#include <stdio.h>

#define	BUFFER_CAPACITY		1024 * 1024 * 25

#define INDICES_EXPECTED	32
#define INDICES_MAXIMUM		40
#define INDICES_WRITE		16

#define	PRINT_FREQUENCY		16

int		main (int argc, char* argv[])
{
	unsigned char*	bufferArray;
	unsigned long	bufferSize;
	unsigned long	indicesArray[INDICES_MAXIMUM + 1];
	unsigned long	indicesCount;
	unsigned long	indicesWrite[INDICES_WRITE] = {0, 1, 14, 7, 8, 16, 10, 12, 13, 11, 9, 25, 26, 27, 17, 18};
	FILE*			streamWriter;
	FILE*			streamReader;
	unsigned char	pipe = '|';
	unsigned long	ln;
	unsigned long	i;
	unsigned long	j;

	if (argc < 3)
	{
		printf ("usage: %s <input> <output>\n", argv[0]);

		return 0;
	}

	streamReader = fopen (argv[1], "rb");

	if (!streamReader)
	{
		fprintf (stderr, "cannot open input file \"%s\" for reading\n", argv[1]);

		return 1;
	}

	streamWriter = fopen (argv[2], "wb");

	if (!streamWriter)
	{
		fprintf (stderr, "cannot open output file \"%s\" for writing\n", argv[2]);
		fclose (streamReader);

		return 1;
	}

	bufferArray = malloc (sizeof (*bufferArray) * BUFFER_CAPACITY);
	bufferSize = 0;
	indicesArray[0] = 0;
	indicesCount = 1;
	ln = 0;

	printf ("starting process...\n");

	for (i = 0; i < bufferSize || !feof (streamReader); ++i)
	{
		// End of buffer reached: content must be shifted to the left before
		// buffer is populated with incoming data from input stream
		if (i == bufferSize)
		{
			i = bufferSize - indicesArray[0];

			memmove (bufferArray, bufferArray + indicesArray[0], i * sizeof (*bufferArray));

			bufferSize = i + fread (bufferArray + i, sizeof (*bufferArray), BUFFER_CAPACITY - i, streamReader);

			for (j = indicesCount; j--; )
				indicesArray[j] -= indicesArray[0];

			if (i >= bufferSize)
				break;
		}

		// End of item found: save starting index of the next one
		if (bufferArray[i] == '|')
		{
			if (indicesCount < INDICES_MAXIMUM)
				indicesArray[indicesCount++] = i + 1;
		}

		// End of line found: write required indices and flush list
		else if (bufferArray[i] < ' ')
		{
			if (indicesCount == INDICES_EXPECTED)
			{
				indicesArray[indicesCount] = i + 1;

				for (j = 0; j + 1 < INDICES_WRITE; ++j)
				{	
					fwrite (bufferArray + indicesArray[indicesWrite[j]], sizeof (*bufferArray), indicesArray[indicesWrite[j] + 1] - indicesArray[indicesWrite[j]] - 1, streamWriter);
					fwrite (&pipe, sizeof (*bufferArray), 1, streamWriter);
				}

				if (j < INDICES_WRITE)
					fwrite (bufferArray + indicesArray[indicesWrite[j]], sizeof (*bufferArray), indicesArray[indicesWrite[j] + 1] - indicesArray[indicesWrite[j]] - 1, streamWriter);

				if ((++ln & (((unsigned)1 << PRINT_FREQUENCY) - 1)) == 0)
					printf ("writing line %lu...\n", ln);
			}

			fwrite (bufferArray + i, sizeof (*bufferArray), 1, streamWriter);

			indicesArray[0] = i + 1;
			indicesCount = 1;
		}
	}

	if ((ln & (((unsigned)1 << PRINT_FREQUENCY) - 1)) != 0)
		printf ("writing line %lu...\n", ln);

	printf ("done.\n");

	fclose (streamWriter);
	fclose (streamReader);
	free (bufferArray);

	return 0;
}