From 68e76ae63605193e89b05eab90dc6fdfa6f37053 Mon Sep 17 00:00:00 2001
From: Tor Andersson <tor.andersson@artifex.com>
Date: Thu, 7 Jan 2016 13:21:53 +0100
Subject: Add pool allocator.

---
 include/mupdf/fitz.h      |  3 ++-
 include/mupdf/fitz/pool.h | 26 ++++++++++++++++++++++++++
 source/fitz/pool.c        | 44 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 72 insertions(+), 1 deletion(-)
 create mode 100644 include/mupdf/fitz/pool.h
 create mode 100644 source/fitz/pool.c

diff --git a/include/mupdf/fitz.h b/include/mupdf/fitz.h
index 11accf6d..cf78060c 100644
--- a/include/mupdf/fitz.h
+++ b/include/mupdf/fitz.h
@@ -9,9 +9,10 @@
 #include "mupdf/fitz/getopt.h"
 #include "mupdf/fitz/hash.h"
 #include "mupdf/fitz/math.h"
+#include "mupdf/fitz/pool.h"
 #include "mupdf/fitz/string.h"
-#include "mupdf/fitz/ucdn.h"
 #include "mupdf/fitz/tree.h"
+#include "mupdf/fitz/ucdn.h"
 #include "mupdf/fitz/xml.h"
 
 /* I/O */
diff --git a/include/mupdf/fitz/pool.h b/include/mupdf/fitz/pool.h
new file mode 100644
index 00000000..924fb804
--- /dev/null
+++ b/include/mupdf/fitz/pool.h
@@ -0,0 +1,26 @@
+#ifndef MUPDF_FITZ_POOL_H
+#define MUPDF_FITZ_POOL_H
+
+#include "mupdf/fitz/system.h"
+#include "mupdf/fitz/context.h"
+
+typedef struct fz_pool_s fz_pool;
+typedef struct fz_pool_node_s fz_pool_node;
+
+struct fz_pool_s
+{
+	fz_pool_node *head, *tail;
+	char *pos, *end;
+};
+
+struct fz_pool_node_s
+{
+	fz_pool_node *next;
+	char mem[64 << 10]; /* 64k blocks */
+};
+
+fz_pool *fz_new_pool(fz_context *ctx);
+void *fz_pool_alloc(fz_context *ctx, fz_pool *pool, size_t size);
+void fz_drop_pool(fz_context *ctx, fz_pool *pool);
+
+#endif
diff --git a/source/fitz/pool.c b/source/fitz/pool.c
new file mode 100644
index 00000000..e676947f
--- /dev/null
+++ b/source/fitz/pool.c
@@ -0,0 +1,44 @@
+#include "mupdf/fitz.h"
+
+fz_pool *fz_new_pool(fz_context *ctx)
+{
+	fz_pool *pool = fz_malloc_struct(ctx, fz_pool);
+	fz_pool_node *node = fz_malloc_struct(ctx, fz_pool_node);
+	pool->head = pool->tail = node;
+	pool->pos = node->mem;
+	pool->end = node->mem + sizeof node->mem;
+	return pool;
+}
+
+void *fz_pool_alloc(fz_context *ctx, fz_pool *pool, size_t size)
+{
+	char *ptr;
+
+	/* round size to pointer alignment (we don't expect to use doubles) */
+	size = ((size + sizeof(void*) - 1) / sizeof(void*)) * sizeof(void*);
+
+	if (pool->pos + size > pool->end)
+	{
+		fz_pool_node *node = fz_malloc_struct(ctx, fz_pool_node);
+		pool->tail = pool->tail->next = node;
+		pool->pos = node->mem;
+		pool->end = node->mem + sizeof node->mem;
+		if (pool->pos + size > pool->end)
+			fz_throw(ctx, FZ_ERROR_GENERIC, "out of memory: allocation too large to fit in pool");
+	}
+	ptr = pool->pos;
+	pool->pos += size;
+	return ptr;
+}
+
+void fz_drop_pool(fz_context *ctx, fz_pool *pool)
+{
+	fz_pool_node *node = pool->head;
+	while (node)
+	{
+		fz_pool_node *next = node->next;
+		fz_free(ctx, node);
+		node = next;
+	}
+	fz_free(ctx, pool);
+}
-- 
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