From: John Darrington <john@darrington.wattle.id.au>
Date: Wed, 10 Jun 2009 03:36:05 +0000 (+0800)
Subject: Added a new casereader translator to consolodate cases.
X-Git-Tag: build37~50^2~25
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2896dffb3e6af00a5c764f0b3c0f67bd292ef51e;p=pspp-builds.git

Added a new casereader translator to consolodate cases.

This new translator creates a reader which provides
a list of distinct cases in the input, with the weights
consolodated, where applicable.
---

diff --git a/src/data/casereader-translator.c b/src/data/casereader-translator.c
index 548c22fb..62b38b99 100644
--- a/src/data/casereader-translator.c
+++ b/src/data/casereader-translator.c
@@ -359,3 +359,117 @@ car_translate (struct ccase *input, void *car_)
 }
 
 
+
+
+struct consolodator
+{
+  const struct variable *key;
+  const struct variable *weight;
+  double cc;
+  double prev_cc;
+
+  casenumber n;
+  struct casereader *clone;
+  struct caseproto *proto;
+};
+
+static bool
+uniquify (const struct ccase *c, void *aux)
+{
+  struct consolodator *cdr = aux;
+  const union value *current_value = case_data (c, cdr->key);
+  const int key_width = var_get_width (cdr->key);
+  const double weight = cdr->weight ? case_data (c, cdr->weight)->f : 1.0;
+  const struct ccase *next_case = casereader_peek (cdr->clone, cdr->n + 1);
+
+  cdr->n ++;
+  cdr->cc += weight;
+
+  if ( NULL == next_case)
+      goto end;
+    
+  if ( 0 != value_compare_3way (case_data (next_case, cdr->key),
+				current_value, key_width))
+    goto end;
+
+  
+  return false;
+
+ end:
+  cdr->prev_cc = cdr->cc;
+  cdr->cc = 0;
+  return true;
+}
+
+
+
+static struct ccase *
+consolodate_weight (struct ccase *input, void *aux)
+{
+  struct consolodator *cdr = aux;
+  struct ccase *c;
+
+  c = case_unshare_and_resize (input, cdr->proto);
+
+  if (cdr->weight)
+    case_data_rw (c, cdr->weight)->f = cdr->prev_cc;
+  else
+    case_data_rw_idx (c, caseproto_get_n_widths (cdr->proto) - 1)->f = cdr->prev_cc;    
+
+  return c;
+}
+
+
+static bool
+uniquify_destroy (void *aux)
+{
+  struct consolodator *cdr = aux;
+
+  casereader_destroy (cdr->clone);
+  free (cdr);
+
+  return true;
+}
+
+
+
+/* Returns a new casereader which is based upon INPUT, but which contains a maximum 
+   of one case for each distinct value of KEY.
+   If WEIGHT is non-null, then the new casereader's values for this variable
+   will be the sum of all values matching KEY.
+   IF WEIGHT is null, then the new casereader will have an additional numeric
+   value appended, which will contain the total number of cases containing
+   KEY.
+   INPUT must be sorted on KEY
+*/
+struct casereader *
+casereader_create_distinct (struct casereader *input,
+					       const struct variable *key,
+					       const struct variable *weight)
+{
+  struct casereader *u ;
+  struct casereader *ud ;
+  struct caseproto *output_proto = casereader_get_proto (input);
+
+  struct consolodator *cdr = xmalloc (sizeof (*cdr));
+  cdr->n = 0;
+  cdr->key = key;
+  cdr->weight = weight;
+  cdr->cc = 0;
+  cdr->clone = casereader_clone (input);
+
+  if ( NULL == cdr->weight )
+    output_proto = caseproto_add_width (output_proto, 0);
+
+  cdr->proto = output_proto;
+
+  u = casereader_create_filter_func (input, uniquify,
+				     NULL, cdr, NULL);
+
+  ud = casereader_create_translator (u,
+				     output_proto,
+				     consolodate_weight,
+				     uniquify_destroy,
+				     cdr);
+}
+
diff --git a/src/data/casereader.h b/src/data/casereader.h
index d4f2966a..3b903bbf 100644
--- a/src/data/casereader.h
+++ b/src/data/casereader.h
@@ -140,5 +140,10 @@ casereader_create_append_rank (struct casereader *,
 			       enum rank_error *err,
 			       distinct_func *distinct_callback, void *aux);
 
+struct casereader *
+casereader_create_distinct (struct casereader *input,
+			    const struct variable *key,
+			    const struct variable *weight);
+
 
 #endif /* data/casereader.h */