/*

  Simple DirectMedia Layer

  Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied

  warranty.  In no event will the authors be held liable for any damages

  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,

  including commercial applications, and to alter it and redistribute it

  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not

     claim that you wrote the original software. If you use this software

     in a product, an acknowledgment in the product documentation would be

     appreciated but is not required.

  2. Altered source versions must be plainly marked as such, and must not be

     misrepresented as being the original software.

  3. This notice may not be removed or altered from any source distribution.

*/

/* Need this so Linux systems define fseek64o, ftell64o and off64_t */

#define _LARGEFILE64_SOURCE

#include "../SDL_internal.h"

#if defined(__WIN32__)

#include "../core/windows/SDL_windows.h"

#endif

/* 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 __APPLE__

#include "cocoa/SDL_rwopsbundlesupport.h"

#endif /* __APPLE__ */

#ifdef __ANDROID__

#include "../core/android/SDL_android.h"

#include "SDL_system.h"

#endif

#if __NACL__

#include "nacl_io/nacl_io.h"

#endif

#ifdef __WIN32__

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

#ifndef INVALID_SET_FILE_POINTER

#define INVALID_SET_FILE_POINTER 0xFFFFFFFF

#endif

#define READAHEAD_BUFFER_SIZE   1024

static int SDLCALL

windows_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)

        return -1;              /* failed (invalid call) */

    context->hidden.windowsio.h = INVALID_HANDLE_VALUE;   /* mark this as unusable */

    context->hidden.windowsio.buffer.data = NULL;

    context->hidden.windowsio.buffer.size = 0;

    context->hidden.windowsio.buffer.left = 0;

    /* "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) */

    context->hidden.windowsio.buffer.data =

        (char *) SDL_malloc(READAHEAD_BUFFER_SIZE);

    if (!context->hidden.windowsio.buffer.data) {

        return SDL_OutOfMemory();

    }

    /* Do not open a dialog box if failure */

    old_error_mode =

        SetErrorMode(SEM_NOOPENFILEERRORBOX | SEM_FAILCRITICALERRORS);

    {

        LPTSTR tstr = WIN_UTF8ToString(filename);

        h = CreateFile(tstr, (w_right | r_right),

                       (w_right) ? 0 : FILE_SHARE_READ, NULL,

                       (must_exist | truncate | a_mode),

                       FILE_ATTRIBUTE_NORMAL, NULL);

        SDL_free(tstr);

    }

    /* restore old behavior */

    SetErrorMode(old_error_mode);

    if (h == INVALID_HANDLE_VALUE) {

        SDL_free(context->hidden.windowsio.buffer.data);

        context->hidden.windowsio.buffer.data = NULL;

        SDL_SetError("Couldn't open %s", filename);

        return -2;              /* failed (CreateFile) */

    }

    context->hidden.windowsio.h = h;

    context->hidden.windowsio.append = a_mode ? SDL_TRUE : SDL_FALSE;

    return 0;                   /* ok */

}

static Sint64 SDLCALL

windows_file_size(SDL_RWops * context)

{

    LARGE_INTEGER size;

    if (!context || context->hidden.windowsio.h == INVALID_HANDLE_VALUE) {

        return SDL_SetError("windows_file_size: invalid context/file not opened");

    }

    if (!GetFileSizeEx(context->hidden.windowsio.h, &size)) {

        return WIN_SetError("windows_file_size");

    }

    return size.QuadPart;

}

static Sint64 SDLCALL

windows_file_seek(SDL_RWops * context, Sint64 offset, int whence)

{

    DWORD windowswhence;

    LARGE_INTEGER windowsoffset;

    if (!context || context->hidden.windowsio.h == INVALID_HANDLE_VALUE) {

        return SDL_SetError("windows_file_seek: invalid context/file not opened");

