#include "mpool.h"

#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

static int bit_cmp(const struct elem *p, const struct elem *q)
{
    int len = q->len < p->len ? q->len : p->len;
    int df = len % 8, bytes = len / 8;
    int cmp = memcmp(p->data, q->data, bytes);
    
    if (cmp || !df) {
        return cmp;
    }
    uint8_t c1 = p->data[bytes] >> (8 - df);
    uint8_t c2 = q->data[bytes] >> (8 - df);
    if (c1 != c2) {
        if (c1 < c2) return -1;
        else return 1;
    }
    return 0;
}

static int byte_cmp(const struct elem *p, const struct elem *q)
{
    if (p->len != q->len) {
        return p->len < q->len ? -1 : 1;
    }
    return memcmp(p->data, q->data, p->len);
}

static int host_cmp(const struct elem *p, const struct elem *q)
{
    int len = q->len < p->len ? q->len : p->len;
    char *pd = p->data + p->len, *qd = q->data + q->len;
    
    while (len-- > 0) {
        if (*--pd != *--qd) {
            return *pd < *qd ? -1 : 1;
        }
    }
    if (p->len == q->len 
            || (p->len > q->len ? pd[-1] : qd[-1]) == '.')
        return 0;
    
    return p->len > q->len ? 1 : -1;
}

static int scmp(const struct elem *p, const struct elem *q)
{
    switch (p->cmp_type) {
    case CMP_BITS:
        return bit_cmp(p, q);
    case CMP_HOST:
        return host_cmp(p, q);
    default:
        return byte_cmp(p, q);
    }
}

KAVL_INIT(my, struct elem, head, scmp)


struct mphdr *mem_pool(bool is_static, unsigned char cmp_type)
{
    struct mphdr *hdr = calloc(sizeof(struct mphdr), 1);
    if (hdr) {
        hdr->static_data = is_static;
        hdr->cmp_type = cmp_type;
    }
    return hdr;
}


struct elem *mem_get(const struct mphdr *hdr, const char *str, int len)
{
    struct elem temp = { 
        .cmp_type = hdr->cmp_type,
        .len = len, .data = (char *)str 
    };
    return kavl_find(my, hdr->root, &temp, 0);
}


struct elem *mem_add(struct mphdr *hdr, char *str, int len, size_t struct_size)
{
    struct elem *v, *e = calloc(struct_size, 1);
    if (!e) {
        return 0;
    }
    e->len = len;
    e->cmp_type = hdr->cmp_type;
    e->data = str;
    
    v = kavl_insert(my, &hdr->root, e, 0);
    while (e != v && e->len < v->len) {
        mem_delete(hdr, v->data, v->len);
        v = kavl_insert(my, &hdr->root, e, 0);
    }
    if (e != v) {
        if (!hdr->static_data)
            free(e->data);
        free(e);
    }
    else hdr->count++;
    return v;
}


void mem_delete(struct mphdr *hdr, const char *str, int len)
{
    struct elem temp = { 
        .cmp_type = hdr->cmp_type,
        .len = len, .data = (char *)str 
    };
    struct elem *e = kavl_erase(my, &hdr->root, &temp, 0);
    if (!e) {
        return;
    }
    if (!hdr->static_data) {
        free(e->data);
        e->data = 0;
    }
    free(e);
    hdr->count--;
}


void mem_destroy(struct mphdr *hdr)
{
    while (hdr->root) {
        struct elem *e = kavl_erase_first(my, &hdr->root);
        if (!e) {
            break;
        }
        if (!hdr->static_data) {
            free(e->data);
        }
        e->data = 0;
        free(e);
    }
    free(hdr);
}