/*=============================================================================

                            pamdepth

===============================================================================

  Change the maxval in a Netpbm image.

  This replaces Pnmdepth.

  By Bryan Henderson January 2006.

  Contributed to the public domain by its author.

=============================================================================*/

#include <assert.h>

#include "pm_c_util.h"

#include "mallocvar.h"

#include "shhopt.h"

#include "pam.h"

struct cmdlineInfo {

    /* All the information the user supplied in the command line,

       in a form easy for the program to use.

    */

    const char * inputFileName;

    unsigned int newMaxval;

    unsigned int verbose;

};

static void

parseCommandLine(int argc, const char ** argv,

                 struct cmdlineInfo *cmdlineP) {

/*----------------------------------------------------------------------------

   Note that the file spec strings we return are stored in the storage that

   was passed to us as the argv array.

-----------------------------------------------------------------------------*/

    optEntry * option_def;

        /* Instructions to pm_optParseOptions3 on how to parse our options.

         */

    optStruct3 opt;

    unsigned int option_def_index;

    MALLOCARRAY_NOFAIL(option_def, 100);

    option_def_index = 0;   /* incremented by OPTENTRY */

    OPTENT3(0, "verbose",  OPT_STRING, NULL, 

            &cmdlineP->verbose, 0);

    opt.opt_table = option_def;

    opt.short_allowed = FALSE;  /* We have no short (old-fashioned) options */

    opt.allowNegNum = FALSE;  /* We may have parms that are negative numbers */

    pm_optParseOptions3(&argc, (char **)argv, opt, sizeof(opt), 0);

        /* Uses and sets argc, argv, and some of *cmdlineP and others. */

    if (argc-1 < 1)

        pm_error("You must specify at least one argument -- the new maxval");

    else {

        int const intval = atoi(argv[1]);

        if (intval < 1)

            pm_error("New maxval must be at least 1.  You specified %d",

                     intval);

        else if (intval > PNM_OVERALLMAXVAL)

            pm_error("newmaxval (%d) is too large.\n"

                     "The maximum allowed by the PNM formats is %d.",

                     intval, PNM_OVERALLMAXVAL);

        else

            cmdlineP->newMaxval = intval;

        if (argc-1 < 2)

            cmdlineP->inputFileName = "-";

        else

            cmdlineP->inputFileName = argv[2];

    }

}

static void

createSampleMap(sample   const oldMaxval,

                sample   const newMaxval,

                sample** const sampleMapP) {

    unsigned int i;

    sample * sampleMap;

    MALLOCARRAY_NOFAIL(sampleMap, oldMaxval+1);

    for (i = 0; i <= oldMaxval; ++i)

        sampleMap[i] = ROUNDDIV(i * newMaxval, oldMaxval);

    *sampleMapP = sampleMap;

}

static void

transformRaster(struct pam * const inpamP,

                struct pam * const outpamP) {

    tuple * tuplerow;

    unsigned int row;

    sample * sampleMap;  /* malloc'ed */

    createSampleMap(inpamP->maxval, outpamP->maxval, &sampleMap);

    assert(inpamP->height == outpamP->height);

    assert(inpamP->width  == outpamP->width);

    assert(inpamP->depth  == outpamP->depth);

    tuplerow = pnm_allocpamrow(inpamP);

    for (row = 0; row < inpamP->height; ++row) {

        unsigned int col;

        pnm_readpamrow(inpamP, tuplerow);

        for (col = 0; col < inpamP->width; ++col) {

            unsigned int plane;

            for (plane = 0; plane < inpamP->depth; ++plane)

                tuplerow[col][plane] = sampleMap[tuplerow[col][plane]];

        }

        pnm_writepamrow(outpamP, tuplerow);

	}

    pnm_freepamrow(tuplerow);

    free(sampleMap);

}

int

main(int argc, const char * argv[]) {

    struct cmdlineInfo cmdline;

    FILE * ifP;

    struct pam inpam;

    struct pam outpam;

    int eof;

    pm_proginit(&argc, argv);

    parseCommandLine(argc, argv, &cmdline);

    ifP = pm_openr(cmdline.inputFileName);

    eof = FALSE;

    while (!eof) {

        pnm_readpaminit(ifP, &inpam, PAM_STRUCT_SIZE(tuple_type));

        outpam = inpam;  /* initial value */

        outpam.file = stdout;

        outpam.maxval = cmdline.newMaxval;

        if (PNM_FORMAT_TYPE(inpam.format) == PBM_TYPE) {

            pm_message( "promoting from PBM to PGM" );

            outpam.format = PGM_TYPE;

        } else

            outpam.format = inpam.format;

        pnm_writepaminit(&outpam);

        transformRaster(&inpam, &outpam);

        pnm_nextimage(ifP, &eof;;

    }

    pm_close(ifP);

    pm_close(stdout);

    return 0;

}