SDL_rwops.c
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2006 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library 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
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Sam Lantinga
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slouken@libsdl.org
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*/
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#include "SDL_config.h"
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/* This file provides a general interface for SDL to read and write
data sources. It can easily be extended to files, memory, etc.
*/
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#include "SDL_endian.h"
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#include "SDL_rwops.h"
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#if defined(__WIN32__) && !defined(__SYMBIAN32__)
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/* Functions to read/write Win32 API file pointers */
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/* Will not use it on WinCE because stdio is buffered, it means
faster, and all stdio functions anyway are embedded in coredll.dll -
the main wince dll*/
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#define WINDOWS_LEAN_AND_MEAN
#include <windows.h>
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#ifndef INVALID_SET_FILE_POINTER
#define INVALID_SET_FILE_POINTER 0xFFFFFFFF
#endif
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#define READAHEAD_BUFFER_SIZE 1024
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static int SDLCALL win32_file_open(SDL_RWops *context, const char *filename, const char *mode)
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{
#ifndef _WIN32_WCE
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UINT old_error_mode;
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HANDLE h;
DWORD r_right, w_right;
DWORD must_exist, truncate;
int a_mode;
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if (!context)
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return -1;
context->hidden.win32io.h = INVALID_HANDLE_VALUE; /* mark this as unusable */
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context->hidden.win32io.buffer.data = (char *)SDL_malloc(READAHEAD_BUFFER_SIZE);
if (!context->hidden.win32io.buffer.data) {
SDL_OutOfMemory();
return -1;
}
context->hidden.win32io.buffer.size = 0;
context->hidden.win32io.buffer.left = 0;
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/* "r" = reading, file must exist */
/* "w" = writing, truncate existing, file may not exist */
/* "r+"= reading or writing, file must exist */
/* "a" = writing, append file may not exist */
/* "a+"= append + read, file may not exist */
/* "w+" = read, write, truncate. file may not exist */
must_exist = ( SDL_strchr(mode,'r') != NULL ) ? OPEN_EXISTING : 0;
truncate = ( SDL_strchr(mode,'w') != NULL ) ? CREATE_ALWAYS : 0;
r_right = ( SDL_strchr(mode,'+') != NULL || must_exist ) ? GENERIC_READ : 0;
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a_mode = ( SDL_strchr(mode,'a') != NULL ) ? OPEN_ALWAYS : 0;
w_right = ( a_mode || SDL_strchr(mode,'+') || truncate ) ? GENERIC_WRITE : 0;
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if (!r_right && !w_right) /* inconsistent mode */
return -1; /* failed (invalid call)*/
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#ifdef _WIN32_WCE
{
size_t size = SDL_strlen(filename)+1;
wchar_t *filenameW = SDL_stack_alloc(wchar_t, size);
if ( MultiByteToWideChar(CP_UTF8, 0, filename, -1, filenameW, size) == 0 ) {
SDL_SetError("Unable to convert filename to Unicode");
SDL_stack_free(filenameW);
return -1;
}
h = CreateFile(filenameW, (w_right|r_right), (w_right)? 0 : FILE_SHARE_READ,
NULL, (must_exist|truncate|a_mode), FILE_ATTRIBUTE_NORMAL,NULL);
SDL_stack_free(filenameW);
}
#else
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/* Do not open a dialog box if failure */
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old_error_mode = SetErrorMode(SEM_NOOPENFILEERRORBOX|SEM_FAILCRITICALERRORS);
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h = CreateFile(filename, (w_right|r_right), (w_right)? 0 : FILE_SHARE_READ,
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NULL, (must_exist|truncate|a_mode), FILE_ATTRIBUTE_NORMAL,NULL);
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/* restore old behaviour */
SetErrorMode(old_error_mode);
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#endif /* _WIN32_WCE */
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if (h==INVALID_HANDLE_VALUE) {
SDL_SetError("Couldn't open %s",filename);
return -2; /* failed (CreateFile) */
}
context->hidden.win32io.h = h;
context->hidden.win32io.append = a_mode;
return 0; /* ok */
}
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DWORD win32whence;
int file_pos;
if (!context || context->hidden.win32io.h == INVALID_HANDLE_VALUE) {
SDL_SetError("win32_file_seek: invalid context/file not opened");
return -1;
}
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/* FIXME: We may be able to satisfy the seek within buffered data */
