//
// rdbmp.c
//
// Copyright (C) 1994-1996, Thomas G. Lane.
// This file is part of the Independent JPEG Group's software.
// For conditions of distribution and use, see the accompanying README file.
//
// This file contains routines to read input images in Microsoft "BMP"
// format (MS Windows 3.x, OS/2 1.x, and OS/2 2.x flavors).
// Currently, only 8-bit and 24-bit images are supported, not 1-bit or
// 4-bit (feeding such low-depth images into JPEG would be silly anyway).
// Also, we don't support RLE-compressed files.
//
// These routines may need modification for non-Unix environments or
// specialized applications.  As they stand, they assume input from
// an ordinary stdio stream.  They further assume that reading begins
// at the start of the file; start_input may need work if the
// user interface has already read some data (e.g., to determine that
// the file is indeed BMP format).
//
// This code contributed by James Arthur Boucher.
 

#include "cdjpeg.h"		// Common decls for cjpeg/djpeg applications 

#ifdef BMP_SUPPORTED

// Macros to deal with unsigned chars as efficiently as compiler allows 

#ifdef HAVE_UNSIGNED_CHAR
typedef unsigned char U_CHAR;
#define UCH(x)	((int) (x))
#else // !HAVE_UNSIGNED_CHAR 
#ifdef CHAR_IS_UNSIGNED
typedef char U_CHAR;
#define UCH(x)	((int) (x))
#else
typedef char U_CHAR;
#define UCH(x)	((int) (x) & 0xFF)
#endif
#endif // HAVE_UNSIGNED_CHAR 

#ifndef NOT_USE_FILES 
#define	ReadOK(file,buffer,len)	(JFREAD(file,buffer,len) == ((size_t) (len)))
#endif

// Private version of data source object 

typedef struct _bmp_source_struct *bmp_source_ptr;

typedef struct _bmp_source_struct {
  	struct cjpeg_source_struct pub; 	// public fields 
  	j_compress_ptr cinfo;				// back link saves passing separate parm 
  	JSAMPARRAY colormap;				// BMP colormap (converted to my format) 
  	jvirt_sarray_ptr whole_image;		// Needed to reverse row order 
  	JDIMENSION source_row;				// Current source row number 
  	JDIMENSION row_width;				// Physical width of scanlines in file 
  	int bits_per_pixel;					// remembers 8- or 24-bit format 
} bmp_source_struct;


LOCAL(int) read_byte (bmp_source_ptr sinfo) 
// Read next byte from BMP file 
{
  	#ifdef NOT_USE_FILES 
  		register int c = 0;

  		if (sinfo->pub.buffer_in_index >= sinfo->pub.buffer_in_size) {
  			ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);  			
  		} else {
  			c = sinfo->pub.buffer_in[sinfo->pub.buffer_in_index++];  		
		}
  	#else
  		register FILE *infile = sinfo->pub.input_file;
  		register int c;

  		if ((c = getc(infile)) == EOF)
    		ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
  	#endif
  	
  	return c;
}


LOCAL(void) read_colormap (bmp_source_ptr sinfo, int cmaplen, int mapentrysize)
// Read the colormap from a BMP file 
{
  int i;

  switch (mapentrysize) {
  case 3:
    // BGR format (occurs in OS/2 files) 
    for (i = 0; i < cmaplen; i++) {
      sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
      sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
      sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
    }
    break;
  case 4:
    // BGR0 format (occurs in MS Windows files) 
    for (i = 0; i < cmaplen; i++) {
      sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
      sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
      sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
      (void) read_byte(sinfo);
    }
    break;
  default:
    ERREXIT(sinfo->cinfo, JERR_BMP_BADCMAP);
    break;
  }
}


//
// Read one row of pixels.
// The image has been read into the whole_image array, but is otherwise
// unprocessed.  We must read it out in top-to-bottom row order, and if
// it is an 8-bit image, we must expand colormapped pixels to 24bit format.
 

METHODDEF(JDIMENSION)
get_8bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
// This version is for reading 8-bit colormap indexes 
{
  bmp_source_ptr source = (bmp_source_ptr) sinfo;
  register JSAMPARRAY colormap = source->colormap;
  JSAMPARRAY image_ptr;
  register int t;
  register JSAMPROW inptr, outptr;
  register JDIMENSION col;

  // Fetch next row from virtual array 
  source->source_row--;
  image_ptr = (*cinfo->mem->access_virt_sarray)
    ((j_common_ptr) cinfo, source->whole_image,
     source->source_row, (JDIMENSION) 1, FALSE);

