Function pj_expand_init_internal

src/init.cpp:366–407

/

/*****************************************************************************/
static paralist *pj_expand_init_internal(PJ_CONTEXT *ctx, paralist *init,
                                         int allow_init_epsg) {
    /******************************************************************************
    Append expansion of <key> to the paralist <init>. The expansion is appended,
    rather than inserted at <init>'s place, since <init> may contain
    overrides to the expansion. These must take precedence, and hence come first
    in the expanded list.

    Consider e.g. the key 'foo:bar' which (hypothetically) expands to 'proj=utm
    zone=32 ellps=GRS80', i.e. a UTM projection on the GRS80 ellipsoid.

    The expression 'init=foo:bar ellps=intl' will then expand to:

               'init=foo:bar ellps=intl proj=utm zone=32 ellps=GRS80',

    where 'ellps=intl' precedes 'ellps=GRS80', and hence takes precedence,
    turning the expansion into an UTM projection on the Hayford ellipsoid.

    Note that 'init=foo:bar' stays in the list. It is ignored after expansion.

    ******************************************************************************/
    paralist *last;
    paralist *expn;

    /* Nowhere to start? */
    if (nullptr == init)
        return nullptr;

    expn = get_init(ctx, init->param, allow_init_epsg);

    /* Nothing in expansion? */
    if (nullptr == expn)
        return nullptr;

    /* Locate  the end of the list */
    for (last = init; last && last->next; last = last->next)
        ;

    /* Then append and return */
    last->next = expn;
    return init;
}

paralist *pj_expand_init(PJ_CONTEXT *ctx, paralist *init) {
    return pj_expand_init_internal(ctx, init, TRUE);