/*
* IMG_ImageIO.c
* SDL_image
*
* Created by Eric Wing on 1/2/09.
* Copyright 2009 __MyCompanyName__. All rights reserved.
*
*/
#include "SDL_image.h"
#import <UIKit/UIKit.h>
#import <MobileCoreServices/MobileCoreServices.h> // for UTCoreTypes.h

// Once we have our image, we need to get it into an SDL_Surface
// (Copied straight from the ImageIO backend.)
static SDL_Surface* Create_SDL_Surface_From_CGImage(CGImageRef image_ref)
{
/* This code is adapted from Apple's Documentation found here:
* http://developer.apple.com/documentation/GraphicsImaging/Conceptual/OpenGL-MacProgGuide/index.html
* Listing 9-4â€ â€ Using a Quartz image as a texture source.
* Unfortunately, this guide doesn't show what to do about
* non-RGBA image formats so I'm making the rest up.
* All this code should be scrutinized.
*/

size_t w = CGImageGetWidth(image_ref);
size_t h = CGImageGetHeight(image_ref);
CGRect rect = {{0, 0}, {w, h}};

CGImageAlphaInfo alpha = CGImageGetAlphaInfo(image_ref);
//size_t bits_per_pixel = CGImageGetBitsPerPixel(image_ref);
size_t bits_per_component = 8;

SDL_Surface* surface;
Uint32 Amask;
Uint32 Rmask;
Uint32 Gmask;
Uint32 Bmask;

CGContextRef bitmap_context;
CGBitmapInfo bitmap_info;
CGColorSpaceRef color_space = CGColorSpaceCreateDeviceRGB();

if (alpha == kCGImageAlphaNone ||
alpha == kCGImageAlphaNoneSkipFirst ||
alpha == kCGImageAlphaNoneSkipLast) {
bitmap_info = kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Host; /* XRGB */
Amask = 0x00000000;
} else {
/* kCGImageAlphaFirst isn't supported */
//bitmap_info = kCGImageAlphaFirst | kCGBitmapByteOrder32Host; /* ARGB */
bitmap_info = kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host; /* ARGB */
Amask = 0xFF000000;
}

Rmask = 0x00FF0000;
Gmask = 0x0000FF00;
Bmask = 0x000000FF;

surface = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 32, Rmask, Gmask, Bmask, Amask);
if (surface)
{
// Sets up a context to be drawn to with surface->pixels as the area to be drawn to
bitmap_context = CGBitmapContextCreate(
surface->pixels,
surface->w,
surface->h,
bits_per_component,
surface->pitch,
color_space,
bitmap_info
);

// Draws the image into the context's image_data
CGContextDrawImage(bitmap_context, rect, image_ref);

CGContextRelease(bitmap_context);

// FIXME: Reverse the premultiplied alpha
if ((bitmap_info & kCGBitmapAlphaInfoMask) == kCGImageAlphaPremultipliedFirst) {
int i, j;
Uint8 *p = (Uint8 *)surface->pixels;
for (i = surface->h * surface->pitch/4; i--; ) {
#if __LITTLE_ENDIAN__
Uint8 A = p[3];
if (A) {
for (j = 0; j < 3; ++j) {
p[j] = (p[j] * 255) / A;
}
}
#else
Uint8 A = p[0];
if (A) {
for (j = 1; j < 4; ++j) {
p[j] = (p[j] * 255) / A;
}
}
#endif /* ENDIAN */
p += 4;
}
}
}

if (color_space)
{
CGColorSpaceRelease(color_space);
}

return surface;
}

static SDL_Surface* LoadImageFromRWops(SDL_RWops* rw_ops, CFStringRef uti_string_hint)
{
NSAutoreleasePool* autorelease_pool = [[NSAutoreleasePool alloc] init];
SDL_Surface* sdl_surface;
UIImage* ui_image;

int bytes_read = 0;
// I don't know what a good size is.
// Max recommended texture size is 1024x1024 on iPhone so maybe base it on that?
const int block_size = 1024*4;
char temp_buffer[block_size];

NSMutableData* ns_data = [[NSMutableData alloc] initWithCapacity:1024*1024*4];

do
{
bytes_read = SDL_RWread(rw_ops, temp_buffer, 1, block_size);
[ns_data appendBytes:temp_buffer length:bytes_read];
} while(bytes_read > 0);

ui_image = [[UIImage alloc] initWithData:ns_data];

sdl_surface = Create_SDL_Surface_From_CGImage([ui_image CGImage]);

