Hello, I have completed PSET 4 and passed check50 (at least, for the less comfortable version). However, I somehow have a memory leak of 11 bytes that I cannot diagnose. My complete code is here: For convenience, the relevant section (i.e. where I am using malloc) is below:
// iterate over infile's scanlines
for (int i = 0, biHeight = abs(bi.biHeight); i < biHeight; i++)
{
//allocate memory to store each line
RGBTRIPLE *lineBuffer = malloc(bi.biWidth * sizeof(RGBTRIPLE));
//check to make sure there is enough memory
if (lineBuffer == NULL)
{
fprintf(stderr, "Not enough memory to store a scanline \n");
exit(1);
}
//READ SCANLINE
// iterate over pixels in scanline
for (int j = 0; j < bi.biWidth; j++)
{
// temporary storage
RGBTRIPLE triple;
// read RGB triple from infile
fread(&triple, sizeof(RGBTRIPLE), 1, inptr);
// SAVE EACH PIXEL TO ALLOC MEMORY
(lineBuffer + j)->rgbtRed = triple.rgbtRed;
(lineBuffer + j)->rgbtGreen = triple.rgbtGreen;
(lineBuffer + j)->rgbtBlue = triple.rgbtBlue;
}
// skip over padding, if any
fseek(inptr, padding, SEEK_CUR);
// write the pixels to the outfile, adjusting for scaling
for (int m = 0; m < scaleFactor; m++)
{
writeLine(lineBuffer, outptr, scaleFactor, bi.biWidth, newPadding);
}
// free memory
free(lineBuffer);
}
And here is the the function writeLine
void writeLine(RGBTRIPLE *line, FILE *dest, long scalingFactor, LONG
width, int pad)
{
//PURPOSE: write each scanline to a new file, accounting for a given
scaling factor
// determine padding for scanlines (output file)
for (int i = 0; i < width; i++)
{
for (int j = 0; j < scalingFactor; j++)
{
fwrite(line + i, sizeof(RGBTRIPLE), 1, dest);
}
}
for (int k = 0; k < pad; k++)
{
fputc(0x00, dest);
}
}
My result from running valgrind resize 1 small.bmp large.bmp
- ==6217== HEAP SUMMARY:
- ==6217== in use at exit: 11 bytes in 1 blocks
- ==6217== total heap usage: 1 allocs, 0 frees, 11 bytes allocated
- ==6217==
- ==6217== 11 bytes in 1 blocks are definitely lost in loss record 1 of 1
- ==6217== at 0x4C2AB80: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
- ==6217== by 0x401D3E: ??? (in /usr/bin/resize)
- ==6217== by 0x400F9C: ??? (in /usr/bin/resize)
- ==6217== by 0x4E58F44: (below main) (libc-start.c:287)
- ==6217==
- ==6217== LEAK SUMMARY:
- ==6217== definitely lost: 11 bytes in 1 blocks
- ==6217== indirectly lost: 0 bytes in 0 blocks
- ==6217== possibly lost: 0 bytes in 0 blocks
- ==6217== still reachable: 0 bytes in 0 blocks
- ==6217== suppressed: 0 bytes in 0 blocks
- ==6217==
- ==6217== For counts of detected and suppressed errors, rerun with: -v
- ==6217== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
What I don't understand is that no matter the size of the input bmp (and varying bmp widths), my leakage is a constant 11 bytes. The error also persists if I implement the lineBuffer as an RGBTRIPLE array, instead of a struct pointer.
I'm relatively new to C, so it's possible that I'm missing something obvious. Any help is appreciated. Thank you!
