keep cache of blocks of isl_ints

1 files changed, 69 insertions, 18 deletions

diff --git a/isl_blk.c b/isl_blk.c
index 0cb833cb..246b40d4 100644
--- a/isl_blk.c
+++ b/isl_blk.c
@@ -1,49 +1,80 @@
 #include "isl_blk.h"
+#include "isl_ctx.h"
 
 struct isl_blk isl_blk_empty()
 {
 	struct isl_blk block;
+	block.size = 0;
+	block.data = NULL;
+	return block;
+}
+
+static int isl_blk_is_empty(struct isl_blk block)
+{
+	return block.size == 0 && block.data == NULL;
+}
+
+static struct isl_blk isl_blk_error()
+{
+	struct isl_blk block;
 	block.size = -1;
 	block.data = NULL;
 	return block;
 }
 
+int isl_blk_is_error(struct isl_blk block)
+{
+	return block.size == -1 && block.data == NULL;
+}
+
 struct isl_blk isl_blk_alloc(struct isl_ctx *ctx, size_t n)
 {
+	int i;
 	struct isl_blk block;
 
-	block.data = isl_alloc_array(ctx, isl_int, n);
-	if (!block.data)
-		block.size = -1;
-	else {
-		int i;
-		block.size = n;
-		for (i = 0; i < n; ++i)
-			isl_int_init(block.data[i]);
-	}
+	if (ctx->n_cached) {
+		int best = 0;
+		for (i = 1; ctx->cache[best].size != n && i < ctx->n_cached; ++i) {
+			if (ctx->cache[best].size < n) {
+				if (ctx->cache[i].size > ctx->cache[best].size)
+					best = i;
+			} else if (ctx->cache[i].size >= n &&
+				   ctx->cache[i].size < ctx->cache[best].size)
+					best = i;
+		}
+		block = ctx->cache[best];
+		if (--ctx->n_cached != best)
+			ctx->cache[best] = ctx->cache[ctx->n_cached];
+	} else
+		block = isl_blk_empty();
 
-	return block;
+	return isl_blk_extend(ctx, block, n);
 }
 
 struct isl_blk isl_blk_extend(struct isl_ctx *ctx, struct isl_blk block,
 				size_t new_n)
 {
+	int i;
+	isl_int *p;
+
 	if (block.size >= new_n)
 		return block;
+
+	p = block.data;
 	block.data = isl_realloc_array(ctx, block.data, isl_int, new_n);
-	if (!block.data)
-		block.size = -1;
-	else {
-		int i;
-		for (i = block.size; i < new_n; ++i)
-			isl_int_init(block.data[i]);
-		block.size = new_n;
+	if (!block.data) {
+		free(p);
+		return isl_blk_error();
 	}
 
+	for (i = block.size; i < new_n; ++i)
+		isl_int_init(block.data[i]);
+	block.size = new_n;
+
 	return block;
 }
 
-void isl_blk_free(struct isl_ctx *ctx, struct isl_blk block)
+static void isl_blk_free_force(struct isl_ctx *ctx, struct isl_blk block)
 {
 	int i;
 
@@ -51,3 +82,23 @@ void isl_blk_free(struct isl_ctx *ctx, struct isl_blk block)
 		isl_int_clear(block.data[i]);
 	free(block.data);
 }
+
+void isl_blk_free(struct isl_ctx *ctx, struct isl_blk block)
+{
+	if (isl_blk_is_empty(block) || isl_blk_is_error(block))
+		return;
+
+	if (ctx->n_cached < ISL_BLK_CACHE_SIZE)
+		ctx->cache[ctx->n_cached++] = block;
+	else
+		isl_blk_free_force(ctx, block);
+}
+
+void isl_blk_clear_cache(struct isl_ctx *ctx)
+{
+	int i;
+
+	for (i = 0; i < ctx->n_cached; ++i)
+		isl_blk_free_force(ctx, ctx->cache[i]);
+	ctx->n_cached = 0;
+}