From aeb96466fac59d9d7294d865d2f469bac280461d Mon Sep 17 00:00:00 2001
From: Alex 'AdUser' Z <ad_user@runbox.com>
Date: Fri, 20 Mar 2015 17:30:31 +1000
Subject: [PATCH] * imdb_search : use imdb_search_t

---
 src/database.c | 51 ++++++++++++++++++++++++++++++++++++++++++--------
 src/database.h |  6 +++++-
 src/util.c     |  6 +++++-
 3 files changed, 53 insertions(+), 10 deletions(-)

diff --git a/src/database.c b/src/database.c
index d593595..816c89a 100644
--- a/src/database.c
+++ b/src/database.c
@@ -192,17 +192,34 @@ int imdb_write_list(imdb_t *db, imdb_rec_t *list, size_t list_len)
   return processed;
 }
 
-int imdb_search(imdb_t *db, imdb_rec_t *sample, float tresh, imdb_match_t **matches)
+inline float
+ratio_from_rec_data(unsigned char * const data) {
+  uint16_t iw, ih;
+
+  iw = *((uint16_t *)(data + REC_OFF_IW));
+  ih = *((uint16_t *)(data + REC_OFF_IH));
+
+  return (iw > 0 && ih > 0) ? (iw / ih) : 0.0;
+}
+
+int
+imdb_search(imdb_t        * const db,
+            imdb_rec_t    * const sample,
+            imdb_search_t * const search,
+            imdb_match_t  **matches)
 {
+  imdb_block_t blk;
   const int blk_size = 4096;
   uint64_t found = 0;
-  imdb_block_t blk;
   unsigned int i = 0;
-  unsigned char *p = NULL, *t = NULL;
+  unsigned char *p = NULL;
   float diff = 0.0;
+  float ratio_s = 0.0; /* source */
+  float ratio_t = 0.0; /* tested */
 
   assert(db      != NULL);
   assert(sample  != NULL);
+  assert(search  != NULL);
   assert(matches != NULL);
 
   memset(&blk, 0x0, sizeof(imdb_block_t));
@@ -219,17 +236,31 @@ int imdb_search(imdb_t *db, imdb_rec_t *sample, float tresh, imdb_match_t **matc
     return -1;
   }
 
+  if (search->tresh_ratio > 0.0)
+    ratio_s = ratio_from_rec_data(sample->data);
+
   *matches = NULL;
   while (imdb_read_blk(db, &blk) > 0) {
     p = blk.data;
     for (i = 0; i < blk.records; i++, p += IMDB_REC_LEN) {
-      t = p + REC_OFF_RU;
-      if (*t == 0x0) continue;
+      if (*(p + REC_OFF_RU) == 0x0)
+        continue; /* record missing */
+
+      /* - compare ratio - cheap */
+      if (ratio_s > 0.0 && (ratio_t = ratio_from_rec_data(p)) > 0.0) {
+        diff  =  ratio_s - ratio_t;
+        diff *= (ratio_s > ratio_t) ? 1.0 : -1.0;
+        if (diff > search->tresh_ratio)
+          continue;
+      } else {
+        /* either ratio not set, can't compare, skipping test */
+      }
 
-      t = p + REC_OFF_BM;
-      diff  = (float) bitmap_compare(t, sample->data + REC_OFF_BM);
+      /* - compare bitmap - more expensive */
+      diff  = (float) bitmap_compare(p + REC_OFF_BM, sample->data + REC_OFF_BM);
       diff /= BITMAP_BITS;
-      if (diff > tresh) continue;
+      if (diff > search->tresh_bitmap)
+        continue;
 
       /* allocate more memory, if needed */
       if (found % 10 == 0) {
@@ -246,8 +277,12 @@ int imdb_search(imdb_t *db, imdb_rec_t *sample, float tresh, imdb_match_t **matc
       (*matches)[found].num  = blk.start + i;
       (*matches)[found].diff = diff;
       found++;
+      if (search->limit && found >= search->limit)
+        break;
     }
     FREE(blk.data);
+    if (search->limit && found >= search->limit)
+      break;
     blk.start += blk_size;
   }
 
diff --git a/src/database.h b/src/database.h
index 0ec1aad..477049b 100644
--- a/src/database.h
+++ b/src/database.h
@@ -92,6 +92,10 @@ extern int imdb_close(imdb_t *db);
    0 if nothing found
   >0 if found some matches
  */
-extern int imdb_search(imdb_t *db, imdb_rec_t *sample, float tresh, imdb_match_t **matches);
+extern int
+imdb_search(imdb_t        * const db,
+            imdb_rec_t    * const sample,
+            imdb_search_t * const search,
+            imdb_match_t  **matches);
 
 #endif
diff --git a/src/util.c b/src/util.c
index 4655d65..082c97a 100644
--- a/src/util.c
+++ b/src/util.c
@@ -44,8 +44,12 @@ int search_similar(imdb_t *db, imdb_rec_t *sample, float tresh)
 {
   int ret = 0, i = 0;
   imdb_match_t *matches = NULL;
+  imdb_search_t search;
+  memset(&search, 0x0, sizeof(search));
+  search.tresh_ratio  = tresh;
+  search.tresh_bitmap = tresh;
 
-  ret = imdb_search(db, sample, tresh, &matches);
+  ret = imdb_search(db, sample, &search, &matches);
   if (ret == -1) {
     printf("%s\n", db->errstr);
     exit(EXIT_FAILURE);