/****************************************************************************
Copyright (c) 2010 cocos2d-x.org

http://www.cocos2d-x.org

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
****************************************************************************/

#include <string.h>
#include <stdlib.h>

#include "TGAlib.h"

namespace   cocos2d {

// load the image header fields. We only keep those that matter!
void tgaLoadHeader(FILE *pFile, tImageTGA *psInfo) {
	unsigned char cGarbage;
	signed short iGarbage;

	fread(&cGarbage, sizeof(unsigned char), 1, pFile);
	fread(&cGarbage, sizeof(unsigned char), 1, pFile);

	// type must be 2 or 3
	fread(&psInfo->type, sizeof(unsigned char), 1, pFile);

	fread(&iGarbage, sizeof(signed short), 1, pFile);
	fread(&iGarbage, sizeof(signed short), 1, pFile);
	fread(&cGarbage, sizeof(unsigned char), 1, pFile);
	fread(&iGarbage, sizeof(signed short), 1, pFile);
	fread(&iGarbage, sizeof(signed short), 1, pFile);

	fread(&psInfo->width, sizeof(signed short), 1, pFile);
	fread(&psInfo->height, sizeof(signed short), 1, pFile);
	fread(&psInfo->pixelDepth, sizeof(unsigned char), 1, pFile);

	fread(&cGarbage, sizeof(unsigned char), 1, pFile);
	
	psInfo->flipped = 0;
	if ( cGarbage & 0x20 ) 
	{
		psInfo->flipped = 1;
	}
}

// loads the image pixels. You shouldn't call this function directly
void tgaLoadImageData(FILE *pFile, tImageTGA *psInfo) {
	
	int mode,total,i;
	unsigned char aux;
	
	// mode equal the number of components for each pixel
	mode = psInfo->pixelDepth / 8;
	// total is the number of unsigned chars we'll have to read
	total = psInfo->height * psInfo->width * mode;
	
	fread(psInfo->imageData,sizeof(unsigned char),total,pFile);
	
	// mode=3 or 4 implies that the image is RGB(A). However TGA
	// stores it as BGR(A) so we'll have to swap R and B.
	if (mode >= 3)
		for (i=0; i < total; i+= mode) {
			aux = psInfo->imageData[i];
			psInfo->imageData[i] = psInfo->imageData[i+2];
			psInfo->imageData[i+2] = aux;
		}
}

// loads the RLE encoded image pixels. You shouldn't call this function directly
void tgaLoadRLEImageData(FILE *pFile, tImageTGA *psInfo)
{
	unsigned int mode,total,i, index = 0;
	unsigned char aux[4], runlength = 0;
	unsigned int skip = 0, flag = 0;
	
	// mode equal the number of components for each pixel
	mode = psInfo->pixelDepth / 8;
	// total is the number of unsigned chars we'll have to read
	total = psInfo->height * psInfo->width;
	
	for( i = 0; i < total; i++ )
	{
		// if we have a run length pending, run it
		if ( runlength != 0 )
		{
			// we do, update the run length count
			runlength--;
			skip = (flag != 0);
		}
		else
		{
			// otherwise, read in the run length token
			if ( fread(&runlength,sizeof(unsigned char),1,pFile) != 1 )
				return;
			
			// see if it's a RLE encoded sequence
			flag = runlength & 0x80;
			if ( flag ) runlength -= 128;
			skip = 0;
		}
		
		// do we need to skip reading this pixel?
		if ( !skip )
		{
			// no, read in the pixel data
			if ( fread(aux,sizeof(unsigned char),mode,pFile) != mode )
				return;
			
			// mode=3 or 4 implies that the image is RGB(A). However TGA
			// stores it as BGR(A) so we'll have to swap R and B.
			if ( mode >= 3 )
			{
				unsigned char tmp;
				
				tmp = aux[0];
				aux[0] = aux[2];
				aux[2] = tmp;
			}
		}
		
		// add the pixel to our image
		memcpy(&psInfo->imageData[index], aux, mode);
		index += mode;
	}
}

void tgaFlipImage( tImageTGA *psInfo )
{
	// mode equal the number of components for each pixel
	int mode = psInfo->pixelDepth / 8;
	int rowbytes = psInfo->width*mode;
	unsigned char *row = (unsigned char *)malloc(rowbytes);
	int y;
	
	if (row == NULL) return;
	
	for( y = 0; y < (psInfo->height/2); y++ )
	{
		memcpy(row, &psInfo->imageData[y*rowbytes],rowbytes);
		memcpy(&psInfo->imageData[y*rowbytes], &psInfo->imageData[(psInfo->height-(y+1))*rowbytes], rowbytes);
		memcpy(&psInfo->imageData[(psInfo->height-(y+1))*rowbytes], row, rowbytes);
	}
	
	free(row);
	psInfo->flipped = 0;
}

// this is the function to call when we want to load an image
tImageTGA * tgaLoad(const char *pszFilename) {
	
