Reading from a file?

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Socoder -> C/C++/C#/Other -> Reading from a file?
Fri, 27 Jul 2007, 07:41
spinal	I am trying to convert some blitz code to C, and I'm not getting very far. The code is supposed to read a 32bit int from a specific part of a .nds file header, then read the icon data starting at the location in the file the first number points to. here is the blitz, working just fine. ndsfile=ReadFile(CommandLine$()) Dim filearray(2112) iconlocation=$068 SeekFile(ndsfile,$068) offset=ReadInt(ndsfile) Print offset SeekFile(ndsfile,offset+832) ; t+832 = english title Repeat filearray(t)=ReadByte(ndsfile) t=t+1 Until Eof(ndsfile) Or t=255 x=0: y=4 For t=0 To 255 Step 2 ;title is padded to 128 char or 256 bytes b1=filearray(t) b2=filearray(t+1) temp= makeint(0,0,b2,b1,0) If temp=10 Then x=0 y=y+1 Else If temp<>0 Then Text x10,y13, Chr$(temp) x=x+1 If x>=41 Then x=0 y=y+1 End If End If Next ; Try to read the palette Dim palette(16) SeekFile(ndsfile,offset+544) ; t+544 = icon palette t=0 Repeat filearray(t)=ReadByte(ndsfile) t=t+1 Until Eof(ndsfile) Or t=32 ;Graphics 640,480,1,0 For t=0 To 15 b1=filearray(t2) b2=filearray(t2+1) temp= makeint(0,0,b2,b1,0) palette(t)= temp r=(temp And $1f)Shl 3 g=((temp Shr 5) And $1f)Shl 3 b=((temp Shr 10) And $1f)Shl 3 ; Color r,g,b ; Rect t8,0,7,7,1 Next ;icon data ;Dim picture(512) t=0 SeekFile(ndsfile,offset+32) ; t+32 = icon pixels (4bit) Repeat filearray(t)=ReadByte(ndsfile) t=t+1 Until Eof(ndsfile) Or t=512 CloseFile ndsfile ; we dont need the file open anymore t=0: x1=0:y1=0 x=0:y=0 For yy=0 To 3 For xx=0 To 3 x=0:y=0 While y<8 c2=palette((filearray(t) Shr 4) And $f) ; first 4 bits c1=palette(filearray(t) And $f) ; second 4 bits t=t+1 ; convert To r,g,b for plotting r1=(c1 And $1f)Shl 3 g1=((c1 Shr 5) And $1f)Shl 3 b1=((c1 Shr 10) And $1f)Shl 3 r2=(c2 And $1f)Shl 3 g2=((c2 Shr 5) And $1f)Shl 3 b2=((c2 Shr 10) And $1f)Shl 3 ;Plot Color r1,g1,b1 Plot (xx8)+x,yy8+y+20 Color r2,g2,b2 Plot (xx8)+x+1,yy8+y+20 x=x+2 If x>=8 Then x=0:y=y+1 Wend Next Next WaitKey() End ; convert 4 8bit numbers to a single 32bit int Function MakeInt( b1,b2,b3,b4,Reverse=0 ) If Reverse=0 Then Return ( b1 Shl 24 )+( b2 Shl 16 )+( b3 Shl 8 )+( b4 ) If Reverse=1 Then Return ( b4 Shl 24 )+( b3 Shl 16 )+( b2 Shl 8 )+( b1 ) End Function --v here is the start of the C void readheader(const char filename) { // int offset=0x068; //0x068 FILE* testRead = fopen (filename, "r"); //rb = read u8 filetext[4]={0,0,0,0}; // 32bit int? (4 bytes) fseek(testRead,0x068,SEEK_SET); fread(&filetext, sizeof(filetext), 4, testRead); fclose(testRead); // Replace PA_OutputText() with whatever text output you like/use PA_OutputText(0,1,1, "%d", filetext[1]); PA_OutputText(0,1,2, "%d", filetext[2]); PA_OutputText(0,1,3, "%d", filetext[3]); PA_OutputText(0,1,4, "%d", filetext[4]); PA_OutputText(0,1,5, "%d", makeint(filetext[1],filetext[2],filetext[3],filetext[4],0)); } int makeint(int b1, int b2, int b3, int b4, int reversed) { if(reversed) { return (b1<<24)+(b2<<16)+(b3<<8)+b4; } else { return (b4<<24)+(b3<<16)+(b2<<8)+b1; } } --v However my first number seems to be different, although it should be the same (reading from the same location 0x068) in both codes. Any help? -=-=- Check out my excellent homepage!
Sat, 28 Jul 2007, 23:34
Evil Roy Ferguso	I'm not familiar with your PA library or your u8 data type, but C arrays are 0-based, not 1-based, so the indices in an array with four elements are 0, 1, 2, 3, and not 1, 2, 3, 4 as you are using. That alone may not be enough to solve your problem but it ought to be a start.