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Error in File write of dat file

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ambarisha.kn ambarisha.kn is offline Offline
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Error in File write of dat file

 
0
  #1
Nov 5th, 2008
Consider d_type=POINT_LONG in the following program.
and data.Long=0xA;

In the following program i am getting correct output in constDataArea[0],constDataArea[1],constDataArea[2], constDataArea[3]
which is oxA, 0x0, 0x0, 0x0.

But not able to write the same into ambi.dat file. Some junk value is inserting in the front.
and writing 5 bytes instead of 4 bytes.
Output file(ambi.dat)is as follows
-----------------
0D 0A 00 00 00
-----------------

Expected output in dat file is
---------------
0A 00 00 00
--------------
What is the error in this code. plz give me suggestion




c Syntax (Toggle Plain Text) 
  1. char *constDataArea;
  2. const size_t BUFSIZE = 1024*1024;	
  3. constDataArea=(char *)malloc(BUFSIZE);
  4. size_t datasize=0, nextpos=0, freepos=0;
  5. for(int nv_data=0,indx=0;nv_data<nonVoltleData;nv_data++)
  6. {
  7. switch(d_type)
  8. {
  9. 	case POINT_BOOL:
  10. 			data.Bool=(char)tmpbuf[index+2+nv_data+indx];				
  11. 			fprintf(out_fp,"\nBool Data1:%x\n", data.Bool);
  12. 			datasize=1;
  13.  
  14. 			nextpos=freepos+datasize;
  15. 			memcpy(constDataArea+freepos,(char *)&data.Bool, datasize);   /*data.bool から　ConstDataArea　にコピー*/
  16. 			freepos=nextpos;
  17. 			break;
  18. 	case POINT_CHAR:
  19. 			data.Char=(char)tmpbuf[index+2+nv_data+indx];
  20. 			fprintf(out_fp,"\nChar Data1:%x\n", data.Char);
  21. 			datasize=sizeof(data.Char);
  22.  
  23. 			nextpos=freepos+datasize;
  24. 			memcpy(constDataArea+freepos,(char *)&data.Char, datasize);		/*data.Char から　ConstDataArea　にコピー*/
  25. 			freepos=nextpos;
  26. 			break;
  27. 	case POINT_SHORT:
  28. 			data.Short=(short)tmpbuf[index+2+nv_data+indx];
  29. 			fprintf(out_fp,"\nShort Data1:%x\n", data.Short);
  30. 			datasize=sizeof(data.Short);
  31.  
  32. 			if(freepos % sizeof(data.Short))
  33. 			{
  34. 				freepos+= sizeof(data.Short)-freepos % sizeof(data.Short);
  35. 			}
  36. 			nextpos = freepos + datasize;
  37. 			fprintf(out_fp,"S:ConstArea:%d\tfreepos:%d\n", constDataArea, freepos);
  38. 			memcpy(constDataArea+freepos,(char *)&data.Short,datasize);		/*data.Short から　ConstDataArea　にコピー*/
  39. 			freepos=nextpos;
  40. 			break;
  41. 	case POINT_LONG:
  42. 			data.Long=(long)tmpbuf[index+2+nv_data+indx];
  43. 			fprintf(out_fp,"\nLong Data1:%x\n", data.Long);
  44. 			datasize=sizeof(data.Long);
  45.  
  46. 			if(freepos % sizeof(data.Long))
  47. 			{
  48. 				freepos+= sizeof(data.Long)-freepos % sizeof(data.Long);
  49. 			}
  50. 			nextpos=freepos+datasize;
  51. 			memcpy(constDataArea+freepos,(char *)&data.Long, datasize);		/*data.Long から　ConstDataArea　にコピー*/
  52. 			freepos=nextpos;
  53. 			break;
  54. 	case POINT_FLOAT:
  55. 			data.Float=*(float*)&tmpbuf[index+2+nv_data+indx];
  56. 			fprintf(out_fp,"\nFloat Data1:%f\n", data.Float);
  57. 			datasize=sizeof(data.Float);
  58.  
  59. 			if(freepos % sizeof(data.Float))
  60. 			{
  61. 				freepos+= sizeof(data.Float)-freepos % sizeof(data.Float);
  62. 			}
  63. 			nextpos=freepos+datasize;
  64. 			memcpy(constDataArea+freepos,(char *)&data.Float, datasize);	/*data.Float から　ConstDataArea　にコピー*/
  65. 			freepos=nextpos;
  66. 			break;
  67. 	case POINT_DOUBLE:
  68. 			data.Double = *(double*)&tmpbuf[index+2+nv_data+indx];
  69. 			fprintf(out_fp,"\nDouble Data1:%lf(0x%0x)\n", data.Double, data.Double);
  70. 			datasize=sizeof(data.Double);
  71.  
  72. 			if(freepos % sizeof(data.Double))
  73. 			{
  74. 				freepos+= sizeof(data.Double)-freepos % sizeof(data.Double);
  75. 			}	
  76. 			nextpos=freepos+datasize;
  77. 			memcpy(constDataArea+freepos,(char *)&data.Double, datasize);	/*data.Double　から　ConstDataArea　にコピー*/
  78. 			freepos=nextpos;
  79. 			break;										
  80. 	}
  81. }
  82. FILE *f1;
  83. f1=fopen("c:\\ambi.dat", "w");
  84. fwrite(constDataArea, 1,4, f1); 	
  85. fclose(f1);
  86.  
  87. printf("\nconst area:0x%x\t0x%x\t0x%x\t0x%x\n\n",constDataArea[0],constDataArea[1],constDataArea[2], constDataArea[3]);
Last edited by ambarisha.kn; Nov 5th, 2008 at 12:59 am.
Ambarish
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ambarisha.kn ambarisha.kn is offline Offline
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Re: Error in File write of dat file

 
0
  #2
Nov 5th, 2008
Its so simple, we have to write "wb" in fwrite instead of "w" , while writing binary file.
c Syntax (Toggle Plain Text) 
  1. FILE *f1;
  2. f1=fopen("c:\\ambi.dat", "wb");
  3. fwrite(constDataArea, 1,4, f1); 	
  4. fclose(f1);


I did changes as above and i got output..
Last edited by ambarisha.kn; Nov 5th, 2008 at 10:54 pm.
Ambarish
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