/*
 * wrtarga.c
 *
 * This file was part of the Independent JPEG Group's software:
 * Copyright (C) 1991-1996, Thomas G. Lane.
 * It was modified by The libjpeg-turbo Project to include only code and
 * information relevant to libjpeg-turbo.
 * For conditions of distribution and use, see the accompanying README.ijg
 * file.
 *
 * This file contains routines to write output images in Targa format.
 *
 * These routines may need modification for non-Unix environments or
 * specialized applications.  As they stand, they assume output to
 * an ordinary stdio stream.
 *
 * Based on code contributed by Lee Daniel Crocker.
 */

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

#ifdef TARGA_SUPPORTED


/*
 * To support 12-bit JPEG data, we'd have to scale output down to 8 bits.
 * This is not yet implemented.
 */

#if BITS_IN_JSAMPLE != 8
  Sorry, this code only copes with 8-bit JSAMPLEs. /* deliberate syntax err */
#endif


/* Private version of data destination object */

typedef struct {
  struct djpeg_dest_struct pub; /* public fields */

  char *iobuffer;               /* physical I/O buffer */
  JDIMENSION buffer_width;      /* width of one row */
} tga_dest_struct;

typedef tga_dest_struct *tga_dest_ptr;


LOCAL(void)
write_header (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, int num_colors)
/* Create and write a Targa header */
{
  char targaheader[18];

  /* Set unused fields of header to 0 */
  MEMZERO(targaheader, sizeof(targaheader));

  if (num_colors > 0) {
	targaheader[1] = 1;         /* color map type 1 */
	targaheader[5] = (char) (num_colors & 0xFF);
	targaheader[6] = (char) (num_colors >> 8);
	targaheader[7] = 24;        /* 24 bits per cmap entry */
  }

  targaheader[12] = (char) (cinfo->output_width & 0xFF);
  targaheader[13] = (char) (cinfo->output_width >> 8);
  targaheader[14] = (char) (cinfo->output_height & 0xFF);
  targaheader[15] = (char) (cinfo->output_height >> 8);
  targaheader[17] = 0x20;       /* Top-down, non-interlaced */

  if (cinfo->out_color_space == JCS_GRAYSCALE) {
	targaheader[2] = 3;         /* image type = uncompressed grayscale */
	targaheader[16] = 8;        /* bits per pixel */
  } else {                      /* must be RGB */
	if (num_colors > 0) {
	  targaheader[2] = 1;       /* image type = colormapped RGB */
	  targaheader[16] = 8;
	} else {
	  targaheader[2] = 2;       /* image type = uncompressed RGB */
	  targaheader[16] = 24;
	}
  }

  if (JFWRITE(dinfo->output_file, targaheader, 18) != (size_t) 18)
	ERREXIT(cinfo, JERR_FILE_WRITE);
}


/*
 * Write some pixel data.
 * In this module rows_supplied will always be 1.
 */

METHODDEF(void)
put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
				JDIMENSION rows_supplied)
/* used for unquantized full-color output */
{
  tga_dest_ptr dest = (tga_dest_ptr) dinfo;
  register JSAMPROW inptr;
  register char *outptr;
  register JDIMENSION col;

  inptr = dest->pub.buffer[0];
  outptr = dest->iobuffer;
  for (col = cinfo->output_width; col > 0; col--) {
	outptr[0] = (char) GETJSAMPLE(inptr[2]); /* RGB to BGR order */
	outptr[1] = (char) GETJSAMPLE(inptr[1]);
	outptr[2] = (char) GETJSAMPLE(inptr[0]);
	inptr += 3, outptr += 3;
  }
  (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
}

METHODDEF(void)
put_gray_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
			   JDIMENSION rows_supplied)
/* used for grayscale OR quantized color output */
{
  tga_dest_ptr dest = (tga_dest_ptr) dinfo;
  register JSAMPROW inptr;
  register char *outptr;
  register JDIMENSION col;

  inptr = dest->pub.buffer[0];
  outptr = dest->iobuffer;
  for (col = cinfo->output_width; col > 0; col--) {
	*outptr++ = (char) GETJSAMPLE(*inptr++);
  }
  (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
}


