Source:NetHack 3.2.0/dlb.c

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Below is the full text to dlb.c from the source code of NetHack 3.2.0. To link to a particular line, write [[NetHack 3.2.0/dlb.c#line123]], for example.

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1.    /*	SCCS Id: @(#)dlb.c	3.2	96/02/14	*/
2.    /* Copyright (c) Kenneth Lorber, Bethesda, Maryland, 1993. */
3.    /* NetHack may be freely redistributed.  See license for details. */
4.    
5.    #include "config.h"
6.    #include "dlb.h"
7.    
8.    #ifdef DLB
9.    /*
10.    * Data librarian.  Present a STDIO-like interface to NetHack while
11.    * multiplexing on one or more "data" libraries.  If a file is not found
12.    * in a given library, look for it outside the libraries.
13.    *
14.    * When initialized, we open all library files and read in their tables
15.    * of contents.  The library files stay open all the time.  When
16.    * a open is requested, the libraries' directories are searched.  If
17.    * successful, we return a descriptor that contains the library, file
18.    * size, and current file mark.  This descriptor is used for all
19.    * successive calls.
20.    *
21.    * The ability to open more than one library is supported but used
22.    * only in the Amiga port (the second library holds the sound files).
23.    * For Unix, the idea would be to split the NetHack library
24.    * into text and binary parts, where the text version could be shared.
25.    */
26.   
27.   
28.   #define MAX_LIBS 4
29.   static library dlb_libs[MAX_LIBS];
30.   static boolean dlb_initialized = FALSE;
31.   
32.   static boolean FDECL(readlibdir,(library *lp));
33.   static boolean FDECL(find_file,(const char *name, library **lib, long *startp,
34.   								long *sizep));
35.   
36.   /* not static because shared with dlb_main.c */
37.   boolean FDECL(open_library,(const char *lib_name, library *lp));
38.   void FDECL(close_library,(library *lp));
39.   
40.   /* without extern.h via hack.h, these haven't been declared for us */
41.   extern char *FDECL(eos, (char *));
42.   extern FILE *FDECL(fopen_datafile, (const char *,const char *));
43.   
44.   /*
45.    * Read the directory out of the library.  Return 1 if successful,
46.    * 0 if it failed.
47.    *
48.    * NOTE: An improvement of the file structure should be the file
49.    * size as part of the directory entry or perhaps in place of the
50.    * offset -- the offset can be calculated by a running tally of
51.    * the sizes.
52.    *
53.    * Library file structure:
54.    *
55.    * HEADER:
56.    * %3ld	library FORMAT revision (currently rev 1)
57.    * %1c	space
58.    * %8ld	# of files in archive (includes 1 for directory)
59.    * %1c	space
60.    * %8ld	size of allocation for string space for directory names
61.    * %1c	space
62.    * %8ld	library offset - sanity check - lseek target for start of first file
63.    * %1c	space
64.    * %8ld	size - sanity check - byte size of complete archive file
65.    *
66.    * followed by one DIRECTORY entry for each file in the archive, including
67.    *  the directory itself:
68.    * %1c	handling information (compression, etc.)  Always ' ' in rev 1.
69.    * %s	file name
70.    * %1c	space
71.    * %8ld	offset in archive file of start of this file
72.    * %c	newline
73.    *
74.    * followed by the contents of the files
75.    */
76.   #define DLB_MIN_VERS  1	/* min library version readable by this code */
77.   #define DLB_MAX_VERS  1	/* max library version readable by this code */
78.   
79.   /*
80.    * Read the directory from the library file.   This will allocate and
81.    * fill in our globals.  The file pointer is reset back to position
82.    * zero.  If any part fails, leave nothing that needs to be deallocated.
83.    *
84.    * Return TRUE on success, FALSE on failure.
85.    */
86.   static boolean
87.   readlibdir(lp)
88.       library *lp;	/* library pointer to fill in */
89.   {
90.       int i;
91.       char *sp;
92.       long liboffset, totalsize;
93.   
94.       if (fscanf(lp->fdata, "%ld %ld %ld %ld %ld\n",
95.   	    &lp->rev,&lp->nentries,&lp->strsize,&liboffset,&totalsize) != 5)
96.   	return FALSE;
97.       if (lp->rev > DLB_MAX_VERS || lp->rev < DLB_MIN_VERS) return FALSE;
98.   
99.       lp->dir = (libdir *) alloc(lp->nentries * sizeof(libdir));
100.      lp->sspace = (char *) alloc(lp->strsize);
101.  
