/*
 * PostgreSQL type definitions for CITEXT 2.0.
 */

#include "postgres.h"

#include "access/hash.h"
#include "fmgr.h"
#include "utils/builtins.h"
#include "utils/formatting.h"

#ifdef PG_MODULE_MAGIC
PG_MODULE_MAGIC;
#endif

/*
 *      ====================
 *      FORWARD DECLARATIONS
 *      ====================
 */

static int32  citextcmp      (text *left, text *right);
extern Datum  citext_cmp     (PG_FUNCTION_ARGS);
extern Datum  citext_hash    (PG_FUNCTION_ARGS);
extern Datum  citext_eq      (PG_FUNCTION_ARGS);
extern Datum  citext_ne      (PG_FUNCTION_ARGS);
extern Datum  citext_gt      (PG_FUNCTION_ARGS);
extern Datum  citext_ge      (PG_FUNCTION_ARGS);
extern Datum  citext_lt      (PG_FUNCTION_ARGS);
extern Datum  citext_le      (PG_FUNCTION_ARGS);
extern Datum  citext_smaller (PG_FUNCTION_ARGS);
extern Datum  citext_larger  (PG_FUNCTION_ARGS);

/*
 *      =================
 *      UTILITY FUNCTIONS
 *      =================
 */


/* citextcmp()
 * Internal comparison function for citext strings.
 * Returns int32 negative, zero, or positive.
 */

static int32
citextcmp (text *left, text *right)
{
    char   *lcstr, *rcstr;
    int32	result;

    lcstr = str_tolower(VARDATA_ANY(left), VARSIZE_ANY_EXHDR(left));
    rcstr = str_tolower(VARDATA_ANY(right), VARSIZE_ANY_EXHDR(right));

    result = varstr_cmp(lcstr, strlen(lcstr),
						rcstr, strlen(rcstr));

    pfree(lcstr);
    pfree(rcstr);

    return result;
}

/*
 *      ==================
 *      INDEXING FUNCTIONS
 *      ==================
 */

PG_FUNCTION_INFO_V1(citext_cmp);

Datum
citext_cmp(PG_FUNCTION_ARGS)
{
    text *left  = PG_GETARG_TEXT_PP(0);
    text *right = PG_GETARG_TEXT_PP(1);
    int32 result;

    result = citextcmp(left, right);

    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);

    PG_RETURN_INT32(result);
}

PG_FUNCTION_INFO_V1(citext_hash);

Datum
citext_hash(PG_FUNCTION_ARGS)
{
    text       *txt = PG_GETARG_TEXT_PP(0);
    char       *str;
    Datum       result;

    str    = str_tolower(VARDATA_ANY(txt), VARSIZE_ANY_EXHDR(txt));
    result = hash_any((unsigned char *) str, strlen(str));
    pfree(str);

    /* Avoid leaking memory for toasted inputs */
    PG_FREE_IF_COPY(txt, 0);

    PG_RETURN_DATUM(result);
}

/*
 *      ==================
 *      OPERATOR FUNCTIONS
 *      ==================
 */

PG_FUNCTION_INFO_V1(citext_eq);

Datum
citext_eq(PG_FUNCTION_ARGS)
{
    text *left  = PG_GETARG_TEXT_PP(0);
    text *right = PG_GETARG_TEXT_PP(1);
    char *lcstr, *rcstr;
    bool  result;

    lcstr = str_tolower(VARDATA_ANY(left), VARSIZE_ANY_EXHDR(left));
    rcstr = str_tolower(VARDATA_ANY(right), VARSIZE_ANY_EXHDR(right));
    
    /*
     * We can't do the length-comparison optimization here, as is done for the
     * text type in varlena.c, because sometimes the lengths can be different.
     * The canonical example is the turkish dotted i: the lowercase version is
     * the standard ASCII i, but the uppercase version is multibyte.
     * Otherwise, since we only care about equality or not-equality, we can
     * avoid all the expense of strcoll() here, and just do bitwise
     * comparison.
     */
    result = (strcmp(lcstr, rcstr) == 0);

    pfree(lcstr);
    pfree(rcstr);
    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);

