// -*- mode: c++; c-set-style: "stroustrup"; tab-width: 4; -*-
//
// CReaderPFM.c
//
// Copyright (C) 2004 Koji Nakamaru
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2, or (at your option)
// any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation,
// Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//

#include "common.h"
#include "CReaderPFM.h"

static const char *_magic[] = {
	"PF",
	"Pf",
	NULL,
};

// public functions

CReaderPFM::CReaderPFM()
: CReader(),
  _is_color(true),
  _is_swapped(false)
{
	magic = _magic;
}

CReaderPFM::~CReaderPFM()
{
}

bool CReaderPFM::initialize(
	CFile *fp,
	char *magic)
{
	_is_color = (strcmp(magic, _magic[0]) == 0);
	char buf[256];
	if (fp->gets(buf, sizeof(buf)) == NULL
		|| buf[0] != '\n') {
		return false;
	}
	if (fp->gets(buf, sizeof(buf)) == NULL
		|| buf[strlen(buf) - 1] != '\n'
		|| sscanf(buf, "%d %d", &_w, &_h) != 2
		|| _w <= 0
		|| _h <= 0) {
		return false;
	}
	if (fp->gets(buf, sizeof(buf)) == NULL
		|| buf[strlen(buf) - 1] != '\n'
		|| sscanf(buf, "%f", &_scale) != 1
		|| _scale == 0.0f) {
		return false;
	}
	_is_swapped = (isLittleEndian() && _scale > 0.0 || ! isLittleEndian() && _scale < 0.0);
	return true;
}

void CReaderPFM::read(
	CFile *fp,
	CImage<float, 4> *image)
{
	float *data = image->pixel(0, 0);
	int c = (_is_color) ? 3 : 1;
	for (int y = 0; y < _h; y++) {
		for (int x = 0; x < _w; x += 64) {
			int n0 = min(64, _w - x);
			int n;
			float tmp[c * 64];
			if ((n = (fp->read(tmp, c * sizeof(float) * n0) / (c * sizeof(float)))) == 0) {
				return;
			}
			image->lock();
			float *tp = tmp;
			if (_is_color) {
				for (int i = 0; i < n; i++) {
					swap4(tp);
					*data++ = *tp++;
					swap4(tp);
					*data++ = *tp++;
					swap4(tp);
					*data++ = *tp++;
					*data++ = 1.0;
				}
			} else {
				for (int i = 0; i < n; i++) {
					swap4(tp);
					*data++ = *tp;
					*data++ = *tp;
					*data++ = *tp++;
					*data++ = 1.0;
				}
			}
			image->setChanged(true);
			image->unlock();
			if (n < n0) {
				return;
			}
		}
	}
}

// protected functions

void CReaderPFM::swap4(
	float *f)
{
	if (! _is_swapped)
		return;
	uint8_t *p = (uint8_t *)&f;
	swap(p[0], p[3]);
	swap(p[1], p[2]);
}

// private functions
// local functions