/*
 * Write some demapped pixel data when color quantization is in effect.
 * For Targa, this is only applied to grayscale data.
 */

METHODDEF(void)
put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
				   JDIMENSION rows_supplied)
{
  tga_dest_ptr dest = (tga_dest_ptr) dinfo;
  register JSAMPROW inptr;
  register char *outptr;
  register JSAMPROW color_map0 = cinfo->colormap[0];
  register JDIMENSION col;

  inptr = dest->pub.buffer[0];
  outptr = dest->iobuffer;
  for (col = cinfo->output_width; col > 0; col--) {
	*outptr++ = (char) GETJSAMPLE(color_map0[GETJSAMPLE(*inptr++)]);
  }
  (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
}


/*
 * Startup: write the file header.
 */

METHODDEF(void)
start_output_tga (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
{
  tga_dest_ptr dest = (tga_dest_ptr) dinfo;
  int num_colors, i;
  FILE *outfile;

  if (cinfo->out_color_space == JCS_GRAYSCALE) {
	/* Targa doesn't have a mapped grayscale format, so we will */
	/* demap quantized gray output.  Never emit a colormap. */
	write_header(cinfo, dinfo, 0);
	if (cinfo->quantize_colors)
	  dest->pub.put_pixel_rows = put_demapped_gray;
	else
	  dest->pub.put_pixel_rows = put_gray_rows;
  } else if (cinfo->out_color_space == JCS_RGB) {
	if (cinfo->quantize_colors) {
	  /* We only support 8-bit colormap indexes, so only 256 colors */
	  num_colors = cinfo->actual_number_of_colors;
	  if (num_colors > 256)
		ERREXIT1(cinfo, JERR_TOO_MANY_COLORS, num_colors);
	  write_header(cinfo, dinfo, num_colors);
	  /* Write the colormap.  Note Targa uses BGR byte order */
	  outfile = dest->pub.output_file;
	  for (i = 0; i < num_colors; i++) {
		putc(GETJSAMPLE(cinfo->colormap[2][i]), outfile);
		putc(GETJSAMPLE(cinfo->colormap[1][i]), outfile);
		putc(GETJSAMPLE(cinfo->colormap[0][i]), outfile);
	  }
	  dest->pub.put_pixel_rows = put_gray_rows;
	} else {
	  write_header(cinfo, dinfo, 0);
	  dest->pub.put_pixel_rows = put_pixel_rows;
	}
  } else {
	ERREXIT(cinfo, JERR_TGA_COLORSPACE);
  }
}


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

METHODDEF(void)
finish_output_tga (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
{
  /* Make sure we wrote the output file OK */
  fflush(dinfo->output_file);
  if (ferror(dinfo->output_file))
	ERREXIT(cinfo, JERR_FILE_WRITE);
}


/*
 * The module selection routine for Targa format output.
 */

GLOBAL(djpeg_dest_ptr)
jinit_write_targa (j_decompress_ptr cinfo)
{
  tga_dest_ptr dest;

  /* Create module interface object, fill in method pointers */
  dest = (tga_dest_ptr)
	  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
								  sizeof(tga_dest_struct));
  dest->pub.start_output = start_output_tga;
  dest->pub.finish_output = finish_output_tga;

  /* Calculate output image dimensions so we can allocate space */
  jpeg_calc_output_dimensions(cinfo);

  /* Create I/O buffer. */
  dest->buffer_width = cinfo->output_width * cinfo->output_components;
  dest->iobuffer = (char *)
	(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
								(size_t) (dest->buffer_width * sizeof(char)));

  /* Create decompressor output buffer. */
  dest->pub.buffer = (*cinfo->mem->alloc_sarray)
	((j_common_ptr) cinfo, JPOOL_IMAGE, dest->buffer_width, (JDIMENSION) 1);
  dest->pub.buffer_height = 1;

  return (djpeg_dest_ptr) dest;
}

#endif /* TARGA_SUPPORTED */
