wad->handle, 0); wad->wad.mapped = result; if (result == NULL) { fprintf(stderr, "W_POSIX_OpenFile: Unable to mmap() %s - %s\n", filename, strerror(errno)); } } unsigned int GetFileLength(int handle) { return lseek(handle, 0, SEEK_END); } static wad_file_t *W_POSIX_OpenFile(char *path) { posix_wad_file_t *result; int handle; handle = open(path, 0); if (handle < 0) { return NULL; } // Create a new posix_wad_file_t to hold the file handle. result = Z_Malloc(sizeof(posix_wad_file_t), PU_STATIC, 0); result->wad.file_class = &posix_wad_file; result->wad.length = GetFileLength(handle); result->handle = handle; // Try to map the file into memory with mmap: MapFile(result, path); return &result->wad; } static void W_POSIX_CloseFile(wad_file_t *wad) { posix_wad_file_t *posix_wad; posix_wad = (posix_wad_file_t *) wad; // If mapped, unmap it. // Close the file close(posix_wad->handle); Z_Free(posix_wad); } // Read data from the specified position in the file into the // provided buffer. Returns the number of bytes read. size_t W_POSIX_Read(wad_file_t *wad, unsigned int offset, void *buffer, size_t buffer_len) { posix_wad_file_t *posix_wad; byte *byte_buffer; size_t bytes_read; int result; posix_wad = (posix_wad_file_t *) wad; // Jump to the specified position in the file. lseek(posix_wad->handle, offset, SEEK_SET); // Read into the buffer. bytes_read = 0; byte_buffer = buffer; while (buffer_len > 0) { result = read(posix_wad->handle, byte_buffer, buffer_len); if (result < 0) { perror("W_POSIX_Read"); break; } else if (result == 0) { break; } // Successfully read some bytes byte_buffer += result; buffer_len -= result; bytes_read += result; } return bytes_read; } wad_file_class_t posix_wad_file = { W_POSIX_OpenFile, W_POSIX_CloseFile, W_POSIX_Read, }; #endif /* #ifdef HAVE_MMAP */