  // Expand the colormap indexes to real data 
  inptr = image_ptr[0];
  outptr = source->pub.buffer[0];
  for (col = cinfo->image_width; col > 0; col--) {
    t = GETJSAMPLE(*inptr++);
    *outptr++ = colormap[0][t];	// can omit GETJSAMPLE() safely 
    *outptr++ = colormap[1][t];
    *outptr++ = colormap[2][t];
  }

  return 1;
}


METHODDEF(JDIMENSION)
get_24bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
// This version is for reading 24-bit pixels 
{
  	bmp_source_ptr source = (bmp_source_ptr) sinfo;
  	JSAMPARRAY image_ptr;
  	register JSAMPROW inptr, outptr;
  	register JDIMENSION col;

  	// Fetch next row from virtual array 
  	source->source_row--;
  	image_ptr = (*cinfo->mem->access_virt_sarray)
    			((j_common_ptr) cinfo, source->whole_image,
     			source->source_row, (JDIMENSION) 1, FALSE);

  	// Transfer data.  Note source values are in BGR order
  	// (even though Microsoft's own documents say the opposite).
   
  	inptr = image_ptr[0];
  	outptr = source->pub.buffer[0];
  	
  	for (col = cinfo->image_width; col > 0; col--) {
    	outptr[2] = *inptr++;	// can omit GETJSAMPLE() safely 
    	outptr[1] = *inptr++;
    	outptr[0] = *inptr++;
    	outptr += 3;
  	}

  	return 1;
}


//
// This method loads the image into whole_image during the first call on
// get_pixel_rows.  The get_pixel_rows pointer is then adjusted to call
// get_8bit_row or get_24bit_row on subsequent calls.
 

METHODDEF(JDIMENSION) preload_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo) {
  	bmp_source_ptr source = (bmp_source_ptr) sinfo;
  	#ifdef NOT_USE_FILES 
  		register int c = 0;
  	#else
  		register FILE *infile = source->pub.input_file;
  		register int c;
  	#endif
  	register JSAMPROW out_ptr;
  	JSAMPARRAY image_ptr;
  	JDIMENSION row, col;
  	
  	cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;

  	// Read the data into a virtual array in input-file row order. 
  	for (row = 0; row < cinfo->image_height; row++) {
    	if (progress != NULL) {
      		progress->pub.pass_counter = (long) row;
      		progress->pub.pass_limit = (long) cinfo->image_height;
      		(*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
    	}
    
    	image_ptr = (*cinfo->mem->access_virt_sarray)
      				((j_common_ptr) cinfo, source->whole_image,
       				row, (JDIMENSION) 1, TRUE);
    	out_ptr = image_ptr[0];
    	
    	for (col = source->row_width; col > 0; col--) {
  			// inline copy of read_byte() for speed 
  			#ifdef NOT_USE_FILES 
  			 			
	   			if (source->pub.buffer_in_index >= source->pub.buffer_in_size) {
					ERREXIT(cinfo, JERR_INPUT_EOF);
				} else {
					c = (int)source->pub.buffer_in[source->pub.buffer_in_index++];  		
				}
      		
      			*out_ptr++ = (JSAMPLE) c;
      		#else
      		
      			if ((c = getc(infile)) == EOF)
					ERREXIT(cinfo, JERR_INPUT_EOF);
      			*out_ptr++ = (JSAMPLE) c;
      		#endif
    	}
  	}
  
  	if (progress != NULL)
    	progress->completed_extra_passes++;

  	// Set up to read from the virtual array in top-to-bottom order 
  	switch (source->bits_per_pixel) {
  		case 8:
    		source->pub.get_pixel_rows = get_8bit_row;
    		break;
  		case 24:
    		source->pub.get_pixel_rows = get_24bit_row;
    		break;
  		default:
    		ERREXIT(cinfo, JERR_BMP_BADDEPTH);
  	}
  	
  	source->source_row = cinfo->image_height;

  	// And read the first row 
  	return (*source->pub.get_pixel_rows) (cinfo, sinfo);
}


//
// Read the file header; return image size and component count.
METHODDEF(void) start_input_bmp (j_compress_ptr cinfo, cjpeg_source_ptr sinfo) {
  	bmp_source_ptr source = (bmp_source_ptr) sinfo;
  	
  	U_CHAR bmpfileheader[14];
  	U_CHAR bmpinfoheader[64];
	
	#define GET_2B(array,offset)  ((unsigned int) UCH(array[offset]) + \
			       (((unsigned int) UCH(array[offset+1])) << 8))
	#define GET_4B(array,offset)  ((INT32) UCH(array[offset]) + \
			       (((INT32) UCH(array[offset+1])) << 8) + \
			       (((INT32) UCH(array[offset+2])) << 16) + \
			       (((INT32) UCH(array[offset+3])) << 24))
  
