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SDL-mirror/src/file/SDL_rwops.c
Sam Lantinga ec48a1ec62 Date: Mon, 27 Feb 2006 02:17:29 +0100 
From: "William Petiot [exoide]"
Subject: Re: [SDL] cvs version: questions regarding HAVE_STDIO_H in standard w

I managed to get a first implementation of it, which I tested for "simple" use
with tests sample apps, they work ok. I think this needs more tests.

Here is the diff against CVS/SDL12, attached.

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%401450
2006-02-27 03:48:48 +00:00

537 lines
13 KiB
C
Raw Blame History

/*
SDL - Simple DirectMedia Layer
Copyright (C) 1997-2006 Sam Lantinga
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
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
Lesser General Public License for more details.
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
Sam Lantinga
slouken@libsdl.org
*/
#include "SDL_config.h"
/* This file provides a general interface for SDL to read and write
data sources. It can easily be extended to files, memory, etc.
*/
#include "SDL_endian.h"
#include "SDL_rwops.h"
#ifdef HAVE_STDIO_H
/* Functions to read/write stdio file pointers */
static int stdio_seek(SDL_RWops *context, int offset, int whence)
{
if ( fseek(context->hidden.stdio.fp, offset, whence) == 0 ) {
return(ftell(context->hidden.stdio.fp));
} else {
SDL_Error(SDL_EFSEEK);
return(-1);
}
}
static int stdio_read(SDL_RWops *context, void *ptr, int size, int maxnum)
{
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);
}
static int stdio_write(SDL_RWops *context, const void *ptr, int size, int num)
{
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);
}
static int stdio_close(SDL_RWops *context)
{
if ( context ) {
if ( context->hidden.stdio.autoclose ) {
/* WARNING: Check the return value here! */
fclose(context->hidden.stdio.fp);
}
SDL_FreeRW(context);
}
return(0);
}
#else /* HAVE_STDIO_H */
#ifdef __WIN32__
#define WINDOWS_LEAN_AND_MEAN
#include <windows.h>
static int win32_file_open(SDL_RWops *context, const char *filename, const char *mode) {
UINT old_error_mode;
HANDLE h;
DWORD r_right, w_right;
DWORD must_exist, truncate;
int a_mode;
if (!context || !filename || !mode)
return -1;
context->hidden.win32io.h = INVALID_HANDLE_VALUE; /* mark this as unusable */
/* "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;
a_mode = ( SDL_strchr(mode,'a') != NULL );
w_right = ( a_mode || SDL_strchr(mode,'w') || truncate ) ? GENERIC_WRITE : 0;
if (!r_right && !w_right) /* inconsistent mode */
return -1; /* failed (invalid call)*/
/* Do not open a dialog box if failure */
old_error_mode = SetErrorMode(SEM_NOOPENFILEERRORBOX|SEM_FAILCRITICALERRORS);
h = CreateFile(filename, (w_right|r_right), (w_right)? 0 : FILE_SHARE_READ,
NULL, (must_exist|truncate), FILE_ATTRIBUTE_NORMAL,NULL);
/* restore old behaviour */
SetErrorMode(old_error_mode);
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 */
}
static int win32_file_seek(SDL_RWops *context, int offset, int whence) {
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;
}
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;
}
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 */
}
static int win32_file_read(SDL_RWops *context, void *ptr, int size, int maxnum) {
int total_bytes;
DWORD byte_read,nread;
total_bytes = size*maxnum;
if (!context || context->hidden.win32io.h == INVALID_HANDLE_VALUE || total_bytes<=0 || !size)
return 0;
if (!ReadFile(context->hidden.win32io.h,ptr,total_bytes,&byte_read,NULL)) {
SDL_Error(SDL_EFREAD);
return 0;
}
nread = byte_read/size;
return nread;
}
static int win32_file_write(SDL_RWops *context, const void *ptr, int size, int num) {
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;
/* 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;
}