if (whence == RW_SEEK_CUR && context->hidden.win32io.buffer.left) {
offset -= context->hidden.win32io.buffer.left;
}
context->hidden.win32io.buffer.left = 0;
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switch (whence) {
case RW_SEEK_SET:
win32whence = FILE_BEGIN; break;
case RW_SEEK_CUR:
win32whence = FILE_CURRENT; break;
case RW_SEEK_END:
win32whence = FILE_END; break;
default:
SDL_SetError("win32_file_seek: Unknown value for 'whence'");
return -1;
}
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file_pos = SetFilePointer(context->hidden.win32io.h,offset,NULL,win32whence);
if ( file_pos != INVALID_SET_FILE_POINTER )
return file_pos; /* success */
SDL_Error(SDL_EFSEEK);
return -1; /* error */
}
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static int SDLCALL win32_file_read(SDL_RWops *context, void *ptr, int size, int maxnum)
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int total_need;
int total_read = 0;
int read_ahead;
DWORD byte_read;
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total_need = size*maxnum;
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if (!context || context->hidden.win32io.h == INVALID_HANDLE_VALUE || total_need<=0 || !size)
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return 0;
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if (context->hidden.win32io.buffer.left > 0) {
void *data = (char *)context->hidden.win32io.buffer.data +
context->hidden.win32io.buffer.size -
context->hidden.win32io.buffer.left;
read_ahead = SDL_min(total_need, context->hidden.win32io.buffer.left);
SDL_memcpy(ptr, data, read_ahead);
context->hidden.win32io.buffer.left -= read_ahead;
if (read_ahead == total_need) {
return maxnum;
}
ptr = (char *)ptr + read_ahead;
total_need -= read_ahead;
total_read += read_ahead;
}
if (total_need < READAHEAD_BUFFER_SIZE) {
if (!ReadFile(context->hidden.win32io.h,context->hidden.win32io.buffer.data,READAHEAD_BUFFER_SIZE,&byte_read,NULL)) {
SDL_Error(SDL_EFREAD);
return 0;
}
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read_ahead = SDL_min(total_need, (int)byte_read);
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SDL_memcpy(ptr, context->hidden.win32io.buffer.data, read_ahead);
context->hidden.win32io.buffer.size = byte_read;
context->hidden.win32io.buffer.left = byte_read-read_ahead;
total_read += read_ahead;
} else {
if (!ReadFile(context->hidden.win32io.h,ptr,total_need,&byte_read,NULL)) {
SDL_Error(SDL_EFREAD);
return 0;
}
total_read += byte_read;
}
return (total_read/size);
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static int SDLCALL win32_file_write(SDL_RWops *context, const void *ptr, int size, int num)
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int total_bytes;
DWORD byte_written,nwritten;
total_bytes = size*num;
if (!context || context->hidden.win32io.h==INVALID_HANDLE_VALUE || total_bytes<=0 || !size)
return 0;
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if (context->hidden.win32io.buffer.left) {
SetFilePointer(context->hidden.win32io.h,-context->hidden.win32io.buffer.left,NULL,FILE_CURRENT);
context->hidden.win32io.buffer.left = 0;
}
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/* if in append mode, we must go to the EOF before write */
if (context->hidden.win32io.append) {
if ( SetFilePointer(context->hidden.win32io.h,0L,NULL,FILE_END) == INVALID_SET_FILE_POINTER ) {
SDL_Error(SDL_EFWRITE);
return 0;
}
}
if (!WriteFile(context->hidden.win32io.h,ptr,total_bytes,&byte_written,NULL)) {
SDL_Error(SDL_EFWRITE);
return 0;
}
nwritten = byte_written/size;
return nwritten;
}
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if ( context ) {
if (context->hidden.win32io.h != INVALID_HANDLE_VALUE) {
CloseHandle(context->hidden.win32io.h);
context->hidden.win32io.h = INVALID_HANDLE_VALUE; /* to be sure */
}
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if (context->hidden.win32io.buffer.data) {
SDL_free(context->hidden.win32io.buffer.data);
context->hidden.win32io.buffer.data = NULL;
}
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SDL_FreeRW(context);
}
return(0);
}
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#endif /* __WIN32__ */
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#ifdef HAVE_STDIO_H
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/* Functions to read/write stdio file pointers */
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{
if ( fseek(context->hidden.stdio.fp, offset, whence) == 0 ) {
return(ftell(context->hidden.stdio.fp));
} else {
SDL_Error(SDL_EFSEEK);
return(-1);
}
}
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{
size_t nread;
nread = fread(ptr, size, maxnum, context->hidden.stdio.fp);
if ( nread == 0 && ferror(context->hidden.stdio.fp) ) {
SDL_Error(SDL_EFREAD);
}
return(nread);
}
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static int SDLCALL stdio_write(SDL_RWops *context, const void *ptr, int size, int num)
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{
size_t nwrote;
nwrote = fwrite(ptr, size, num, context->hidden.stdio.fp);
if ( nwrote == 0 && ferror(context->hidden.stdio.fp) ) {
SDL_Error(SDL_EFWRITE);
}
return(nwrote);
}
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{
