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SDL_rwops.c
627 lines (536 loc) · 16.5 KB
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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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#ifdef __WIN32__
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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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#endif
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HANDLE h;
DWORD r_right, w_right;
DWORD must_exist, truncate;
int a_mode;
if (!context)
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;
a_mode = (SDL_strchr(mode, 'a') != NULL) ? OPEN_ALWAYS : 0;
w_right = (a_mode || SDL_strchr(mode, '+')
|| truncate) ? GENERIC_WRITE : 0;
if (!r_right && !w_right) /* inconsistent mode */
return -1; /* failed (invalid call) */
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#ifdef _WIN32_WCE
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{
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);
}
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#else
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/* Do not open a dialog box if failure */
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, 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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}
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static long SDLCALL
win32_file_seek(SDL_RWops * context, long offset, int whence)
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{
DWORD win32whence;
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long file_pos;
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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 */
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SDL_Error(SDL_EFSEEK);
return -1; /* error */
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}
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static size_t SDLCALL
win32_file_read(SDL_RWops * context, void *ptr, size_t size, size_t maxnum)
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{
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size_t total_need;
size_t total_read = 0;
size_t read_ahead;
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DWORD byte_read;
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total_need = size * maxnum;
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if (!context || context->hidden.win32io.h == INVALID_HANDLE_VALUE
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|| !total_need)
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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;
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}
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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;
}
read_ahead = SDL_min(total_need, (int) byte_read);
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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}
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static size_t SDLCALL
win32_file_write(SDL_RWops * context, const void *ptr, size_t size,
size_t num)
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{
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size_t total_bytes;
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DWORD byte_written, nwritten;
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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) {
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if (SetFilePointer(context->hidden.win32io.h, 0L, NULL, FILE_END) ==
INVALID_SET_FILE_POINTER) {
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SDL_Error(SDL_EFWRITE);
return 0;
}
}
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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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}
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static int SDLCALL
win32_file_close(SDL_RWops * context)
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{
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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);
}
#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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static long SDLCALL
stdio_seek(SDL_RWops * context, long offset, int whence)
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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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}
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static size_t SDLCALL
stdio_read(SDL_RWops * context, void *ptr, size_t size, size_t maxnum)
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{
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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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}
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static size_t SDLCALL
stdio_write(SDL_RWops * context, const void *ptr, size_t size, size_t num)
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{
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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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}
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static int SDLCALL
stdio_close(SDL_RWops * context)
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{
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int status = 0;
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if (context) {
if (context->hidden.stdio.autoclose) {
/* WARNING: Check the return value here! */
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if (fclose(context->hidden.stdio.fp) != 0) {
SDL_Error(SDL_EFWRITE);
status = -1;
}
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}
SDL_FreeRW(context);
}
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return status;
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}
#endif /* !HAVE_STDIO_H */
/* Functions to read/write memory pointers */
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static long SDLCALL
mem_seek(SDL_RWops * context, long offset, int whence)
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{
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);
}
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static size_t SDLCALL
mem_read(SDL_RWops * context, void *ptr, size_t size, size_t maxnum)
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{
size_t total_bytes;
size_t mem_available;
total_bytes = (maxnum * size);
if ((maxnum <= 0) || (size <= 0)
|| ((total_bytes / maxnum) != (size_t) 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);
}
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static size_t SDLCALL
mem_write(SDL_RWops * context, const void *ptr, size_t size, size_t 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;
}
SDL_memcpy(context->hidden.mem.here, ptr, num * size);
context->hidden.mem.here += num * size;
return (num);
}
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static size_t SDLCALL
mem_writeconst(SDL_RWops * context, const void *ptr, size_t size, size_t num)
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{
SDL_SetError("Can't write to read-only memory");
return (-1);
}
static int SDLCALL
mem_close(SDL_RWops * context)
{
if (context) {
SDL_FreeRW(context);
}
return (0);
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}
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/* Functions to create SDL_RWops structures from various data sources */
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SDL_RWops *
