/*!
* \brief l_asetCreateFromSarray()
*
* \param[in] sa
* \return set using a string hash into a uint32 as the key
*/
L_ASET *
l_asetCreateFromSarray(SARRAY *sa)
{
char *str;
l_int32 i, n;
l_uint64 hash;
L_ASET *set;
RB_TYPE key;
PROCNAME("l_asetCreateFromSarray");
if (!sa)
return (L_ASET *)ERROR_PTR("sa not defined", procName, NULL);
set = l_asetCreate(L_UINT_TYPE);
n = sarrayGetCount(sa);
for (i = 0; i < n; i++) {
str = sarrayGetString(sa, i, L_NOCOPY);
l_hashStringToUint64(str, &hash);
key.utype = hash;
l_asetInsert(set, key);
}
return set;
}
/*!
* \brief l_dnaHashCreateFromSarray()
*
* \param[in] sa
* \return dahash, or NULL on error
*/
L_DNAHASH *
l_dnaHashCreateFromSarray(SARRAY *sa)
{
char *str;
l_int32 i, n;
l_uint32 nsize;
l_uint64 key;
L_DNAHASH *dahash;
/* Build up dnaHash of indices, hashed by a 64-bit key that
* should randomize the lower bits used in bucket selection.
* Having about 20 pts in each bucket is roughly optimal. */
n = sarrayGetCount(sa);
findNextLargerPrime(n / 20, &nsize); /* buckets in hash table */
/* fprintf(stderr, "Prime used: %d\n", nsize); */
/* Add each string, using the hash as key and the index into %sa
* as the value. Storing the index enables operations that check
* for duplicates. */
dahash = l_dnaHashCreate(nsize, 8);
for (i = 0; i < n; i++) {
str = sarrayGetString(sa, i, L_NOCOPY);
l_hashStringToUint64(str, &key);
l_dnaHashAdd(dahash, key, (l_float64)i);
}
return dahash;
}
/*!
* \brief sarrayRemoveDupsByAset()
*
* \param[in] sas
* \return sad with duplicates removed, or NULL on error
*
* <pre>
* Notes:
* (1) This is O(nlogn), considerably slower than
* sarrayRemoveDupsByHash() for large string arrays.
* (2) The key for each string is a 64-bit hash.
* (3) Build a set, using hashed strings as keys. As the set is
* built, first do a find; if not found, add the key to the
* set and add the string to the output sarray.
* </pre>
*/
SARRAY *
sarrayRemoveDupsByAset(SARRAY *sas)
{
char *str;
l_int32 i, n;
l_uint64 hash;
L_ASET *set;
RB_TYPE key;
SARRAY *sad;
PROCNAME("sarrayRemoveDupsByAset");
if (!sas)
return (SARRAY *)ERROR_PTR("sas not defined", procName, NULL);
set = l_asetCreate(L_UINT_TYPE);
sad = sarrayCreate(0);
n = sarrayGetCount(sas);
for (i = 0; i < n; i++) {
str = sarrayGetString(sas, i, L_NOCOPY);
l_hashStringToUint64(str, &hash);
key.utype = hash;
if (!l_asetFind(set, key)) {
sarrayAddString(sad, str, L_COPY);
l_asetInsert(set, key);
}
}
l_asetDestroy(&set);
return sad;
}
/* Build all possible strings, up to a max of 5 roman alphabet characters */
static SARRAY *
BuildShortStrings(l_int32 nchars, /* 3, 4 or 5 */
l_int32 add_dups)
{
char buf[64];
l_int32 i, j, k, l, m;
l_uint64 hash;
SARRAY *sa;
sa = sarrayCreate(1000);
for (i = 0; i < 26; i++) {
sprintf(buf, "%c", i + 0x61);
sarrayAddString(sa, buf, L_COPY);
for (j = 0; j < 26; j++) {
sprintf(buf, "%c%c", i + 0x61, j + 0x61);
sarrayAddString(sa, buf, L_COPY);
for (k = 0; k < 26; k++) {
sprintf(buf, "%c%c%c", i + 0x61, j + 0x61, k + 0x61);
sarrayAddString(sa, buf, L_COPY);
if (add_dups && k < 4) /* add redundant strings */
sarrayAddString(sa, buf, L_COPY);
if (nchars > 3) {
for (l = 0; l < 26; l++) {
sprintf(buf, "%c%c%c%c", i + 0x61, j + 0x61,
k + 0x61, l + 0x61);
sarrayAddString(sa, buf, L_COPY);
if (add_dups && l < 4) /* add redundant strings */
sarrayAddString(sa, buf, L_COPY);
if (nchars > 4) {
for (m = 0; m < 26; m++) {
sprintf(buf, "%c%c%c%c%c", i + 0x61, j + 0x61,
k + 0x61, l + 0x61, m + 0x61);
sarrayAddString(sa, buf, L_COPY);
if (!add_dups && i == 17 && j == 12 &&
k == 4 && l == 21) {
l_hashStringToUint64(buf, &hash);
fprintf(stderr, " %llx\n", hash);
}
if (add_dups && m < 4) /* add redundant */
sarrayAddString(sa, buf, L_COPY);
}
}
}
}
}
}
}
return sa;
}
/*!
