Rewrite save/resume in idiomatic C. Savefile version bumped to 26.

Makefile

@@ -14,7 +14,7 @@
 VERS=1.0
 
 CC?=gcc
-CCFLAGS+=-std=c99 -D _DEFAULT_SOURCE
+CCFLAGS+=-std=c99 -D _DEFAULT_SOURCE -g
 LIBS=
 UNAME_S := $(shell uname -s)
 ifeq ($(UNAME_S),Linux)

NEWS

@@ -3,6 +3,7 @@
 Repository head::
   Include tests directory in generated tarball.
   Support command-line editing with arrow keys and Emacs keystrokes.
+  Save format has changed.
 
 1.0: 2016-06-05::
   Forward port of Crowther & Woods's 430-point Adventure 2.5.

advent.adoc

@@ -41,8 +41,8 @@ There have been no gameplay changes.
 
 == BUGS ==
 
-The binary save file format is fragile and unlikely to survive
+The binary save file format is fragile, dependent on your machine word
-through version bumps.
+size and endianness, and unlikely to survive through version bumps.
 
 == REPORTING BUGS ==
 Report bugs to Eric S. Raymond <esr@thyrsus.com>.  The project page is

history.adoc

@@ -173,6 +173,13 @@ The adventure.text file is no longer required at runtime.  Instead, it
 is compiled at build time to a source module containing C structures,
 which is then linked to the advent binary.
 
+The game-save format has changed.  This was done to simplify
+FORTRAN-derived code that formerly implemented these functions;
+without C's fread(3)/fwrite() and structs it was necessarily pretty
+ugly by modern stabdards. Encryption and checksumming have been
+discarded - it's pointless to try tamper-prooing saves when everyone
+has the source code.
+
 == Sources ==
 
 [bibliography]

saveresume.c

@@ -1,217 +1,94 @@
 #include <stdlib.h>
+#include <string.h>
 
 #include "advent.h"
 #include "database.h"
 #include "linenoise/linenoise.h"
 
-#define VRSION	25	/* bump on save format change */
+/*
+ * (ESR) This replaces  a bunch of particularly nasty FORTRAN-derived code;
+ * see the history.adoc file in the source distribution for discussion.
+ */
 
-static void fSAVWDS(long*,long*,long*,long*,long*,long*,long*);
+#define VRSION	26	/* bump on save format change */
-#define SAVWDS(W1,W2,W3,W4,W5,W6,W7) fSAVWDS(&W1,&W2,&W3,&W4,&W5,&W6,&W7)
-static void fSAVARR(long*,long);
-#define SAVARR(ARR,N) fSAVARR(ARR,N)
-static void fSAVWRD(long,long*);
-#define SAVWRD(OP,WORD) fSAVWRD(OP,&WORD)
-static void fSAVEIO(long,long,long*);
-#define SAVEIO(OP,IN,ARR) fSAVEIO(OP,IN,ARR)
 