SDL_RWFromFile(const char *file, const char *mode)
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{
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SDL_RWops *rwops = NULL;
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#ifdef HAVE_STDIO_H
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FILE *fp = NULL;
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#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__)
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rwops = SDL_AllocRW();
if (!rwops)
return NULL; /* SDL_SetError already setup by 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;
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#elif HAVE_STDIO_H
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fp = fopen(file, mode);
if (fp == NULL) {
SDL_SetError("Couldn't open %s", file);
} else {
rwops = SDL_RWFromFP(fp, 1);
}
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#else
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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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}
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#ifdef HAVE_STDIO_H
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SDL_RWops *
SDL_RWFromFP(FILE * fp, int autoclose)
{
SDL_RWops *rwops = NULL;
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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}
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#endif /* HAVE_STDIO_H */
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SDL_RWops *
SDL_RWFromMem(void *mem, int size)
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{
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SDL_RWops *rwops;
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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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}
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SDL_RWops *
SDL_RWFromConstMem(const void *mem, int size)
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{
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SDL_RWops *rwops;
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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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}
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SDL_RWops *
SDL_AllocRW(void)
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{
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SDL_RWops *area;
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area = (SDL_RWops *) SDL_malloc(sizeof *area);
if (area == NULL) {
SDL_OutOfMemory();
}
return (area);
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}
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void
SDL_FreeRW(SDL_RWops * area)
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{
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SDL_free(area);
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}
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/* Functions for dynamically reading and writing endian-specific values */
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Uint16
SDL_ReadLE16(SDL_RWops * src)
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{
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Uint16 value;
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SDL_RWread(src, &value, (sizeof value), 1);
return (SDL_SwapLE16(value));
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}
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Uint16
SDL_ReadBE16(SDL_RWops * src)
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{
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Uint16 value;
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SDL_RWread(src, &value, (sizeof value), 1);
return (SDL_SwapBE16(value));
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}
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Uint32
SDL_ReadLE32(SDL_RWops * src)
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{
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Uint32 value;
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SDL_RWread(src, &value, (sizeof value), 1);
return (SDL_SwapLE32(value));
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}
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Uint32
SDL_ReadBE32(SDL_RWops * src)
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{
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Uint32 value;
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SDL_RWread(src, &value, (sizeof value), 1);
return (SDL_SwapBE32(value));
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}
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Uint64
SDL_ReadLE64(SDL_RWops * src)
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{
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Uint64 value;
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SDL_RWread(src, &value, (sizeof value), 1);
return (SDL_SwapLE64(value));
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}
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Uint64
SDL_ReadBE64(SDL_RWops * src)
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{
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Uint64 value;
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SDL_RWread(src, &value, (sizeof value), 1);
return (SDL_SwapBE64(value));
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}
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int
SDL_WriteLE16(SDL_RWops * dst, Uint16 value)
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{
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value = SDL_SwapLE16(value);
return (SDL_RWwrite(dst, &value, (sizeof value), 1));
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}
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int
SDL_WriteBE16(SDL_RWops * dst, Uint16 value)
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{
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value = SDL_SwapBE16(value);
return (SDL_RWwrite(dst, &value, (sizeof value), 1));
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}
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int
SDL_WriteLE32(SDL_RWops * dst, Uint32 value)
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{
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value = SDL_SwapLE32(value);
return (SDL_RWwrite(dst, &value, (sizeof value), 1));
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}
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int
SDL_WriteBE32(SDL_RWops * dst, Uint32 value)
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{
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value = SDL_SwapBE32(value);
return (SDL_RWwrite(dst, &value, (sizeof value), 1));
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}
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int
SDL_WriteLE64(SDL_RWops * dst, Uint64 value)
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{
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value = SDL_SwapLE64(value);
return (SDL_RWwrite(dst, &value, (sizeof value), 1));
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}
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int
SDL_WriteBE64(SDL_RWops * dst, Uint64 value)
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{
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value = SDL_SwapBE64(value);
return (SDL_RWwrite(dst, &value, (sizeof value), 1));
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}
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/* vi: set ts=4 sw=4 expandtab: */