scratch: add stack frame support

[secp256k1.git] / src / scratch.h

diff --git a/src/scratch.h b/src/scratch.h
index aba56e215eb23e7b99e5e450fd1a3fd041972ceb..fef377af0d94203efcbde83e854b1443b1cce8a4 100644 (file)
--- a/src/scratch.h
+++ b/src/scratch.h
@@ -7,29 +7,33 @@
 #ifndef _SECP256K1_SCRATCH_
 #define _SECP256K1_SCRATCH_
 
+#define SECP256K1_SCRATCH_MAX_FRAMES   5
+
 /* The typedef is used internally; the struct name is used in the public API
  * (where it is exposed as a different typedef) */
 typedef struct secp256k1_scratch_space_struct {
-    void *data;
-    size_t offset;
-    size_t init_size;
+    void *data[SECP256K1_SCRATCH_MAX_FRAMES];
+    size_t offset[SECP256K1_SCRATCH_MAX_FRAMES];
+    size_t frame_size[SECP256K1_SCRATCH_MAX_FRAMES];
+    size_t frame;
     size_t max_size;
     const secp256k1_callback* error_callback;
 } secp256k1_scratch;
 
-static secp256k1_scratch* secp256k1_scratch_create(const secp256k1_callback* error_callback, size_t init_size, size_t max_size);
+static secp256k1_scratch* secp256k1_scratch_create(const secp256k1_callback* error_callback, size_t max_size);
+
 static void secp256k1_scratch_destroy(secp256k1_scratch* scratch);
 
+/** Attempts to allocate a new stack frame with `n` available bytes. Returns 1 on success, 0 on failure */
+static int secp256k1_scratch_allocate_frame(secp256k1_scratch* scratch, size_t n, size_t objects);
+
+/** Deallocates a stack frame */
+static void secp256k1_scratch_deallocate_frame(secp256k1_scratch* scratch);
+
 /** Returns the maximum allocation the scratch space will allow */
 static size_t secp256k1_scratch_max_allocation(const secp256k1_scratch* scratch, size_t n_objects);
 
-/** Attempts to allocate so that there are `n` available bytes. Returns 1 on success, 0 on failure */
-static int secp256k1_scratch_resize(secp256k1_scratch* scratch, size_t n, size_t n_objects);
-
-/** Returns a pointer into the scratch space or NULL if there is insufficient available space */
+/** Returns a pointer into the most recently allocated frame, or NULL if there is insufficient available space */
 static void *secp256k1_scratch_alloc(secp256k1_scratch* scratch, size_t n);
 
-/** Resets the returned pointer to the beginning of space */
-static void secp256k1_scratch_reset(secp256k1_scratch* scratch);
-
 #endif