path: root/contrib/libs/croaring/src/containers/run.c

#include <stdio.h>
#include <stdlib.h>

#include <roaring/containers/run.h>
#include <roaring/portability.h>
#include <roaring/memory.h>

#if CROARING_IS_X64
#ifndef CROARING_COMPILER_SUPPORTS_AVX512
#error "CROARING_COMPILER_SUPPORTS_AVX512 needs to be defined."
#endif // CROARING_COMPILER_SUPPORTS_AVX512
#endif

#ifdef __cplusplus
extern "C" { namespace roaring { namespace internal {
#endif

extern inline uint16_t run_container_minimum(const run_container_t *run);
extern inline uint16_t run_container_maximum(const run_container_t *run);
extern inline int32_t interleavedBinarySearch(const rle16_t *array,
                                              int32_t lenarray, uint16_t ikey);
extern inline bool run_container_contains(const run_container_t *run,
                                          uint16_t pos);
extern inline int run_container_index_equalorlarger(const run_container_t *arr, uint16_t x);
extern inline bool run_container_is_full(const run_container_t *run);
extern inline bool run_container_nonzero_cardinality(const run_container_t *rc);
extern inline int32_t run_container_serialized_size_in_bytes(int32_t num_runs);
extern inline run_container_t *run_container_create_range(uint32_t start,
                                                   uint32_t stop);
extern inline int run_container_cardinality(const run_container_t *run);


bool run_container_add(run_container_t *run, uint16_t pos) {
    int32_t index = interleavedBinarySearch(run->runs, run->n_runs, pos);
    if (index >= 0) return false;  // already there
    index = -index - 2;            // points to preceding value, possibly -1
    if (index >= 0) {              // possible match
        int32_t offset = pos - run->runs[index].value;
        int32_t le = run->runs[index].length;
        if (offset <= le) return false;  // already there
        if (offset == le + 1) {
            // we may need to fuse
            if (index + 1 < run->n_runs) {
                if (run->runs[index + 1].value == pos + 1) {
                    // indeed fusion is needed
                    run->runs[index].length = run->runs[index + 1].value +
                                              run->runs[index + 1].length -
                                              run->runs[index].value;
                    recoverRoomAtIndex(run, (uint16_t)(index + 1));
                    return true;
                }
            }
            run->runs[index].length++;
            return true;
        }
        if (index + 1 < run->n_runs) {
            // we may need to fuse
            if (run->runs[index + 1].value == pos + 1) {
                // indeed fusion is needed
                run->runs[index + 1].value = pos;
                run->runs[index + 1].length = run->runs[index + 1].length + 1;
                return true;
            }
        }
    }
    if (index == -1) {
        // we may need to extend the first run
        if (0 < run->n_runs) {
            if (run->runs[0].value == pos + 1) {
                run->runs[0].length++;
                run->runs[0].value--;
                return true;
            }
        }
    }
    makeRoomAtIndex(run, (uint16_t)(index + 1));
    run->runs[index + 1].value = pos;
    run->runs[index + 1].length = 0;
    return true;
}

/* Create a new run container. Return NULL in case of failure. */
run_container_t *run_container_create_given_capacity(int32_t size) {
    run_container_t *run;
    /* Allocate the run container itself. */
    if ((run = (run_container_t *)roaring_malloc(sizeof(run_container_t))) == NULL) {
        return NULL;
    }
    if (size <= 0 ) { // we don't want to rely on malloc(0)
        run->runs = NULL;
    } else if ((run->runs = (rle16_t *)roaring_malloc(sizeof(rle16_t) * size)) == NULL) {
        roaring_free(run);
        return NULL;
    }
    run->capacity = size;
    run->n_runs = 0;
    return run;
}

int run_container_shrink_to_fit(run_container_t *src) {
    if (src->n_runs == src->capacity) return 0;  // nothing to do
    int savings = src->capacity - src->n_runs;
    src->capacity = src->n_runs;
    rle16_t *oldruns = src->runs;
    src->runs = (rle16_t *)roaring_realloc(oldruns, src->capacity * sizeof(rle16_t));
    if (src->runs == NULL) roaring_free(oldruns);  // should never happen?
    return savings;
}
/* Create a new run container. Return NULL in case of failure. */
run_container_t *run_container_create(void) {
    return run_container_create_given_capacity(RUN_DEFAULT_INIT_SIZE);
}

run_container_t *run_container_clone(const run_container_t *src) {
    run_container_t *run = run_container_create_given_capacity(src->capacity);
    if (run == NULL) return NULL;
    run->capacity = src->capacity;
    run->n_runs = src->n_runs;
    memcpy(run->runs, src->runs, src->n_runs * sizeof(rle16_t));
    return run;
}

