From 6095427926bce69548b25a58abbd29e318232817 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Mon, 1 Jun 2015 19:49:52 +0200
Subject: [PATCH] Fix admesh's STL parser in order to make it more tolerant for
 broken STL files having multiple 'solid' definitions. Still not the ideal STL
 parser, but handles the cases that were reported so far. #2471 #2842

---
 xs/src/admesh/stlinit.c | 42 ++++++++++++++++++++++-------------------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/xs/src/admesh/stlinit.c b/xs/src/admesh/stlinit.c
index efc4e11ba2..e92af81047 100644
--- a/xs/src/admesh/stlinit.c
+++ b/xs/src/admesh/stlinit.c
@@ -152,18 +152,19 @@ stl_count_facets(stl_file *stl, char *file) {
     }
     
     /* Find the number of facets */
-    j = 0;
-    for(i = 0; i < file_size ; i++) {
-      j++;
-      if(getc(stl->fp) == '\n') {
-        if(j > 4) { /* don't count short lines */
-          num_lines++;
-        }
-        j = 0;
-      }
+    char linebuf[100];
+    while (fgets(linebuf, 100, stl->fp) != NULL) {
+        /* don't count short lines */
+        if (strlen(linebuf) <= 4) continue;
+        
+        /* skip solid/endsolid lines as broken STL file generators may put several of them */
+        if (strncmp(linebuf, "solid", 5) == 0 || strncmp(linebuf, "endsolid", 8) == 0) continue;
+        
+        ++num_lines;
     }
+    
     rewind(stl->fp);
-
+    
     /* Get the header */
     for(i = 0;
         (i < 80) && (stl->stats.header[i] = getc(stl->fp)) != '\n'; i++);
@@ -269,8 +270,6 @@ stl_read(stl_file *stl, int first_facet, int first) {
     fseek(stl->fp, HEADER_SIZE, SEEK_SET);
   } else {
     rewind(stl->fp);
-    /* Skip the first line of the file */
-    while(getc(stl->fp) != '\n');
   }
 
   for(i = first_facet; i < stl->stats.number_of_facets; i++) {
@@ -288,13 +287,18 @@ stl_read(stl_file *stl, int first_facet, int first) {
     } else
       /* Read a single facet from an ASCII .STL file */
     {
-      if((fscanf(stl->fp, "%*s %*s %f %f %f\n", &facet.normal.x, &facet.normal.y, &facet.normal.z) + \
-          fscanf(stl->fp, "%*s %*s") + \
-          fscanf(stl->fp, "%*s %f %f %f\n", &facet.vertex[0].x, &facet.vertex[0].y,  &facet.vertex[0].z) + \
-          fscanf(stl->fp, "%*s %f %f %f\n", &facet.vertex[1].x, &facet.vertex[1].y,  &facet.vertex[1].z) + \
-          fscanf(stl->fp, "%*s %f %f %f\n", &facet.vertex[2].x, &facet.vertex[2].y,  &facet.vertex[2].z) + \
-          fscanf(stl->fp, "%*s") + \
-          fscanf(stl->fp, "%*s")) != 12) {
+      // skip solid/endsolid
+      // (in this order, otherwise it won't work when they are paired in the middle of a file)
+      fscanf(stl->fp, "endsolid\n");
+      fscanf(stl->fp, "solid %*s\n");
+      
+      if((fscanf(stl->fp, " facet normal %f %f %f\n", &facet.normal.x, &facet.normal.y, &facet.normal.z) + \
+          fscanf(stl->fp, " outer loop\n") + \
+          fscanf(stl->fp, " vertex %f %f %f\n", &facet.vertex[0].x, &facet.vertex[0].y,  &facet.vertex[0].z) + \
+          fscanf(stl->fp, " vertex %f %f %f\n", &facet.vertex[1].x, &facet.vertex[1].y,  &facet.vertex[1].z) + \
+          fscanf(stl->fp, " vertex %f %f %f\n", &facet.vertex[2].x, &facet.vertex[2].y,  &facet.vertex[2].z) + \
+          fscanf(stl->fp, " endloop\n") + \
+          fscanf(stl->fp, " endfacet\n")) != 12) {
         perror("Something is syntactically very wrong with this ASCII STL!");
         stl->error = 1;
         return;