gistfile1.txt

mat_coo_t* create_coo_from_mmfile(const char* filename) {
	MTR_BEGIN_FUNC();
	const int BufferSize = 1024;

	FILE* fp = fopen(filename, "r");
	char line[BufferSize];

	int state = 0; //0: size, else: content
	mat_coo_t* coo;
	int itr = 0;

	enum {
		GENERAL,
		SYMMETRIC,
		SKEW,
		HERMITIAN
	} attr;

	if (fgets(line, BufferSize, fp) != NULL) {
		char object[16];
		char format[16];
		char field[16];
		char attribute[16];
		sscanf(line, "%%%%MatrixMarket %15s %15s %15s %15s", object, format, field, attribute);

		if (strcmp(object, "matrix") != 0) {
			printf("mmfile: not a matrix file(%s)\n", object);
			assert(false);
		}

		if (strcmp(format, "coordinate") != 0) {
			printf("mmfile: unsupported format(%s)\n", format);
			assert(false);
		}

		if (strcmp(field, "real") != 0) {
			printf("mmfile: unsupported field(%s)\n", field);
			assert(false);
		}

		if (strcmp(attribute, "general") == 0) {
			attr = GENERAL;
		} else if(strcmp(attribute, "symmetric") == 0) {
			attr = SYMMETRIC;
		} else {
			printf("mmfile: unsupported attribute (%s)\n", attribute);
			assert(false);
		}


	} else {
		printf("empty file\n");
		assert(false);
	}

	while (fgets(line, BufferSize, fp) != NULL) {

		if (line[0] == '%') continue;

		if (state == 0) {
			int cols;
			int rows;
			int nnz;
			sscanf(line, "%d %d %d", &cols, &rows, &nnz);

			if (attr == SYMMETRIC) {
				nnz -= cols;
				nnz *= 2;
				nnz += cols;
			}

			coo = new_mat_coo(cols, rows, nnz);

			state = 1;
		} else {
			int col;
			int row;
			double val;
			sscanf(line, "%d %d %lf", &col, &row, &val);

			coo->colind[itr] = col-1;
			coo->rowind[itr] = row-1;
			coo->data[itr] = val;
			itr++;

			if (attr == SYMMETRIC) {
				if (col != row) {
					coo->colind[itr] = row-1;
					coo->rowind[itr] = col-1;
					coo->data[itr] = val;
					itr++;
				}
			}

		}
	}


	fclose(fp);
	MTR_END_FUNC();

	return coo;
}