    PG_RETURN_BOOL(result);
}

PG_FUNCTION_INFO_V1(citext_ne);

Datum
citext_ne(PG_FUNCTION_ARGS)
{
    text *left  = PG_GETARG_TEXT_PP(0);
    text *right = PG_GETARG_TEXT_PP(1);
    char *lcstr, *rcstr;
    bool  result;

    lcstr = str_tolower(VARDATA_ANY(left), VARSIZE_ANY_EXHDR(left));
    rcstr = str_tolower(VARDATA_ANY(right), VARSIZE_ANY_EXHDR(right));
    
    /*
     * We can't do the length-comparison optimization here, as is done for the
     * text type in varlena.c, because sometimes the lengths can be different.
     * The canonical example is the turkish dotted i: the lowercase version is
     * the standard ASCII i, but the uppercase version is multibyte.
     * Otherwise, since we only care about equality or not-equality, we can
     * avoid all the expense of strcoll() here, and just do bitwise
     * comparison.
     */
    result = (strcmp(lcstr, rcstr) != 0);

    pfree(lcstr);
    pfree(rcstr);
    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);

    PG_RETURN_BOOL(result);
}

PG_FUNCTION_INFO_V1(citext_lt);

Datum
citext_lt(PG_FUNCTION_ARGS)
{
    text *left  = PG_GETARG_TEXT_PP(0);
    text *right = PG_GETARG_TEXT_PP(1);
    bool  result;
    
    result = citextcmp(left, right) < 0;

    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);

    PG_RETURN_BOOL(result);
}

PG_FUNCTION_INFO_V1(citext_le);

Datum
citext_le(PG_FUNCTION_ARGS)
{
    text *left  = PG_GETARG_TEXT_PP(0);
    text *right = PG_GETARG_TEXT_PP(1);
    bool  result;
    
    result = citextcmp(left, right) <= 0;

    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);

    PG_RETURN_BOOL(result);
}

PG_FUNCTION_INFO_V1(citext_gt);

Datum
citext_gt(PG_FUNCTION_ARGS)
{
    text *left  = PG_GETARG_TEXT_PP(0);
    text *right = PG_GETARG_TEXT_PP(1);
    bool  result;
    
    result = citextcmp(left, right) > 0;

    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);

    PG_RETURN_BOOL(result);
}

PG_FUNCTION_INFO_V1(citext_ge);

Datum
citext_ge(PG_FUNCTION_ARGS)
{
    text *left  = PG_GETARG_TEXT_PP(0);
    text *right = PG_GETARG_TEXT_PP(1);
    bool  result;
    
    result = citextcmp(left, right) >= 0;

    PG_FREE_IF_COPY(left, 0);
    PG_FREE_IF_COPY(right, 1);

    PG_RETURN_BOOL(result);
}

/*
 *      ===================
 *      AGGREGATE FUNCTIONS
 *      ===================
 */

PG_FUNCTION_INFO_V1(citext_smaller);

Datum
citext_smaller(PG_FUNCTION_ARGS)
{
    text *left  = PG_GETARG_TEXT_PP(0);
    text *right = PG_GETARG_TEXT_PP(1);
    text *result;

    result = citextcmp(left, right) < 0 ? left : right;
    PG_RETURN_TEXT_P(result);
}

PG_FUNCTION_INFO_V1(citext_larger);

Datum
citext_larger(PG_FUNCTION_ARGS)
{
    text *left  = PG_GETARG_TEXT_PP(0);
    text *right = PG_GETARG_TEXT_PP(1);
    text *result;

    result = citextcmp(left, right) > 0 ? left : right;
    PG_RETURN_TEXT_P(result);
}