void run_container_offset(const run_container_t *c,
                          container_t **loc, container_t **hic,
                          uint16_t offset) {
    run_container_t *lo = NULL, *hi = NULL;

    bool split;
    int lo_cap, hi_cap;
    int top, pivot;

    top = (1 << 16) - offset;
    pivot = run_container_index_equalorlarger(c, top);

    if (pivot == -1) {
        split = false;
        lo_cap = c->n_runs;
        hi_cap = 0;
    } else {
        split = c->runs[pivot].value < top;
        lo_cap = pivot + (split ? 1 : 0);
        hi_cap = c->n_runs - pivot;
    }

    if (loc && lo_cap) {
        lo = run_container_create_given_capacity(lo_cap);
        memcpy(lo->runs, c->runs, lo_cap*sizeof(rle16_t));
        lo->n_runs = lo_cap;
        for (int i = 0; i < lo_cap; ++i) {
            lo->runs[i].value += offset;
        }
        *loc = (container_t*)lo;
    }

    if (hic && hi_cap) {
        hi = run_container_create_given_capacity(hi_cap);
        memcpy(hi->runs, c->runs+pivot, hi_cap*sizeof(rle16_t));
        hi->n_runs = hi_cap;
        for (int i = 0; i < hi_cap; ++i) {
            hi->runs[i].value += offset;
        }
        *hic = (container_t*)hi;
    }

    // Fix the split.
    if (split) {
        if (lo != NULL) {
            // Add the missing run to 'lo', exhausting length.
            lo->runs[lo->n_runs-1].length = (1 << 16) - lo->runs[lo->n_runs-1].value - 1;
        }

        if (hi != NULL) {
            // Fix the first run in 'hi'.
            hi->runs[0].length -= UINT16_MAX - hi->runs[0].value + 1;
            hi->runs[0].value = 0;
        }
    }
}

/* Free memory. */
void run_container_free(run_container_t *run) {
    if(run->runs != NULL) {// Jon Strabala reports that some tools complain otherwise
      roaring_free(run->runs);
      run->runs = NULL;  // pedantic
    }
    roaring_free(run);
}

void run_container_grow(run_container_t *run, int32_t min, bool copy) {
    int32_t newCapacity =
        (run->capacity == 0)
            ? RUN_DEFAULT_INIT_SIZE
            : run->capacity < 64 ? run->capacity * 2
                                 : run->capacity < 1024 ? run->capacity * 3 / 2
                                                        : run->capacity * 5 / 4;
    if (newCapacity < min) newCapacity = min;
    run->capacity = newCapacity;
    assert(run->capacity >= min);
    if (copy) {
        rle16_t *oldruns = run->runs;
        run->runs =
            (rle16_t *)roaring_realloc(oldruns, run->capacity * sizeof(rle16_t));
        if (run->runs == NULL) roaring_free(oldruns);
    } else {
        // Jon Strabala reports that some tools complain otherwise
        if (run->runs != NULL) {
          roaring_free(run->runs);
        }
        run->runs = (rle16_t *)roaring_malloc(run->capacity * sizeof(rle16_t));
    }
    // We may have run->runs == NULL.
}

/* copy one container into another */
void run_container_copy(const run_container_t *src, run_container_t *dst) {
    const int32_t n_runs = src->n_runs;
    if (src->n_runs > dst->capacity) {
        run_container_grow(dst, n_runs, false);
    }
    dst->n_runs = n_runs;
    memcpy(dst->runs, src->runs, sizeof(rle16_t) * n_runs);
}

/* Compute the union of `src_1' and `src_2' and write the result to `dst'
 * It is assumed that `dst' is distinct from both `src_1' and `src_2'. */
void run_container_union(const run_container_t *src_1,
                         const run_container_t *src_2, run_container_t *dst) {
    // TODO: this could be a lot more efficient

