/* ybmtopbm.c - read a file from Bennet Yee's 'xbm' program and write a pbm.

**

** Written by Jamie Zawinski based on code (C) 1988 by Jef Poskanzer.

**

** Permission to use, copy, modify, and distribute this software and its

** documentation for any purpose and without fee is hereby granted, provided

** that the above copyright notice appear in all copies and that both that

** copyright notice and this permission notice appear in supporting

** documentation.  This software is provided "as is" without express or

** implied warranty.

*/

#include "pm.h"

#include "pbm.h"

#include "bitreverse.h"

static short const ybmMagic = ( ( '!' << 8 ) | '!' );

static void

getinit(FILE *  const ifP,

        short * const colsP,

        short * const rowsP,

        short * const depthP) {

    short magic;

    int rc;

    rc = pm_readbigshort(ifP, &magic);

    if (rc == -1)

        pm_error("EOF / read error");

    if (magic != ybmMagic)

        pm_error("bad magic number in YBM file");

    rc = pm_readbigshort(ifP, colsP);

    if (rc == -1 )

        pm_error("EOF / read error");

    rc = pm_readbigshort(ifP, rowsP);

    if (rc == -1)

        pm_error("EOF / read error");

    *depthP = 1;

}

int

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

    FILE * ifP;

    bit * bitrow;

    short rows, cols;

    unsigned int row;

    short depth;

    const char * inputFile;

    pm_proginit(&argc, argv);

    if (argc-1 < 1)

        inputFile = "-";

    else {

        inputFile = argv[1];

        if (argc-1 > 1)

            pm_error("Too many arguments.  The only argument is the optional "

                     "input file name");

    }

    ifP = pm_openr(inputFile);

    getinit(ifP, &cols, &rows, &depth);

    if (depth != 1)

        pm_error("YBM file has depth of %u, must be 1", (unsigned)depth);

    pbm_writepbminit(stdout, cols, rows, 0);

    bitrow = pbm_allocrow_packed(cols + 8);

    for (row = 0; row < rows; ++row) {

        uint16_t *   const itemrow = (uint16_t *) bitrow;

        unsigned int const itemCt  = (cols + 15) / 16;

        unsigned int i;

        /* Get raster. */

        for (i = 0; i < itemCt; ++i) {

            short int item;

            pm_readbigshort(ifP, &item);

            itemrow[i] = (uint16_t) item; 

        }

        for (i = 0; i < pbm_packed_bytes(cols); ++i)

            bitrow[i] = bitreverse[bitrow[i]];

        pbm_cleanrowend_packed(bitrow, cols);

        pbm_writepbmrow_packed(stdout, bitrow, cols, 0);

    }

    pbm_freerow_packed(bitrow);

    pm_close(ifP);

    pm_close(stdout);

    return 0;

}