[babl/daniel-tolerance-hacks: 4/14] Runtime tolerance, hack in progress stage 2

[Daniel Sabo <daniels src gnome org>]

commit 9017f93a5e85e8a2211dd1f10d072dea63906d0f
Author: Daniel Sabo <DanielSabo gmail com>
Date:   Tue Jan 29 01:59:42 2013 -0800

    Runtime tolerance, hack in progress stage 2

 babl/babl-fish-path.c |   21 +++++--------
 babl/babl-fish.c      |   80 ++++++++++++++++++++++++++++++-------------------
 babl/babl.h           |   12 +++++++
 3 files changed, 69 insertions(+), 44 deletions(-)
---
diff --git a/babl/babl-fish-path.c b/babl/babl-fish-path.c
index b452e6c..c7b4c47 100644
--- a/babl/babl-fish-path.c
+++ b/babl/babl-fish-path.c
@@ -385,8 +385,6 @@ babl_fish_path (const Babl *source,
        */
       return babl;
     }
-  
-  babl_log("Inserting %s into babl_fish_db\n", name);
 
   babl = babl_calloc (1, sizeof (BablFishPath) +
                       strlen (name) + 1);
@@ -461,6 +459,7 @@ babl_fish_path (const Babl *source,
     }
   }
   
+  /*
   printf("%d canidate conversions:\n", babl_list_size(conversion_list->fish_path_list.path_list));
   {
     int i;
@@ -472,21 +471,17 @@ babl_fish_path (const Babl *source,
       babl_introspect(babl);
     }
   }
-  
-  //FIXME: Throw away the list for now:
-  babl_free (conversion_list);
-
-  if (babl_list_size (babl->fish_path.conversion_list) == 0)
-    {
-      babl_free (babl);
-      return NULL;
-    }
+  */
+    
+  babl_free (babl); //FIXME: This object is from the old system and should be removed
 
   /* Since there is not an already registered instance by the required
    * name, inserting newly created class into database.
    */
-  babl_db_insert (babl_fish_db (), babl);
-  return babl;
+  babl_log("Inserting %s into babl_fish_db\n", conversion_list->instance.name);
+
+  babl_db_insert (babl_fish_db (), conversion_list);
+  return conversion_list;
 }
 
 static long
diff --git a/babl/babl-fish.c b/babl/babl-fish.c
index 76cb53d..ba7d8b0 100644
--- a/babl/babl-fish.c
+++ b/babl/babl-fish.c
@@ -24,11 +24,28 @@
 #include <string.h>
 #include <stdarg.h>
 
+#define BABL_LEGAL_ERROR           0.000001
+static double legal_error (void)
+{
+  static double error = 0.0;
+  const char   *env;
+
+  if (error != 0.0)
+    return error;
+
+  env = getenv ("BABL_TOLERANCE");
+  if (env && env[0] != '\0')
+    error = atof (env);
+  else
+    error = BABL_LEGAL_ERROR;
+  return error;
+}
+
 typedef struct _BablFindFish BablFindFish;
 
 typedef struct _BablFindFish
 {
-  Babl       *fish_path;
+  Babl       *fish_path_list;
   Babl       *fish_ref;
   Babl       *fish_fish;
   int        fishes;
@@ -62,9 +79,9 @@ find_fish_path (Babl *item,
           ffish->fish_ref = item;
           ffish->fishes++;
         }
-      else if (item->instance.class_type == BABL_FISH_PATH)
+      else if (item->instance.class_type == BABL_FISH_PATH_LIST)
         {
-          ffish->fish_path = item;
+          ffish->fish_path_list = item;
           ffish->fishes++;
         }
       else if (item->instance.class_type == BABL_FISH)
@@ -142,6 +159,14 @@ const Babl *
 babl_fish (const void *source,
            const void *destination)
 {
+  return babl_fish_with_tolerance (source, destination, legal_error());
+}
+
+const Babl *
+babl_fish_with_tolerance (const void *source,
+                          const void *destination,
+                          double tolerance)
+{
   const Babl *source_format      = NULL;
   const Babl *destination_format = NULL;
 
@@ -213,41 +238,34 @@ babl_fish (const void *source,
          * insert it into the fish database to indicate non-existent fish
          * path.
          */
+        Babl *conversion_list = NULL;
+        Babl *fish_path = NULL;
+        int i;
+        
         babl_hash_table_find (id_htable, hashval, find_fish_path, (void *) &ffish);
-
-        if (ffish.fish_path)
+        
+        if (ffish.fish_path_list)
           {
             /* we have found suitable fish path in the database */
-            return ffish.fish_path;
+            conversion_list = ffish.fish_path_list;
           }
-        if (!ffish.fish_fish)
+        else
           {
             /* we haven't tried to search for suitable path yet */
-            Babl *fish_path = babl_fish_path (source_format, destination_format);
-
-            if (fish_path)
-              {
-                return fish_path;
-              }
-            else
-              {
-                /* there isn't a suitable path for requested formats,
-                 * let's create a dummy BABL_FISH instance and insert
-                 * it into the fish database to indicate that such path
-                 * does not exist.
-                 */
-                char *name = "X"; /* name does not matter */
-                Babl *fish = babl_calloc (1, sizeof (BablFish) + strlen (name) + 1);
-
-                fish->class_type                = BABL_FISH;
-                fish->instance.id               = babl_fish_get_id (source_format, destination_format);
-                fish->instance.name             = ((char *) fish) + sizeof (BablFish);
-                strcpy (fish->instance.name, name);
-                fish->fish.source               = source_format;
-                fish->fish.destination          = destination_format;
-                babl_db_insert (babl_fish_db (), fish);
-              }
+            conversion_list = babl_fish_path (source_format, destination_format);
           }
+
+        /* find a conversion with an acceptable tolerance */
+        for (i = 0; i < babl_list_size(conversion_list->fish_path_list.path_list); ++i) {
+          Babl *candidate_path = babl_list_get_n(conversion_list->fish_path_list.path_list, i);
+          if (candidate_path->fish.error <= tolerance)
+            fish_path = candidate_path;
+          else
+            break;
+        }
+        
+        if (fish_path)
+          return fish_path;
       }
 
     if (ffish.fish_ref)
diff --git a/babl/babl.h b/babl/babl.h
index 546fad6..248f9c3 100644
--- a/babl/babl.h
+++ b/babl/babl.h
@@ -98,6 +98,18 @@ const Babl * babl_fish      (const void *source_format,
                              const void *destination_format);
 
 /**
+ * babl_fish:
+ *
+ *  Create a babl fish capable of converting from source_format to
+ *  destination_format with the given error tolerance, source
+ *  and destination can be either strings with the names of the
+ *  formats or Babl-format objects.
+ */
+const Babl * babl_fish_with_tolerance (const void *source,
+                                       const void *destination,
+                                       double tolerance);
+
+/**
  * babl_process:
  *
  *  Process n pixels from source to destination using babl_fish,