2020/19 (C): cleanup code

2020/day19/aoc-c.c

@@ -39,36 +39,66 @@ static struct mesg {
 } mesg[MAX_MSG];
 static int nrules, nmesg;
 
-static void printall()
+
+static int match(struct mesg *msg, int *pos, int rule)
 {
-    for (int i = 0; i < nrules; ++i) {
+    struct rule *r = rules + rule;
-        printf("rule %3d : ", i);
+    int found = 0, postmp, recurse = 0;
-        if (rules[i].type == CHR) {
+
-            printf("[%c]\n", rules[i].str);
+    if (r->type == CHR)
-            continue;
+        return rules[rule].str == msg->str[(*pos)++];
+    for (int side = 0; side < 2; ++side, recurse = 0, found = 0) {
+        if (r->sub.rule[side][0] == -1)
+            break;
+        postmp = *pos;
+        found = 1;
+        for (int sub = 0; sub < 3 && r->sub.rule[side][sub] >= 0; ++sub) {
+            if (*pos == msg->len)
+                return recurse;
+            recurse = r->sub.rule[side][sub] == rule;
+            if (!match(msg, pos, r->sub.rule[side][sub])) {
+                found = 0;
+                *pos = postmp;                    /* roll back */
+                break;
+            }
         }
-        for (int j = 0; j < 3 && rules[i].sub.rule[0][j] != -1; ++j)
+        if (found)
-            printf("%d ", rules[i].sub.rule[0][j]);
+            break;
-        for (int j = 0; j < 3 && rules[i].sub.rule[1][j] != -1; ++j)
-            printf("%s%d ", j? "": "| ", rules[i].sub.rule[1][j]);
-        printf("\n");
-    }
-    for (int i = 0; i < nmesg; ++i) {
-        printf("%3d: len=%d %s\n", i, mesg[i].len, mesg[i].str);
     }
+    return found;
+}
+
+static long part1()
+{
+    int ret = 0;
+
+    for (int msg = 0, pos = 0; msg < nmesg; ++msg, pos = 0)
+        if (match(mesg + msg, &pos, 0))
+            ret += pos == mesg[msg].len;
+    return ret;
+}
+
+static long part2()
+{
+    static const struct subrule new[2] = {
+        {{{42, -1, -1}, {42,  8, -1}}},
+        {{{42, 31, -1}, {42, 11, 31}}}
+    };
+    rules[8].sub  = new[0];
+    rules[11].sub  = new[1];
+
+    return part1();
 }
 
-/**
- * parse - parse input.
- */
 static void parse()
 {
     size_t alloc;
     ssize_t len;
     char *buf = NULL, *tok;
     int rule;
+
     while ((len = getline(&buf, &alloc, stdin)) > 0) {
-        int or = 0, sub = 0;
+        int set = 0, sub = 0;
 
         buf[--len] = 0;
         if (len == 0)
@@ -87,104 +117,23 @@ static void parse()
                     case 'b':
                         rules[rule].type = CHR;
                         rules[rule].str = *tok;
-                        goto nextline;
+                        break;
                     case '|':                     /* second ruleset */
-                        or++;
+                        set++;
                         sub = 0;
                         break;
                     default:
                         rules[rule].type = SUB;
-                        rules[rule].sub.rule[or][sub] = atoi(tok);
+                        rules[rule].sub.rule[set][sub] = atoi(tok);
                         sub++;
                         break;
                 }
             }
         }
-    nextline: ;
     }
     free(buf);
 }
 
-static int match(struct mesg *msg, int *pos, int rule, int depth)
-{
-    struct rule *r = rules+rule;
-    int found = 0, postmp, recurse = 0;
-    char *space = "                                     ";
-    log_f(3, "%.*sstr=%s pos=%d rule=%d\n", depth * 2, space, msg->str,
-          *pos, rule);
-    if (r->type == CHR)
-        return rules[rule].str == msg->str[(*pos)++];
-    for (int side = 0; side < 2; ++side) {
-        if (r->sub.rule[side][0] == -1) {
-            found = 0;
-            break;
-        }
-        postmp = *pos;
-        recurse = 0;
-        found = 1;
-        for (int sub = 0; sub < 3 && r->sub.rule[side][sub] >= 0; ++sub) {
-            if (*pos == msg->len)
-                return recurse;
-            if (r->sub.rule[side][sub] == rule) {
-                log(3, "recursing %d rule\n", rule);
-                recurse = 1;
-            }
-            if (!match(msg, pos, r->sub.rule[side][sub], depth + 1)) {
-                found = 0;
-                *pos = postmp;
-                break;
-            }
-        }
-        if (found)
-            break;
-    }
-    /* check for exact length */
-    if (depth == 0 && msg->str[*pos]) {
-        log_f(3, "pos=%d len=%d chars remaining !\n", *pos, msg->len);
-        found = 0;
-    }
-    log_f(3, "%.*sstr=%s pos=%d rule=%d ret=%s\n",
-          depth * 2, space, msg->str+*pos, *pos, rule, found? "ok": "NOK");
-    return found;                                     /* not reached */
-}
-
-static long part1()
-{
-    int ok = 0, pos;
-    for (int msg = 0; msg < nmesg; ++msg) {
-        pos = 0;
-        if (match(mesg + msg, &pos, 0, 0)) {
-            log(2, "len=%d pos=%d %s: ok\n", mesg[msg].len, pos, mesg[msg].str);
-            ok++;
-        } else {
-            log(2, "len=%d pos=%d %s: NOK\n", mesg[msg].len, pos, mesg[msg].str);
-        }
-    }
-    return ok;
-}
-
-static long part2()
-{
-    static const struct subrule new[2] = {
-        {{{42, -1, -1}, {42,  8, -1}}},
-        {{{42, 31, -1}, {42, 11, 31}}}
-    };
-    rules[8].sub  = new[0];
-    rules[11].sub  = new[1];
-
-    int ok = 0, pos;
-    for (int msg = 0; msg < nmesg; ++msg) {
-        pos = 0;
-        if (match(mesg + msg, &pos, 0, 0)) {
-            log(2, "len=%d pos=%d %s: ok\n", mesg[msg].len, pos, mesg[msg].str);
-            ok++;
-        } else {
-            log(2, "len=%d pos=%d %s: NOK\n", mesg[msg].len, pos, mesg[msg].str);
-        }
-    }
-    return ok;
-}
-
 static int usage(char *prg)
 {
     fprintf(stderr, "Usage: %s [-d debug_level] [-p part]\n", prg);
@@ -212,6 +161,5 @@ int main(ac, av)
 
     parse();
     printf("%s : res=%ld\n", *av, part == 1? part1(): part2());
-    //printall();
     exit (0);
 }