/* cmuwmtopbm.c - read a CMU window manager bitmap and produce a PBM image.

**

** Copyright (C) 1989 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.

*/

/* 2006.10 (afu)

   Changed bitrow from plain to raw, read function from getc() to fread(),

   write function from pbm_writepbmrow() to pbm_writepbmrow_packed().

   Retired bitwise transformation functions.

   This program does not check the pad bits at the end of each row.

*/

#include "pbm.h"

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

  CMUWN Header format:

  32 bit const magic = 0xf10040bb ;

  32 bit int   width;

  32 bit int   height;

  16 bit int   depth;

  values are big-endian.

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

static void

readCmuwmHeader(FILE *         const ifP,

                unsigned int * const colsP,

                unsigned int * const rowsP,

                unsigned int * const depthP) {

    const char * const initReadError =

        "CMU window manager header EOF / read error";

    uint32_t const cmuwmMagic = 0xf10040bb;

    long l;

    short s;

    int rc;

    rc = pm_readbiglong(ifP, &l);

    if (rc == -1 )

        pm_error("%s", initReadError);

    if ((uint32_t)l != cmuwmMagic)

        pm_error("bad magic number in CMU window manager file");

    rc = pm_readbiglong(ifP, &l);

    if (rc == -1)

        pm_error("%s", initReadError);

    *colsP = l;

    rc = pm_readbiglong(ifP, &l);

    if (rc == -1 )

        pm_error("%s", initReadError);

    *rowsP = l;

    rc = pm_readbigshort(ifP, &s);

    if (rc == -1)

        pm_error("%s", initReadError);

    *depthP = s;

}

int

main(int           argc,

     const char ** argv) {

    FILE * ifP;

    unsigned char * bitrow;

    unsigned int rows, cols, depth;

    unsigned int row;

    const char * inputFileName;

    pm_proginit(&argc, argv);

    if (argc-1 > 1)

        pm_error("Too many arguments (%u).  "

                 "Only argument is optional input file", argc-1);

    if (argc-1 == 1)

        inputFileName = argv[1];

    else

        inputFileName = "-";

    ifP = pm_openr(inputFileName);

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

    if (depth != 1)

        pm_error("CMU window manager file has depth of %u, must be 1", depth);

    pbm_writepbminit(stdout, cols, rows, 0);

    bitrow = pbm_allocrow_packed(cols);

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

        unsigned int const bytesPerRow = pbm_packed_bytes(cols);

        unsigned int byteSeq;

        size_t bytesRead;

        bytesRead = fread(bitrow, 1, bytesPerRow, ifP);

        if (bytesRead != bytesPerRow)

            pm_error("CWU window manager bitmap EOF / read error");

        /* Invert all bits in row - raster formats are similar.

           CMUWM Black:0 White:1  End of row padded with 1

           PBM   Black:1 White:0  End preferably padded with 0

        */

        for (byteSeq = 0; byteSeq < bytesPerRow; ++byteSeq)

            bitrow[byteSeq] = ~bitrow[byteSeq];

        pbm_writepbmrow_packed(stdout, bitrow, cols, 0);

    }

    pbm_freerow_packed(bitrow);

    pm_close(ifP);

    pm_close(stdout);

    return 0;

}