    }

    /* FIXME: We may be able to satisfy the seek within buffered data */

    if (whence == RW_SEEK_CUR && context->hidden.windowsio.buffer.left) {

        offset -= (long)context->hidden.windowsio.buffer.left;

    }

    context->hidden.windowsio.buffer.left = 0;

    switch (whence) {

    case RW_SEEK_SET:

        windowswhence = FILE_BEGIN;

        break;

    case RW_SEEK_CUR:

        windowswhence = FILE_CURRENT;

        break;

    case RW_SEEK_END:

        windowswhence = FILE_END;

        break;

    default:

        return SDL_SetError("windows_file_seek: Unknown value for 'whence'");

    }

    windowsoffset.QuadPart = offset;

    if (!SetFilePointerEx(context->hidden.windowsio.h, windowsoffset, &windowsoffset, windowswhence)) {

        return WIN_SetError("windows_file_seek");

    }

    return windowsoffset.QuadPart;

}

static size_t SDLCALL

windows_file_read(SDL_RWops * context, void *ptr, size_t size, size_t maxnum)

{

    size_t total_need;

    size_t total_read = 0;

    size_t read_ahead;

    DWORD byte_read;

    total_need = size * maxnum;

    if (!context || context->hidden.windowsio.h == INVALID_HANDLE_VALUE

        || !total_need)

        return 0;

    if (context->hidden.windowsio.buffer.left > 0) {

        void *data = (char *) context->hidden.windowsio.buffer.data +

            context->hidden.windowsio.buffer.size -

            context->hidden.windowsio.buffer.left;

        read_ahead =

            SDL_min(total_need, context->hidden.windowsio.buffer.left);

        SDL_memcpy(ptr, data, read_ahead);

        context->hidden.windowsio.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.windowsio.h, context->hidden.windowsio.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.windowsio.buffer.data, read_ahead);

        context->hidden.windowsio.buffer.size = byte_read;

        context->hidden.windowsio.buffer.left = byte_read - read_ahead;

        total_read += read_ahead;

    } else {

        if (!ReadFile

            (context->hidden.windowsio.h, ptr, (DWORD)total_need, &byte_read, NULL)) {

            SDL_Error(SDL_EFREAD);

            return 0;

        }

        total_read += byte_read;

    }

    return (total_read / size);

}

static size_t SDLCALL

windows_file_write(SDL_RWops * context, const void *ptr, size_t size,

                 size_t num)

{

    size_t total_bytes;

    DWORD byte_written;

    size_t nwritten;

    total_bytes = size * num;

    if (!context || context->hidden.windowsio.h == INVALID_HANDLE_VALUE

        || total_bytes <= 0 || !size)

        return 0;

    if (context->hidden.windowsio.buffer.left) {

        SetFilePointer(context->hidden.windowsio.h,

                       -(LONG)context->hidden.windowsio.buffer.left, NULL,

                       FILE_CURRENT);

        context->hidden.windowsio.buffer.left = 0;

    }

    /* if in append mode, we must go to the EOF before write */

    if (context->hidden.windowsio.append) {

        if (SetFilePointer(context->hidden.windowsio.h, 0L, NULL, FILE_END) ==

            INVALID_SET_FILE_POINTER) {

            SDL_Error(SDL_EFWRITE);

            return 0;

        }

    }

    if (!WriteFile

        (context->hidden.windowsio.h, ptr, (DWORD)total_bytes, &byte_written, NULL)) {

        SDL_Error(SDL_EFWRITE);

        return 0;

    }

    nwritten = byte_written / size;

    return nwritten;

}

static int SDLCALL

windows_file_close(SDL_RWops * context)

{

    if (context) {

        if (context->hidden.windowsio.h != INVALID_HANDLE_VALUE) {

            CloseHandle(context->hidden.windowsio.h);

            context->hidden.windowsio.h = INVALID_HANDLE_VALUE;   /* to be sure */

        }

        SDL_free(context->hidden.windowsio.buffer.data);

        context->hidden.windowsio.buffer.data = NULL;