	FILE *file;
	tImageTGA *info;
	int mode,total;
	
	// allocate memory for the info struct and check!
	info = (tImageTGA *)malloc(sizeof(tImageTGA));
	if (info == NULL)
		return(NULL);
	
	
	// open the file for reading (binary mode)
	if(!(file = fopen(pszFilename, "rb")))
	{
		free(info);
		return NULL;
	}
	if (file == NULL) {
		info->status = TGA_ERROR_FILE_OPEN;
		return(info);
	}
	
	// load the header
	tgaLoadHeader(file,info);
	
	// check for errors when loading the header
	if (ferror(file)) {
		info->status = TGA_ERROR_READING_FILE;
		fclose(file);
		return(info);
	}
	
	// check if the image is color indexed
	if (info->type == 1) {
		info->status = TGA_ERROR_INDEXED_COLOR;
		fclose(file);
		return(info);
	}
	// check for other types (compressed images)
	if ((info->type != 2) && (info->type !=3) && (info->type !=10) ) {
		info->status = TGA_ERROR_COMPRESSED_FILE;
		fclose(file);
		return(info);
	}
	
	// mode equals the number of image components
	mode = info->pixelDepth / 8;
	// total is the number of unsigned chars to read
	total = info->height * info->width * mode;
	// allocate memory for image pixels
	info->imageData = (unsigned char *)malloc(sizeof(unsigned char) *
											  total);
	
	// check to make sure we have the memory required
	if (info->imageData == NULL) {
		info->status = TGA_ERROR_MEMORY;
		fclose(file);
		return(info);
	}
	// finally load the image pixels
	if ( info->type == 10 )
		tgaLoadRLEImageData(file, info);
	else
		tgaLoadImageData(file,info);
	
	// check for errors when reading the pixels
	if (ferror(file)) {
		info->status = TGA_ERROR_READING_FILE;
		fclose(file);
		return(info);
	}
	fclose(file);
	info->status = TGA_OK;
	
	if ( info->flipped )
	{
		tgaFlipImage( info );
		if ( info->flipped ) info->status = TGA_ERROR_MEMORY;
	}
	
	return(info);
}

// converts RGB to greyscale
void tgaRGBtogreyscale(tImageTGA *psInfo) {
	
	int mode,i,j;
	
	unsigned char *newImageData;
	
	// if the image is already greyscale do nothing
	if (psInfo->pixelDepth == 8)
		return;
	
	// compute the number of actual components
	mode = psInfo->pixelDepth / 8;
	
	// allocate an array for the new image data
	newImageData = (unsigned char *)malloc(sizeof(unsigned char) * 
										   psInfo->height * psInfo->width);
	if (newImageData == NULL) {
		return;
	}
	
	// convert pixels: greyscale = o.30 * R + 0.59 * G + 0.11 * B
	for (i = 0,j = 0; j < psInfo->width * psInfo->height; i +=mode, j++)
		newImageData[j] =	
		(unsigned char)(0.30 * psInfo->imageData[i] + 
						0.59 * psInfo->imageData[i+1] +
						0.11 * psInfo->imageData[i+2]);
	
	
	//free old image data
	free(psInfo->imageData);
	
	// reassign pixelDepth and type according to the new image type
	psInfo->pixelDepth = 8;
	psInfo->type = 3;
	// reassing imageData to the new array.
	psInfo->imageData = newImageData;
}

// releases the memory used for the image
void tgaDestroy(tImageTGA *psInfo) {
	
	if (psInfo != NULL) {
		if (psInfo->imageData != NULL)
		{
			free(psInfo->imageData);
		}

		free(psInfo);
	}
}
}//namespace   cocos2d