-/*  Suspend/resume I/O routines (SAVWDS, SAVARR, SAVWRD) */
+/*
-
+ * If you change the first three members, the resume function may not properly
-static void fSAVWDS(long *W1, long *W2, long *W3, long *W4,
+ * reject saves from older versions.  Yes, this glues us to a hardware-
-	     long *W5, long *W6, long *W7)
+ * dependent length of long.  Later members can change, but bump the version
-/* Write or read 7 variables.  See SAVWRD. */
+ * when you do that.
-{
+ */
-    SAVWRD(0,(*W1));
+struct save_t {
-    SAVWRD(0,(*W2));
+    long savetime;
-    SAVWRD(0,(*W3));
+    long mode;		/* not used, must be present for version detection */
-    SAVWRD(0,(*W4));
+    long version;
-    SAVWRD(0,(*W5));
+    struct game_t game;
-    SAVWRD(0,(*W6));
+    long bird;
-    SAVWRD(0,(*W7));
+    long bivalve;
-}
+};
-
+struct save_t save;
-static void fSAVARR(long arr[], long n)
-/* Write or read an array of n words.  See SAVWRD. */
-{
-    long i;
-
-    for (i=1; i<=n; i++) {
-	SAVWRD(0,arr[i]);
-    }
-    return;
-}
-
-static void fSAVWRD(long op, long *pword) 
-/*  If OP<0, start writing a file, using word to initialise encryption; save
- *  word in the file.  If OP>0, start reading a file; read the file to find
- *  the value with which to decrypt the rest.  In either case, if a file is
- *  already open, finish writing/reading it and don't start a new one.  If OP=0,
- *  read/write a single word.  Words are buffered in case that makes for more
- *  efficient disk use.  We also compute a simple checksum to catch elementary
- *  poking within the saved file.  When we finish reading/writing the file,
- *  we store zero into *PWORD if there's no checksum error, else nonzero. */
-{
-    static long buf[250], cksum = 0, h1, hash = 0, n = 0, state = 0;
-
-    if (op != 0)
-    {
-	long ifvar = state; 
-	switch (ifvar<0 ? -1 : (ifvar>0 ? 1 : 0)) 
-	{ 
-	case -1:
-	case 1:
-	    if (n == 250)SAVEIO(1,state > 0,buf);
-	    n=MOD(n,250)+1;
-	    if (state <= 0) {
-		n--; buf[n]=cksum; n++;
-		SAVEIO(1,false,buf);
-	    }
-	    n--; *pword=buf[n]-cksum; n++;
-	    SAVEIO(-1,state > 0,buf);
-	    state=0;
-	    break;
-	case 0:	/* FIXME: Huh? should be impossible */
-	    state=op;
-	    SAVEIO(0,state > 0,buf);
-	    n=1;
-	    if (state <= 0) {
-		hash=MOD(*pword,1048576L);
-		buf[0]=1234L*5678L-hash;
-	    }
-	    SAVEIO(1,true,buf);
-	    hash=MOD(1234L*5678L-buf[0],1048576L);
-	    cksum=buf[0];
-	    return;
-	}
-    }
-    if (state == 0)
-	return;
-    if (n == 250)
-	SAVEIO(1,state > 0,buf);
-    n=MOD(n,250)+1;
-    h1=MOD(hash*1093L+221573L,1048576L);
-    hash=MOD(h1*1093L+221573L,1048576L);
-    h1=MOD(h1,1234)*765432+MOD(hash,123);
-    n--;
-    if (state > 0)
-	*pword=buf[n]+h1;
-    buf[n]=*pword-h1;
-    n++;
-    cksum=MOD(cksum*13+*pword,1000000000L);
-}
-
-static void fSAVEIO(long op, long in, long arr[]) 
-/*  If OP=0, ask for a file name and open a file.  (If IN=true, the file is for
- *  input, else output.)  If OP>0, read/write ARR from/into the previously-opened
- *  file.  (ARR is a 250-integer array.)  If OP<0, finish reading/writing the
- *  file.  (Finishing writing can be a no-op if a "stop" statement does it
- *  automatically.  Finishing reading can be a no-op as long as a subsequent
- *  SAVEIO(0,false,X) will still work.) */
-{
-    static FILE *fp = NULL;
-    char* name;
-
-    switch (op < 0 ? -1 : (op > 0 ? 1 : 0)) 
-    { 
-    case -1:
-	fclose(fp);
-	break;
-    case 0:
-	while (fp == NULL) {
-	    name = linenoise("File name: ");
-	    fp = fopen(name,(in ? READ_MODE : WRITE_MODE));
-	    if (fp == NULL)
-		printf("Can't open file %s, try again.\n", name); 
-	}
-	linenoiseFree(name);
-	break;
-    case 1: 
-	if (in)
-	    IGNORE(fread(arr,sizeof(long),250,fp));
-	else
-	    IGNORE(fwrite(arr,sizeof(long),250,fp));
-	break;
-    }
-}
 
 int saveresume(FILE *input, bool resume)
 /* Suspend and resume */
 {
-    int kk;
+    long i, k;
-    long i;
+    FILE *fp = NULL;
+    char *name;
+ 
     if (!resume) {
 	/*  Suspend.  Offer to save things in a file, but charging
 	 *  some points (so can't win by using saved games to retry
 	 *  battles or to start over after learning zzword). */
-	SPK=201;
 	RSPEAK(260);
 	if (!YES(input,200,54,54)) return(2012);
 	game.saved=game.saved+5;
-	kk= -1;
     }
     else
     {
 	/*  Resume.  Read a suspended game back from a file. */
-	kk=1;
 	if (game.loc != 1 || game.abbrev[1] != 1) {
 	    RSPEAK(268);
 	    if (!YES(input,200,54,54)) return(2012);
 	}
     }
 
