/* radare - LGPL - Copyright 2009-2010 pancake<nopcode.org> */

#include <r_diff.h>

R_API RDiff *r_diff_new(ut64 off_a, ut64 off_b) {

	RDiff *d = R_NEW (RDiff);

	if (d) {

		d->delta = 1;

		d->user = NULL;

		d->off_a = off_a;

		d->off_b = off_b;

	}

	return d;

}

R_API RDiff *r_diff_free(RDiff *d) {

	free (d);

	return NULL;

}

R_API int r_diff_set_callback(RDiff *d, RDiffCallback callback, void *user) {

	d->callback = callback;

	d->user = user;

	return 1;

}

R_API int r_diff_set_delta(RDiff *d, int delta) {

	d->delta = delta;

	return 1;

}

R_API int r_diff_buffers_static(RDiff *d, const ut8 *a, int la, const ut8 *b, int lb) {

	int i, len;

	int hit = 0;

	la = R_ABS(la);

	lb = R_ABS(lb);

	if (la != lb) {

	 	len = R_MIN(la, lb);

		fprintf(stderr,

			"Buffer truncated to %d bytes (%d not compared)\n",

			len, R_ABS(lb-la));

	} else len = la;

	for(i = 0; i<len; i++) {

		if (a[i]!=b[i]) {

			hit++;

		} else {

			if (hit>0) {

				struct r_diff_op_t o = {

					.a_off = d->off_a+i-hit, .a_buf = a+i-hit, .a_len = hit,

					.b_off = d->off_b+i-hit, .b_buf = b+i-hit, .b_len = hit 

				};

				d->callback (d, d->user, &o);

				hit = 0;

			}

		}

	}

	if (hit>0) {

		struct r_diff_op_t o = {

			.a_off = d->off_a+i-hit, .a_buf = a+i-hit, .a_len = hit,

			.b_off = d->off_b+i-hit, .b_buf = b+i-hit, .b_len = hit 

		};

		d->callback (d, d->user, &o);

		hit = 0;

	}

	return 0;

}

R_API int r_diff_buffers_radiff(RDiff *d, const ut8 *a, int la, const ut8 *b, int lb) {

	char *ptr, *str, buf[64];

	FILE *fd;

	char oop = 0;

	int ret, atl, btl, hit;

	ut8 at[128], bt[128];

	ut64 ooa, oob;

	hit = atl = btl = 0;

	ooa = oob = 0LL;

	oop = -1;

	r_file_dump (".a", a, la);

	r_file_dump (".b", b, lb);

	r_sys_cmd ("radiff -d .a .b | rsc uncolor > .d");

	fd = fopen (".d", "r");

	while (!feof (fd)) {

		ut64 oa, ob; // offset

		int ba, bb = 0; // byte

		char op; // operation

		oa = ob = 0LL;

		if (!fgets (buf, 63, fd))

			break;

		if (feof (fd))

			break;

		str = buf;

		ptr = strchr (buf, ' ');

		if (!ptr) continue;

		*ptr='\0';

		sscanf (str, "0x%08"PFMT64x"", &oa);

		str = r_str_ichr (ptr+1, ' ');

		if (*str!='|'&&*str!='>'&&*str!='<') {

			ptr = strchr (str, ' ');

			if (!ptr) continue;

			*ptr='\0';

			sscanf (str, "%02x", &ba);

		} else ba = 0;

		str = r_str_ichr (ptr+1, ' ');

		ptr = strchr (str, ' ');

		if (!ptr) continue;

		*ptr='\0';

		sscanf (str, "%c", &op);

		str = r_str_ichr (ptr+1, ' ');

		if (str[0]!='0' || str[1]!='x') {

			ptr = strchr(str, ' ');

			if (!ptr) continue;

			*ptr = '\0';

			sscanf (str, "%02x", &bb);

		}

		str = ptr+1;

		ptr = strchr (str, '\n');

		if (!ptr) continue;

		*ptr='\0';

		sscanf (str, "0x%08"PFMT64x"", &ob);

		if (oop == op || oop==-1) {

			if (hit == 0) {

				ooa = oa;

				oob = ob;

			}

			at[atl] = ba;

			bt[btl] = bb;

			switch (op) {

			case '|':

				atl++;

				btl++;

				break;

			case '>':

				btl++;

				break;

			case '<':

				atl++;

				break;

			}

			hit++;

		} else {

			if (hit>0) {

				struct r_diff_op_t o = {

					.a_off = ooa, .a_buf = at, .a_len = atl,

					.b_off = oob, .b_buf = bt, .b_len = btl

				};

				ret = d->callback(d, d->user, &o);

					break;

				atl = btl = 0;

				hit = 0;

				if (!ret)

					break;

			}

		}

		oop = op;

	}

	if (hit>0) {

		struct r_diff_op_t o = {

			.a_off = ooa, .a_buf = at, .a_len = atl,

			.b_off = oob, .b_buf = bt, .b_len = btl

		};

		if (!d->callback (d, d->user, &o))

			return 0;

		atl = btl = 0;

		hit = 0;

	}

	fclose(fd);

	unlink(".a");

	unlink(".b");

	unlink(".d");

	return 0;

}

R_API int r_diff_buffers(RDiff *d, const ut8 *a, ut32 la, const ut8 *b, ut32 lb) {

	if (d->delta)

		return r_diff_buffers_delta (d, a, la, b, lb);

	return r_diff_buffers_static (d, a, la, b, lb);

}

/* TODO: Move into r_util maybe? */

R_API int r_diff_buffers_distance(RDiff *d, const ut8 *a, ut32 la, const ut8 *b, ut32 lb,

		ut32 *distance, double *similarity) {

	int i, j, cost, tmin, **m;

	if (!a || !b || la < 1 || lb < 1)

		return R_FALSE;

	if ((m = malloc ((la+1) * sizeof(int*))) == NULL)

		return R_FALSE;

	for(i = 0; i <= la; i++)

		if ((m[i] = malloc ((lb+1) * sizeof(int))) == NULL)

			return R_FALSE;

	for (i = 0; i <= la; i++)

		m[i][0] = i;

	for (j = 0; j <= lb; j++)

		m[0][j] = j;

	for (i = 1; i <= la; i++) {

		for (j = 1; j <= lb; j++) {

			if (a[i-1] == b[j-1])

				cost = 0;

			else cost = 1;

			tmin = R_MIN (m[i-1][j] + 1, m[i][j-1] + 1);

			m[i][j] = R_MIN (tmin, m[i-1][j-1] + cost);

		}

	}

	if (distance != NULL)

		*distance = m[la][lb];

	if (similarity != NULL) {

		if (la == 0 || lb == 0)

			*similarity = 0;

		else

			*similarity = (double)1 - (double)(m[la][lb])/(double)(R_MAX(la, lb));

	}

	for(i = 0; i <= la; i++)

		free (m[i]);

	free (m);

	return R_TRUE;

}