#include <stdio.h>#include <stdlib.h>#include <assert.h>/* CP mask code *//* The original CP code was written by Hirotsuna Mizuno and is * Copyright (c) 1998 Hirotsuna Mizuno <s1041150@u-aizu.ac.jp> * * I heavily modified his code. * as for speed, this algorithm could be improved without end, * and alternative algorithms might exist that might be several orders * of magnitude faster. *//* this is faster */typedef unsigned int UI;static UI image_width;static UI image_height;static u8 *image_data;static UI transform_width;static UI transform_height;static u8 *transform_data;typedef struct  {    UI dst_x, dst_y;    int mirror;  }cp_cell;static UI cp_cells;static cp_cell *cp_trans;static int *cp_table;static UI cp_width;static UI cp_height;#define CP_CODE_MAX_LENGTH	16#define CP_CELL_SIZE		8#define CP_BPP			3#define OFFSET_X		0#define OFFSET_Y		0/* the maximum size of the transformed image in cells */#define MAX_SIZE		4#define MAX_CP_WIDTH		2048#define src_pixel(x,y,c) image_data     [((y)*image_width    +(x)) * CP_BPP + (c)]#define dst_pixel(x,y,c) transform_data [((y)*transform_width+(x)) * CP_BPP + (c)]static voidload_img (const char *name){  FILE *img;  UI image_depth;  if (image_data)    fprintf (stderr, "cannot load more than one image\n");  else    {      img = fopen (name, "rb");      if (img)	{	  if (fscanf (img, "P6 ") == EOF)	    perror ("no BINARY PPM header detected");	  else	    {	      fscanf (img, "#%*[^\012\015] ");	/* comment */	      if (fscanf (img, "%u ", &image_width) != 1)		fprintf (stderr, "unable to read image width\n");	      else		{		  fscanf (img, "#%*[^\012\015] ");	/* comment */		  if (fscanf (img, "%u ", &image_height) != 1)		    fprintf (stderr, "unable to read image height\n");		  else		    {		      fscanf (img, "#%*[^\012\015] ");	/* comment */		      if (fscanf (img, "%u%*[ \012\015] ", &image_depth) != 1)			fprintf (stderr, "unable to read image depth\n");		      else			{			  if (image_depth != 255)			    fprintf (stderr, "pixel maxval %d (!= 255) is not supported\n", image_depth);			  else			    {			      image_data = (u8 *) malloc (image_width * image_height * CP_BPP);			      if (!image_data)				fprintf (stderr, "unable to allocate memory for image\n");			      else				{				  if (fread (image_data, image_width * image_height * CP_BPP, 1, img) != 1)				    fprintf (stderr, "unable to read image data\n");				  else				    {				      /*fprintf (stderr, "read image %dx%d, %d\n", image_width, image_height, image_depth); */				      file_path[file_count++] = name;				    }				}			    }			}		    }		}	      fclose (img);	    }	}    }}/* if you are interested, the following code can detect hidden passwords * stored in CP-masked-JPEG files. *//* * sorry, the detect code was removed ;) *//*----------------------------------------------------------------------------*/static u8 cp_key[] ={0x10, 0x17, 0x13, 0x15, 0x09, 0x08, 0x0a, 0x14, 0x06, 0x05, 0x16, 0x02, 0x0d,0x03, 0x01, 0x04, 0x19, 0x0c, 0x0f, 0x0e, 0x12, 0x07, 0x0b, 0x18, 0x11, 0x1a};static cp_table_lu1[MAX_CP_WIDTH];static cp_table_lu2[MAX_CP_WIDTH];/* this is a bottleneck */static voidcp_set_pw (u8 * pw, u8 * pw_end){  u8 *cursor;  int i, j, x, y, len;  int *table;  cp_cell *trans;  len = pw_end - pw;  for (i = x = y = 0, table = cp_table, trans = cp_trans;       i < cp_cells;       i++)    {      *table++ = -1;      trans->dst_x = x;      trans->dst_y = y;      trans->mirror = 0;      trans++;      if (++x == cp_width)	{	  x = 0;	  y++;	}    }  x = cp_cells - 1;  y = len + cp_cells % len;  for (i = 0, cursor = pw; i < cp_cells; i++)    {      x = cp_key[*cursor - 'A'] + x + y;      if (++cursor == pw_end)	cursor = pw;      if (x >= cp_cells)	x -= cp_cells;      if (x >= cp_cells)	x -= cp_cells;      while (cp_table[x] != -1)	{	  ++x;	  if (x >= cp_cells)	    x = 0;	}      cp_table[x] = i;      y++;      if (++i >= cp_cells)	break;      x = cp_key[*cursor - 'A'] + x + y;      if (++cursor == pw_end)	cursor = pw;      if (x >= cp_cells)	x -= cp_cells;      if (x >= cp_cells)	x -= cp_cells;      while (cp_table[x] != -1)	{	  if (x == 0)	    x = cp_cells;	  x--;	}      cp_table[x] = i;      y++;    }  for (i = 0, j = cp_cells - 1; i < j; i++, j--)    {      