    // we start out with inexpensive checks
    const bool if1 = run_container_is_full(src_1);
    const bool if2 = run_container_is_full(src_2);
    if (if1 || if2) {
        if (if1) {
            run_container_copy(src_1, dst);
            return;
        }
        if (if2) {
            run_container_copy(src_2, dst);
            return;
        }
    }
    const int32_t neededcapacity = src_1->n_runs + src_2->n_runs;
    if (dst->capacity < neededcapacity)
        run_container_grow(dst, neededcapacity, false);
    dst->n_runs = 0;
    int32_t rlepos = 0;
    int32_t xrlepos = 0;

    rle16_t previousrle;
    if (src_1->runs[rlepos].value <= src_2->runs[xrlepos].value) {
        previousrle = run_container_append_first(dst, src_1->runs[rlepos]);
        rlepos++;
    } else {
        previousrle = run_container_append_first(dst, src_2->runs[xrlepos]);
        xrlepos++;
    }

    while ((xrlepos < src_2->n_runs) && (rlepos < src_1->n_runs)) {
        rle16_t newrl;
        if (src_1->runs[rlepos].value <= src_2->runs[xrlepos].value) {
            newrl = src_1->runs[rlepos];
            rlepos++;
        } else {
            newrl = src_2->runs[xrlepos];
            xrlepos++;
        }
        run_container_append(dst, newrl, &previousrle);
    }
    while (xrlepos < src_2->n_runs) {
        run_container_append(dst, src_2->runs[xrlepos], &previousrle);
        xrlepos++;
    }
    while (rlepos < src_1->n_runs) {
        run_container_append(dst, src_1->runs[rlepos], &previousrle);
        rlepos++;
    }
}

/* Compute the union of `src_1' and `src_2' and write the result to `src_1'
 */
void run_container_union_inplace(run_container_t *src_1,
                                 const run_container_t *src_2) {
    // TODO: this could be a lot more efficient

    // we start out with inexpensive checks
    const bool if1 = run_container_is_full(src_1);
    const bool if2 = run_container_is_full(src_2);
    if (if1 || if2) {
        if (if1) {
            return;
        }
        if (if2) {
            run_container_copy(src_2, src_1);
            return;
        }
    }
    // we move the data to the end of the current array
    const int32_t maxoutput = src_1->n_runs + src_2->n_runs;
    const int32_t neededcapacity = maxoutput + src_1->n_runs;
    if (src_1->capacity < neededcapacity)
        run_container_grow(src_1, neededcapacity, true);
    memmove(src_1->runs + maxoutput, src_1->runs,
            src_1->n_runs * sizeof(rle16_t));
    rle16_t *inputsrc1 = src_1->runs + maxoutput;
    const int32_t input1nruns = src_1->n_runs;
    src_1->n_runs = 0;
    int32_t rlepos = 0;
    int32_t xrlepos = 0;

    rle16_t previousrle;
    if (inputsrc1[rlepos].value <= src_2->runs[xrlepos].value) {
        previousrle = run_container_append_first(src_1, inputsrc1[rlepos]);
        rlepos++;
    } else {
        previousrle = run_container_append_first(src_1, src_2->runs[xrlepos]);
        xrlepos++;
    }
    while ((xrlepos < src_2->n_runs) && (rlepos < input1nruns)) {
        rle16_t newrl;
        if (inputsrc1[rlepos].value <= src_2->runs[xrlepos].value) {
            newrl = inputsrc1[rlepos];
            rlepos++;
        } else {
            newrl = src_2->runs[xrlepos];
            xrlepos++;
        }
        run_container_append(src_1, newrl, &previousrle);
    }
    while (xrlepos < src_2->n_runs) {
        run_container_append(src_1, src_2->runs[xrlepos], &previousrle);
        xrlepos++;
    }
    while (rlepos < input1nruns) {
        run_container_append(src_1, inputsrc1[rlepos], &previousrle);
        rlepos++;
    }
}

/* Compute the symmetric difference of `src_1' and `src_2' and write the result
 * to `dst'
 * It is assumed that `dst' is distinct from both `src_1' and `src_2'. */
void run_container_xor(const run_container_t *src_1,
                       const run_container_t *src_2, run_container_t *dst) {
    // don't bother to convert xor with full range into negation
    // since negation is implemented similarly

    const int32_t neededcapacity = src_1->n_runs + src_2->n_runs;
    if (dst->capacity < neededcapacity)
        run_container_grow(dst, neededcapacity, false);

    int32_t pos1 = 0;
    int32_t pos2 = 0;
    dst->n_runs = 0;

    while ((pos1 < src_1->n_runs) && (pos2 < src_2->n_runs)) {
        if (src_1->runs[pos1].value <= src_2->runs[pos2].value) {
            run_container_smart_append_exclusive(dst, src_1->runs[pos1].value,
                                                 src_1->runs[pos1].length);
            pos1++;
        } else {
            run_container_smart_append_exclusive(dst, src_2->runs[pos2].value,
                                                 src_2->runs[pos2].length);
            pos2++;
        }
    }
    while (pos1 < src_1->n_runs) {
        run_container_smart_append_exclusive(dst, src_1->runs[pos1].value,
                                             src_1->runs[pos1].length);
        pos1++;
    }

    while (pos2 < src_2->n_runs) {
        run_container_smart_append_exclusive(dst, src_2->runs[pos2].value,
                                             src_2->runs[pos2].length);
        pos2++;
    }
}

