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/*
* This file is part of the HDRL
* Copyright (C) 2013 European Southern Observatory
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
/*-----------------------------------------------------------------------------
Includes
-----------------------------------------------------------------------------*/
#include "hdrl_iter.h"
#include "hdrl_types.h"
#include <cpl.h>
/*-----------------------------------------------------------------------------
Static
-----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------*/
/**
@defgroup hdrl_iter Iterator
*/
/*----------------------------------------------------------------------------*/
/**@{*/
/** @cond EXPERIMENTAL */
/** @cond PRIVATE */
struct _hdrl_iter_ {
/* returns next value in sequence iterated on (e.g. image, imagelist) */
hdrl_iter_next_f * next;
/* optional, resets the iteration to the first element */
hdrl_iter_reset_f * reset;
/* optional, returns length of the iterator */
hdrl_iter_length_f * length;
/* state destructor */
hdrl_free * destructor;
/* iterator flags */
hdrl_iter_flags flags;
/* state structure of iterator */
void * state;
};
/* ---------------------------------------------------------------------------*/
/**
* @internal
* @brief initialize an iterator
*
* @param next function pointer returning next value in sequence iterated on
* @param reset function pointer or NULL, reseting iteration to first element
* @param length function pointer or NULL, returning length of sequence
* @param flags flags of iterator
* @param state state structure of iterator
*
* An iterator iterates on a sequence of data (e.g. imagelist, files on
* disk, ...) and returns an element of that sequence on each call to the
* next function. When the sequence is exhausted it returns NULL.
*
* Each member function is called with the iterator as first argument, from
* this the state can be received with hdrl_iter_state(it), the state is a
* user defined structure typically containing the current position in the
* sequence.
*
* The iterator type defines what kind of data is returned by each next call.
* The options are:
* HDRL_ITER_INPUT: data provided is input data to be processed, it will be
freed by the caller of next. (FIXME: add flag to not free?)
* HDRL_ITER_OUTPUT: data is an empty output buffer for the caller of next
* to place its results into. Its memory is managed by the
* iterator.
* HDRL_ITER_IMAGE: the return of next is a cpl_image
* HDRL_ITER_IMAGELIST: the return of next is a cpl_imagelist
*/
/* ---------------------------------------------------------------------------*/
hdrl_iter *
hdrl_iter_init(hdrl_iter_next_f * next,
hdrl_iter_reset_f * reset,
hdrl_iter_length_f * length,
hdrl_free * destructor,
hdrl_iter_flags flags,
void * state)
{
/* exactly one each set */
hdrl_iter_flags inout = (HDRL_ITER_INPUT | HDRL_ITER_OUTPUT);
hdrl_iter_flags retflags = (HDRL_ITER_IMAGE | HDRL_ITER_IMAGELIST);
cpl_ensure(((flags & inout) == HDRL_ITER_INPUT) ||
((flags & inout) == HDRL_ITER_OUTPUT),
CPL_ERROR_ILLEGAL_INPUT, NULL);
cpl_ensure(((flags & retflags) == HDRL_ITER_IMAGE) ||
((flags & retflags) == HDRL_ITER_IMAGELIST),
CPL_ERROR_ILLEGAL_INPUT, NULL);
cpl_ensure(state, CPL_ERROR_NULL_INPUT, NULL);
cpl_ensure(next, CPL_ERROR_NULL_INPUT, NULL);
cpl_ensure(flags != 0, CPL_ERROR_NULL_INPUT, NULL);
hdrl_iter * it = cpl_malloc(sizeof(*it));
it->next = next;
it->length = length;
it->reset = reset;
it->destructor = destructor ? destructor : &cpl_free;
it->flags = flags;
it->state = state;
return it;
}
/* ---------------------------------------------------------------------------*/
/**
* @internal
* @brief return the state structure of the iterator
* @param it iterator
* @return state structure
*/
/* ---------------------------------------------------------------------------*/
void * hdrl_iter_state(const hdrl_iter * it)
{
cpl_ensure(it, CPL_ERROR_NULL_INPUT, NULL);
return it->state;
}
/* ---------------------------------------------------------------------------*/
/**
* @internal
* @brief check if iterator has a certain flag
* @param it iterator
* @param flags flag to check
* @return true or false depending wheter iterator has flags set
*/
/* ---------------------------------------------------------------------------*/
cpl_boolean hdrl_iter_check(hdrl_iter * it, hdrl_iter_flags flags)
{
cpl_ensure(it, CPL_ERROR_NULL_INPUT, CPL_FALSE);
return (it->flags & flags) == flags;
}
/** @endcond */
/* ---------------------------------------------------------------------------*/
/**
* @brief delete iterator structure
* @param it iterator
* @note will not delete the state structure, typically this is called in the
* user iterator destructor
*/
/* ---------------------------------------------------------------------------*/
void hdrl_iter_delete(hdrl_iter * it)
{
if (it) {
if (it->destructor) {
it->destructor(it);
}
cpl_free(it);
}
}
/* ---------------------------------------------------------------------------*/
/**
* @brief return next element in sequence or NULL if done
* @param it iterator
* @return object or NULL, type of object depends on iterator type
*/
/* ---------------------------------------------------------------------------*/
void * hdrl_iter_next(hdrl_iter * it)
{
cpl_ensure(it, CPL_ERROR_NULL_INPUT, NULL);
return it->next(it);
}
/* ---------------------------------------------------------------------------*/
/**
* @brief reset iterator to beginning of sequence
* @param it iterator
*/
/* ---------------------------------------------------------------------------*/
void hdrl_iter_reset(hdrl_iter * it)
{
if (!it) {
cpl_error_set_message(cpl_func, CPL_ERROR_NULL_INPUT,
"Iterator Null");
} else if (it->reset == NULL) {
cpl_error_set_message(cpl_func, CPL_ERROR_UNSUPPORTED_MODE,
"Iterator has no reset method");
} else {
it->reset(it);
}
}
/* ---------------------------------------------------------------------------*/
/**
* @brief return length of sequence
* @param it iterator
* @return length of sequence
*/
/* ---------------------------------------------------------------------------*/
cpl_size hdrl_iter_length(hdrl_iter * it)
{
if (!it) {
cpl_error_set_message(cpl_func, CPL_ERROR_NULL_INPUT,
"Iterator Null");
return -1;
} else if (it->length == NULL) {
cpl_error_set_message(cpl_func, CPL_ERROR_UNSUPPORTED_MODE,
"Iterator has no length method");
return -1;
}
return it->length(it);
}
/**@}*/
/** @endcond */
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