add new comparison method rgb_difference that resembles arithmetical difference per...
[imager.git] / limits.c
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CommitLineData
1/*
2=head1 NAME
3
4limits.c - manages data/functions for limiting the sizes of images read from files.
5
6=head1 SYNOPSIS
7
8 // user code
9 if (!i_set_image_file_limits(max_width, max_height, max_bytes)) {
10 // error
11 }
12 i_get_image_file_limits(&max_width, &max_height, &max_bytes);
13
14 // file reader implementations
15 if (!i_int_check_image_file_limits(width, height, channels, sizeof(i_sample_t))) {
16 // error handling
17 }
18
19=head1 DESCRIPTION
20
21Manage limits for image files read by Imager.
22
23Setting a value of zero means that limit will be ignored.
24
25=over
26
27=cut
28 */
29
30#define IMAGER_NO_CONTEXT
31#include "imageri.h"
32
33/*
34=item im_set_image_file_limits(ctx, width, height, bytes)
35X<im_set_image_file_limits API>X<i_set_image_file_limits API>
36=category Files
37=synopsis im_set_image_file_limits(aIMCTX, 500, 500, 1000000);
38=synopsis i_set_image_file_limits(500, 500, 1000000);
39
40Set limits on the sizes of images read by Imager.
41
42Setting a limit to 0 means that limit is ignored.
43
44Negative limits result in failure.
45
46Parameters:
47
48=over
49
50=item *
51
52i_img_dim width, height - maximum width and height.
53
54=item *
55
56size_t bytes - maximum size in memory in bytes. A value of zero sets
57this limit to one gigabyte.
58
59=back
60
61Returns non-zero on success.
62
63Also callable as C<i_set_image_file_limits(width, height, bytes)>.
64
65=cut
66*/
67
68int
69im_set_image_file_limits(pIMCTX, i_img_dim width, i_img_dim height, size_t bytes) {
70 i_clear_error();
71
72 if (width < 0) {
73 i_push_error(0, "width must be non-negative");
74 return 0;
75 }
76 if (height < 0) {
77 i_push_error(0, "height must be non-negative");
78 return 0;
79 }
80
81 aIMCTX->max_width = width;
82 aIMCTX->max_height = height;
83 aIMCTX->max_bytes = bytes ? bytes : DEF_BYTES_LIMIT;
84
85 return 1;
86}
87
88/*
89=item im_get_image_file_limits(ctx, &width, &height, &bytes)
90X<im_get_image_file_limits API>X<i_get_image_file_limits>
91=category Files
92=synopsis im_get_image_file_limits(aIMCTX, &width, &height, &bytes)
93=synopsis i_get_image_file_limits(&width, &height, &bytes)
94
95Retrieves the file limits set by i_set_image_file_limits().
96
97=over
98
99=item *
100
101i_img_dim *width, *height - the maximum width and height of the image.
102
103=item *
104
105size_t *bytes - size in memory of the image in bytes.
106
107=back
108
109Also callable as C<i_get_image_file_limits(&width, &height, &bytes)>.
110
111=cut
112*/
113
114int
115im_get_image_file_limits(pIMCTX, i_img_dim *width, i_img_dim *height, size_t *bytes) {
116 im_clear_error(aIMCTX);
117
118 *width = aIMCTX->max_width;
119 *height = aIMCTX->max_height;
120 *bytes = aIMCTX->max_bytes;
121
122 return 1;
123}
124
125/*
126=item im_int_check_image_file_limits(width, height, channels, sample_size)
127X<im_int_check_image_file_limits API>X<i_int_check_image_file_limits>
128=category Files
129=synopsis im_int_check_image_file_limits(aIMCTX, width, height, channels, sizeof(i_sample_t))
130=synopsis i_int_check_image_file_limits(width, height, channels, sizeof(i_sample_t))
131
132Checks the size of a file in memory against the configured image file
133limits.
134
135This also range checks the values to those permitted by Imager and
136checks for overflows in calculating the size.
137
138Returns non-zero if the file is within limits.
139
140This function is intended to be called by image file read functions.
141
142Also callable as C<i_int_check_image_file_limits(width, height, channels, sizeof(i_sample_t)>.
143
144=cut
145*/
146
147int
148im_int_check_image_file_limits(pIMCTX, i_img_dim width, i_img_dim height, int channels, size_t sample_size) {
149 size_t bytes;
150 im_clear_error(aIMCTX);
151
152 if (width <= 0) {
153 im_push_errorf(aIMCTX, 0, "file size limit - image width of %" i_DF " is not positive",
154 i_DFc(width));
155 return 0;
156 }
157 if (aIMCTX->max_width && width > aIMCTX->max_width) {
158 im_push_errorf(aIMCTX, 0, "file size limit - image width of %" i_DF " exceeds limit of %" i_DF,
159 i_DFc(width), i_DFc(aIMCTX->max_width));
160 return 0;
161 }
162
163 if (height <= 0) {
164 im_push_errorf(aIMCTX, 0, "file size limit - image height of %" i_DF " is not positive",
165 i_DFc(height));
166 return 0;
167 }
168
169 if (aIMCTX->max_height && height > aIMCTX->max_height) {
170 im_push_errorf(aIMCTX, 0, "file size limit - image height of %" i_DF
171 " exceeds limit of %" i_DF, i_DFc(height), i_DFc(aIMCTX->max_height));
172 return 0;
173 }
174
175 if (channels < 1 || channels > MAXCHANNELS) {
176 im_push_errorf(aIMCTX, 0, "file size limit - channels %d out of range",
177 channels);
178 return 0;
179 }
180
181 if (sample_size < 1 || sample_size > sizeof(long double)) {
182 im_push_errorf(aIMCTX, 0, "file size limit - sample_size %ld out of range",
183 (long)sample_size);
184 return 0;
185 }
186
187 /* This overflow check is a bit more paranoid than usual.
188 We don't protect it under max_bytes since we always want to check
189 for overflow.
190 */
191 bytes = width * height * channels * sample_size;
192 if (bytes / width != height * channels * sample_size
193 || bytes / height != width * channels * sample_size) {
194 im_push_error(aIMCTX, 0, "file size limit - integer overflow calculating storage");
195 return 0;
196 }
197 if (aIMCTX->max_bytes) {
198 if (bytes > aIMCTX->max_bytes) {
199 im_push_errorf(aIMCTX, 0, "file size limit - storage size of %lu "
200 "exceeds limit of %lu", (unsigned long)bytes,
201 (unsigned long)aIMCTX->max_bytes);
202 return 0;
203 }
204 }
205
206 return 1;
207}