/*
 * Copyright (c) 1999-2000 Image Power, Inc. and the University of
 *   British Columbia.
 * Copyright (c) 2001-2002 Michael David Adams.
 * All rights reserved.
 */

/* __START_OF_JASPER_LICENSE__
 *
 * JasPer License Version 2.0
 *
 * Copyright (c) 2001-2006 Michael David Adams
 * Copyright (c) 1999-2000 Image Power, Inc.
 * Copyright (c) 1999-2000 The University of British Columbia
 *
 * All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person (the
 * "User") 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, 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:
 *
 * 1.  The above copyright notices and this permission notice (which
 * includes the disclaimer below) shall be included in all copies or
 * substantial portions of the Software.
 *
 * 2.  The name of a copyright holder shall not be used to endorse or
 * promote products derived from the Software without specific prior
 * written permission.
 *
 * THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS
 * LICENSE.  NO USE OF THE SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER
 * THIS DISCLAIMER.  THE SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS
 * "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 OF THIRD PARTY RIGHTS.  IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL
 * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING
 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.  NO ASSURANCES ARE
 * PROVIDED BY THE COPYRIGHT HOLDERS THAT THE SOFTWARE DOES NOT INFRINGE
 * THE PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS OF ANY OTHER ENTITY.
 * EACH COPYRIGHT HOLDER DISCLAIMS ANY LIABILITY TO THE USER FOR CLAIMS
 * BROUGHT BY ANY OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL
 * PROPERTY RIGHTS OR OTHERWISE.  AS A CONDITION TO EXERCISING THE RIGHTS
 * GRANTED HEREUNDER, EACH USER HEREBY ASSUMES SOLE RESPONSIBILITY TO SECURE
 * ANY OTHER INTELLECTUAL PROPERTY RIGHTS NEEDED, IF ANY.  THE SOFTWARE
 * IS NOT FAULT-TOLERANT AND IS NOT INTENDED FOR USE IN MISSION-CRITICAL
 * SYSTEMS, SUCH AS THOSE USED IN THE OPERATION OF NUCLEAR FACILITIES,
 * AIRCRAFT NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL
 * SYSTEMS, DIRECT LIFE SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH
 * THE FAILURE OF THE SOFTWARE OR SYSTEM COULD LEAD DIRECTLY TO DEATH,
 * PERSONAL INJURY, OR SEVERE PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH
 * RISK ACTIVITIES").  THE COPYRIGHT HOLDERS SPECIFICALLY DISCLAIM ANY
 * EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR HIGH RISK ACTIVITIES.
 *
 * __END_OF_JASPER_LICENSE__
 */

/*
 * Portable Pixmap/Graymap Format Support
 *
 * $Id$
 */

/******************************************************************************\
* Includes.
\******************************************************************************/

#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>

#include "jasper/jas_math.h"

#include "pnm_cod.h"

/******************************************************************************\
* Miscellaneous utilities.
\******************************************************************************/

/* Determine the PNM type (i.e., PGM or PPM) from the magic number. */
int pnm_type(uint_fast16_t magic)
{
    int type;
    switch (magic) {
    case PNM_MAGIC_TXTPPM:
    case PNM_MAGIC_BINPPM:
        type = PNM_TYPE_PPM;
        break;
    case PNM_MAGIC_TXTPGM:
    case PNM_MAGIC_BINPGM:
        type = PNM_TYPE_PGM;
        break;
    case PNM_MAGIC_TXTPBM:
    case PNM_MAGIC_BINPBM:
        type = PNM_TYPE_PBM;
        break;
    default:
        /* This should not happen. */
        abort();
        break;
    }
    return type;
}

/* Determine the PNM format (i.e., text or binary) from the magic number. */
int pnm_fmt(uint_fast16_t magic)
{
    int fmt;
    switch (magic) {
    case PNM_MAGIC_TXTPBM:
    case PNM_MAGIC_TXTPGM:
    case PNM_MAGIC_TXTPPM:
        fmt = PNM_FMT_TXT;
        break;
    case PNM_MAGIC_BINPBM:
    case PNM_MAGIC_BINPGM:
    case PNM_MAGIC_BINPPM:
        fmt = PNM_FMT_BIN;
        break;
    default:
        /* This should not happen. */
        abort();
        break;
    }
    return fmt;
}

/* Determine the depth (i.e., precision) from the maximum value. */
int pnm_maxvaltodepth(uint_fast32_t maxval)
{
    int n;

    n = 0;
    while (maxval > 0) {
        maxval >>= 1;
        ++n;
    }
    return n;
}