diff options
Diffstat (limited to 'render/imagecache.c')
| -rw-r--r-- | render/imagecache.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/render/imagecache.c b/render/imagecache.c index ec2ff4d0..9ebaec13 100644 --- a/render/imagecache.c +++ b/render/imagecache.c @@ -22,12 +22,15 @@ static gboolean RrImagePicEqual(const RrImagePic *p1, const RrImagePic *p2); -RrImageCache* RrImageCacheNew() +RrImageCache* RrImageCacheNew(gint max_resized_saved) { RrImageCache *self; + g_assert(max_resized_saved >= 0); + self = g_new(RrImageCache, 1); self->ref = 1; + self->max_resized_saved = max_resized_saved; self->table = g_hash_table_new((GHashFunc)RrImagePicHash, (GEqualFunc)RrImagePicEqual); return self; @@ -59,9 +62,6 @@ RrImage* RrImageCacheFind(RrImageCache *self, return g_hash_table_lookup(self->table, &pic); } -/* This is a fast, reversable hash function called "lookup3", found here: - http://burtleburtle.net/bob/c/lookup3.c -*/ #define hashsize(n) ((RrPixel32)1<<(n)) #define hashmask(n) (hashsize(n)-1) #define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k)))) @@ -87,6 +87,13 @@ RrImage* RrImageCacheFind(RrImageCache *self, c ^= b; c -= rot(b,24); \ } +/* This is a fast, reversable hash function called "lookup3", found here: + http://burtleburtle.net/bob/c/lookup3.c, by Bob Jenkins + + This hashing algorithm is "reversible", that is, not cryptographically + secure at all. But we don't care about that, we just want something to + tell when images are the same or different relatively quickly. +*/ guint32 hashword(const guint32 *key, gint length, guint32 initval) { guint32 a,b,c; @@ -119,6 +126,9 @@ guint32 hashword(const guint32 *key, gint length, guint32 initval) return c; } +/*! This is some arbitrary initial value for the hashing function. It's + constant so that you get the same result from the same data each time. +*/ #define HASH_INITVAL 0xf00d guint RrImagePicHash(const RrImagePic *p) |