From 2b05f07c1fc545954bfd10d7b46fc13422f802c9 Mon Sep 17 00:00:00 2001
From: alex-s168 <alexandernutz68@gmail.com>
Date: Thu, 4 Sep 2025 19:17:52 +0200
Subject: [PATCH] wip

---
 adj_matrix.c |  12 +++
 common.h     | 201 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 213 insertions(+)
 create mode 100644 adj_matrix.c
 create mode 100644 common.h

diff --git a/adj_matrix.c b/adj_matrix.c
new file mode 100644
index 0000000..73587a6
--- /dev/null
+++ b/adj_matrix.c
@@ -0,0 +1,12 @@
+#include "common.h"
+
+int main(int argc, char **argv) {
+  char buf[512];
+  char *dest;
+
+  while (( dest = slowgraph_next_edge(stdin, buf, slowgraph_lenof(buf), 0) )) {
+    printf("%s -> %s\n", buf, dest);
+  }
+
+  return 0;
+}
diff --git a/common.h b/common.h
new file mode 100644
index 0000000..b461d93
--- /dev/null
+++ b/common.h
@@ -0,0 +1,201 @@
+#ifndef SLOWGRAPH_COMMON_H
+#define SLOWGRAPH_COMMON_H
+
+#include <ctype.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define slowgraph_lenof(x) (sizeof((x)) / sizeof(*(x)))
+
+static unsigned
+slowgraph_hash(char const *buf) {
+  unsigned res = 5381;
+  for (; *buf; buf++) {
+    res = (res << 5) + res + *buf;
+  }
+  return res;
+}
+
+static unsigned
+slowgraph_hashn(void const *bufp, int len) {
+  char const* buf = (char const *) bufp;
+  unsigned res = 5381;
+  for (; buf != buf + len; buf ++) {
+    res = (res << 5) + res + *buf;
+  }
+  return res;
+}
+
+static char *
+slowgraph_next_edge(
+    FILE* inp,
+    char* buf, int bufn,
+    void (*opt_attr_clbk)(char* node, char* key, char* val))
+{
+  int c;
+  char *n, *k, *v, *retv = 0;
+
+  c = fgetc(inp);
+
+  for (;;) {
+    if (c == EOF) {
+      retv = 0;
+      break;
+    }
+
+    for (; isspace(c); c = fgetc(inp))
+      ;
+
+    if (c == '#') {
+      c = fgetc(inp);
+      if (c == '#' && opt_attr_clbk && buf == fgets(buf, bufn, inp)) {
+        n = strtok(buf+1, " \r\n");
+        k = strtok(0, " \r\n");
+        v = strtok(0, " \r\n");
+        opt_attr_clbk(n, k, v);
+      } else {
+        for (; c != EOF && c != '\n'; c = fgetc(inp))
+          ;
+        c = fgetc(inp);
+      }
+      continue;
+    }
+
+    for (k = buf; c != EOF && !isspace(c); k ++) {
+      *k = c;
+      c = fgetc(inp);
+    }
+
+    *k++=0;
+
+    for (; isspace(c); c = fgetc(inp))
+      ;
+
+    for (v = k; c != EOF && !isspace(c); v ++) {
+      *v = c;
+      c = fgetc(inp);
+    }
+    *v = 0;
+
+    retv = k;
+    break;
+  }
+
+  ungetc(c, inp);
+  return retv;
+}
+
+typedef struct SlowGraph SlowGraph;
+typedef struct SlowGraphNode SlowGraphNode;
+typedef struct SlowGraphEdge SlowGraphEdge;
+typedef struct SlowGraphAttr SlowGraphAttr;
+
+struct SlowGraphAttr {
+  SlowGraphAttr* next;
+  unsigned hash;
+  char *key, *val;
+};
+
+static char*
+SlowGraphAttr_find(SlowGraphAttr* a, unsigned hash) {
+  for (; a; a = a->next)
+    if (a->hash == hash)
+      return a->val;
+  return 0;
+}
+
+struct SlowGraphNode {
+  SlowGraphNode *next;
+
+  unsigned name_hash;
+  char *name;
+  SlowGraphAttr* attr;
+  SlowGraphEdge* children;
+
+  unsigned gc_used : 1;
+};
+
+struct SlowGraphEdge {
+  SlowGraphEdge *next;
+  unsigned cost;
+  unsigned aig_inv : 1;
+  unsigned user_attr;
+
+  SlowGraphNode *node;
+};
+
+struct SlowGraph {
+  SlowGraphNode *first;
+};
+
+// Step 1: call SlowGraph_markAllUnused(graph)
+// 
+// Step 2: manually mark input nodes as used
+//
+// Step 3: call SlowGraph_gcUnused(graph)   // only deletes nodes not used by manually marked used nodes
+static void
+SlowGraph_markAllUnused(SlowGraph *graph) {
+  SlowGraphNode *n;
+  for (n = graph->first; n; n = n->next)
+    n->gc_used = 0;
+}
+
+// Step 1: call SlowGraph_markAllUnused(graph)
+// 
+// Step 2: manually mark input nodes as used
+//
+// Step 3: call SlowGraph_gcUnused(graph)   // only deletes nodes not used by manually marked used nodes
+static void
+SlowGraph_gcUnused(SlowGraph *graph) {
+  int changed = 0;
+  SlowGraphNode *n, *o, **prev;
+  SlowGraphEdge *e, *oe;
+  SlowGraphAttr *a, *oa;
+
+  do {
+    for (n = graph->first; n; n = n->next) {
+      if (n->gc_used) {
+        for (e = n->children; e; e = e->next) {
+          if (!e->node->gc_used) {
+            e->node->gc_used = 1;
+            changed = 1;
+          }
+        }
+      }
+    }
+  } while (changed);
+
+  prev = &graph->first;
+  for (n = graph->first; n; ) {
+    if (n->gc_used) {
+      prev = &n->next;
+      n = n->next;
+    } else {
+      o = n;
+      n = n->next;
+      *prev = n;
+
+      for (e = o->children; e; ) {
+        oe = e;
+        e = e->next;
+        free(oe);
+      }
+
+      for (a = o->attr; a; ) {
+        oa = a;
+        a = a->next;
+
+        free(a->key);
+        free(a->val);
+        free(a);
+      }
+
+      free(o->name);
+      free(o);
+    }
+  }
+}
+
+#endif