if ( context ) {
if ( context->hidden.stdio.autoclose ) {
/* WARNING: Check the return value here! */
fclose(context->hidden.stdio.fp);
}
SDL_FreeRW(context);
}
return(0);
}
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#endif /* !HAVE_STDIO_H */
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/* Functions to read/write memory pointers */
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{
Uint8 *newpos;
switch (whence) {
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case RW_SEEK_SET:
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newpos = context->hidden.mem.base+offset;
break;
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case RW_SEEK_CUR:
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newpos = context->hidden.mem.here+offset;
break;
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case RW_SEEK_END:
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newpos = context->hidden.mem.stop+offset;
break;
default:
SDL_SetError("Unknown value for 'whence'");
return(-1);
}
if ( newpos < context->hidden.mem.base ) {
newpos = context->hidden.mem.base;
}
if ( newpos > context->hidden.mem.stop ) {
newpos = context->hidden.mem.stop;
}
context->hidden.mem.here = newpos;
return(context->hidden.mem.here-context->hidden.mem.base);
}
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{
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size_t total_bytes;
size_t mem_available;
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total_bytes = (maxnum * size);
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if ( (maxnum <= 0) || (size <= 0) || ((total_bytes / maxnum) != (size_t) size) ) {
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return 0;
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}
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mem_available = (context->hidden.mem.stop - context->hidden.mem.here);
if (total_bytes > mem_available) {
total_bytes = mem_available;
}
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SDL_memcpy(ptr, context->hidden.mem.here, total_bytes);
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context->hidden.mem.here += total_bytes;
return (total_bytes / size);
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}
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static int SDLCALL mem_write(SDL_RWops *context, const void *ptr, int size, int num)
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{
if ( (context->hidden.mem.here + (num*size)) > context->hidden.mem.stop ) {
num = (context->hidden.mem.stop-context->hidden.mem.here)/size;
}
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SDL_memcpy(context->hidden.mem.here, ptr, num*size);
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context->hidden.mem.here += num*size;
return(num);
}
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static int SDLCALL mem_writeconst(SDL_RWops *context, const void *ptr, int size, int num)
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{
SDL_SetError("Can't write to read-only memory");
return(-1);
}
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{
if ( context ) {
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SDL_FreeRW(context);
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}
return(0);
}
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/* Functions to create SDL_RWops structures from various data sources */
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#ifdef __MACOS__
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/*
* translate unix-style slash-separated filename to mac-style colon-separated
* name; return malloced string
*/
static char *unix_to_mac(const char *file)
{
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int flen = SDL_strlen(file);
char *path = SDL_malloc(flen + 2);
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const char *src = file;
char *dst = path;
if(*src == '/') {
/* really depends on filesystem layout, hope for the best */
src++;
} else {
/* Check if this is a MacOS path to begin with */
if(*src != ':')
*dst++ = ':'; /* relative paths begin with ':' */
}
while(src < file + flen) {
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const char *end = SDL_strchr(src, '/');
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int len;
if(!end)
end = file + flen; /* last component */
len = end - src;
if(len == 0 || (len == 1 && src[0] == '.')) {
/* remove repeated slashes and . */
} else {
if(len == 2 && src[0] == '.' && src[1] == '.') {
/* replace .. with the empty string */
} else {
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SDL_memcpy(dst, src, len);
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dst += len;
}
if(end < file + flen)
*dst++ = ':';
}
src = end + 1;
}
*dst++ = '\0';
return path;
}
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#endif /* __MACOS__ */
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SDL_RWops *SDL_RWFromFile(const char *file, const char *mode)
{
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SDL_RWops *rwops = NULL;
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#ifdef HAVE_STDIO_H
FILE *fp = NULL;
#endif
