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/*=============================================================================
pamshuffle
===============================================================================
Part of the Netpbm package.
Relocate pixels in row, randomly, using Fisher-Yates shuffling.
By Akira F. Urushibata
Contributed to the public domain by its author.
=============================================================================*/
#include <assert.h>
#include "pm_c_util.h"
#include "pam.h"
#include "rand.h"
#include "shhopt.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 column;
unsigned int randomseedSpec;
unsigned int randomseed;
};
static void
parseCommandLine(int argc, const char ** const argv,
struct CmdlineInfo * const cmdlineP) {
/*----------------------------------------------------------------------------
Note that the file spec array we return is stored in the storage that
was passed to us as the argv array.
-----------------------------------------------------------------------------*/
optEntry * option_def;
/* Instructions to OptParseOptions3 on how to parse our options. */
optStruct3 opt;
unsigned int option_def_index;
MALLOCARRAY(option_def, 100);
opt.opt_table = option_def;
opt.short_allowed = false; /* We have no short (old-fashioned) options */
opt.allowNegNum = true; /* We have no parms that are negative numbers */
option_def_index = 0; /* incremented by OPTENT3 */
OPTENT3(0, "column", OPT_FLAG, NULL,
&cmdlineP->column, 0);
OPTENT3(0, "randomseed", OPT_UINT, &cmdlineP->randomseed,
&cmdlineP->randomseedSpec, 0);
pm_optParseOptions3(&argc, (char **)argv, opt, sizeof(opt), 0);
/* Uses and sets argc, argv, and some of *cmdlineP and others. */
free(option_def);
if (argc-1 > 1)
pm_error("Too many arguments (%u). "
"The only possible argument is the input file name.", argc-1);
else if (argc-1 < 1)
cmdlineP->inputFileName = "-";
else
cmdlineP->inputFileName = argv[1];
}
static void
shuffleRow(tuple * const tuplerow,
unsigned int const cols,
struct pm_randSt * const randStP) {
unsigned int col;
for (col = 0; col + 1 < cols; ++col) {
tuple const temp = tuplerow[col];
unsigned int const randcol = col + pm_rand(randStP) % (cols - col);
assert(randcol >= col );
assert(randcol < cols);
/* swap */
tuplerow[col] = tuplerow[randcol];
tuplerow[randcol] = temp;
}
}
int
main(int argc, const char * argv[]) {
FILE * ifP;
int eof; /* no more images in input stream */
struct CmdlineInfo cmdline;
struct pam inpam; /* Input PAM image */
struct pam outpam; /* Output PAM image */
struct pm_randSt randSt;
pm_proginit(&argc, argv);
parseCommandLine(argc, argv, &cmdline);
ifP = pm_openr(cmdline.inputFileName);
pm_randinit(&randSt);
pm_srand2(&randSt, cmdline.randomseedSpec, cmdline.randomseed);
for (eof = FALSE; !eof;) {
tuple * inrow; /* Input row buffer */
tuple * outrow; /* Pointers into the input row buffer to reorder it */
unsigned int row, col;
pnm_readpaminit(ifP, &inpam, PAM_STRUCT_SIZE(tuple_type));
outpam = inpam;
outpam.file = stdout;
pnm_writepaminit(&outpam);
inrow = pnm_allocpamrow(&inpam);
MALLOCARRAY(outrow, inpam.width);
if (!outrow)
pm_error("Unable to allocate memory for %u-column output buffer",
inpam.width);
for (col = 0; col < inpam.width; ++col)
outrow[col] = inrow[col];
for (row = 0; row < inpam.height; ++row) {
pnm_readpamrow(&inpam, inrow);
if (cmdline.column && row > 0) {
/* Use the same shuffle ('outrow') as the previous row */
} else
shuffleRow(outrow, inpam.width, &randSt);
pnm_writepamrow(&outpam, outrow);
}
pnm_freepamrow(inrow);
free(outrow);
pnm_nextimage(ifP, &eof);
}
pm_randterm(&randSt);
return 0;
}
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