  	INT32 bfOffBits;
  	INT32 headerSize;
  	INT32 biWidth = 0;		// initialize to avoid compiler warning 
  	INT32 biHeight = 0;
  	unsigned int biPlanes;
  	INT32 biCompression;
  	INT32 biXPelsPerMeter,biYPelsPerMeter;
  	INT32 biClrUsed = 0;
  	int mapentrysize = 0;		// 0 indicates no colormap 
  	INT32 bPad;
  	JDIMENSION row_width;

  	// Read and verify the bitmap file header 
  	#ifdef NOT_USE_FILES 
  		memcpy(bmpfileheader, source->pub.buffer_in, 14);
  	#else
  		if (! ReadOK(source->pub.input_file, bmpfileheader, 14))
    		ERREXIT(cinfo, JERR_INPUT_EOF);
    #endif
  	
  	if (GET_2B(bmpfileheader,0) != 0x4D42) // 'BM' 
    	ERREXIT(cinfo, JERR_BMP_NOT);
  	
  	bfOffBits = (INT32) GET_4B(bmpfileheader,10);
  	// We ignore the remaining fileheader fields 

  	// The infoheader might be 12 bytes (OS/2 1.x), 40 bytes (Windows),
  	// or 64 bytes (OS/2 2.x).  Check the first 4 bytes to find out which.
  	#ifdef NOT_USE_FILES 
  		memcpy(bmpinfoheader, source->pub.buffer_in+14, 4);
  	#else
  		if (! ReadOK(source->pub.input_file, bmpinfoheader, 4))
    		ERREXIT(cinfo, JERR_INPUT_EOF);
    #endif
  	
  	headerSize = (INT32) GET_4B(bmpinfoheader,0);
  
  	if (headerSize < 12 || headerSize > 64)
    	ERREXIT(cinfo, JERR_BMP_BADHEADER);
  
  	#ifdef NOT_USE_FILES 
  		memcpy(bmpinfoheader+4, source->pub.buffer_in+18, headerSize-4);
  	#else
  		if (! ReadOK(source->pub.input_file, bmpinfoheader+4, headerSize-4))
    		ERREXIT(cinfo, JERR_INPUT_EOF);
    #endif

  	switch ((int) headerSize) {
  	case 12:
    	// Decode OS/2 1.x header (Microsoft calls this a BITMAPCOREHEADER) 
    	biWidth = (INT32) GET_2B(bmpinfoheader,4);
    	biHeight = (INT32) GET_2B(bmpinfoheader,6);
    	biPlanes = GET_2B(bmpinfoheader,8);
    	source->bits_per_pixel = (int) GET_2B(bmpinfoheader,10);

    	switch (source->bits_per_pixel) {
    	case 8:			// colormapped image 
      		mapentrysize = 3;		// OS/2 uses RGBTRIPLE colormap 
      		TRACEMS2(cinfo, 1, JTRC_BMP_OS2_MAPPED, (int) biWidth, (int) biHeight);
      		break;
    	case 24:			// RGB image 
      		TRACEMS2(cinfo, 1, JTRC_BMP_OS2, (int) biWidth, (int) biHeight);
      		break;
    	default:
      		ERREXIT(cinfo, JERR_BMP_BADDEPTH);
      		break;
    	}
    	
    	if (biPlanes != 1)
      		ERREXIT(cinfo, JERR_BMP_BADPLANES);
    	
    	break;
  	case 40:
  	case 64:
    	// Decode Windows 3.x header (Microsoft calls this a BITMAPINFOHEADER) 
    	// or OS/2 2.x header, which has additional fields that we ignore 
    	biWidth = GET_4B(bmpinfoheader,4);
    	biHeight = GET_4B(bmpinfoheader,8);
    	biPlanes = GET_2B(bmpinfoheader,12);
    	source->bits_per_pixel = (int) GET_2B(bmpinfoheader,14);
    	biCompression = GET_4B(bmpinfoheader,16);
    	biXPelsPerMeter = GET_4B(bmpinfoheader,24);
    	biYPelsPerMeter = GET_4B(bmpinfoheader,28);
    	biClrUsed = GET_4B(bmpinfoheader,32);
    	// biSizeImage, biClrImportant fields are ignored 

	    switch (source->bits_per_pixel) {
    	case 8:			// colormapped image 
      		mapentrysize = 4;		// Windows uses RGBQUAD colormap 
      		TRACEMS2(cinfo, 1, JTRC_BMP_MAPPED, (int) biWidth, (int) biHeight);
      		break;
    	case 24:			// RGB image 
      		TRACEMS2(cinfo, 1, JTRC_BMP, (int) biWidth, (int) biHeight);
      		break;
    	default:
      		ERREXIT(cinfo, JERR_BMP_BADDEPTH);
      		break;
    	}
    	
