From: Ian Jackson <ian@liberator.relativity.greenend.org.uk>
Date: Sun, 20 Feb 2011 14:03:49 +0000 (+0000)
Subject: hostside: hidrawconv: factor out most of the reporter functions' bodies into macros
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ijackson/git?a=commitdiff_plain;h=f7dce805;p=trains.git

hostside: hidrawconv: factor out most of the reporter functions' bodies into macros
---

diff --git a/hostside/hidrawconv.c b/hostside/hidrawconv.c
index 3321ccf..9a298b5 100644
--- a/hostside/hidrawconv.c
+++ b/hostside/hidrawconv.c
@@ -20,31 +20,64 @@ void die_hook(void) { }
 
 static LastReports lasts;
 
-void reportbits(const uint8_t msg[], const uint8_t last[],
-		int len, const KeyBit *bit) {
-  for (; bit->str; bit++) {
-    if (bit->pos >= len) continue;
-    uint8_t m= msg[bit->pos] & bit->mask;
-    uint8_t l= last[bit->pos] & bit->mask;
-    if (m==l) continue;
-    printf("%s %d\n", bit->str, !!m);
+
+/*---------- helpful macros for reporter functions ----------*/
+
+/*
+ * These expect/define:
+ *
+ *   const uint8_t msg[], last[];
+ *   int len;
+ *   const EntType *ent;
+ *   uint8_t mb, lb;  // bits from the message, masked but unshifted
+ *
+ *   typedef struct {
+ *     const char *str;
+ *     uint8_t mask;
+ *     int pos;
+ *   } EntType;
+ */
+
+#define FOR_REPORTENTRIES(ent)			\
+  /* Like for(;;) */				\
+  for (; (ent)->str; (ent)++)			\
+    if ((ent)->pos >= len) continue;		\
+    else
+
+#define MSG_BITS(ent)  (msg[(ent)->pos] & (ent)->mask)
+#define LAST_BITS(ent) (msg[(ent)->pos] & (ent)->mask)
+  /* uint8_t MSG_BITS(EntType *ent);
+   * uint8_t LAST_BITS(EntType *ent);
+   */
+
+#define DEFINE_STANDARD_REPORTER(EntType, ent, BODY_BLOCK)		\
+  void report##ent##s(const uint8_t msg[], const uint8_t last[],	\
+		      int len, const EntType *ent) {			\
+    FOR_REPORTENTRIES(ent) {						\
+      uint8_t mb= MSG_BITS(ent);					\
+      uint8_t lb= LAST_BITS(ent);					\
+      if (mb==lb) continue;						\
+      BODY_BLOCK							\
+    }									\
   }
-}
 
-void reportlocs(const uint8_t msg[], const uint8_t last[],
-		int len, const ValLoc *loc) {
-  for (; loc->str; loc++) {
-    if (loc->pos >= len) continue;
-    uint8_t mb= msg[loc->pos] & loc->mask;
-    uint8_t lb= last[loc->pos] & loc->mask;
-    if (mb==lb) continue;
+
+/*---------- reporter functions ----------*/
+
+DEFINE_STANDARD_REPORTER(KeyBit, bit, {
+    printf("%s %d\n", bit->str, !!mb);
+  })
+
+DEFINE_STANDARD_REPORTER(ValLoc, loc, {
     mb >>= loc->rshift;
     mb -= loc->zero;
     double val= (int8_t)mb;
     val /= (val >= 0 ? 127 : 128);
     printf("%s %.5f\n", loc->str, loc->sign * val);
-  }
-}
+  })
+
+
+/*---------- core functions ----------*/
 
 void dispatch(LastReports *lasts, const char *message_prefix,
 	      ProcessReport *const report_processors[MAXREPORTS],
@@ -72,6 +105,8 @@ void dispatch(LastReports *lasts, const char *message_prefix,
   memcpy(last->msg, msg, l);
 }  
 
+/*---------- main program ----------*/
+
 static void events(int verbose) {
   uint8_t msg[MAXREPORTLEN+1];
   char phys[PATH_MAX], name[PATH_MAX];
diff --git a/hostside/hidrawconv.h b/hostside/hidrawconv.h
index 6ffd35e..3887537 100644
--- a/hostside/hidrawconv.h
+++ b/hostside/hidrawconv.h
@@ -23,26 +23,30 @@ typedef void ProcessReport(const uint8_t *msg, int msglen, const uint8_t *last);
 extern const char *const descriptor;
 extern ProcessReport *const report_processors[MAXREPORTS];
 
+void dispatch(LastReports *lasts, const char *message_prefix,
+	      ProcessReport *const report_processors[MAXREPORTS],
+	      const uint8_t *msg, int l);
+
+/*---------- specific reporters ----------*/
+
 typedef struct {
   const char *str;
   int pos;
   uint8_t mask;
 } KeyBit;
 
+void reportbits(const uint8_t msg[], const uint8_t last[],
+		int len, const KeyBit bits[]);
+
+
 typedef struct {
   const char *str;
   int pos, rshift, sign; /* mask is applied before rshift */
   uint8_t mask, zero;
 } ValLoc;
 
-void reportbits(const uint8_t msg[], const uint8_t last[],
-		int len, const KeyBit bits[]);
-
 void reportlocs(const uint8_t msg[], const uint8_t last[],
 		int len, const ValLoc locs[]);
 
-void dispatch(LastReports *lasts, const char *message_prefix,
-	      ProcessReport *const report_processors[MAXREPORTS],
-	      const uint8_t *msg, int l);
 
 #endif /*HIDRAWCONV_H*/