-    /*  Suspend vs resume cases are distinguished by the value of kk
+    while (fp == NULL) {
-     *  (-1 for suspend, +1 for resume). */
+	name = linenoise("File name: ");
+	fp = fopen(name,(resume ? READ_MODE : WRITE_MODE));
+	if (fp == NULL)
+	    printf("Can't open file %s, try again.\n", name); 
+    }
+    linenoiseFree(name);
     
-    /* 
+    DATIME(&i,&k);
-     * FIXME: This is way more complicated than it needs to be in C.
+    k=i+650*k;
-     * What we ought to do is define a save-block structure that
+    if (!resume)
-     * includes a game state block and then use a single fread/fwrite
+    {
-     * for I/O. All the SAV* functions can be scrapped.
+	save.savetime = k;
-     */
+	save.mode = -1;
-
+	save.version = VRSION;
-    DATIME(&i,&K);
+	memcpy(&save.game, &game, sizeof(struct game_t));
-    K=i+650*K;
+	save.bird = OBJSND[BIRD];
-    SAVWRD(kk,K);
+	save.bivalve = OBJTXT[OYSTER];
-    K=VRSION;
+	IGNORE(fwrite(&save, sizeof(struct save_t), 1, fp));
-    SAVWRD(0,K);
+	fclose(fp);
-    if (K != VRSION) {
+	RSPEAK(266);
-	SETPRM(1,K/10,MOD(K,10));
+	exit(0);
+    } else {
+	IGNORE(fread(&save, sizeof(struct save_t), 1, fp));
+	fclose(fp);
+	if (save.version != VRSION) {
+	    SETPRM(1,k/10,MOD(k,10));
 	    SETPRM(3,VRSION/10,MOD(VRSION,10));
 	    RSPEAK(269);
 	    return(2000);
 	}
-    /* Herewith are all the variables whose values can change during a game,
+	memcpy(&game, &save.game, sizeof(struct game_t));
-     * omitting a few (such as I, J) whose values between turns are
+	OBJSND[BIRD] = save.bird;
-     * irrelevant and some whose values when a game is
+	OBJTXT[OYSTER] = save.bivalve;
-     * suspended or resumed are guaranteed to match.  If unsure whether a value
-     * needs to be saved, include it.  Overkill can't hurt.  Pad the last savwds
-     * with junk variables to bring it up to 7 values. */
-    SAVWDS(game.abbnum,game.blklin,game.bonus,game.clock1,game.clock2,game.closed,game.closng);
-    SAVWDS(game.detail,game.dflag,game.dkill,game.dtotal,game.foobar,game.holdng,game.iwest);
-    SAVWDS(game.knfloc,game.limit,K,game.lmwarn,game.loc,game.newloc,game.numdie);
-    SAVWDS(K,game.oldlc2,game.oldloc,game.oldobj,game.panic,game.saved,game.setup);
-    SAVWDS(SPK,game.tally,game.thresh,game.trndex,game.trnluz,game.turns,OBJTXT[OYSTER]);
-    SAVWDS(K,WD1,WD1X,WD2,game.wzdark,game.zzword,OBJSND[BIRD]);
-    SAVWDS(OBJTXT[SIGN],game.clshnt,game.novice,K,K,K,K);
-    SAVARR(game.abbrev,LOCSIZ);
-    SAVARR(game.atloc,LOCSIZ);
-    SAVARR(game.dloc,NDWARVES);
-    SAVARR(game.dseen,NDWARVES);
-    SAVARR(game.fixed,NOBJECTS);
-    SAVARR(game.hinted,HNTSIZ);
-    SAVARR(game.hintlc,HNTSIZ);
-    SAVARR(game.link,NOBJECTS*2);
-    SAVARR(game.odloc,NDWARVES);
-    SAVARR(game.place,NOBJECTS);
-    SAVARR(game.prop,NOBJECTS);
-    SAVWRD(kk,K);
-    if (K != 0) {
-	RSPEAK(270);
-	exit(0);
-    }
-    K=NUL;
 	game.zzword=RNDVOC(3,game.zzword);
-    if (kk > 0) return(8);
+	return(2000);
-    RSPEAK(266);
+    }
-    exit(0);
 }
+
+/* end */