    	if (biPlanes != 1)
      		ERREXIT(cinfo, JERR_BMP_BADPLANES);
    	if (biCompression != 0)
      		ERREXIT(cinfo, JERR_BMP_COMPRESSED);

    	if (biXPelsPerMeter > 0 && biYPelsPerMeter > 0) {
      	// Set JFIF density parameters from the BMP data 
      		cinfo->X_density = (UINT16) (biXPelsPerMeter/100); // 100 cm per meter 
      		cinfo->Y_density = (UINT16) (biYPelsPerMeter/100);
      		cinfo->density_unit = 2;	// dots/cm 
    	}
    	break;
  	default:
    	ERREXIT(cinfo, JERR_BMP_BADHEADER);
    	break;
  	}

  	// Compute distance to bitmap data --- will adjust for colormap below 
  	bPad = bfOffBits - (headerSize + 14);

  	// Read the colormap, if any 
  	if (mapentrysize > 0) {
    	if (biClrUsed <= 0)
      		biClrUsed = 256;		// assume it's 256 
    	else if (biClrUsed > 256)
      		ERREXIT(cinfo, JERR_BMP_BADCMAP);
    	
    	// Allocate space to store the colormap 
    	source->colormap = 	(*cinfo->mem->alloc_sarray) 
    						((j_common_ptr) cinfo, JPOOL_IMAGE,
       						(JDIMENSION) biClrUsed, (JDIMENSION) 3);
    	// and read it from the file 
    	read_colormap(source, (int) biClrUsed, mapentrysize);
    	// account for size of colormap 
    	bPad -= biClrUsed * mapentrysize;
  	}

  	// Skip any remaining pad bytes 
  	if (bPad < 0)			// incorrect bfOffBits value? 
    	ERREXIT(cinfo, JERR_BMP_BADHEADER);
  	while (--bPad >= 0) {
    	(void) read_byte(source);
  	}

  	// Compute row width in file, including padding to 4-byte boundary 
  	if (source->bits_per_pixel == 24)
    	row_width = (JDIMENSION) (biWidth * 3);
  	else
    	row_width = (JDIMENSION) biWidth;
  	
  	while ((row_width & 3) != 0) row_width++;
  	source->row_width = row_width;

  	// Allocate space for inversion array, prepare for preload pass 
  	source->whole_image = 	(*cinfo->mem->request_virt_sarray)
    						((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
     						row_width, (JDIMENSION) biHeight, (JDIMENSION) 1);
  	source->pub.get_pixel_rows = preload_image;
  	
  	if (cinfo->progress != NULL) {
    	cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
    	progress->total_extra_passes++; // count file input as separate pass 
  	}

  	// Allocate one-row buffer for returned data 
  	source->pub.buffer = 	(*cinfo->mem->alloc_sarray)
    						((j_common_ptr) cinfo, JPOOL_IMAGE,
     						(JDIMENSION) (biWidth * 3), (JDIMENSION) 1);
  	
  	#ifdef NOT_USE_FILES 
  		//source->pub.header_size = bfOffBits;
		source->pub.buffer_in_index = bfOffBits;
	#endif
  	
  	source->pub.buffer_height = 1;
  	cinfo->in_color_space = JCS_RGB;
  	cinfo->input_components = 3;
  	cinfo->data_precision = 8;
  	cinfo->image_width = (JDIMENSION) biWidth;
  	cinfo->image_height = (JDIMENSION) biHeight;
}


//
// Finish up at the end of the file.
 

METHODDEF(void) finish_input_bmp (j_compress_ptr cinfo, cjpeg_source_ptr sinfo) {
  // no work 
}


//
// The module selection routine for BMP format input.
 

GLOBAL(cjpeg_source_ptr) jinit_read_bmp (j_compress_ptr cinfo) {
  	bmp_source_ptr source;

  	// ALOCA RAM PARA A INTERFACE
  	source = 	(bmp_source_ptr)
      			(*cinfo->mem->alloc_small) 
      			((j_common_ptr) cinfo, JPOOL_IMAGE, SIZEOF(bmp_source_struct));
  	source->cinfo = cinfo;							// Guarda o link de retorno para a subrotina
  	
  	// PREENCHE OS PONTEIROS DAS FUNÇÃO PAA CHAMADA DO INICIO E FIM DA COMPATAÇÃO
  	source->pub.start_input = start_input_bmp;		// Ponteiro da função que inicializa o tratamento de leitura bmp
  	source->pub.finish_input = finish_input_bmp;	// Ponteiro da função que finaliza o tratamento de leitura bmp

  	return (cjpeg_source_ptr) source;				// Retorna endereço da fonte de imagem
}

#endif // BMP_SUPPORTED 