* \brief sarrayIntersectionByHash()
*
* \param[in] sa1, sa2
* \return sad intersection of the strings, or NULL on error
*
* <pre>
* Notes:
* (1) This is faster than sarrayIntersectionByAset(), because the
* bucket lookup is O(n).
* </pre>
*/
SARRAY *
sarrayIntersectionByHash(SARRAY *sa1,
SARRAY *sa2)
{
char *str;
l_int32 n1, n2, nsmall, i, index1, index2;
l_uint32 nsize2;
l_uint64 key;
L_DNAHASH *dahash1, *dahash2;
SARRAY *sa_small, *sa_big, *sad;
PROCNAME("sarrayIntersectionByHash");
if (!sa1)
return (SARRAY *)ERROR_PTR("sa1 not defined", procName, NULL);
if (!sa2)
return (SARRAY *)ERROR_PTR("sa2 not defined", procName, NULL);
/* Put the elements of the biggest sarray into a dnahash */
n1 = sarrayGetCount(sa1);
n2 = sarrayGetCount(sa2);
sa_small = (n1 < n2) ? sa1 : sa2; /* do not destroy sa_small */
sa_big = (n1 < n2) ? sa2 : sa1; /* do not destroy sa_big */
dahash1 = l_dnaHashCreateFromSarray(sa_big);
/* Build up the intersection of strings. Add to %sad
* if the string is in sa_big (using dahash1) but hasn't
* yet been seen in the traversal of sa_small (using dahash2). */
sad = sarrayCreate(0);
nsmall = sarrayGetCount(sa_small);
findNextLargerPrime(nsmall / 20, &nsize2); /* buckets in hash table */
dahash2 = l_dnaHashCreate(nsize2, 0);
for (i = 0; i < nsmall; i++) {
str = sarrayGetString(sa_small, i, L_NOCOPY);
sarrayFindStringByHash(sa_big, dahash1, str, &index1);
if (index1 >= 0) {
sarrayFindStringByHash(sa_small, dahash2, str, &index2);
if (index2 == -1) {
sarrayAddString(sad, str, L_COPY);
l_hashStringToUint64(str, &key);
l_dnaHashAdd(dahash2, key, (l_float64)i);
}
}
}
l_dnaHashDestroy(&dahash1);
l_dnaHashDestroy(&dahash2);
return sad;
}
/*!
* \brief sarrayRemoveDupsByHash()
*
* \param[in] sas
* \param[out] psad unique set of strings; duplicates removed
* \param[out] pdahash [optional] dnahash used for lookup
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) Generates a sarray with unique values.
* (2) The dnahash is built up with sad to assure uniqueness.
* It can be used to find if a string is in the set:
* sarrayFindValByHash(sad, dahash, str, \&index)
* (3) The hash of the string location is simple and fast. It scales
* up with the number of buckets to insure a fairly random
* bucket selection input strings.
* (4) This is faster than sarrayRemoveDupsByAset(), because the
* bucket lookup is O(n), although there is a double-loop
* lookup within the dna in each bucket.