cp_trans[cp_table[i]].dst_x = cp_table_lu1[j];      cp_trans[cp_table[i]].dst_y = cp_table_lu2[j];      cp_trans[cp_table[j]].dst_x = cp_table_lu1[i];      cp_trans[cp_table[j]].dst_y = cp_table_lu2[i];      if ((cp_table[i] ^ cp_table[j]) & 1)	{	  cp_trans[cp_table[i]].mirror = 1;	  cp_trans[cp_table[j]].mirror = 1;	}    }}/*----------------------------------------------------------------------------*/static voidcp_do_mask (void){  UI x, y, src_x, src_y;  UI u, v, dst_x, dst_y;  UI xx;  int rot;  cp_cell *cell = cp_trans;  for (y = 0; y < cp_height; ++y)    {      for (x = 0; x < cp_width; ++x)	{	  {	    u = cell->dst_x;	    v = cell->dst_y;	    rot = cell->mirror;	    cell++;	    dst_x = x * CP_CELL_SIZE + OFFSET_X;	    dst_y = y * CP_CELL_SIZE + OFFSET_Y;	    src_x = u * CP_CELL_SIZE + OFFSET_X;	    src_y = v * CP_CELL_SIZE + OFFSET_Y;	  }#define   COPY(sx,sy,dx,dy) do { \            u8 *s = &src_pixel (src_x + (sx), src_y + (sy), 0);	\            u8 *d = &dst_pixel (dst_x + (dx), dst_y + (dy), 0);	\            *d++ = *s++;	\            *d++ = *s++;	\            *d++ = *s++;	\	  } while(0)	  if (dst_x + CP_CELL_SIZE <= transform_width &&	      dst_y + CP_CELL_SIZE <= transform_height)	    {	      if (rot)		{		  /* this is shit */		  for (xx = CP_CELL_SIZE - 1; xx--;)		    {		      COPY (xx + 1, 0, 0, xx + 1);		      COPY (0, xx, xx, 0);		      COPY (xx, CP_CELL_SIZE - 1, CP_CELL_SIZE - 1, xx);		      COPY (CP_CELL_SIZE - 1, xx + 1, xx + 1, CP_CELL_SIZE - 1);		    }		}	      else		{		  for (xx = CP_CELL_SIZE; xx--;)		    {		      COPY (xx + 1, 0, xx + 1, 0);		      COPY (0, xx, 0, xx);		      COPY (xx, CP_CELL_SIZE - 1, xx, CP_CELL_SIZE - 1);		      COPY (CP_CELL_SIZE - 1, xx + 1, CP_CELL_SIZE - 1, xx + 1);		    }		}	    }#undef COPY	}    }//  {FILE *f=fopen("x.ppm","wb"); fprintf (f,"P6 %d %d %d ",transform_width,transform_height,255); fwrite(transform_data,transform_width*transform_height*CP_BPP,1,f); fclose(f); }}static voidcp_cleanup (void){  if (cp_table)    free (cp_table);  if (cp_trans)    free (cp_trans);}static voidinit_cpmask (void){  UI i;  assert (image_data);  cp_width = image_width / CP_CELL_SIZE;  cp_height = image_height / CP_CELL_SIZE;  cp_cells = cp_width * cp_height;  cp_table = (int *) malloc (sizeof (int) * cp_cells);  cp_trans = (cp_cell *) malloc (sizeof (cp_cell) * cp_cells);  if (cp_width > MAX_CP_WIDTH)    {      printf ("maximum image width in this version is %d\n", MAX_CP_WIDTH * CP_CELL_SIZE);      exit (1);    }  for (i = 0; i < MAX_CP_WIDTH; i++)    {      cp_table_lu1[i] = i % cp_width;      cp_table_lu2[i] = i / cp_width;    }  transform_width = image_width < CP_CELL_SIZE * MAX_SIZE ? image_width : CP_CELL_SIZE * MAX_SIZE;  transform_height = image_height < CP_CELL_SIZE * MAX_SIZE ? image_height : CP_CELL_SIZE * MAX_SIZE;  transform_data = (u8 *) malloc (transform_width * transform_height * CP_BPP);}static intcrack_cpmask (gen_func genfunc, callback_func cbfunc){  unsigned long minimum = 1 << 31;  unsigned long current;  int changed = -1;  int x, y;  do    {      if (changed >= 4 && verbosity)	printf ("checking pw %s\r", pw), fflush (stdout);      if (changed < 0)	pw_end = pw + strlen (pw);      cp_set_pw (pw, pw_end);      cp_do_mask ();#define P(x,y,c) (UI)dst_pixel((x),(y),(c))      current = 0;      for (x = CP_CELL_SIZE; x < transform_width; x += CP_CELL_SIZE)	for (y = transform_height; y--;)	  {	    current += abs (P (x - 1, y, 0) - P (x, y, 0));	    current += abs (P (x - 1, y, 1) - P (x, y, 1));	    current += abs (P (x - 1, y, 2) - P (x, y, 2));            if (current > minimum)              goto overflow;	  }      for (y = CP_CELL_SIZE; y < transform_height && current < minimum; y += CP_CELL_SIZE)	for (x = transform_width; x-- && current < minimum;)	  {	    current += abs (P (x, y - 1, 0) - P (x, y, 0));	    current += abs (P (x, y - 1, 1) - P (x, y, 1));	    current += abs (P (x, y - 1, 2) - P (x, y, 2));            if (current > minimum)              goto overflow;	  }#undef Poverflow:      if (current < minimum)	{	  char info[80];	  minimum = current + 99;	  sprintf (info, "badness %ld", current);	  if ((changed = cbfunc (pw, info)))	    return changed;	}    }  while ((changed = genfunc ()));  return 0;}