2 * Copyright (C) Volition, Inc. 1999. All rights reserved.
4 * All source code herein is the property of Volition, Inc. You may not sell
5 * or otherwise commercially exploit the source or things you created based on
10 * $Logfile: /Freespace2/code/CFile/CfileArchive.cpp $
15 * Low-level code for reading data out of large archive files or normal files. All
16 * reads/seeks come through here.
19 * Revision 1.2 2002/06/09 04:41:15 relnev
20 * added copyright header
22 * Revision 1.1.1.1 2002/05/03 03:28:08 root
26 * 4 2/22/99 10:31p Andsager
27 * Get rid of unneeded includes.
29 * 3 1/06/99 2:24p Dave
30 * Stubs and release build fixes.
32 * 2 10/07/98 10:52a Dave
35 * 1 10/07/98 10:48a Dave
37 * 12 5/14/98 8:10p Lawrance
38 * Fix bug with trying to read past the end of a file (when from a
41 * 11 5/11/98 11:48a John
42 * fixed bug with memory mapped files
44 * 10 5/11/98 10:59a John
47 * 9 5/11/98 10:59a John
48 * Moved the low-level file reading code into cfilearchive.cpp.
50 * 8 4/30/98 4:53p John
51 * Restructured and cleaned up cfile code. Added capability to read off
52 * of CD-ROM drive and out of multiple pack files.
54 * 7 4/20/98 11:49a Hoffoss
55 * Fixed bug with directory name getting.
57 * 6 4/10/98 12:18a Hoffoss
58 * Make pilot image search in pack file possible.
60 * 5 1/19/98 9:37p Allender
61 * Great Compiler Warning Purge of Jan, 1998. Used pragma's in a couple
62 * of places since I was unsure of what to do with code.
64 * 4 12/30/97 5:31p Lawrance
65 * fixed problem for people that didn't have a VP file
67 * 3 12/30/97 4:31p Sandeep
68 * Changed pakfile format
70 * 2 12/28/97 12:42p John
71 * Put in support for reading archive files; Made missionload use the
72 * cf_get_file_list function. Moved demos directory out of data tree.
74 * 1 12/28/97 11:48a John
79 #define _CFILE_INTERNAL
90 #include "cfilearchive.h"
92 #define CHECK_POSITION
94 // Called once to setup the low-level reading code.
96 void cf_init_lowlevel_read_code( CFILE * cfile, int offset, int size )
98 SDL_assert(cfile != NULL);
101 SDL_assert(cfile->id >= 0 && cfile->id < MAX_CFILE_BLOCKS);
102 cb = &Cfile_block_list[cfile->id];
104 cb->lib_offset = offset;
105 cb->raw_position = 0;
109 if ( cb->lib_offset ) {
110 fseek( cb->fp, cb->lib_offset, SEEK_SET );
113 #if defined(CHECK_POSITION) && !defined(NDEBUG)
114 int raw_position = ftell(cb->fp) - cb->lib_offset;
115 SDL_assert(raw_position == cb->raw_position);
122 // cfeof() Tests for end-of-file on a stream
124 // returns a nonzero value after the first read operation that attempts to read
125 // past the end of the file. It returns 0 if the current position is not end of file.
126 // There is no error return.
128 int cfeof(CFILE *cfile)
130 SDL_assert(cfile != NULL);
133 SDL_assert(cfile->id >= 0 && cfile->id < MAX_CFILE_BLOCKS);
134 cb = &Cfile_block_list[cfile->id];
138 SDL_assert(cb->fp != NULL);
140 #if defined(CHECK_POSITION) && !defined(NDEBUG)
141 int raw_position = ftell(cb->fp) - cb->lib_offset;
142 SDL_assert(raw_position == cb->raw_position);
145 if (cb->raw_position >= cb->size ) {
154 // cftell() returns offset into file
156 // returns: success ==> offset into the file
159 int cftell( CFILE * cfile )
161 SDL_assert(cfile != NULL);
163 SDL_assert(cfile->id >= 0 && cfile->id < MAX_CFILE_BLOCKS);
164 cb = &Cfile_block_list[cfile->id];
166 SDL_assert(cb->fp != NULL);
168 #if defined(CHECK_POSITION) && !defined(NDEBUG)
169 int raw_position = ftell(cb->fp) - cb->lib_offset;
170 SDL_assert(raw_position == cb->raw_position);
173 return cb->raw_position;
177 // cfseek() moves the file pointer
179 // returns: success ==> 0
180 // error ==> non-zero
182 int cfseek( CFILE *cfile, int offset, int where )
185 SDL_assert(cfile != NULL);
187 SDL_assert(cfile->id >= 0 && cfile->id < MAX_CFILE_BLOCKS);
188 cb = &Cfile_block_list[cfile->id];
190 SDL_assert( cb->fp != NULL );
196 goal_position = offset+cb->lib_offset;
200 goal_position = cb->raw_position+offset+cb->lib_offset;
204 goal_position = cb->size+offset+cb->lib_offset;
211 int result = fseek(cb->fp, goal_position, SEEK_SET );
212 cb->raw_position = goal_position - cb->lib_offset;
214 #if defined(CHECK_POSITION) && !defined(NDEBUG)
215 int tmp_offset = ftell(cb->fp) - cb->lib_offset;
216 SDL_assert(tmp_offset==cb->raw_position);
223 // cfread() reads from a file
225 // returns: returns the number of full elements read
228 int cfread(void *buf, int elsize, int nelem, CFILE *cfile)
230 SDL_assert(cfile != NULL);
231 SDL_assert(buf != NULL);
232 SDL_assert(cfile->id >= 0 && cfile->id < MAX_CFILE_BLOCKS);
235 cb = &Cfile_block_list[cfile->id];
237 SDL_assert(cb->fp != NULL);
239 int size = elsize*nelem;
241 SDL_assert(nelem > 0);
242 SDL_assert(elsize > 0);
243 SDL_assert(size > 0);
245 if ( (cb->raw_position+size) > cb->size ) {
246 size = cb->size - cb->raw_position;
250 //mprintf(( "CFILE: EOF encountered in file\n" ));
253 int bytes_read = fread( buf, 1, size, cb->fp );
254 if ( bytes_read > 0 ) {
255 cb->raw_position += bytes_read;
258 #if defined(CHECK_POSITION) && !defined(NDEBUG)
259 int tmp_offset = ftell(cb->fp) - cb->lib_offset;
260 SDL_assert(tmp_offset==cb->raw_position);
263 return bytes_read / elsize;