ecbuf: Remove _pry() macro

It's rather trivial to implement if the using application needs it.
Not necessary to always keep an extra variable around for functionality
that may not be used.

2 files changed, 12 insertions, 21 deletions

diff --git a/ecbuf.h b/ecbuf.h
index e41c493..e2f702b 100644
--- a/ecbuf.h
+++ b/ecbuf.h
@@ -21,8 +21,8 @@
 */
 
 /* This is an efficient circular buffer implementation that automatically
- * expands the buffer when it's full. As such, it behaves like any other FIFO
- * queue.
+ * expands the buffer when it's full. As such, it behaves like any other
+ * unbounded FIFO queue.
  *
  * Usage:
  *
@@ -35,8 +35,6 @@
  *    ecbuf_push(queue, 7);
  *    ecbuf_push(queue, 11);
  *
- *    // = 11
- *    printf("Most recently queued = %d\n", ecbuf_pry(queue));
  *    // = 3
  *    printf("Least recently queued = %d\n", ecbuf_peek(queue));
  *    // = 4
@@ -53,9 +51,8 @@
  * The concept is explained at
  * http://blog.labix.org/2010/12/23/efficient-algorithm-for-expanding-circular-buffers
  *
- * This implementation is slightly different, in that it provides a macro to
- * read back the most recently written value, without adding more overhead in
- * terms of the number of variables to keep track of.
+ * This implementation is slightly different, in that it is slightly smaller
+ * and requires one less variable to keep track of.
  */
 
 #ifndef ECBUF_H
@@ -66,14 +63,13 @@
 
 /* The variables are:
  *  l: Number of items in the queue
- *  i: Last index we've written to in the last push()
  *  o: Index we're going to read from in the next pop()
  *  b: Index of the last written item before the buffer has been expanded.
  * cn: Number of slots in the cirbular buffer
  * bn: Number of slots in the complete buffer
  */
 #define ecbuf_t(type) struct {\
-		int l, i, o, b, cn, bn;\
+		int l, o, b, cn, bn;\
 		type *a;\
 	}
 
@@ -83,7 +79,7 @@ typedef ecbuf_t(void) ecbuf__t;
 
 #define ecbuf_init(v) do {\
 		(v).bn = (v).cn = 32;\
-		(v).o = (v).i = (v).l = 0;\
+		(v).o = (v).l = 0;\
 		(v).b = -1;\
 		(v).a = malloc((v).bn*sizeof(*(v).a));\
 	} while(0)
@@ -98,10 +94,6 @@ typedef ecbuf_t(void) ecbuf__t;
 /* Peek into the queue, requires !ecbuf_empty(v) */
 #define ecbuf_peek(v) ((v).a[(v).o])
 
-/* Similar to peek, but reads back the most *recently* queued item.
- * (I'm bad at naming, I know) */
-#define ecbuf_pry(v) ((v).a[(v).i])
-
 #define ecbuf_push(v, x) do {\
 		if((v).l == (v).bn) {\
 			if((v).cn == (v).bn)\
@@ -109,11 +101,11 @@ typedef ecbuf_t(void) ecbuf__t;
 			(v).bn <<= 1;\
 			(v).a = realloc((v).a, (v).bn*sizeof(*(v).a));\
 		}\
-		(v).i = (v).l + (v).o - (v).b - 1;\
-		if((v).bn == (v).cn) (v).i &= (v).cn-1;\
-		else if((v).o <= (v).b) (v).i += (v).cn;\
+		int _ecbuf_i = (v).l + (v).o - (v).b - 1;\
+		if((v).bn == (v).cn) _ecbuf_i &= (v).cn-1;\
+		else if((v).o <= (v).b) _ecbuf_i += (v).cn;\
 		(v).l++;\
-		(v).a[(v).i] = (x);\
+		(v).a[_ecbuf_i] = (x);\
 	} while(0)
 
 
diff --git a/test/ecbuf.c b/test/ecbuf.c
index db2dc2f..1027e58 100644
--- a/test/ecbuf.c
+++ b/test/ecbuf.c
@@ -30,7 +30,7 @@
 
 
 /* This is the original implementation provided in the article (converted to C,
- * obviously). Provided here for testing, but doesn't have a _pry(). */
+ * obviously). Provided here for testing. */
 #else
 
 #define ecbuf_t(type) struct {\
@@ -47,7 +47,6 @@ typedef ecbuf_t(void) ecbuf__t;
 #define ecbuf_len(v) ((v).buflen)
 #define ecbuf_empty(v) ((v).buflen == 0)
 #define ecbuf_peek(v) ((v).a[(v).popi])
-#define ecbuf_pry(v) /* Doesn't work */
 #define ecbuf_push(v, x) do {\
 		int expandbuf = 0, expandring = 0;\
 		if((v).ringcap != (v).bufcap) {\
@@ -159,7 +158,7 @@ int main(int argc, char **argv) {
 	for(i=0; i<100; i++) {
 		for(j=0; j<100; j++) {
 			ecbuf_push(lst, w);
-			assert(ecbuf_pry(lst) == w++);
+			w++;
 			assert(ecbuf_len(lst) == w-r);
 		}
 		for(j=0; j<99; j++) {