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if ( !file || !*file || !mode || !*mode ) {
SDL_SetError("SDL_RWFromFile(): No file or no mode specified");
return NULL;
}
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#if defined(__WIN32__) && !defined(__SYMBIAN32__)
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rwops = SDL_AllocRW();
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if (!rwops)
return NULL; /* SDL_SetError already setup by SDL_AllocRW() */
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rwops->hidden.win32io.h = INVALID_HANDLE_VALUE;
if (win32_file_open(rwops,file,mode)) {
SDL_FreeRW(rwops);
return NULL;
}
rwops->seek = win32_file_seek;
rwops->read = win32_file_read;
rwops->write = win32_file_write;
rwops->close = win32_file_close;
#elif HAVE_STDIO_H
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#ifdef __MACOS__
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{
char *mpath = unix_to_mac(file);
fp = fopen(mpath, mode);
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SDL_free(mpath);
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}
#else
fp = fopen(file, mode);
#endif
if ( fp == NULL ) {
SDL_SetError("Couldn't open %s", file);
} else {
rwops = SDL_RWFromFP(fp, 1);
}
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#else
SDL_SetError("SDL not compiled with stdio support");
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#endif /* !HAVE_STDIO_H */
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return(rwops);
}
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#ifdef HAVE_STDIO_H
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SDL_RWops *SDL_RWFromFP(FILE *fp, int autoclose)
{
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SDL_RWops *rwops = NULL;
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rwops = SDL_AllocRW();
if ( rwops != NULL ) {
rwops->seek = stdio_seek;
rwops->read = stdio_read;
rwops->write = stdio_write;
rwops->close = stdio_close;
rwops->hidden.stdio.fp = fp;
rwops->hidden.stdio.autoclose = autoclose;
}
return(rwops);
}
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#endif /* HAVE_STDIO_H */
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SDL_RWops *SDL_RWFromMem(void *mem, int size)
{
SDL_RWops *rwops;
rwops = SDL_AllocRW();
if ( rwops != NULL ) {
rwops->seek = mem_seek;
rwops->read = mem_read;
rwops->write = mem_write;
rwops->close = mem_close;
rwops->hidden.mem.base = (Uint8 *)mem;
rwops->hidden.mem.here = rwops->hidden.mem.base;
rwops->hidden.mem.stop = rwops->hidden.mem.base+size;
}
return(rwops);
}
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SDL_RWops *SDL_RWFromConstMem(const void *mem, int size)
{
SDL_RWops *rwops;
rwops = SDL_AllocRW();
if ( rwops != NULL ) {
rwops->seek = mem_seek;
rwops->read = mem_read;
rwops->write = mem_writeconst;
rwops->close = mem_close;
rwops->hidden.mem.base = (Uint8 *)mem;
rwops->hidden.mem.here = rwops->hidden.mem.base;
rwops->hidden.mem.stop = rwops->hidden.mem.base+size;
}
return(rwops);
}
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SDL_RWops *SDL_AllocRW(void)
{
SDL_RWops *area;
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area = (SDL_RWops *)SDL_malloc(sizeof *area);
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if ( area == NULL ) {
SDL_OutOfMemory();
}
return(area);
}
void SDL_FreeRW(SDL_RWops *area)
{
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SDL_free(area);
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}
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/* Functions for dynamically reading and writing endian-specific values */
Uint16 SDL_ReadLE16 (SDL_RWops *src)
{
Uint16 value;
SDL_RWread(src, &value, (sizeof value), 1);
return(SDL_SwapLE16(value));
}
Uint16 SDL_ReadBE16 (SDL_RWops *src)
{
Uint16 value;
SDL_RWread(src, &value, (sizeof value), 1);
return(SDL_SwapBE16(value));
}
Uint32 SDL_ReadLE32 (SDL_RWops *src)
{
Uint32 value;
SDL_RWread(src, &value, (sizeof value), 1);
return(SDL_SwapLE32(value));
}
Uint32 SDL_ReadBE32 (SDL_RWops *src)
{
Uint32 value;
SDL_RWread(src, &value, (sizeof value), 1);
return(SDL_SwapBE32(value));
}
Uint64 SDL_ReadLE64 (SDL_RWops *src)
{
Uint64 value;
SDL_RWread(src, &value, (sizeof value), 1);
return(SDL_SwapLE64(value));
}
Uint64 SDL_ReadBE64 (SDL_RWops *src)
{
Uint64 value;
SDL_RWread(src, &value, (sizeof value), 1);
return(SDL_SwapBE64(value));
}
int SDL_WriteLE16 (SDL_RWops *dst, Uint16 value)
{
value = SDL_SwapLE16(value);
return(SDL_RWwrite(dst, &value, (sizeof value), 1));
}
int SDL_WriteBE16 (SDL_RWops *dst, Uint16 value)
{
value = SDL_SwapBE16(value);
return(SDL_RWwrite(dst, &value, (sizeof value), 1));
}
int SDL_WriteLE32 (SDL_RWops *dst, Uint32 value)
{
value = SDL_SwapLE32(value);
return(SDL_RWwrite(dst, &value, (sizeof value), 1));
}
int SDL_WriteBE32 (SDL_RWops *dst, Uint32 value)
{
value = SDL_SwapBE32(value);
return(SDL_RWwrite(dst, &value, (sizeof value), 1));
}
int SDL_WriteLE64 (SDL_RWops *dst, Uint64 value)
{
value = SDL_SwapLE64(value);
return(SDL_RWwrite(dst, &value, (sizeof value), 1));
}
int SDL_WriteBE64 (SDL_RWops *dst, Uint64 value)
{
value = SDL_SwapBE64(value);
return(SDL_RWwrite(dst, &value, (sizeof value), 1));
}