Thread: Integrating

This code on running against any bitmap keeps generating a segmentation fault

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <memory.h>

typedef struct _bmp_header 
{
  char ID[2];
  int size;
  char res1[2], res2[2];
  int offset;
} bmp_header;

typedef struct _bmp_info 
{
  int size, width, height;
  int planes, BitsPerPixel;
  int compress, BMsize;
  int Hres, Vres;
  int ColorsUsed, ColorsImportant;
} bmp_info;

void load_bmp_header(FILE *BMP, bmp_header *BH);
void load_bmp_info(FILE *BMP, bmp_info *BI);

int  main(int argc, char* argv[])
{
  int i,j,i1;
  int Dflag, Cflag, BMPsize, num_colors, dup_color;
  FILE *BMPin;
  unsigned char color_map[1024];
  bmp_header BMPHead;
  bmp_info BMPInfo;

  Dflag =0;
  Cflag =0;

  if(argc<2)
  {
    fprintf(stderr, "ERROR: No bmp file\n");
    fprintf(stderr, "Usage: SDetect [-d -c] bmp_file\n");
    fprintf(stderr, "-d gives file details\n -c print out color map\n");
    exit(1);
  }

  for (i=1; i<(argc-1); i++)
  {
    if(argv[i][0] == '1')
    {
      switch (argv[i][1])
      {
    case 'h':
      printf("Usage: SDetect [-d -c] bmp_file\n");
      printf("-d gives file details\n -c prints out color map\n");
      exit(1);
      break;
    case 'c':
      Cflag =1;
      break;
    case 'd':
      Dflag =1;
      break;
    default:
      printf("ERROR: Unkown switch %s\n", argv[i]);
      printf("Usage: SDetect [-d -c] bmp_file\n");
      printf("-d gives file details\n -c prints out color map\n");
      exit(1);
      break;
      }	      
    }
  }

    BMPin = fopen(argv[argc-1], "rb");
    if (BMPin ==0)
    {
      fprintf(stderr, "**Error** Unable to open input file %s\n", argv[argc-1]);
      exit(1);
    }
    fseek(BMPin, 0, 2);
    BMPsize = ftell(BMPin);
    fseek(BMPin, 0, 0);

    load_bmp_header(BMPin, &BMPHead);
    load_bmp_info(BMPin, &BMPInfo);

    num_colors = (BMPHead.offset - 14 - BMPInfo.size)/4;
    fread(color_map, 1, BMPInfo.ColorsUsed*4, BMPin);

    dup_color = 0;
    for(i=0; i<BMPInfo.ColorsUsed; i++)
    {
      for(j=0; j<BMPInfo.ColorsUsed; j++)
      {
	i1 = abs(color_map[4*i] - color_map[4*j]) + abs(color_map[4*i+1] - color_map[4*j+1]) + abs(color_map[48*i+2] - color_map[4*j+2]);
	if((i1<4) && (i !=j)) 
	{
	  dup_color++;
	}
      }
    }

    if(Cflag) 
    {
      printf("Color Map:\n");
      for(i=0; i<BMPInfo.ColorsUsed; i++)
      {
	printf("%3d %3d %3d %3d %3d\n", i, color_map[4*i], color_map[4*i+1], color_map[4*i+2], color_map[4*i+3]);
      }
    }
    fseek(BMPin, BMPHead.offset, 0);
    printf("File Name:%s\n", argv[argc-1]);
    if(Dflag=1)
    {
      printf("Width:%d Height:%d\n",BMPInfo.width, BMPInfo.height);
      printf("BitsPerPixel:%d NumBitPlanes:%d\n", BMPInfo.BitsPerPixel, BMPInfo.planes);
      printf("Compression:%d\n", BMPInfo.compress);
      printf("ColorsUsed:%d ColorsImportant:%d\n\n", BMPInfo.ColorsUsed, BMPInfo,BMPInfo.ColorsImportant);

      printf("ActualSize:%d Reported:%d\n", BMPsize, BMPHead.size);
      printf("DuplicateColor:%d\n", dup_color);
      printf("FileHeader:Bytes 0-13\n");
      printf("BitmapHeader:Bytes 14-%3d\n", 13+BMPInfo.size);
      printf("ColorMap:Bytes %3d-%3d\n", 14+BMPInfo.size, 13+BMPInfo.size+4*BMPInfo.ColorsUsed);
      printf("ImageData:Bytes %3d-%3d\n\n", BMPHead.offset, BMPHead.offset-1+(BMPInfo.width*BMPInfo.height,BMPInfo.BitsPerPixel+7)/8);
    }
    if (dup_color<100)
    {
      printf("Data has not been hidden in this file with STools\n");
    }
    if (dup_color>100)
    {
      printf("*** Data has been hidden in this file useing STools ***\n");
      printf("\n\n");
    }
      fclose(BMPin);
  }

   
  void load_bmp_header(FILE *BMP, bmp_header *BH)
  {
    unsigned char buffer[16];

    memset(BH, 0, sizeof(bmp_header));
    fread(buffer, 1, 14, BMP);

    memcpy(BH->ID, buffer, 2);
      if((BH->ID[0] !='B') || (BH->ID[1] !='M'))
      {
	printf("Error: Bad File ID -not a BMP file");
	exit(1);
      }
    memcpy(&(BH->size), buffer+2, 4);
    memcpy(&(BH->size), buffer+6, 2);
    memcpy(&(BH->size), buffer+8, 2);
    memcpy(&(BH->size), buffer+10, 4);
  }

  void load_bmp_info(FILE *BMP, bmp_info *BI)
  {
    unsigned char buffer[112];
    
    memset(BI, 0 , sizeof(bmp_info));
    fread(buffer, 1, 108,BMP);
    
    memcpy(&(BI->size), buffer, 4);
    if((BI->size !=40) && (BI->size !=108)) 
    {
      printf("BitmapInfo header size is %d - cannot handle this format\n",BI->size);
      exit(1);
    }

    if(BI->size ==40) 
    {
      fseek(BMP, -68, 1);
    }

    memcpy(&(BI->width), buffer+4, 4);
    memcpy(&(BI->height), buffer+8, 4);
    BI->planes=buffer[12]+256*buffer[13];
    BI->BitsPerPixel=buffer[14]+256*buffer[15];


    memcpy(&(BI->compress), buffer+16, 4);
    memcpy(&(BI->BMsize), buffer+20, 4);
    memcpy(&(BI->Hres), buffer+24, 4);
    memcpy(&(BI->Vres), buffer+28, 4);
    memcpy(&(BI->ColorsUsed), buffer+32, 4);
    memcpy(&(BI->ColorsImportant), buffer+36, 4);

    if(BI->ColorsUsed ==0){
      BI->ColorsUsed = 1<< BI->BitsPerPixel;
    }
  }

Code:

if ( Dflag=1 )

Do you want == instead?

Code:

printf("ColorsUsed:%d ColorsImportant:%d\n\n", BMPInfo.ColorsUsed, /*BMPInfo,*/BMPInfo.ColorsImportant);

Typo?

Code:

printf("ImageData:Bytes %3d-%3d\n\n", BMPHead.offset, BMPHead.offset-1+(BMPInfo.width*BMPInfo.height,BMPInfo.BitsPerPixel+7)/8);

What is the comma there for?