src/adg/adg-segment.c

   1 /* ADG - Automatic Drawing Generation
   2  * Copyright (C) 2007,2008,2009,2010,2011,2012  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  * Since: 1.0
  32  **/
  33
  34 /**
  35  * AdgSegment:
  36  *
  37  * Another name for #CpmlSegment: check its documentation for the
  38  * fields description and visibility details.
  39  *
  40  * Since: 1.0
  41  **/
  42
  43
  44 #include "adg-internal.h"
  45 #include "adg-segment.h"
  46 #include <string.h>
  47
  48
  49 GType
  50 adg_segment_get_type(void)
  51 {
  52     static GType segment_type = 0;
  53
  54     if (G_UNLIKELY(segment_type == 0))
  55         segment_type = g_boxed_type_register_static("AdgSegment",
  56                                                     (GBoxedCopyFunc) adg_segment_dup,
  57                                                     g_free);
  58
  59     return segment_type;
  60 }
  61
  62 /**
  63  * adg_segment_dup:
  64  * @segment: an #AdgSegment structure
  65  *
  66  * Duplicates @segment. This function makes a shallow duplication,
  67  * that is the internal pointers of the resulting segment struct
  68  * refer to the same memory as the original @segment. Check out
  69  * adg_segment_deep_dup() if it is required also the content
  70  * duplication.
  71  *
  72  * Returns: (transfer full): a shallow duplicate of @segment: must be freed with g_free() when no longer needed.
  73  *
  74  * Since: 1.0
  75  **/
  76 AdgSegment *
  77 adg_segment_dup(const AdgSegment *segment)
  78 {
  79     return g_memdup(segment, sizeof(AdgSegment));
  80 }
  81
  82 /**
  83  * adg_segment_deep_dup:
  84  * @segment: an #AdgSegment structure
  85  *
  86  * Duplicates @segment. This function makes a deep duplication,
  87  * that is it duplicates also the underlying data that defines
  88  * the segment. The <structfield>path</structfield> field
  89  * is set to %NULL as <structfield>data</structfield> is no
  90  * more referring to the original cairo path.
  91  *
  92  * All the data is allocated in the same chunk of memory so freeing
  93  * the returned pointer releases all the occupied memory.
  94  *
  95  * Returns: (transfer full): a deep duplicate of @segment: must be freed with g_free() when no longer needed.
  96  *
  97  * Since: 1.0
  98  **/
  99 AdgSegment *
 100 adg_segment_deep_dup(const AdgSegment *segment)
 101 {
 102     AdgSegment *dest;
 103     int num_data;
 104     gsize segment_size, data_size;
 105     cairo_path_data_t *p_data;
 106
 107     g_return_val_if_fail(segment != NULL, NULL);
 108
 109     num_data = segment->num_data;
 110     segment_size = sizeof(AdgSegment);
 111     data_size = segment->data ? sizeof(cairo_path_data_t) * num_data : 0;
 112     dest = (AdgSegment *) g_malloc(segment_size + data_size);
 113     p_data = (cairo_path_data_t *) ((gchar *) dest + segment_size);
 114
 115     dest->path = NULL;
 116
 117     if (data_size > 0) {
 118         dest->data = memcpy(p_data, segment->data, data_size);
 119         dest->num_data = num_data;
 120     } else {
 121         dest->data = NULL;
 122         dest->num_data = 0;
 123     }
 124
 125     return dest;
 126 }
 127
 128 /**
 129  * adg_segment_deep_copy:
 130  * @segment: an #AdgSegment structure
 131  * @src: the source segment to copy
 132  *
 133  * Makes a deep copy of @src to @segment. For a shallow copy, check out
 134  * the cpml_segment_copy() API provided by the CPML library.
 135  *
 136  * This could seem a somewhat unusual operation because @segment should
 137  * be "compatible" with @src: it is expected that they have the same
 138  * <structfield>num_data</structfield> value. Anyway, it is convenient
 139  * in some situation, such as when restoring the original data from a
 140  * deep duplicated source:
 141  *
 142  * |[
 143  * AdgSegment *backup;
 144  *
 145  * backup = adg_segment_deep_dup(&segment);
 146  * // Now &segment can be modified
 147  * ...
 148  * adg_segment_deep_copy(&segment, backup);
 149  * g_free(backup);
 150  * ]|
 151  *
 152  * The struct fields of @segment are left untouched and used only to
 153  * check if it is compatible with @src.
 154  *
 155  * Since: 1.0
 156  **/
 157 void
 158 adg_segment_deep_copy(AdgSegment *segment, const AdgSegment *src)
 159 {
 160     g_return_if_fail(segment != NULL);
 161     g_return_if_fail(src != NULL);
 162     g_return_if_fail(segment->num_data == src->num_data);
 163
 164     if (src->num_data > 0) {
 165         size_t n = sizeof(cairo_path_data_t) * segment->num_data;
 166         memcpy(segment->data, src->data, n);
 167     }
 168 }