[ui_image release];
[ns_data release];

[autorelease_pool drain];

return sdl_surface;
}

static SDL_Surface* LoadImageFromFile(const char *file)
{
NSAutoreleasePool* autorelease_pool = [[NSAutoreleasePool alloc] init];
SDL_Surface* sdl_surface = NULL;
UIImage* ui_image;
NSString* ns_string;

ns_string = [[NSString alloc] initWithUTF8String:file];
ui_image = [[UIImage alloc] initWithContentsOfFile:ns_string];
if(ui_image != NULL)
{
sdl_surface = Create_SDL_Surface_From_CGImage([ui_image CGImage]);
}

[ui_image release];
[ns_string release];

[autorelease_pool drain];

return sdl_surface;
}

/* Since UIImage doesn't really support streams well, we should optimize for the file case. */
SDL_Surface *IMG_Load(const char *file)
{
SDL_Surface* sdl_surface = NULL;

sdl_surface = LoadImageFromFile(file);
if(NULL == sdl_surface)
{
// Either the file doesn't exist or ImageIO doesn't understand the format.
// For the latter case, fallback to the native SDL_image handlers.

SDL_RWops *src = SDL_RWFromFile(file, "rb");
char *ext = strrchr(file, '.');
if(ext) {
ext++;
}
if(!src) {
/* The error message has been set in SDL_RWFromFile */
return NULL;
}
sdl_surface = IMG_LoadTyped_RW(src, 1, ext);
}
return sdl_surface;
}

int IMG_InitJPG()
{
return 0;
}

void IMG_QuitJPG()
{
}

int IMG_InitPNG()
{
return 0;
}

void IMG_QuitPNG()
{
}

int IMG_InitTIF()
{
return 0;
}

void IMG_QuitTIF()
{
}

/* Copied straight from other files so I don't have to alter them. */
static int IMG_isICOCUR(SDL_RWops *src, int type)
{
int start;
int is_ICOCUR;

/* The Win32 ICO file header (14 bytes) */
Uint16 bfReserved;
Uint16 bfType;
Uint16 bfCount;

if ( !src )
return 0;
start = SDL_RWtell(src);
is_ICOCUR = 0;
bfReserved = SDL_ReadLE16(src);
bfType = SDL_ReadLE16(src);
bfCount = SDL_ReadLE16(src);
if ((bfReserved == 0) && (bfType == type) && (bfCount != 0))
is_ICOCUR = 1;
SDL_RWseek(src, start, SEEK_SET);

return (is_ICOCUR);
}

int IMG_isICO(SDL_RWops *src)
{
return IMG_isICOCUR(src, 1);
}

int IMG_isCUR(SDL_RWops *src)
{
return IMG_isICOCUR(src, 2);
}

int IMG_isBMP(SDL_RWops *src)
{
int start;
int is_BMP;
char magic[2];

if ( !src )
return 0;
start = SDL_RWtell(src);
is_BMP = 0;
if ( SDL_RWread(src, magic, sizeof(magic), 1) ) {
if ( strncmp(magic, "BM", 2) == 0 ) {
is_BMP = 1;
}
}
SDL_RWseek(src, start, SEEK_SET);
return(is_BMP);
}

int IMG_isGIF(SDL_RWops *src)
{
int start;
int is_GIF;
char magic[6];

if ( !src )
return 0;
start = SDL_RWtell(src);
is_GIF = 0;
if ( SDL_RWread(src, magic, sizeof(magic), 1) ) {
if ( (strncmp(magic, "GIF", 3) == 0) &&
((memcmp(magic + 3, "87a", 3) == 0) ||
(memcmp(magic + 3, "89a", 3) == 0)) ) {
is_GIF = 1;
}
}
SDL_RWseek(src, start, SEEK_SET);
return(is_GIF);
}

int IMG_isJPG(SDL_RWops *src)
{
int start;
int is_JPG;
int in_scan;
Uint8 magic[4];