/* Compute the intersection of src_1 and src_2 and write the result to
 * dst. It is assumed that dst is distinct from both src_1 and src_2. */
void run_container_intersection(const run_container_t *src_1,
                                const run_container_t *src_2,
                                run_container_t *dst) {
    const bool if1 = run_container_is_full(src_1);
    const bool if2 = run_container_is_full(src_2);
    if (if1 || if2) {
        if (if1) {
            run_container_copy(src_2, dst);
            return;
        }
        if (if2) {
            run_container_copy(src_1, dst);
            return;
        }
    }
    // TODO: this could be a lot more efficient, could use SIMD optimizations
    const int32_t neededcapacity = src_1->n_runs + src_2->n_runs;
    if (dst->capacity < neededcapacity)
        run_container_grow(dst, neededcapacity, false);
    dst->n_runs = 0;
    int32_t rlepos = 0;
    int32_t xrlepos = 0;
    int32_t start = src_1->runs[rlepos].value;
    int32_t end = start + src_1->runs[rlepos].length + 1;
    int32_t xstart = src_2->runs[xrlepos].value;
    int32_t xend = xstart + src_2->runs[xrlepos].length + 1;
    while ((rlepos < src_1->n_runs) && (xrlepos < src_2->n_runs)) {
        if (end <= xstart) {
            ++rlepos;
            if (rlepos < src_1->n_runs) {
                start = src_1->runs[rlepos].value;
                end = start + src_1->runs[rlepos].length + 1;
            }
        } else if (xend <= start) {
            ++xrlepos;
            if (xrlepos < src_2->n_runs) {
                xstart = src_2->runs[xrlepos].value;
                xend = xstart + src_2->runs[xrlepos].length + 1;
            }
        } else {  // they overlap
            const int32_t lateststart = start > xstart ? start : xstart;
            int32_t earliestend;
            if (end == xend) {  // improbable
                earliestend = end;
                rlepos++;
                xrlepos++;
                if (rlepos < src_1->n_runs) {
                    start = src_1->runs[rlepos].value;
                    end = start + src_1->runs[rlepos].length + 1;
                }
                if (xrlepos < src_2->n_runs) {
                    xstart = src_2->runs[xrlepos].value;
                    xend = xstart + src_2->runs[xrlepos].length + 1;
                }
            } else if (end < xend) {
                earliestend = end;
                rlepos++;
                if (rlepos < src_1->n_runs) {
                    start = src_1->runs[rlepos].value;
                    end = start + src_1->runs[rlepos].length + 1;
                }

            } else {  // end > xend
                earliestend = xend;
                xrlepos++;
                if (xrlepos < src_2->n_runs) {
                    xstart = src_2->runs[xrlepos].value;
                    xend = xstart + src_2->runs[xrlepos].length + 1;
                }
            }
            dst->runs[dst->n_runs].value = (uint16_t)lateststart;
            dst->runs[dst->n_runs].length =
                (uint16_t)(earliestend - lateststart - 1);
            dst->n_runs++;
        }
    }
}

/* Compute the size of the intersection of src_1 and src_2 . */
int run_container_intersection_cardinality(const run_container_t *src_1,
                                           const run_container_t *src_2) {
    const bool if1 = run_container_is_full(src_1);
    const bool if2 = run_container_is_full(src_2);
    if (if1 || if2) {
        if (if1) {
            return run_container_cardinality(src_2);
        }
        if (if2) {
            return run_container_cardinality(src_1);
        }
    }
    int answer = 0;
    int32_t rlepos = 0;
    int32_t xrlepos = 0;
    int32_t start = src_1->runs[rlepos].value;
    int32_t end = start + src_1->runs[rlepos].length + 1;
    int32_t xstart = src_2->runs[xrlepos].value;
    int32_t xend = xstart + src_2->runs[xrlepos].length + 1;
    while ((rlepos < src_1->n_runs) && (xrlepos < src_2->n_runs)) {
        if (end <= xstart) {
            ++rlepos;
            if (rlepos < src_1->n_runs) {
                start = src_1->runs[rlepos].value;
                end = start + src_1->runs[rlepos].length + 1;
            }
        } else if (xend <= start) {
            ++xrlepos;
            if (xrlepos < src_2->n_runs) {
                xstart = src_2->runs[xrlepos].value;
                xend = xstart + src_2->runs[xrlepos].length + 1;
            }
        } else {  // they overlap
            const int32_t lateststart = start > xstart ? start : xstart;
            int32_t earliestend;
            if (end == xend) {  // improbable
                earliestend = end;
                rlepos++;
                xrlepos++;
                if (rlepos < src_1->n_runs) {
                    start = src_1->runs[rlepos].value;
                    end = start + src_1->runs[rlepos].length + 1;
                }
                if (xrlepos < src_2->n_runs) {
                    xstart = src_2->runs[xrlepos].value;
                    xend = xstart + src_2->runs[xrlepos].length + 1;
                }
            } else if (end < xend) {
                earliestend = end;
                rlepos++;
                if (rlepos < src_1->n_runs) {
                    start = src_1->runs[rlepos].value;
                    end = start + src_1->runs[rlepos].length + 1;
                }

