1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
/* files.c: Glulxe file-handling code.
Designed by Andrew Plotkin <erkyrath@eblong.com>
http://eblong.com/zarf/glulx/index.html
*/
#include "glk.h"
#include "gi_blorb.h"
#include "glulxe.h"
/* is_gamefile_valid():
Check guess what.
*/
int is_gamefile_valid()
{
unsigned char buf[8];
int res;
glui32 version;
glk_stream_set_position(gamefile, gamefile_start, seekmode_Start);
res = glk_get_buffer_stream(gamefile, (char *)buf, 8);
if (res != 8) {
fatal_error("This is too short to be a valid Glulx file.");
return FALSE;
}
if (buf[0] != 'G' || buf[1] != 'l' || buf[2] != 'u' || buf[3] != 'l') {
fatal_error("This is not a valid Glulx file.");
return FALSE;
}
/* We support version 2.0 through 3.1.*. */
version = Read4(buf+4);
if (version < 0x20000) {
fatal_error("This Glulx file is too old a version to execute.");
return FALSE;
}
if (version >= 0x30200) {
fatal_error("This Glulx file is too new a version to execute.");
return FALSE;
}
return TRUE;
}
/* locate_gamefile:
Given that gamefile contains a Glk stream, which may be a Glulx
file or a Blorb archive containing one, locate the beginning and
end of the Glulx data.
*/
int locate_gamefile(int isblorb)
{
if (!isblorb) {
/* The simple case. A bare Glulx file was opened, so we don't use
Blorb at all. */
gamefile_start = 0;
glk_stream_set_position(gamefile, 0, seekmode_End);
gamefile_len = glk_stream_get_position(gamefile);
return TRUE;
}
else {
/* A Blorb file. We now have to open it and find the Glulx chunk. */
giblorb_err_t err;
giblorb_result_t blorbres;
giblorb_map_t *map;
err = giblorb_set_resource_map(gamefile);
if (err) {
init_err = "This Blorb file seems to be invalid.";
return FALSE;
}
map = giblorb_get_resource_map();
err = giblorb_load_resource(map, giblorb_method_FilePos,
&blorbres, giblorb_ID_Exec, 0);
if (err) {
init_err = "This Blorb file does not contain an executable Glulx chunk.";
return FALSE;
}
if (blorbres.chunktype != giblorb_make_id('G', 'L', 'U', 'L')) {
init_err = "This Blorb file contains an executable chunk, but it is not a Glulx file.";
return FALSE;
}
gamefile_start = blorbres.data.startpos;
gamefile_len = blorbres.length;
return TRUE;
}
}
|