/* This detection code is by Steaphan Greene <stea@cs.binghamton.edu> */
/* Blame me, not Sam, if this doesn't work right. */
/* And don't forget to report the problem to the the sdl list too! */

if ( !src )
return 0;
start = SDL_RWtell(src);
is_JPG = 0;
in_scan = 0;
if ( SDL_RWread(src, magic, 2, 1) ) {
if ( (magic[0] == 0xFF) && (magic[1] == 0xD8) ) {
is_JPG = 1;
while (is_JPG == 1) {
if(SDL_RWread(src, magic, 1, 2) != 2) {
is_JPG = 0;
} else if( (magic[0] != 0xFF) && (in_scan == 0) ) {
is_JPG = 0;
} else if( (magic[0] != 0xFF) || (magic[1] == 0xFF) ) {
/* Extra padding in JPEG (legal) */
/* or this is data and we are scanning */
SDL_RWseek(src, -1, SEEK_CUR);
} else if(magic[1] == 0xD9) {
/* Got to end of good JPEG */
break;
} else if( (in_scan == 1) && (magic[1] == 0x00) ) {
/* This is an encoded 0xFF within the data */
} else if( (magic[1] >= 0xD0) && (magic[1] < 0xD9) ) {
/* These have nothing else */
} else if(SDL_RWread(src, magic+2, 1, 2) != 2) {
is_JPG = 0;
} else {
/* Yes, it's big-endian */
Uint32 start;
Uint32 size;
Uint32 end;
start = SDL_RWtell(src);
size = (magic[2] << 8) + magic[3];
end = SDL_RWseek(src, size-2, SEEK_CUR);
if ( end != start + size - 2 ) is_JPG = 0;
if ( magic[1] == 0xDA ) {
/* Now comes the actual JPEG meat */
#ifdef FAST_IS_JPEG
/* Ok, I'm convinced. It is a JPEG. */
break;
#else
/* I'm not convinced. Prove it! */
in_scan = 1;
#endif
}
}
}
}
}
SDL_RWseek(src, start, SEEK_SET);
return(is_JPG);
}

int IMG_isPNG(SDL_RWops *src)
{
int start;
int is_PNG;
Uint8 magic[4];

if ( !src )
return 0;
start = SDL_RWtell(src);
is_PNG = 0;
if ( SDL_RWread(src, magic, 1, sizeof(magic)) == sizeof(magic) ) {
if ( magic[0] == 0x89 &&
magic[1] == 'P' &&
magic[2] == 'N' &&
magic[3] == 'G' ) {
is_PNG = 1;
}
}
SDL_RWseek(src, start, SEEK_SET);
return(is_PNG);
}

int IMG_isTIF(SDL_RWops* src)
{
int start;
int is_TIF;
Uint8 magic[4];

if ( !src )
return 0;
start = SDL_RWtell(src);
is_TIF = 0;
if ( SDL_RWread(src, magic, 1, sizeof(magic)) == sizeof(magic) ) {
if ( (magic[0] == 'I' &&
magic[1] == 'I' &&
magic[2] == 0x2a &&
magic[3] == 0x00) ||
(magic[0] == 'M' &&
magic[1] == 'M' &&
magic[2] == 0x00 &&
magic[3] == 0x2a) ) {
is_TIF = 1;
}
}
SDL_RWseek(src, start, SEEK_SET);
return(is_TIF);
}

SDL_Surface* IMG_LoadCUR_RW(SDL_RWops *src)
{
/* FIXME: Is this a supported type? */
return LoadImageFromRWops(src, CFSTR("com.microsoft.cur"));
}
SDL_Surface* IMG_LoadICO_RW(SDL_RWops *src)
{
return LoadImageFromRWops(src, kUTTypeICO);
}
SDL_Surface* IMG_LoadBMP_RW(SDL_RWops *src)
{
return LoadImageFromRWops(src, kUTTypeBMP);
}
SDL_Surface* IMG_LoadGIF_RW(SDL_RWops *src)
{
return LoadImageFromRWops(src, kUTTypeGIF);
}
SDL_Surface* IMG_LoadJPG_RW(SDL_RWops *src)
{
return LoadImageFromRWops(src, kUTTypeJPEG);
}
SDL_Surface* IMG_LoadPNG_RW(SDL_RWops *src)
{
return LoadImageFromRWops(src, kUTTypePNG);
}
SDL_Surface* IMG_LoadTGA_RW(SDL_RWops *src)
{
return LoadImageFromRWops(src, CFSTR("com.truevision.tga-image"));
}
SDL_Surface* IMG_LoadTIF_RW(SDL_RWops *src)
{
return LoadImageFromRWops(src, kUTTypeTIFF);
}