            } else {  // end > xend
                earliestend = xend;
                xrlepos++;
                if (xrlepos < src_2->n_runs) {
                    xstart = src_2->runs[xrlepos].value;
                    xend = xstart + src_2->runs[xrlepos].length + 1;
                }
            }
            answer += earliestend - lateststart;
        }
    }
    return answer;
}

bool run_container_intersect(const run_container_t *src_1,
                                const run_container_t *src_2) {
    const bool if1 = run_container_is_full(src_1);
    const bool if2 = run_container_is_full(src_2);
    if (if1 || if2) {
        if (if1) {
            return !run_container_empty(src_2);
        }
        if (if2) {
        	return !run_container_empty(src_1);
        }
    }
    int32_t rlepos = 0;
    int32_t xrlepos = 0;
    int32_t start = src_1->runs[rlepos].value;
    int32_t end = start + src_1->runs[rlepos].length + 1;
    int32_t xstart = src_2->runs[xrlepos].value;
    int32_t xend = xstart + src_2->runs[xrlepos].length + 1;
    while ((rlepos < src_1->n_runs) && (xrlepos < src_2->n_runs)) {
        if (end <= xstart) {
            ++rlepos;
            if (rlepos < src_1->n_runs) {
                start = src_1->runs[rlepos].value;
                end = start + src_1->runs[rlepos].length + 1;
            }
        } else if (xend <= start) {
            ++xrlepos;
            if (xrlepos < src_2->n_runs) {
                xstart = src_2->runs[xrlepos].value;
                xend = xstart + src_2->runs[xrlepos].length + 1;
            }
        } else {  // they overlap
            return true;
        }
    }
    return false;
}


/* Compute the difference of src_1 and src_2 and write the result to
 * dst. It is assumed that dst is distinct from both src_1 and src_2. */
void run_container_andnot(const run_container_t *src_1,
                          const run_container_t *src_2, run_container_t *dst) {
    // following Java implementation as of June 2016

    if (dst->capacity < src_1->n_runs + src_2->n_runs)
        run_container_grow(dst, src_1->n_runs + src_2->n_runs, false);

    dst->n_runs = 0;

    int rlepos1 = 0;
    int rlepos2 = 0;
    int32_t start = src_1->runs[rlepos1].value;
    int32_t end = start + src_1->runs[rlepos1].length + 1;
    int32_t start2 = src_2->runs[rlepos2].value;
    int32_t end2 = start2 + src_2->runs[rlepos2].length + 1;

    while ((rlepos1 < src_1->n_runs) && (rlepos2 < src_2->n_runs)) {
        if (end <= start2) {
            // output the first run
            dst->runs[dst->n_runs++] = MAKE_RLE16(start, end - start - 1);
            rlepos1++;
            if (rlepos1 < src_1->n_runs) {
                start = src_1->runs[rlepos1].value;
                end = start + src_1->runs[rlepos1].length + 1;
            }
        } else if (end2 <= start) {
            // exit the second run
            rlepos2++;
            if (rlepos2 < src_2->n_runs) {
                start2 = src_2->runs[rlepos2].value;
                end2 = start2 + src_2->runs[rlepos2].length + 1;
            }
        } else {
            if (start < start2) {
                dst->runs[dst->n_runs++] =
                    MAKE_RLE16(start, start2 - start - 1);
            }
            if (end2 < end) {
                start = end2;
            } else {
                rlepos1++;
                if (rlepos1 < src_1->n_runs) {
                    start = src_1->runs[rlepos1].value;
                    end = start + src_1->runs[rlepos1].length + 1;
                }
            }
        }
    }
    if (rlepos1 < src_1->n_runs) {
        dst->runs[dst->n_runs++] = MAKE_RLE16(start, end - start - 1);
        rlepos1++;
        if (rlepos1 < src_1->n_runs) {
            memcpy(dst->runs + dst->n_runs, src_1->runs + rlepos1,
                   sizeof(rle16_t) * (src_1->n_runs - rlepos1));
            dst->n_runs += src_1->n_runs - rlepos1;
        }
    }
}

