#include "constmap.h"
#include "alloc.h"
#include "case.h"

/**
  * @file constmap.c
  * @author djb
  * @ref qmail
  * @brief constant hash table
  * @brief Attention! constmap is both function and struct
  */


static constmap_hash hash(char *s,int len)
{
  unsigned char ch;
  constmap_hash h;
  h = 5381;
  while (len > 0) {
    ch = *s++ - 'A';
    if (ch <= 'Z' - 'A') ch += 'a' - 'A';
    h = ((h << 5) + h) ^ ch;
    --len;
  }
  return h;
}

char *constmap(struct constmap *cm,char *s,int len)
{
  constmap_hash h;
  int pos;
  h = hash(s,len);
  pos = cm->first[h & cm->mask];
  while (pos != -1) {
    if (h == cm->hash[pos])
      if (len == cm->inputlen[pos])
        if (!case_diffb(cm->input[pos],len,s))
          return cm->input[pos] + cm->inputlen[pos] + 1;
    pos = cm->next[pos];
  }
  return 0;
}

int constmap_init(struct constmap *cm,char *s,int len,int flagcolon)
{
  int i;
  int j;
  int k;
  int pos;
  constmap_hash h;
 
  cm->num = 0;
  for (j = 0; j < len; ++j) if (!s[j]) ++cm->num;
 
  h = 64;
  while (h && (h < cm->num)) h += h;
  cm->mask = h - 1;
 
  cm->first = (int *) alloc(sizeof(int) * h);
  if (cm->first) {
    cm->input = (char **) alloc(sizeof(char *) * cm->num);
    if (cm->input) {
      cm->inputlen = (int *) alloc(sizeof(int) * cm->num);
      if (cm->inputlen) {
        cm->hash = (constmap_hash *) alloc(sizeof(constmap_hash) * cm->num);
        if (cm->hash) {
          cm->next = (int *) alloc(sizeof(int) * cm->num);
          if (cm->next) {
            for (h = 0; h <= cm->mask; ++h)
               cm->first[h] = -1;
            pos = 0;
            i = 0;
            for (j = 0; j < len; ++j)
              if (!s[j]) {
                k = j - i;
                if (flagcolon) {
                  for (k = i; k < j; ++k)
                    if (s[k] == ':') break;
                  if (k >= j) { i = j + 1; continue; }
                  k -= i;
                }
                cm->input[pos] = s + i;
                cm->inputlen[pos] = k;
                h = hash(s + i,k);
                cm->hash[pos] = h;
                h &= cm->mask;
                cm->next[pos] = cm->first[h];
                cm->first[h] = pos;
                ++pos;
                i = j + 1;
              }
            return 1;
          }
          alloc_free(cm->hash);
        }
        alloc_free(cm->inputlen);
      }
      alloc_free(cm->input);
    }
    alloc_free(cm->first);
  }
  return 0;
}

int constmap_init_char(struct constmap *cm,char *s,int len,int flagcolon,char flagchar)
{
  int i;
  int j;
  int k;
  int pos;
  constmap_hash h;

  if (!flagchar || flagchar == 0 || flagchar == '\0') {
    flagchar = ':';
  }

  cm->num = 0;
  for (j = 0; j < len; ++j) if (!s[j]) ++cm->num;

  h = 64;
  while (h && (h < cm->num)) h += h;
  cm->mask = h - 1;

  cm->first = (int *) alloc(sizeof(int) * h);
  if (cm->first) {
    cm->input = (char **) alloc(sizeof(char *) * cm->num);
    if (cm->input) {
      cm->inputlen = (int *) alloc(sizeof(int) * cm->num);
      if (cm->inputlen) {
        cm->hash = (constmap_hash *) alloc(sizeof(constmap_hash) * cm->num);
        if (cm->hash) {
          cm->next = (int *) alloc(sizeof(int) * cm->num);
          if (cm->next) {
            for (h = 0; h <= cm->mask; ++h)
              cm->first[h] = -1;
            pos = 0;
            i = 0;
            for (j = 0; j < len; ++j) {
              if (!s[j]) {
                k = j - i;
                if (flagcolon) {
                  for (k = i; k < j; ++k)
                    if (s[k] == flagchar) break;
                  if (k >= j) { i = j + 1; continue; }
                  k -= i;
                }
                cm->input[pos] = s + i;
                cm->inputlen[pos] = k;
                h = hash(s + i,k);
                cm->hash[pos] = h;
                h &= cm->mask;
                cm->next[pos] = cm->first[h];
                cm->first[h] = pos;
                ++pos;
                i = j + 1;
              }
            }
            return 1;
          }
          alloc_free(cm->hash);
        }
        alloc_free(cm->inputlen);
      }
      alloc_free(cm->input);
    }
    alloc_free(cm->first);
  }
  return 0;
}

void constmap_free(struct constmap *cm)
{
  alloc_free(cm->next);
  alloc_free(cm->hash);
  alloc_free(cm->inputlen);
  alloc_free(cm->input);
  alloc_free(cm->first);
}