/* radare - LGPL - Copyright 2010-2022 - pancake, nibble */

#include <r_anal.h>
#include <r_util.h>
#include <r_list.h>
#include <limits.h>

typedef struct {
	ut64 addr;
	RAnalBlock *ret;
} BBFromOffsetJmpmidCtx;

static bool bb_from_offset_jmpmid_cb(RAnalBlock *bb, void *user) {
	BBFromOffsetJmpmidCtx *ctx = user;
	// If an instruction starts exactly at the search addr, return that basicblock immediately
	if (r_anal_block_op_starts_at (bb, ctx->addr)) {
		ctx->ret = bb;
		return false;
	}
	// else search the closest one
	if (!ctx->ret || ctx->ret->addr < bb->addr) {
		ctx->ret = bb;
	}
	return true;
}

static bool bb_from_offset_first_cb(RAnalBlock *bb, void *user) {
	RAnalBlock **ret = user;
	*ret = bb;
	return false;
}

R_API RAnalBlock *r_anal_bb_from_offset(RAnal *anal, ut64 off) {
	R_RETURN_VAL_IF_FAIL (anal, NULL);
	if (anal->opt.jmpmid && r_anal_is_aligned (anal, off)) {
		BBFromOffsetJmpmidCtx ctx = { off, NULL };
		r_anal_blocks_foreach_in (anal, off, bb_from_offset_jmpmid_cb, &ctx);
		return ctx.ret;
	}

	RAnalBlock *ret = NULL;
	r_anal_blocks_foreach_in (anal, off, bb_from_offset_first_cb, &ret);
	return ret;
}

/* returns the offset of the i-th instruction in the basicblock bb.
 * If the index of the instruction is not valid, it returns UT16_MAX */
R_API ut16 r_anal_bb_offset_inst(const RAnalBlock *bb, int i) {
	R_RETURN_VAL_IF_FAIL (bb, UT16_MAX);
	if (i < 0 || i >= bb->ninstr) {
		return UT16_MAX;
	}
	return (i > 0 && (i - 1) < bb->op_pos_size)? bb->op_pos[i - 1]: 0;
}

/* returns the address of the i-th instruction in the basicblock bb.
 * If the index of the instruction is not valid, it returns UT64_MAX */
R_API ut64 r_anal_bb_opaddr_i(RAnalBlock *bb, int i) {
	R_RETURN_VAL_IF_FAIL (bb, UT64_MAX);
	ut16 offset = r_anal_bb_offset_inst (bb, i);
	if (offset == UT16_MAX) {
		return UT64_MAX;
	}
	return bb->addr + offset;
}

/* set the offset of the i-th instruction in the basicblock bb */
R_API bool r_anal_bb_set_offset(RAnalBlock *bb, int i, ut16 v) {
	R_RETURN_VAL_IF_FAIL (bb, false);
	// callers add or move an instruction of bb with this: the calls its functions counted are stale
	RAnalFunction *fcn;
	RListIter *iter;
	r_list_foreach (bb->fcns, iter, fcn) {
		fcn->meta.numcallrefs = -1;
	}
	// the offset 0 of the instruction 0 is not stored because always 0
	if (i > 0 && v > 0) {
		if (i >= bb->op_pos_size) {
			int new_pos_size = i * 2;
			if (new_pos_size >= UT16_MAX) {
				R_LOG_WARN ("Basic block at 0x%08"PFMT64x" is too large", bb->addr);
				return false;
			}
			ut16 *tmp_op_pos = realloc (bb->op_pos, new_pos_size * sizeof (*bb->op_pos));
			if (!tmp_op_pos) {
				return false;
			}
			bb->op_pos = tmp_op_pos;
#if 0
			// initialize the uninitialized
			// not necessary because its catched earlier when ut16max limit is reached
			for (i = bb->op_pos_size; i < new_pos_size; i++) {
				bb->op_pos[i] = 0;
			}
#endif
			bb->op_pos_size = new_pos_size;
		}
		bb->op_pos[i - 1] = v;
		return true;
	}
	return true;
}

/* returns the address of the instruction that occupies a given offset.
 * If the offset is not part of the given basicblock, UT64_MAX is returned. */
R_API ut64 r_anal_bb_opaddr_at(RAnalBlock *bb, ut64 off) {
	R_RETURN_VAL_IF_FAIL (bb, UT64_MAX);
	ut16 delta, delta_off, last_delta;
	int i;

	if (!r_anal_block_contains (bb, off)) {
		return UT64_MAX;
	}
	last_delta = 0;
	delta_off = off - bb->addr;
	for (i = 0; i < bb->ninstr; i++) {
		delta = r_anal_bb_offset_inst (bb, i);
		if (delta > delta_off) {
			return bb->addr + last_delta;
		}
		last_delta = delta;
	}
	return bb->addr + last_delta;
}

// returns the size of the i-th instruction in a basicblock
R_API ut64 r_anal_bb_size_i(RAnalBlock *bb, int i) {
	R_RETURN_VAL_IF_FAIL (bb, UT64_MAX);
	if (i < 0 || i >= bb->ninstr) {
		return UT64_MAX;
	}
	ut16 idx_cur = r_anal_bb_offset_inst (bb, i);
	ut16 idx_next = r_anal_bb_offset_inst (bb, i + 1);
	return idx_next != UT16_MAX? idx_next - idx_cur: bb->size - idx_cur;
}

/* returns the address of the basicblock that contains addr or UT64_MAX if
 * there is no such basic block */
R_API ut64 r_anal_get_bbaddr(RAnal *anal, ut64 addr) {
	R_RETURN_VAL_IF_FAIL (anal, UT64_MAX);
	RAnalBlock *bb = r_anal_bb_from_offset (anal, addr);
	return bb? bb->addr: UT64_MAX;
}