/*

    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"

#if defined(__WIN32__)

/* Functions to read/write Win32 API file pointers */

/* 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*/

#define WINDOWS_LEAN_AND_MEAN

#include <windows.h>

#ifndef INVALID_SET_FILE_POINTER

#define INVALID_SET_FILE_POINTER 0xFFFFFFFF

#endif

static int SDLCALL

win32_file_open(SDL_RWops * context, const char *filename, const char *mode)

{

#ifndef _WIN32_WCE

    UINT old_error_mode;

#endif

    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 */

    /* "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) */

#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

    /* 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 | a_mode), FILE_ATTRIBUTE_NORMAL,

                   NULL);

    /* restore old behaviour */

    SetErrorMode(old_error_mode);

#endif /* _WIN32_WCE */

    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 SDLCALL

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 SDLCALL

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 SDLCALL

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 SDLCALL

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__ */

#ifdef HAVE_STDIO_H

/* Functions to read/write stdio file pointers */

static int SDLCALL

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 SDLCALL

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 SDLCALL

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 SDLCALL

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);

}

#endif /* !HAVE_STDIO_H */

/* Functions to read/write memory pointers */

static int SDLCALL

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 SDLCALL

mem_read(SDL_RWops * context, void *ptr, int size, int maxnum)

{

    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);

}

static int SDLCALL

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 SDLCALL

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 SDLCALL

mem_close(SDL_RWops * context)

{

    if (context) {

        SDL_FreeRW(context);

    }

    return (0);

}

/* Functions to create SDL_RWops structures from various data sources */

#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 = NULL;

#endif

    if (!file || !*file || !mode || !*mode) {

        SDL_SetError("SDL_RWFromFile(): No file or no mode specified");

        return NULL;

    }

#if defined(__WIN32__)

    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;

#elif HAVE_STDIO_H

#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 {

        rwops = SDL_RWFromFP(fp, 1);

    }

#else

    SDL_SetError("SDL not compiled with stdio support");

#endif /* !HAVE_STDIO_H */

    return (rwops);

}

#ifdef HAVE_STDIO_H

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);

}

#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));

}

/* vi: set ts=4 sw=4 expandtab: */