ALLOW_UNALIGNED
int run_container_to_uint32_array(void *vout, const run_container_t *cont,
                                  uint32_t base) {
    int outpos = 0;
    uint32_t *out = (uint32_t *)vout;
    for (int i = 0; i < cont->n_runs; ++i) {
        uint32_t run_start = base + cont->runs[i].value;
        uint16_t le = cont->runs[i].length;
        for (int j = 0; j <= le; ++j) {
            uint32_t val = run_start + j;
            memcpy(out + outpos, &val,
                   sizeof(uint32_t));  // should be compiled as a MOV on x64
            outpos++;
        }
    }
    return outpos;
}

/*
 * Print this container using printf (useful for debugging).
 */
void run_container_printf(const run_container_t *cont) {
    for (int i = 0; i < cont->n_runs; ++i) {
        uint16_t run_start = cont->runs[i].value;
        uint16_t le = cont->runs[i].length;
        printf("[%d,%d]", run_start, run_start + le);
    }
}

/*
 * Print this container using printf as a comma-separated list of 32-bit
 * integers starting at base.
 */
void run_container_printf_as_uint32_array(const run_container_t *cont,
                                          uint32_t base) {
    if (cont->n_runs == 0) return;
    {
        uint32_t run_start = base + cont->runs[0].value;
        uint16_t le = cont->runs[0].length;
        printf("%u", run_start);
        for (uint32_t j = 1; j <= le; ++j) printf(",%u", run_start + j);
    }
    for (int32_t i = 1; i < cont->n_runs; ++i) {
        uint32_t run_start = base + cont->runs[i].value;
        uint16_t le = cont->runs[i].length;
        for (uint32_t j = 0; j <= le; ++j) printf(",%u", run_start + j);
    }
}

/*
 * Validate the container. Returns true if valid.
 */
bool run_container_validate(const run_container_t *run, const char **reason) {
    if (run->n_runs < 0) {
        *reason = "negative run count";
        return false;
    }
    if (run->capacity < 0) {
        *reason = "negative run capacity";
        return false;
    }
    if (run->capacity < run->n_runs) {
        *reason = "capacity less than run count";
        return false;
    }

    if (run->n_runs == 0) {
        return true;
    }
    if (run->runs == NULL) {
        *reason = "NULL runs";
        return false;
    }

    // Use uint32_t to avoid overflow issues on ranges that contain UINT16_MAX.
    uint32_t last_end = 0;
    for (int i = 0; i < run->n_runs; ++i) {
        uint32_t start = run->runs[i].value;
        uint32_t end = start + run->runs[i].length + 1;
        if (end <= start) {
            *reason = "run start + length overflow";
            return false;
        }
        if (end > (1<<16)) {
            *reason = "run start + length too large";
            return false;
        }
        if (start < last_end) {
            *reason = "run start less than last end";
            return false;
        }
        if (start == last_end && last_end != 0) {
            *reason = "run start equal to last end, should have combined";
            return false;
        }
        last_end = end;
    }
    return true;
}

int32_t run_container_write(const run_container_t *container, char *buf) {
    uint16_t cast_16 = container->n_runs;
    memcpy(buf, &cast_16, sizeof(uint16_t));
    memcpy(buf + sizeof(uint16_t), container->runs,
           container->n_runs * sizeof(rle16_t));
    return run_container_size_in_bytes(container);
}

int32_t run_container_read(int32_t cardinality, run_container_t *container,
                           const char *buf) {
    (void)cardinality;
    uint16_t cast_16;
    memcpy(&cast_16, buf, sizeof(uint16_t));
    container->n_runs = cast_16;
    if (container->n_runs > container->capacity)
        run_container_grow(container, container->n_runs, false);
    if(container->n_runs > 0) {
      memcpy(container->runs, buf + sizeof(uint16_t),
           container->n_runs * sizeof(rle16_t));
    }
    return run_container_size_in_bytes(container);
}

bool run_container_iterate(const run_container_t *cont, uint32_t base,
                           roaring_iterator iterator, void *ptr) {
    for (int i = 0; i < cont->n_runs; ++i) {
        uint32_t run_start = base + cont->runs[i].value;
        uint16_t le = cont->runs[i].length;

        for (int j = 0; j <= le; ++j)
            if (!iterator(run_start + j, ptr)) return false;
    }
    return true;
}

