SplashError SplashBitmap::writePNMFile(FILE *f) {
  SplashColorPtr row, p;
  int x, y;

  switch (mode) {

  case splashModeMono1:
    fprintf(f, "P4\n%d %d\n", width, height);
    row = data;
    for (y = 0; y < height; ++y) {
      p = row;
      for (x = 0; x < width; x += 8) {
	fputc(*p ^ 0xff, f);
	++p;
      }
      row += rowSize;
    }
    break;

  case splashModeMono8:
    fprintf(f, "P5\n%d %d\n255\n", width, height);
    row = data;
    for (y = 0; y < height; ++y) {
      p = row;
      for (x = 0; x < width; ++x) {
	fputc(*p, f);
	++p;
      }
      row += rowSize;
    }
    break;

  case splashModeRGB8:
    fprintf(f, "P6\n%d %d\n255\n", width, height);
    row = data;
    for (y = 0; y < height; ++y) {
      p = row;
      for (x = 0; x < width; ++x) {
	fputc(splashRGB8R(p), f);
	fputc(splashRGB8G(p), f);
	fputc(splashRGB8B(p), f);
	p += 3;
      }
      row += rowSize;
    }
    break;

  case splashModeXBGR8:
    fprintf(f, "P6\n%d %d\n255\n", width, height);
    row = data;
    for (y = 0; y < height; ++y) {
      p = row;
      for (x = 0; x < width; ++x) {
	fputc(splashBGR8R(p), f);
	fputc(splashBGR8G(p), f);
	fputc(splashBGR8B(p), f);
	p += 4;
      }
      row += rowSize;
    }
    break;


  case splashModeBGR8:
    fprintf(f, "P6\n%d %d\n255\n", width, height);
    row = data;
    for (y = 0; y < height; ++y) {
      p = row;
      for (x = 0; x < width; ++x) {
	fputc(splashBGR8R(p), f);
	fputc(splashBGR8G(p), f);
	fputc(splashBGR8B(p), f);
	p += 3;
      }
      row += rowSize;
    }
    break;

#if SPLASH_CMYK
  case splashModeCMYK8:
    break;
#endif
  }
  return splashOk;
}

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.