102.      /* read in each directory entry */
103.      for (i = 0, sp = lp->sspace; i < lp->nentries; i++) {
104.  	lp->dir[i].fname = sp;
105.  	if (fscanf(lp->fdata, "%c%s %ld\n",
106.  			&lp->dir[i].handling, sp, &lp->dir[i].foffset) != 3) {
107.  	    free((genericptr_t) lp->dir);
108.  	    free((genericptr_t) lp->sspace);
109.  	    lp->dir = (libdir *) 0;
110.  	    lp->sspace = (char *) 0;
111.  	    return FALSE;
112.  	}
113.  	sp = eos(sp) + 1;
114.      }
115.  
116.      /* calculate file sizes using offset information */
117.      for (i = 0; i < lp->nentries; i++) {
118.  	if (i == lp->nentries - 1)
119.  	    lp->dir[i].fsize = totalsize - lp->dir[i].foffset;
120.  	else
121.  	    lp->dir[i].fsize = lp->dir[i+1].foffset - lp->dir[i].foffset;
122.      }
123.  
124.      (void) fseek(lp->fdata, 0L, SEEK_SET);	/* reset back to zero */
125.      lp->fmark = 0;
126.  
127.      return TRUE;
128.  }
129.  
130.  /*
131.   * Look for the file in our directory structure.  Return 1 if successful,
132.   * 0 if not found.  Fill in the size and starting position.
133.   */
134.  static boolean
135.  find_file(name, lib, startp, sizep)
136.      const char *name;
137.      library **lib;
138.      long *startp, *sizep;
139.  {
140.      int i, j;
141.      library *lp;
142.  
143.      for (i = 0; i < MAX_LIBS && dlb_libs[i].fdata; i++) {
144.  	lp = &dlb_libs[i];
145.  	for (j = 0; j < lp->nentries; j++) {
146.  	    if (FILENAME_CMP(name, lp->dir[j].fname) == 0) {
147.  		*lib = lp;
148.  		*startp = lp->dir[j].foffset;
149.  		*sizep = lp->dir[j].fsize;
150.  		return TRUE;
151.  	    }
152.  	}
153.      }
154.      *lib = (library *) 0;
155.      *startp = *sizep = 0;
156.      return FALSE;
157.  }
158.  
159.  /*
160.   * Open the library of the given name and fill in the given library
161.   * structure.  Return TRUE if successful, FALSE otherwise.
162.   */
163.  boolean
164.  open_library(lib_name, lp)
165.      const char *lib_name;
166.      library *lp;
167.  {
168.      boolean status = FALSE;
169.  
170.      lp->fdata = fopen_datafile(lib_name, RDBMODE);
171.      if (lp->fdata) {
172.  	if (readlibdir(lp)) {
173.  	    status = TRUE;
174.  	} else {
175.  	    (void) fclose(lp->fdata);
176.  	    lp->fdata = (FILE *) 0;
177.  	}
178.      }
179.      return status;
180.  }
181.  
182.  void
183.  close_library(lp)
184.      library *lp;
185.  {
186.      (void) fclose(lp->fdata);
187.      free((genericptr_t) lp->dir);
188.      free((genericptr_t) lp->sspace);
189.  
190.      (void) memset((char *)lp, 0, sizeof(library));
191.  }
192.  
193.  /*
194.   * Open the library file once using stdio.  Keep it open, but
195.   * keep track of the file position.
196.   */
197.  boolean
198.  dlb_init()
199.  {
200.      if (dlb_initialized) return TRUE;
201.  
202.      /* zero out array */
203.      (void) memset((char *)&dlb_libs[0], 0, sizeof(dlb_libs));
204.  
205.      /* To open more than one library, add open library calls here. */
206.      if (!open_library(DLBFILE, &dlb_libs[0])) return dlb_initialized;
207.  #ifdef DLBFILE2
208.      if (!open_library(DLBFILE2, &dlb_libs[1])) return dlb_initialized;
209.  #endif
210.  
211.      dlb_initialized = TRUE;
212.  
213.      return dlb_initialized;
214.  }
215.  
216.  void
217.  dlb_cleanup()
218.  {
219.      int i;
220.  
221.      if (dlb_initialized) {
222.  	/* close the data file(s) */
223.  	for (i = 0; i < MAX_LIBS && dlb_libs[i].fdata; i++)
224.  	    close_library(&dlb_libs[i]);
225.  
226.  	dlb_initialized = FALSE;
227.      }
228.  }
229.  
230.  dlb *
231.  dlb_fopen(name, mode)
232.      const char *name, *mode;
233.  {
234.      long start, size;
235.      library *lp;
236.      FILE *fp;
237.      dlb *dp = (dlb *) 0;
238.  