bool run_container_iterate64(const run_container_t *cont, uint32_t base,
                             roaring_iterator64 iterator, uint64_t high_bits,
                             void *ptr) {
    for (int i = 0; i < cont->n_runs; ++i) {
        uint32_t run_start = base + cont->runs[i].value;
        uint16_t le = cont->runs[i].length;

        for (int j = 0; j <= le; ++j)
            if (!iterator(high_bits | (uint64_t)(run_start + j), ptr))
                return false;
    }
    return true;
}

bool run_container_is_subset(const run_container_t *container1,
                             const run_container_t *container2) {
    int i1 = 0, i2 = 0;
    while (i1 < container1->n_runs && i2 < container2->n_runs) {
        int start1 = container1->runs[i1].value;
        int stop1 = start1 + container1->runs[i1].length;
        int start2 = container2->runs[i2].value;
        int stop2 = start2 + container2->runs[i2].length;
        if (start1 < start2) {
            return false;
        } else {  // start1 >= start2
            if (stop1 < stop2) {
                i1++;
            } else if (stop1 == stop2) {
                i1++;
                i2++;
            } else {  // stop1 > stop2
                i2++;
            }
        }
    }
    if (i1 == container1->n_runs) {
        return true;
    } else {
        return false;
    }
}

// TODO: write smart_append_exclusive version to match the overloaded 1 param
// Java version (or  is it even used?)

// follows the Java implementation closely
// length is the rle-value.  Ie, run [10,12) uses a length value 1.
void run_container_smart_append_exclusive(run_container_t *src,
                                          const uint16_t start,
                                          const uint16_t length) {
    int old_end;
    rle16_t *last_run = src->n_runs ? src->runs + (src->n_runs - 1) : NULL;
    rle16_t *appended_last_run = src->runs + src->n_runs;

    if (!src->n_runs ||
        (start > (old_end = last_run->value + last_run->length + 1))) {
        *appended_last_run = MAKE_RLE16(start, length);
        src->n_runs++;
        return;
    }
    if (old_end == start) {
        // we merge
        last_run->length += (length + 1);
        return;
    }
    int new_end = start + length + 1;

    if (start == last_run->value) {
        // wipe out previous
        if (new_end < old_end) {
            *last_run = MAKE_RLE16(new_end, old_end - new_end - 1);
            return;
        } else if (new_end > old_end) {
            *last_run = MAKE_RLE16(old_end, new_end - old_end - 1);
            return;
        } else {
            src->n_runs--;
            return;
        }
    }
    last_run->length = start - last_run->value - 1;
    if (new_end < old_end) {
        *appended_last_run = MAKE_RLE16(new_end, old_end - new_end - 1);
        src->n_runs++;
    } else if (new_end > old_end) {
        *appended_last_run = MAKE_RLE16(old_end, new_end - old_end - 1);
        src->n_runs++;
    }
}

bool run_container_select(const run_container_t *container,
                          uint32_t *start_rank, uint32_t rank,
                          uint32_t *element) {
    for (int i = 0; i < container->n_runs; i++) {
        uint16_t length = container->runs[i].length;
        if (rank <= *start_rank + length) {
            uint16_t value = container->runs[i].value;
            *element = value + rank - (*start_rank);
            return true;
        } else
            *start_rank += length + 1;
    }
    return false;
}

int run_container_rank(const run_container_t *container, uint16_t x) {
    int sum = 0;
    uint32_t x32 = x;
    for (int i = 0; i < container->n_runs; i++) {
        uint32_t startpoint = container->runs[i].value;
        uint32_t length = container->runs[i].length;
        uint32_t endpoint = length + startpoint;
        if (x <= endpoint) {
            if (x < startpoint) break;
            return sum + (x32 - startpoint) + 1;
        } else {
            sum += length + 1;
        }
    }
    return sum;
}

int run_container_get_index(const run_container_t *container, uint16_t x) {
    if (run_container_contains(container, x)) {
        int sum = 0;
        uint32_t x32 = x;
        for (int i = 0; i < container->n_runs; i++) {
            uint32_t startpoint = container->runs[i].value;
            uint32_t length = container->runs[i].length;
            uint32_t endpoint = length + startpoint;
            if (x <= endpoint) {
                if (x < startpoint) break;
                return sum + (x32 - startpoint);
            } else {
                sum += length + 1;
            }
        }
        return sum - 1;
    } else {
        return -1;
    }
}

