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#include <libpq-fe.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include "db.h"
#define DB_MAX_FIELDS 64
#define DB_MAX_CHAR 256
static PGconn *g_pConnection = NULL;
static PGresult *g_pResult = NULL;
static char g_pError[DB_MAX_CHAR];
static int db_clear_error(void)
{
memset(&g_pError, 0, (size_t)(sizeof(char) * DB_MAX_CHAR));
return DB_OK;
} // db_clear_error
static int db_set_error(const char *f_pError)
{
db_clear_error();
strcpy(g_pError, f_pError);
return DB_OK;
} // db_set_error
static void db_raise_warning(void)
{
printf("Database exception!\n");
printf("%s", g_pError);
} // db_raise_warning
static void db_raise_error(void)
{
db_raise_warning();
db_close();
exit(1);
} // db_raise_error
static char *db_get_error(void)
{
return g_pError;
} // db_get_error
static int db_check_connection(void)
{
char l_pError[DB_MAX_CHAR];
if (g_pConnection == NULL)
{
sprintf(l_pError, "Database connection lost!");
db_set_error(l_pError);
db_raise_error();
return DB_NO_CONNECTION;
}
return DB_OK;
} // db_check_connection
static int db_check_result(void)
{
char l_pError[DB_MAX_CHAR];
if (g_pResult == NULL)
{
sprintf(l_pError, "Incorrect PostgreSQL result.");
db_set_error(l_pError);
db_raise_warning();
return DB_INCORRECT_RESULT;
}
return DB_OK;
} // db_check_result
int db_init(void)
{
char l_pError[DB_MAX_CHAR];
g_pConnection = PQsetdbLogin(PGHOST, PGPORT, PGOPTIONS, PGTTY, DBNAME, LOGIN, PWD);
if (PQstatus(g_pConnection) == CONNECTION_BAD)
{
sprintf(l_pError, "Connection to database '%s' failed.\n%s", DBNAME, PQerrorMessage(g_pConnection));
db_set_error(l_pError);
db_raise_error();
return DB_NO_CONNECTION;
}
db_clear_error();
return DB_OK;
} // db_init
int db_close(void)
{
PQclear(g_pResult);
PQfinish(g_pConnection);
return DB_OK;
} // db_close
int db_output(void)
{
int l_iNTuples, l_iNFields;
char l_pText[DB_MAX_CHAR];
int l_iColumnWidth[DB_MAX_FIELDS];
int l_iMaxColumnWidth[DB_MAX_FIELDS];
int i, j, k, l;
// check the db connection
if (db_check_connection() != DB_OK)
{
exit(1);
return DB_COULD_NOT_OUTPUT;
}
// check the validity of the result
if (db_check_result() != DB_OK)
{
return DB_COULD_NOT_OUTPUT;
}
l_iNTuples = PQntuples(g_pResult);
l_iNFields = PQnfields(g_pResult);
// copy all tuple names incl. field values
for (i = 0; i < l_iNFields; i++)
{
k = 0;
for (j = 0; j < l_iNTuples; j++)
{
strcpy(l_pText, PQgetvalue(g_pResult, j, i));
l_iColumnWidth[k] = (int)strlen(l_pText);
k++;
}
strcpy(l_pText, PQfname(g_pResult, i));
l_iMaxColumnWidth[i] = (int)strlen(l_pText);
for (j = 1; j < l_iNTuples; j++)
{
l_iMaxColumnWidth[i] = max(l_iMaxColumnWidth[i], l_iColumnWidth[j]);
}
}
// print column names
for (i = 0; i < l_iNFields; i++)
{
int len;
if (i) printf("| ");
strcpy(l_pText, PQfname(g_pResult, i));
printf("%s", l_pText);
len = (int)strlen(PQfname(g_pResult, i)) - 1;
if (i < l_iNFields - 1)
{
for (k = 0; k < l_iMaxColumnWidth[i] - len; k++)
{
printf(" ");
}
}
}
printf("\n");
// print horizontal line
l = 0;
for (k = 0; k < l_iNFields; k++) l += l_iMaxColumnWidth[k];
l += (l_iNFields - 1) * 3;
for (k = 0; k < l; k++) printf("-");
printf("\n");
// print row values
for (i = 0; i < l_iNTuples; i++)
{
for (j = 0; j < l_iNFields; j++)
{
int len;
if (j) printf("| ");
strcpy(l_pText, PQgetvalue(g_pResult, i, j));
printf("%s ", l_pText);
len = (int)strlen(l_pText) - 1;
if (j < l_iNFields - 1)
{
for (k = 1; k < l_iMaxColumnWidth[j] - len; k++)
{
printf(" ");
}
}
}
printf("\n");
}
return DB_OK;
} // db_output
int db_execute(const char* f_pQuery)
{
char l_pError[DB_MAX_CHAR];
char l_pCmdStatus[DB_MAX_CHAR];
// check the db connection
if (db_check_connection() != DB_OK)
{
exit(1);
return DB_COULD_NOT_EXECUTE;
}
g_pResult = PQexec(g_pConnection, f_pQuery);
if (g_pResult == NULL || (PQresultStatus(g_pResult) != PGRES_COMMAND_OK && PQresultStatus(g_pResult) != PGRES_TUPLES_OK))
{
sprintf(l_pError, "Unable to execute query: %s\n%s", f_pQuery, PQerrorMessage(g_pConnection));
db_set_error(l_pError);
db_raise_warning();
return DB_COULD_NOT_EXECUTE;
}
sprintf(l_pCmdStatus, "%s", PQcmdStatus(g_pResult));
if (!strcmp(l_pCmdStatus, "SELECT"))
{
db_output();
}
else
{
printf("%s\n", l_pCmdStatus);
}
return DB_OK;
} // db_execute
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