/*-------------------------------------------------------------------------
 *
 * checksum_utility.c
 *    Generic data and text checksum helpers
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"
#include "fmgr.h"
#include "access/htup_details.h"
#include "utils/builtins.h"

#include "checksum_internal.h"

/*-------------------------------------------------------------------------
 * UTILITY FUNCTIONS
 *-------------------------------------------------------------------------
 */

/*
 * pg_data_checksum - Generic data checksum utility function
 *
 * Computes a checksum for arbitrary binary data. Useful for application
 * developers who want to checksum their own data using the same algorithm.
 *
 * Parameters:
 *   data: Binary data to checksum (bytea)
 *   seed: Initial hash value (can be used for different contexts)
 */
PG_FUNCTION_INFO_V1(pg_data_checksum);

Datum
pg_data_checksum(PG_FUNCTION_ARGS)
{
    bytea *data;
    uint32 seed;
    uint32 checksum;

    if (PG_ARGISNULL(0))
        PG_RETURN_NULL();

    data = PG_GETARG_BYTEA_PP(0);
    seed = PG_GETARG_INT32(1);

    checksum = pg_checksum_data_custom(VARDATA_ANY(data),
                                       VARSIZE_ANY_EXHDR(data),
                                       seed);

    PG_RETURN_INT32((int32)checksum);
}

/*
 * pg_text_checksum - Text data checksum utility function
 *
 * Convenience wrapper for checksumming text data. Useful for string
 * comparison and text content verification.
 */
PG_FUNCTION_INFO_V1(pg_text_checksum);

Datum
pg_text_checksum(PG_FUNCTION_ARGS)
{
    text *input_text;
    uint32 seed;
    uint32 checksum;

    if (PG_ARGISNULL(0))
        PG_RETURN_NULL();

    input_text = PG_GETARG_TEXT_PP(0);
    seed = PG_GETARG_INT32(1);

    checksum = pg_checksum_data_custom(VARDATA_ANY(input_text),
                                       VARSIZE_ANY_EXHDR(input_text),
                                       seed);

    PG_RETURN_INT32((int32)checksum);
}