adg/adg-segment.c

   1 /* ADG - Automatic Drawing Generation
   2  * Copyright (C) 2007,2008,2009 Nicola Fontana <ntd at entidi.it>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA  02110-1301, USA.
  18  */
  19
  20
  21 /**
  22  * SECTION:adg-segment
  23  * @Section_Id:AdgSegment
  24  * @title: AdgSegment
  25  * @short_description: A wrapper for #CpmlSegment
  26  *
  27  * AdgSegment is a wrapper in #GType syntax of the #CpmlSegment struct.
  28  * Furthermore, some dynamic memory functions are provided, such as
  29  * shallow and deep duplication functions.
  30  **/
  31
  32 /**
  33  * AdgSegment:
  34  *
  35  * Another name for #CpmlSegment: check its documentation for the
  36  * fields description and visibility details.
  37  **/
  38
  39
  40 #include "adg-segment.h"
  41
  42 #include <string.h>
  43
  44
  45 GType
  46 adg_segment_get_type(void)
  47 {
  48     static int segment_type = 0;
  49
  50     if (G_UNLIKELY(segment_type == 0))
  51         segment_type = g_boxed_type_register_static("AdgSegment",
  52                                                     (GBoxedCopyFunc) adg_segment_dup,
  53                                                     g_free);
  54
  55     return segment_type;
  56 }
  57
  58 /**
  59  * adg_segment_dup:
  60  * @segment: an #AdgSegment structure
  61  *
  62  * Duplicates @segment. This function makes a shallow duplication,
  63  * that is the internal pointers of the resulting segment struct
  64  * refer to the same memory as the original @segment. Check out
  65  * adg_segment_deep_dup() if it is required also the content
  66  * duplication.
  67  *
  68  * Returns: a shallow duplicate of @segment: must be freed
  69  *          with g_free() when no longer needed.
  70  **/
  71 AdgSegment *
  72 adg_segment_dup(const AdgSegment *segment)
  73 {
  74     return g_memdup(segment, sizeof(AdgSegment));
  75 }
  76
  77 /**
  78  * adg_segment_deep_dup:
  79  * @segment: an #AdgSegment structure
  80  *
  81  * Duplicates @segment. This function makes a deep duplication,
  82  * that is it duplicates also the underlying data that defines
  83  * the segment. The <structfield>path</structfield> field
  84  * is set to %NULL as <structfield>data</structfield> is no
  85  * more referring to the original cairo path.
  86  *
  87  * All the data is allocated in the same chunk of memory so freeing
  88  * the returned pointer releases all the occupied memory.
  89  *
  90  * Returns: a deep duplicate of @segment: must be freed
  91  *          with g_free() when no longer needed.
  92  **/
  93 AdgSegment *
  94 adg_segment_deep_dup(const AdgSegment *segment)
  95 {
  96     AdgSegment *dest;
  97     gsize segment_size, data_size;
  98     cairo_path_data_t *p_data;
  99
 100     segment_size = sizeof(AdgSegment);
 101     data_size = segment->data == NULL ?
 102         0 : sizeof(cairo_path_data_t) * segment->num_data;
 103     dest = (AdgSegment *) g_malloc(segment_size + data_size);
 104     p_data = (cairo_path_data_t *) ((gchar *) dest + segment_size);
 105
 106     dest->path = NULL;
 107
 108     if (data_size > 0) {
 109         dest->data = memcpy(p_data, segment->data, data_size);
 110         dest->num_data = segment->num_data;
 111     } else {
 112         dest->data = NULL;
 113         dest->num_data = 0;
 114     }
 115
 116     return dest;
 117 }
 118
 119 /**
 120  * adg_segment_deep_copy:
 121  * @segment: an #AdgSegment structure
 122  * @src: the source segment to copy
 123  *
 124  * Makes a deep copy of @src to @segment. For a shallow copy, check out
 125  * the cpml_segment_copy() API provided by the CPML library.
 126  *
 127  * This could seem a somewhat unusual operation because @segment should
 128  * be "compatible" with @src: it is expected that they have the same
 129  * <structfield>num_data</structfield> value. Anyway, it is convenient
 130  * in some situation, such as when restoring the original data from a
 131  * deep duplicated source:
 132  *
 133  * |[
 134  * AdgSegment *backup;
 135  *
 136  * backup = adg_segment_deep_dup(&segment);
 137  * // Now &segment can be modified
 138  * ...
 139  * adg_segment_deep_copy(&segment, backup);
 140  * g_free(backup);
 141  * ]|
 142  *
 143  * The struct fields of @segment are left untouched and used only to
 144  * check if it is compatible with @src.
 145  *
 146  * Returns: @segment
 147  **/
 148 AdgSegment *
 149 adg_segment_deep_copy(AdgSegment *segment, const AdgSegment *src)
 150 {
 151     size_t n;
 152
 153     g_return_val_if_fail(segment != NULL, segment);
 154     g_return_val_if_fail(src != NULL, segment);
 155     g_return_val_if_fail(segment->num_data == src->num_data, segment);
 156
 157     if (src->num_data <= 0)
 158         return segment;
 159
 160     n = sizeof(cairo_path_data_t) * segment->num_data;
 161
 162     memcpy(segment->data, src->data, n);
 163
 164     return segment;
 165 }