simple_list.c

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/*-------------------------------------------------------------------------
 *
 * Simple list facilities for frontend code
 *
 * Data structures for simple lists of OIDs and strings.  The support for
 * these is very primitive compared to the backend's List facilities, but
 * it's all we need in, eg, pg_dump.
 *
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/fe_utils/simple_list.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres_fe.h"
 
#include "fe_utils/simple_list.h"
 
 
/*
 * Append an OID to the list.
 */
void
simple_oid_list_append(SimpleOidList *list, Oid val)
{
    SimpleOidListCell *cell;
 
    cell = (SimpleOidListCell *) pg_malloc(sizeof(SimpleOidListCell));
    cell->next = NULL;
    cell->val = val;
 
    if (list->tail)
        list->tail->next = cell;
    else
        list->head = cell;
    list->tail = cell;
}
 
/*
 * Is OID present in the list?
 */
bool
simple_oid_list_member(SimpleOidList *list, Oid val)
{
    SimpleOidListCell *cell;
 
    for (cell = list->head; cell; cell = cell->next)
    {
        if (cell->val == val)
            return true;
    }
    return false;
}
 
/*
 * Append a string to the list.
 *
 * The given string is copied, so it need not survive past the call.
 */
void
simple_string_list_append(SimpleStringList *list, const char *val)
{
    SimpleStringListCell *cell;
 
    cell = (SimpleStringListCell *)
        pg_malloc(offsetof(SimpleStringListCell, val) + strlen(val) + 1);
 
    cell->next = NULL;
    cell->touched = false;
    strcpy(cell->val, val);
 
    if (list->tail)
        list->tail->next = cell;
    else
        list->head = cell;
    list->tail = cell;
}
 
/*
 * Is string present in the list?
 *
 * If found, the "touched" field of the first match is set true.
 */
bool
simple_string_list_member(SimpleStringList *list, const char *val)
{
    SimpleStringListCell *cell;
 
    for (cell = list->head; cell; cell = cell->next)
    {
        if (strcmp(cell->val, val) == 0)
        {
            cell->touched = true;
            return true;
        }
    }
    return false;
}
 
/*
 * Destroy an OID list
 */
void
simple_oid_list_destroy(SimpleOidList *list)
{
    SimpleOidListCell *cell;
 
    cell = list->head;
    while (cell != NULL)
    {
        SimpleOidListCell *next;
 
        next = cell->next;
        pg_free(cell);
        cell = next;
    }
}
 
/*
 * Destroy a string list
 */
void
simple_string_list_destroy(SimpleStringList *list)
{
    SimpleStringListCell *cell;
 
    cell = list->head;
    while (cell != NULL)
    {
        SimpleStringListCell *next;
 
        next = cell->next;
        pg_free(cell);
        cell = next;
    }
}
 
/*
 * Find first not-touched list entry, if there is one.
 */
const char *
simple_string_list_not_touched(SimpleStringList *list)
{
    SimpleStringListCell *cell;
 
    for (cell = list->head; cell; cell = cell->next)
    {
        if (!cell->touched)
            return cell->val;
    }
    return NULL;
}
 
/*
 * Append a pointer to the list.
 *
 * Caller must ensure that the pointer remains valid.
 */
void
simple_ptr_list_append(SimplePtrList *list, void *ptr)
{
    SimplePtrListCell *cell;
 
    cell = (SimplePtrListCell *) pg_malloc(sizeof(SimplePtrListCell));
    cell->next = NULL;
    cell->ptr = ptr;
 
    if (list->tail)
        list->tail->next = cell;
    else
        list->head = cell;
    list->tail = cell;
}
 
/*
 * Destroy only pointer list and not the pointed-to element
 */
void
simple_ptr_list_destroy(SimplePtrList *list)
{
    SimplePtrListCell *cell;
 
    cell = list->head;
    while (cell != NULL)
    {
        SimplePtrListCell *next;
 
        next = cell->next;
        pg_free(cell);
        cell = next;
    }
}