* </pre>
*/
l_int32
sarrayRemoveDupsByHash(SARRAY *sas,
SARRAY **psad,
L_DNAHASH **pdahash)
{
char *str;
l_int32 i, n, index, items;
l_uint32 nsize;
l_uint64 key;
SARRAY *sad;
L_DNAHASH *dahash;
PROCNAME("sarrayRemoveDupsByHash");
if (pdahash) *pdahash = NULL;
if (!psad)
return ERROR_INT("&sad not defined", procName, 1);
*psad = NULL;
if (!sas)
return ERROR_INT("sas not defined", procName, 1);
n = sarrayGetCount(sas);
findNextLargerPrime(n / 20, &nsize); /* buckets in hash table */
dahash = l_dnaHashCreate(nsize, 8);
sad = sarrayCreate(n);
*psad = sad;
for (i = 0, items = 0; i < n; i++) {
str = sarrayGetString(sas, i, L_NOCOPY);
sarrayFindStringByHash(sad, dahash, str, &index);
if (index < 0) { /* not found */
l_hashStringToUint64(str, &key);
l_dnaHashAdd(dahash, key, (l_float64)items);
sarrayAddString(sad, str, L_COPY);
items++;
}
}
if (pdahash)
*pdahash = dahash;
else
l_dnaHashDestroy(&dahash);
return 0;
}
/*!
* \brief sarrayIntersectionByAset()
*
* \param[in] sa1, sa2
* \return sad with the intersection of the string set, or NULL on error
*
* <pre>
* Notes:
* (1) Algorithm: put the smaller sarray into a set, using the string
* hashes as the key values. Then run through the larger sarray,
* building an output sarray and a second set from the strings
* in the larger array: if a string is in the first set but
* not in the second, add the string to the output sarray and hash
* it into the second set. The second set is required to make
* sure only one instance of each string is put into the output sarray.
* This is O(mlogn), {m,n} = sizes of {smaller,larger} input arrays.
* </pre>
*/
SARRAY *
sarrayIntersectionByAset(SARRAY *sa1,
SARRAY *sa2)
{
char *str;
l_int32 n1, n2, i, n;
l_uint64 hash;
L_ASET *set1, *set2;
RB_TYPE key;
SARRAY *sa_small, *sa_big, *sad;
PROCNAME("sarrayIntersectionByAset");
if (!sa1)
return (SARRAY *)ERROR_PTR("sa1 not defined", procName, NULL);
if (!sa2)
return (SARRAY *)ERROR_PTR("sa2 not defined", procName, NULL);
/* Put the elements of the biggest array into a set */
n1 = sarrayGetCount(sa1);
n2 = sarrayGetCount(sa2);
sa_small = (n1 < n2) ? sa1 : sa2; /* do not destroy sa_small */
sa_big = (n1 < n2) ? sa2 : sa1; /* do not destroy sa_big */
set1 = l_asetCreateFromSarray(sa_big);
/* Build up the intersection of strings */
sad = sarrayCreate(0);
n = sarrayGetCount(sa_small);
set2 = l_asetCreate(L_UINT_TYPE);
for (i = 0; i < n; i++) {
str = sarrayGetString(sa_small, i, L_NOCOPY);
l_hashStringToUint64(str, &hash);
key.utype = hash;
if (l_asetFind(set1, key) && !l_asetFind(set2, key)) {
sarrayAddString(sad, str, L_COPY);
l_asetInsert(set2, key);
}
}
l_asetDestroy(&set1);
l_asetDestroy(&set2);
return sad;
}
/*!
* \brief sarrayFindStringByHash()
*
* \param[in] sa
* \param[in] dahash built from sa
* \param[in] str arbitrary string
* \param[out] pindex index into %sa if %str is in %sa;
* -1 otherwise
* \return 0 if OK, 1 on error
*
* <pre>
* Notes:
* (1) Fast lookup in dnaHash associated with a sarray, to see if a
* random string %str is already stored in the hash table.
* </pre>
*/
l_int32
sarrayFindStringByHash(SARRAY *sa,
L_DNAHASH *dahash,
const char *str,
l_int32 *pindex)
{
char *stri;
l_int32 i, nvals, index;
l_uint64 key;
L_DNA *da;
PROCNAME("sarrayFindStringByHash");
if (!pindex)
return ERROR_INT("&index not defined", procName, 1);
*pindex = -1;
if (!sa)
return ERROR_INT("sa not defined", procName, 1);
if (!dahash)
return ERROR_INT("dahash not defined", procName, 1);
l_hashStringToUint64(str, &key);
da = l_dnaHashGetDna(dahash, key, L_NOCOPY);
if (!da) return 0;
/* Run through the da, looking for this string */
nvals = l_dnaGetCount(da);
for (i = 0; i < nvals; i++) {
l_dnaGetIValue(da, i, &index);
stri = sarrayGetString(sa, index, L_NOCOPY);
if (!strcmp(str, stri)) { /* duplicate */
*pindex = index;
return 0;
}
}
return 0;
}
