WIP routesearch; New SQL_DISTINCT_{DECL,STEP}

diff --git a/yarrg/rscommon.h b/yarrg/rscommon.h
index f62fd99d9ed15cdf4d9cd873a6406c3d7a60d38b..5cf25f667601c0b250c1bfb8b61587c77a0cff60 100644 (file)
--- a/yarrg/rscommon.h
+++ b/yarrg/rscommon.h
@@ -30,9 +30,34 @@
 
 void sql_fatal(const char *stmt_what, int sqr, const char *act_what) NORET;
 
-#define SQL_STEP(ssh) (sql_step_wrap((ssh), #ssh, __FILE__, __LINE__))
-int sql_step_wrap(sqlite3_stmt *ssh, const char *ssh_string,
-                 const char *file, int line);
+#define SQL_STEP(ssh) (sql_step((ssh), #ssh, __FILE__, __LINE__))
+int sql_step(sqlite3_stmt *ssh, const char *ssh_string,
+            const char *file, int line);
+
+#define SQL_DISTINCT_DECL(cols, nintcols)      \
+  int cols[nintcols];                          \
+  cols[0]= -1;
+#define SQL_DISTINCT_STEP(ssh, cols, nkeycols)                          \
+  (sql_step_distinct((ssh), #ssh, __FILE__, __LINE__,                   \
+                    (cols), sizeof((cols))/sizeof((cols)[0]), nkeycols))
+int sql_step_distinct(sqlite3_stmt *ssh, const char *ssh_string,
+                     const char *file, int line,
+                     int *cols, int ncols, int nkeycols);
+   /* These work if we're making a query whose columns consist of:
+    *  - keys: integer column(s) on which the results are sorted by the query
+    *  - consequences: zero or more integer cols strictly dependent on the keys
+    *  - extra: zero or more further (possibly non-integer) columns
+    *
+    * Call SQL_DISTINCT_DECL, passing intcols = the total number of keys and
+    * consequences; it will declare  int cols[intfields];
+    *
+    * Then each SQL_DISTINCT_STEP is like SQL_STEP only you have to
+    * pass the number of key columns and it only returns rows with
+    * distinct keys.  Rows with all-identical keys are asserted to
+    * have identical consequences.  After each call to
+    * SQL_DISTINCT_STEP the keys and consequences will be stored in
+    * cols.
+    */
 
 int sql_single_int(const char *stmt);
 

diff --git a/yarrg/rssql.c b/yarrg/rssql.c
index 898ac3b268350b4824021ba987002622600c88e3..bfe60d6c8798be39920fa4cb50c88a336f2831de 100644 (file)
--- a/yarrg/rssql.c
+++ b/yarrg/rssql.c
@@ -57,8 +57,28 @@ sqlite3_stmt *sql_prepare(const char *stmt, const char *what) {
   return ssr;
 }
 
-int sql_step_wrap(sqlite3_stmt *ssh, const char *ssh_string,
-                 const char *file, int line) {
+int sql_step_distinct(sqlite3_stmt *ssh, const char *ssh_string,
+                     const char *file, int line,
+                     int *cols, int ncols, int nkeycols) {
+  for (;;) {
+    if (!sql_step(ssh, ssh_string, file, line)) return 0;
+
+    int i;
+    for (i=0; i<ncols; i++) {
+      int v= sqlite3_column_int(ssh, i);
+      if (v == cols[i]) continue;
+      
+      assert(i<nkeycols);
+      cols[i++]= v;
+      for ( ; i<ncols; i++)
+       cols[i]= sqlite3_column_int(ssh, i);
+      return 1;
+    }
+  }
+}
+
+int sql_step(sqlite3_stmt *ssh, const char *ssh_string,
+            const char *file, int line) {
   for (;;) {
     int sqr;
     sqr= sqlite3_step((ssh));