        SDL_FreeRW(context);

    }

    return 0;

}

#endif /* __WIN32__ */

#ifdef HAVE_STDIO_H

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

static Sint64 SDLCALL

stdio_size(SDL_RWops * context)

{

    Sint64 pos, size;

    pos = SDL_RWseek(context, 0, RW_SEEK_CUR);

    if (pos < 0) {

        return -1;

    }

    size = SDL_RWseek(context, 0, RW_SEEK_END);

    SDL_RWseek(context, pos, RW_SEEK_SET);

    return size;

}

static Sint64 SDLCALL

stdio_seek(SDL_RWops * context, Sint64 offset, int whence)

{

#ifdef HAVE_FSEEKO64

    if (fseeko64(context->hidden.stdio.fp, (off64_t)offset, whence) == 0) {

        return ftello64(context->hidden.stdio.fp);

    }

#elif defined(HAVE_FSEEKO)

    if (fseeko(context->hidden.stdio.fp, (off_t)offset, whence) == 0) {

        return ftello(context->hidden.stdio.fp);

    }

#elif defined(HAVE__FSEEKI64)

    if (_fseeki64(context->hidden.stdio.fp, offset, whence) == 0) {

        return _ftelli64(context->hidden.stdio.fp);

    }

#else

    if (fseek(context->hidden.stdio.fp, offset, whence) == 0) {

        return ftell(context->hidden.stdio.fp);

    }

#endif

    return SDL_Error(SDL_EFSEEK);

}

static size_t SDLCALL

stdio_read(SDL_RWops * context, void *ptr, size_t size, size_t 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 size_t SDLCALL

stdio_write(SDL_RWops * context, const void *ptr, size_t size, size_t 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)

{

    int status = 0;

    if (context) {

        if (context->hidden.stdio.autoclose) {

            /* WARNING:  Check the return value here! */

            if (fclose(context->hidden.stdio.fp) != 0) {

                status = SDL_Error(SDL_EFWRITE);

            }

        }

        SDL_FreeRW(context);

    }

    return status;

}

#endif /* !HAVE_STDIO_H */

/* Functions to read/write memory pointers */

static Sint64 SDLCALL

mem_size(SDL_RWops * context)

{

    return (Sint64)(context->hidden.mem.stop - context->hidden.mem.base);

}

static Sint64 SDLCALL

mem_seek(SDL_RWops * context, Sint64 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:

        return SDL_SetError("Unknown value for 'whence'");

    }

    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 (Sint64)(context->hidden.mem.here - context->hidden.mem.base);

}

static size_t SDLCALL

mem_read(SDL_RWops * context, void *ptr, size_t size, size_t 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 size_t SDLCALL

mem_write(SDL_RWops * context, const void *ptr, size_t size, size_t 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 size_t SDLCALL

mem_writeconst(SDL_RWops * context, const void *ptr, size_t size, size_t num)

{

    SDL_SetError("Can't write to read-only memory");

    return 0;

}

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 */

SDL_RWops *

SDL_RWFromFile(const char *file, const char *mode)

{

    SDL_RWops *rwops = NULL;

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

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

        return NULL;

    }

#if defined(__ANDROID__)

#ifdef HAVE_STDIO_H

    /* Try to open the file on the filesystem first */

    if (*file == '/') {

        FILE *fp = fopen(file, mode);

        if (fp) {

            return SDL_RWFromFP(fp, 1);

        }

    } else {

        /* Try opening it from internal storage if it's a relative path */

        char *path;

        FILE *fp;

        path = SDL_stack_alloc(char, PATH_MAX);

        if (path) {

            SDL_snprintf(path, PATH_MAX, "%s/%s",

                         SDL_AndroidGetInternalStoragePath(), file);

            fp = fopen(path, mode);

            SDL_stack_free(path);

            if (fp) {

                return SDL_RWFromFP(fp, 1);

            }