From c14c190414c1336643cd7d0c29f0626ccc7dea6d Mon Sep 17 00:00:00 2001
From: Olivier Gayot <duskcoder@gmail.com>
Date: Wed, 5 Mar 2014 15:11:03 +0100
Subject: Clean the code and avoid fix some crashes

---
 Makefile    |   4 +-
 god_hands.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 main.c      | 145 -------------------------------------------------
 3 files changed, 178 insertions(+), 147 deletions(-)
 create mode 100644 god_hands.c
 delete mode 100644 main.c

diff --git a/Makefile b/Makefile
index 2a405f9..fa5f19a 100644
--- a/Makefile
+++ b/Makefile
@@ -1,9 +1,9 @@
 CC = gcc
 CFLAGS = -Wall -W -std=c99 -g
 
-god_hands_solver: main.o
+god_hands_solver: god_hands.o
 	$(CC) -o $@ $^ $(LDFLAGS)
 
-main.o: main.c
+god_hands.o: god_hands.c
 	$(CC) -o $@ -c $< $(CFLAGS)
 
diff --git a/god_hands.c b/god_hands.c
new file mode 100644
index 0000000..4ff2f5d
--- /dev/null
+++ b/god_hands.c
@@ -0,0 +1,176 @@
+#include <stdint.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+#include <stdbool.h>
+
+typedef uint8_t byte;
+typedef int8_t rang_t;
+
+typedef struct {
+    byte value;
+    rang_t rang;
+} elem_t;
+
+typedef struct {
+    int len;
+    elem_t *elem;
+} map_t;
+
+map_t *map_g;
+
+/* resolve {{{ */
+
+/* returns true if the map is empty, otherwise returns false */
+static bool map_is_empty(void)
+{
+    for (int i = 0; i < map_g->len; i++) {
+        if (map_g->elem[i].rang == -1) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+/* return the index of the next element */
+static inline int get_next_case(int current)
+{
+    return (current + map_g->elem[current].value) % map_g->len;
+}
+
+/* return the index of the previous element */
+static inline int get_prev_case(int current)
+{
+    int prev = current - map_g->elem[current].value;
+
+    if (current < map_g->elem[current].value)
+        prev += map_g->len;
+
+    return prev;
+}
+
+static int perform_resolve_god_hands(int activated, int offset)
+{
+    int next, prev;
+
+    /* this one is already activated, not possible captain */
+    if (map_g->elem[activated].rang != -1) {
+        return -1;
+    }
+
+    /* activate the current case */
+    map_g->elem[activated].rang = offset;
+
+    if (map_is_empty()) {
+        /* we won */
+        return 0;
+    }
+
+    next = get_next_case(activated);
+    prev = get_prev_case(activated);
+
+    if (perform_resolve_god_hands(next, offset + 1) == 0)
+        return 0;
+
+    if (perform_resolve_god_hands(prev, offset + 1) == 0)
+        return 0;
+
+    /* reset to default */
+    map_g->elem[activated].rang = -1;
+    return -1;
+}
+
+int solve_god_hands(map_t *map)
+{
+    for (int i = 0; i < map->len; i++) {
+        map->elem[i].rang = -1;
+    }
+
+    map_g = map;
+
+    for (int i = 0; i < map->len; i++) {
+        if (perform_resolve_god_hands(i, 0) == 0) {
+            return 0;
+        }
+    }
+
+    return -1;
+}
+
+/* }}} */
+
+static void display_solution(const map_t *map)
+{
+    for (int i = 0; i < map->len; i++) {
+        /* run through the order */
+        for (int j = 0; j < map->len; j++) {
+            /* run through the elems */
+
+            assert (map->elem[j].rang != -1);
+
+            if (map->elem[j].rang == i) {
+                printf("[%d] ", j);
+                break;
+            }
+        }
+    }
+    putchar('\n');
+}
+
+int main(void)
+{
+    map_t map;
+    char buffer[16];
+
+    /* get the length of the map */
+    for (;;) {
+        if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
+            fputs("size of the map: ", stdout);
+        }
+
+        if (fgets(buffer, sizeof(buffer), stdin) == NULL) {
+            return 0;
+        }
+
+        /* TODO replace with strtol to handle errors of type 42(.*) */
+        map.len = atoi(buffer);
+
+        if (map.len <= 0) {