#if defined(CROARING_IS_X64) && CROARING_COMPILER_SUPPORTS_AVX512

CROARING_TARGET_AVX512
ALLOW_UNALIGNED
/* Get the cardinality of `run'. Requires an actual computation. */
static inline int _avx512_run_container_cardinality(const run_container_t *run) {
    const int32_t n_runs = run->n_runs;
    const rle16_t *runs = run->runs;

    /* by initializing with n_runs, we omit counting the +1 for each pair. */
    int sum = n_runs;
    int32_t k = 0;
    const int32_t step = sizeof(__m512i) / sizeof(rle16_t);
    if (n_runs > step) {
        __m512i total = _mm512_setzero_si512();
        for (; k + step <= n_runs; k += step) {
            __m512i ymm1 = _mm512_loadu_si512((const __m512i *)(runs + k));
            __m512i justlengths = _mm512_srli_epi32(ymm1, 16);
            total = _mm512_add_epi32(total, justlengths);
        }

        __m256i lo = _mm512_extracti32x8_epi32(total, 0);
        __m256i hi = _mm512_extracti32x8_epi32(total, 1);

        // a store might be faster than extract?
        uint32_t buffer[sizeof(__m256i) / sizeof(rle16_t)];
        _mm256_storeu_si256((__m256i *)buffer, lo);
        sum += (buffer[0] + buffer[1]) + (buffer[2] + buffer[3]) +
               (buffer[4] + buffer[5]) + (buffer[6] + buffer[7]);

        _mm256_storeu_si256((__m256i *)buffer, hi);
        sum += (buffer[0] + buffer[1]) + (buffer[2] + buffer[3]) +
               (buffer[4] + buffer[5]) + (buffer[6] + buffer[7]);

    }
    for (; k < n_runs; ++k) {
        sum += runs[k].length;
    }

    return sum;
}

CROARING_UNTARGET_AVX512

CROARING_TARGET_AVX2
ALLOW_UNALIGNED
/* Get the cardinality of `run'. Requires an actual computation. */
static inline int _avx2_run_container_cardinality(const run_container_t *run) {
    const int32_t n_runs = run->n_runs;
    const rle16_t *runs = run->runs;

    /* by initializing with n_runs, we omit counting the +1 for each pair. */
    int sum = n_runs;
    int32_t k = 0;
    const int32_t step = sizeof(__m256i) / sizeof(rle16_t);
    if (n_runs > step) {
        __m256i total = _mm256_setzero_si256();
        for (; k + step <= n_runs; k += step) {
            __m256i ymm1 = _mm256_lddqu_si256((const __m256i *)(runs + k));
            __m256i justlengths = _mm256_srli_epi32(ymm1, 16);
            total = _mm256_add_epi32(total, justlengths);
        }
        // a store might be faster than extract?
        uint32_t buffer[sizeof(__m256i) / sizeof(rle16_t)];
        _mm256_storeu_si256((__m256i *)buffer, total);
        sum += (buffer[0] + buffer[1]) + (buffer[2] + buffer[3]) +
               (buffer[4] + buffer[5]) + (buffer[6] + buffer[7]);
    }
    for (; k < n_runs; ++k) {
        sum += runs[k].length;
    }

    return sum;
}

CROARING_UNTARGET_AVX2

/* Get the cardinality of `run'. Requires an actual computation. */
static inline int _scalar_run_container_cardinality(const run_container_t *run) {
    const int32_t n_runs = run->n_runs;
    const rle16_t *runs = run->runs;

    /* by initializing with n_runs, we omit counting the +1 for each pair. */
    int sum = n_runs;
    for (int k = 0; k < n_runs; ++k) {
        sum += runs[k].length;
    }

    return sum;
}

int run_container_cardinality(const run_container_t *run) {
#if CROARING_COMPILER_SUPPORTS_AVX512
  if( croaring_hardware_support() & ROARING_SUPPORTS_AVX512 ) {
    return _avx512_run_container_cardinality(run);
  }
  else
#endif
  if( croaring_hardware_support() & ROARING_SUPPORTS_AVX2 ) {
    return _avx2_run_container_cardinality(run);
  } else {
    return _scalar_run_container_cardinality(run);
  }
}
#else

/* Get the cardinality of `run'. Requires an actual computation. */
int run_container_cardinality(const run_container_t *run) {
    const int32_t n_runs = run->n_runs;
    const rle16_t *runs = run->runs;

    /* by initializing with n_runs, we omit counting the +1 for each pair. */
    int sum = n_runs;
    for (int k = 0; k < n_runs; ++k) {
        sum += runs[k].length;
    }

    return sum;
}
#endif


#ifdef __cplusplus
} } }  // extern "C" { namespace roaring { namespace internal {
#endif