239.      if (!dlb_initialized) return (dlb *) 0;
240.  
241.      /* look up file in directory */
242.      if (find_file(name, &lp, &start, &size)) {
243.  	dp = (dlb *) alloc(sizeof(dlb));
244.  	dp->fp = (FILE *) 0;
245.  	dp->lib = lp;
246.  	dp->start = start;
247.  	dp->size = size;
248.  	dp->mark = 0;
249.      } else if ((fp = fopen_datafile(name, mode)) != 0) {
250.  	/* use an external file */
251.  	dp = (dlb *) alloc(sizeof(dlb));
252.  	dp->fp = fp;
253.  	dp->lib = (library *) 0;
254.  	dp->start = 0;
255.  	dp->size = 0;
256.  	dp->mark = 0;
257.      }
258.      return dp;
259.  }
260.  
261.  int
262.  dlb_fclose(dp)
263.      dlb *dp;
264.  {
265.      if (dlb_initialized) {
266.  	if (dp->fp) (void) fclose(dp->fp);
267.  	free((genericptr_t) dp);
268.  	}
269.      return 0;
270.  }
271.  
272.  int
273.  dlb_fread(buf, size, quan, dp)
274.      char *buf;
275.      int size, quan;
276.      dlb *dp;
277.  {
278.      long pos, nread, nbytes;
279.  
280.      if (!dlb_initialized || size <= 0 || quan <= 0) return 0;
281.      if (dp->fp) return
282.  #ifdef __SASC_60
283.  	 (int)
284.  #endif
285.  	 fread(buf, size, quan, dp->fp);
286.  
287.      /* make sure we don't read into the next file */
288.      if ((dp->size - dp->mark) < (size * quan))
289.  	quan = (dp->size - dp->mark) / size;
290.      if (quan == 0) return 0;
291.  
292.      pos = dp->start + dp->mark;
293.      if (dp->lib->fmark != pos)
294.  	fseek(dp->lib->fdata, pos, SEEK_SET);	/* check for error??? */
295.  
296.      nread = fread(buf, size, quan, dp->lib->fdata);
297.      nbytes = nread * size;
298.      dp->mark += nbytes;
299.      dp->lib->fmark += nbytes;
300.  
301.      return nread;
302.  }
303.  
304.  int
305.  dlb_fseek(dp, pos, whence)
306.      dlb *dp;
307.      long pos;
308.      int whence;
309.  {
310.      long curpos;
311.  
312.      if (!dlb_initialized) return EOF;
313.      if (dp->fp) return fseek(dp->fp, pos, whence);
314.  
315.      switch (whence) {
316.  	case SEEK_CUR:	   curpos = dp->mark + pos;	break;
317.  	case SEEK_END:	   curpos = dp->size - pos;	break;
318.  	default: /* set */ curpos = pos;		break;
319.      }
320.      if (curpos < 0) curpos = 0;
321.      if (curpos > dp->size) curpos = dp->size;
322.  
323.      dp->mark = curpos;
324.      return 0;
325.  }
326.  
327.  char *
328.  dlb_fgets(buf, len, dp)
329.      char *buf;
330.      int len;
331.      dlb *dp;
332.  {
333.      int i;
334.      char *bp, c = 0;
335.  
336.      if (!dlb_initialized) return (char *) 0;
337.      if (dp->fp) return fgets(buf, len, dp->fp);
338.  
339.      if (len <= 0) return buf;	/* sanity check */
340.  
341.      /* return NULL on EOF */
342.      if (dp->mark >= dp->size) return (char *) 0;
343.  
344.      len--;	/* save room for null */
345.      for (i = 0, bp = buf;
346.  		i < len && dp->mark < dp->size && c != '\n'; i++, bp++) {
347.  	if (dlb_fread(bp, 1, 1, dp) <= 0) break;	/* EOF or error */
348.  	c = *bp;
349.      }
350.      *bp = '\0';
351.  
352.      return buf;
353.  }
354.  
355.  int
356.  dlb_fgetc(dp)
357.      dlb *dp;
358.  {
359.      char c;
360.  
361.      if (!dlb_initialized) return EOF;
362.      if (dp->fp) return fgetc(dp->fp);
363.  
364.      if (dlb_fread(&c, 1, 1, dp) != 1) return EOF;
365.      return (int) c;
366.  }
367.  
368.  long
369.  dlb_ftell(dp)
370.      dlb *dp;
371.  {
372.      if (!dlb_initialized) return 0;
373.      if (dp->fp) return ftell(dp->fp);
374.      return dp->mark;
375.  }
376.  
377.  #endif /* DLB */
378.  
379.  /*dlb.c*/