+            fprintf(stderr, "the map has an invalid size\n");
+
+            if (!isatty(STDIN_FILENO))
+                return -1;
+
+            continue;
+        }
+
+        break;
+    }
+
+    map.elem = malloc(sizeof(elem_t) * map.len);
+
+    for (int i = 0; i < map.len; i++) {
+        if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO))
+            printf("(%02d/%02d): ", i + 1, map.len);
+
+        fflush(stdout);
+
+        if (fgets(buffer, sizeof(buffer), stdin) == NULL) {
+            return 0;
+        }
+
+        /* TODO check for errors (i.e. not numbers and negative values */
+        map.elem[i].value = atoi(buffer);
+    }
+
+    if ((solve_god_hands(&map)) != 0) {
+        fputs("cannot solve the paradox, kupo :-/\n", stderr);
+    } else {
+        fputs("we solved the paradox kupo! :-)\n", stdout);
+        display_solution(&map);
+    }
+
+    return 0;
+}
diff --git a/main.c b/main.c
deleted file mode 100644
index f359678..0000000
--- a/main.c
+++ /dev/null
@@ -1,145 +0,0 @@
-#include <stdint.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <assert.h>
-#include <stdbool.h>
-
-typedef uint8_t byte;
-typedef int8_t rang_t;
-
-typedef struct {
-    byte value;
-    rang_t rang;
-} elem_t;
-
-typedef struct {
-    int len;
-    elem_t *elem;
-} map_t;
-
-map_t *map_g;
-
-/* resolve {{{ */
-
-static bool map_is_empty(void)
-{
-    for (int i = 0; i < map_g->len; i++) {
-	if (map_g->elem[i].rang == -1) {
-	    return false;
-	}
-    }
-
-    return true;
-}
-
-static inline int get_next(int current)
-{
-    return (current + map_g->elem[current].value) % map_g->len;
-}
-
-static inline int get_prev(int current)
-{
-    int prev = current - map_g->elem[current].value;
-
-    if (current < map_g->elem[current].value)
-	prev += map_g->len;
-
-    return prev;
-}
-
-static int perform_resolve_god_hands(int activated, int offset)
-{
-    int next, prev;
-
-    /* this one is already activated, not possible captain */
-    if (map_g->elem[activated].rang != -1) {
-	return -1;
-    }
-
-    /* activate the current case */
-    map_g->elem[activated].rang = offset;
-
-    if (map_is_empty()) {
-	/* we won */
-	return 0;
-    }
-
-    next = get_next(activated);
-    prev = get_prev(activated);
-
-    if (perform_resolve_god_hands(next, offset + 1) == 0)
-	return 0;
-
-    if (perform_resolve_god_hands(prev, offset + 1) == 0)
-	return 0;
-
-    /* reset to default */
-    map_g->elem[activated].rang = -1;
-    return -1;
-}
-
-int solve_god_hands(map_t *map)
-{
-    for (int i = 0; i < map->len; i++) {
-	map->elem[i].rang = -1;
-    }
-
-    map_g = map;
-
-    for (int i = 0; i < map->len; i++) {
-	if (perform_resolve_god_hands(i, 0) == 0) {
-	    return 0;
-	}
-    }
-
-    return -1;
-}
-
-/* }}} */
-
-static void display_solution(const map_t *map)
-{
-    for (int i = 0; i < map->len; i++) {
-	/* run through the order */
-	for (int j = 0; j < map->len; j++) {
-	    /* run through the elems */
-
-	    assert (map->elem[j].rang != -1);
-
-	    if (map->elem[j].rang == i) {
-		printf("[%d] ", j);
-		break;
-	    }
-	}
-    }
-    putchar('\n');
-}
-
-int main(void)
-{
-    map_t map;
-    char buffer[16];
-
-    if (isatty(0))
-	fputs("size of the map: ", stdout);
-    map.len = atoi(fgets(buffer, sizeof(buffer), stdin));
-
-    map.elem = malloc(sizeof(elem_t) * map.len);
-
-    for (int i = 0; i < map.len; i++) {
-	if (isatty(0))
-	    printf("(%02d/%02d): ", i + 1, map.len);
-	fflush(stdout);
-	map.elem[i].value = atoi(fgets(buffer, sizeof(buffer), stdin));
-    }
-
-    if ((solve_god_hands(&map)) != 0) {
-	fputs("cannot resolve paradox kupo\n", stderr);
-    } else {
-	fputs("we resolved the paradox kupo\n", stdout);
-	display_solution(&map);
-    }
-
-    return 0;
-}
-- 
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