#include <stdio.h>
#include <stdint.h>

struct crash_mem_range {
        uint64_t start, end;
};

struct crash_mem {
        unsigned int max_nr_ranges;
        unsigned int nr_ranges;
        struct crash_mem_range ranges[];
};

struct crash_mem cmem = {10, 4, {{0x1000, 0x3fff}, {0x40000, 0x9ffff}, {0xf0000, 0x1ffffff}, {0x2000000, 0x20fffff}}};

int crash_exclude_mem_range(struct crash_mem *mem,
			    unsigned long long mstart, unsigned long long mend)
{
	int i, j;
	unsigned long long start, end, p_start, p_end;
	struct crash_mem_range temp_range = {0, 0};

	for (i = 0; i < mem->nr_ranges; i++) {
		start = mem->ranges[i].start;
		end = mem->ranges[i].end;
		p_start = mstart;
		p_end = mend;

		if (mstart > end || mend < start)
			continue;

		/* Truncate any area outside of range */
		if (mstart < start)
			p_start = start;
		if (mend > end)
			p_end = end;

		/* Found completely overlapping range */
		if (p_start == start && p_end == end) {
			mem->ranges[i].start = 0;
			mem->ranges[i].end = 0;
			if (i < mem->nr_ranges - 1) {
				/* Shift rest of the ranges to left */
				for (j = i; j < mem->nr_ranges - 1; j++) {
					mem->ranges[j].start =
						mem->ranges[j+1].start;
					mem->ranges[j].end =
							mem->ranges[j+1].end;
				}

                               /*
                                * Continue to check if there are another overlapping ranges
                                * from the current position because of shifting the above
                                * mem ranges.
                                */
                               i--;
                               mem->nr_ranges--;
                               continue;

			}
			mem->nr_ranges--;
			return 0;
		}

		if (p_start > start && p_end < end) {
			/* Split original range */
			mem->ranges[i].end = p_start - 1;
			temp_range.start = p_end + 1;
			temp_range.end = end;
		} else if (mstart != start)
			mem->ranges[i].end = p_start - 1;
		else
			mem->ranges[i].start = p_end + 1;
		break;
	}

	/* If a split happened, add the split to array */
	if (!temp_range.end)
		return 0;

	/* Split happened */
	if (i == mem->max_nr_ranges - 1)
		return -1;

	/* Location where new range should go */
	j = i + 1;
	if (j < mem->nr_ranges) {
		/* Move over all ranges one slot towards the end */
		for (i = mem->nr_ranges - 1; i >= j; i--)
			mem->ranges[i + 1] = mem->ranges[i];
	}

	mem->ranges[j].start = temp_range.start;
	mem->ranges[j].end = temp_range.end;
	mem->nr_ranges++;
	return 0;
}

void print_cmem(struct crash_mem *mem)
{
	int i;

	for (i = 0; i < mem->nr_ranges; i++)
		printf("%llx - %llx\n", mem->ranges[i].start, mem->ranges[i].end);
}

int main(int argc, char **argv)
{
	crash_exclude_mem_range(&cmem, 0, (1<<20) - 1);
	print_cmem(&cmem);
	return 0;
}