static int win32_file_close(SDL_RWops *context) {
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 */
}
SDL_FreeRW(context);
}
return(0);
}
#endif /* __WIN32__ */
#endif /* !HAVE_STDIO_H */
/* Functions to read/write memory pointers */
static int mem_seek(SDL_RWops *context, int offset, int whence)
{
Uint8 *newpos;
switch (whence) {
case RW_SEEK_SET:
newpos = context->hidden.mem.base+offset;
break;
case RW_SEEK_CUR:
newpos = context->hidden.mem.here+offset;
break;
case RW_SEEK_END:
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);
}
static int mem_read(SDL_RWops *context, void *ptr, int size, int maxnum)
{
int total_bytes;
int mem_available;
total_bytes = (maxnum * size);
if ( (maxnum <= 0) || (size <= 0) || ((total_bytes / maxnum) != size) ) {
return 0;
}
mem_available = (context->hidden.mem.stop - context->hidden.mem.here);
if (total_bytes > mem_available) {
total_bytes = mem_available;
}
SDL_memcpy(ptr, context->hidden.mem.here, total_bytes);
context->hidden.mem.here += total_bytes;
return (total_bytes / size);
}
static int mem_write(SDL_RWops *context, const void *ptr, int size, int num)
{
if ( (context->hidden.mem.here + (num*size)) > context->hidden.mem.stop ) {
num = (context->hidden.mem.stop-context->hidden.mem.here)/size;
}
SDL_memcpy(context->hidden.mem.here, ptr, num*size);
context->hidden.mem.here += num*size;
return(num);
}
static int mem_writeconst(SDL_RWops *context, const void *ptr, int size, int num)
{
SDL_SetError("Can't write to read-only memory");
return(-1);
}
static int mem_close(SDL_RWops *context)
{
if ( context ) {
SDL_FreeRW(context);
}
return(0);
}
/* Functions to create SDL_RWops structures from various data sources */
#ifdef __WIN32__
/* Aggh. You can't (apparently) open a file in an application and
read from it in a DLL.
*/
static int in_sdl = 0;
#endif
#ifdef __MACOS__
/*
* translate unix-style slash-separated filename to mac-style colon-separated
* name; return malloced string
*/
static char *unix_to_mac(const char *file)
{
int flen = SDL_strlen(file);
char *path = SDL_malloc(flen + 2);
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) {
const char *end = SDL_strchr(src, '/');
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 {
SDL_memcpy(dst, src, len);
dst += len;
}
if(end < file + flen)
*dst++ = ':';
}
src = end + 1;
}
*dst++ = '\0';
return path;
}
#endif /* __MACOS__ */
SDL_RWops *SDL_RWFromFile(const char *file, const char *mode)
{
SDL_RWops *rwops = NULL;
#ifdef HAVE_STDIO_H
FILE *fp;
#ifdef __MACOS__
{
char *mpath = unix_to_mac(file);
fp = fopen(mpath, mode);
SDL_free(mpath);
}
#else
fp = fopen(file, mode);
#endif
if ( fp == NULL ) {
SDL_SetError("Couldn't open %s", file);
} else {
#ifdef __WIN32__
in_sdl = 1;
rwops = SDL_RWFromFP(fp, 1);
in_sdl = 0;
#else
rwops = SDL_RWFromFP(fp, 1);
#endif
}
#else /* HAVE_STDIO_H */
#ifdef __WIN32__
rwops = SDL_AllocRW();
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;
#endif /* __WIN32__ */
#endif /* !HAVE_STDIO_H */
return(rwops);
}
#ifdef HAVE_STDIO_H
SDL_RWops *SDL_RWFromFP(FILE *fp, int autoclose)
{
SDL_RWops *rwops = NULL;
#ifdef __WIN32__
if ( ! in_sdl ) {
/* It's when SDL and the app are compiled with different C runtimes */
SDL_SetError("You can't pass a FILE pointer to a DLL (?)");
/*return(NULL);*/
}
#endif
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);
}
#endif /* HAVE_STDIO_H */
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);
}
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);
}
SDL_RWops *SDL_AllocRW(void)
{
SDL_RWops *area;
area = (SDL_RWops *)SDL_malloc(sizeof *area);
if ( area == NULL ) {
SDL_OutOfMemory();
}
return(area);
}
void SDL_FreeRW(SDL_RWops *area)
{
SDL_free(area);
}
/* 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));
}
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