skyline.c

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// SPDX-FileCopyrightText: 2020 GustavoLCR <gugulcr@gmail.com>
// SPDX-License-Identifier: LGPL-3.0-only
 
#include <rz_skyline.h>
 
#define CMP_BEGIN_GTE_PART(addr, part) \
    (((addr) > (rz_itv_begin(((RzSkylineItem *)(part))->itv))) - ((addr) < (rz_itv_begin(((RzSkylineItem *)(part))->itv))))
 
#define CMP_END_GTE_PART(addr, part) \
    (((addr) < (rz_itv_end(((RzSkylineItem *)(part))->itv)) || !rz_itv_end(((RzSkylineItem *)(part))->itv)) ? -1 : 1)
 
RZ_API bool rz_skyline_add(RzSkyline *skyline, RzInterval itv, void *user) {
    rz_return_val_if_fail(skyline, false);
    if (rz_itv_size(itv)) {
        // Allow intervals whose end overflows to 0, but block if it overflows past that
        rz_return_val_if_fail(!UT64_ADD_OVFCHK(rz_itv_begin(itv), rz_itv_size(itv) - 1), false);
    }
    RzVector *skyline_vec = &skyline->v;
    RzSkylineItem new_part = { itv, user };
    const ut64 new_part_end = rz_itv_end(new_part.itv);
 
    // `slot` is the index of the first RzSkylineItem with part->itv.addr >= new_part.itv.addr
    size_t slot;
    rz_vector_lower_bound(skyline_vec, new_part.itv.addr, slot, CMP_BEGIN_GTE_PART);
    const bool is_last = slot == rz_vector_len(skyline_vec);
    bool is_inside_prev_part = false;
    if (slot) {
        RzSkylineItem *prev_part = rz_vector_index_ptr(skyline_vec, slot - 1);
        const ut64 prev_part_end = rz_itv_end(prev_part->itv);
        if (prev_part_end > rz_itv_begin(new_part.itv)) {
            prev_part->itv.size = rz_itv_begin(new_part.itv) - rz_itv_begin(prev_part->itv);
            if (prev_part_end > new_part_end) {
                RzSkylineItem tail;
                tail.user = prev_part->user;
                tail.itv.addr = new_part_end;
                tail.itv.size = prev_part_end - rz_itv_begin(tail.itv);
                rz_vector_insert(skyline_vec, slot, &tail);
                is_inside_prev_part = true;
            }
        }
    }
    if (!is_last && !is_inside_prev_part) {
        RzSkylineItem *part = rz_vector_index_ptr(skyline_vec, slot);
        while (part && rz_itv_include(new_part.itv, part->itv)) {
            // Remove `part` that fits in `new_part`
            rz_vector_remove_at(skyline_vec, slot, NULL);
            part = slot < rz_vector_len(skyline_vec) ? rz_vector_index_ptr(skyline_vec, slot) : NULL;
        }
        if (part && rz_itv_overlap(new_part.itv, part->itv)) {
            // Chop start of last `part` that intersects `new_part`
            const ut64 oaddr = rz_itv_begin(part->itv);
            part->itv.addr = new_part_end;
            part->itv.size -= rz_itv_begin(part->itv) - oaddr;
        }
    }
    rz_vector_insert(skyline_vec, slot, &new_part);
    return true;
}
 
RZ_API const RzSkylineItem *rz_skyline_get_item_intersect(RzSkyline *skyline, ut64 addr, ut64 len) {
    if (!len) {
        return NULL;
    }
    rz_return_val_if_fail(skyline, NULL);
    rz_return_val_if_fail(!UT64_ADD_OVFCHK(addr, len - 1), NULL);
    RzVector *skyline_vec = &skyline->v;
    size_t i, l = rz_vector_len(skyline_vec);
    rz_vector_lower_bound(skyline_vec, addr, i, CMP_END_GTE_PART);
    if (i == l) {
        return false;
    }
    const RzSkylineItem *item = rz_vector_index_ptr(skyline_vec, i);
    const ut64 intersect_end = addr + len;
    return !intersect_end || (item->itv.addr < addr + len) ? item : NULL;
}