hint utils and assert_nn math hint (#373)

* wip: hint utils and assert_nn math hint

* fix std options struct

* fmt and naming style

* make base_addr optional

src/hint_processor/hint_utils.zig

@@ -0,0 +1,103 @@
+const std = @import("std");
+
+const ApTracking = @import("../vm/types/programjson.zig").ApTracking;
+const Felt252 = @import("../math/fields/starknet.zig").Felt252;
+const HintReference = @import("./hint_processor_def.zig").HintReference;
+const CoreVM = @import("../vm/core.zig");
+const OffsetValue = @import("../vm/types/programjson.zig");
+const CairoVM = CoreVM.CairoVM;
+const relocatable = @import("../vm/memory/relocatable.zig");
+const MaybeRelocatable = relocatable.MaybeRelocatable;
+const Relocatable = relocatable.Relocatable;
+
+pub const IdsManager = struct {
+    const Self = @This();
+
+    References: std.AutoHashMap([]const u8, HintReference),
+    HintApTracking: ApTracking,
+    AccessibleScopes: []const []const u8,
+
+    pub fn getFelt(self: *Self, name: []const u8, vm: *CairoVM) !Felt252 {
+        const val = try self.get(name, vm);
+        return try vm.getFelt(val);
+    }
+
+    pub fn get(self: *Self, name: []const u8, vm: *CairoVM) !?*MaybeRelocatable {
+        if (self.References.get(name)) |reference| {
+            if (getValueFromReference(reference, self.HintApTracking, vm)) |val| {
+                return val;
+            }
+        }
+        return error.ErrUnknownIdentifier;
+    }
+};
+
+pub fn getValueFromReference(reference: *HintReference, ap_tracking: ApTracking, vm: *CairoVM) ?*MaybeRelocatable {
+    // Handle the case of immediate
+    if (@typeInfo(reference.offset1) == .immediate) {
+        return MaybeRelocatable.fromFelt(Felt252.fromInt(reference.offset1.immediate));
+    }
+    if (getAddressFromReference(reference, ap_tracking, vm)) |address| {
+        if (reference.dereference) {
+            if (vm.segments.memory.get(address)) |value| {
+                return value;
+            }
+        } else {
+            return MaybeRelocatable.fromRelocatable(address);
+        }
+    }
+    return null;
+}
+
+pub fn getAddressFromReference(reference: *HintReference, ap_tracking: ApTracking, vm: *CairoVM) !?Relocatable {
+    if (@typeInfo(reference.offset1) != .reference) {
+        return null;
+    }
+    const offset1 = getOffsetValueReference(reference.offset1, reference.ap_tracking_data, ap_tracking, vm) catch return null;
+    if (offset1) |*offset1_rel| {
+        switch (reference.offset2) {
+            .reference => {
+                const offset2 = getOffsetValueReference(reference.offset2, reference.ap_tracking_data, ap_tracking, vm) catch return null;
+                if (offset2) |*offset2_val| {
+                    return offset1_rel.AddMaybeRelocatable(offset2_val) catch null;
+                }
+            },
+            .value => {
+                return offset1_rel.AddInt(reference.offset2.Value) catch null;
+            },
+            else => {},
+        }
+    }
+    return null;
+}
+
+pub fn getOffsetValueReference(offset_value: OffsetValue, ref_ap_tracking: ApTracking, hint_ap_tracking: ApTracking, vm: *CairoVM) ?*MaybeRelocatable {
+    var base_addr: ?Relocatable = null;
+    switch (offset_value.reference.Register) {
+        .FP => base_addr = vm.run_context.fp,
+        .AP => {
+            if (applyApTrackingCorrection(vm.run_context.ap, ref_ap_tracking, hint_ap_tracking)) |addr| {
+                base_addr = addr;
+            } else return null;
+        },
+    }
+
+    if (try base_addr.addUint(offset_value.value)) |addr| {
+        if (offset_value.dereference) {
+            if (vm.segments.memory.get(addr)) |value| {
+                return value;
+            }
+        } else {
+            return MaybeRelocatable.fromRelocatable(addr);
+        }
+    }
+
+    return null;
+}
+
+pub fn applyApTrackingCorrection(addr: Relocatable, ref_ap_tracking: ApTracking, hint_ap_tracking: ApTracking) ?Relocatable {
+    if (ref_ap_tracking.group == hint_ap_tracking.group) {
+        return try addr.subUint(hint_ap_tracking.offset - ref_ap_tracking.offset);
+    }
+    return null;
+}

src/hint_processor/math_hints.zig

@@ -0,0 +1,26 @@
+const std = @import("std");
+
+const CoreVM = @import("../vm/core.zig");
+
+const CairoVM = CoreVM.CairoVM;
+const IdsManager = @import("./hint_utils.zig").IdsManager;
+
+//Implements hint:
+// %{
+//     from starkware.cairo.common.math_utils import assert_integer
+//     assert_integer(ids.a)
+//     assert 0 <= ids.a % PRIME < range_check_builtin.bound, f'a = {ids.a} is out of range.'
+// %}
+fn assertNn(ids: IdsManager, vm: *CairoVM) !void {
+    const a = try ids.getFelt("a", vm);
+    for (vm.builtin_runners.items) |*builtin| {
+        switch (builtin.*) {
+            .RangeCheck => |*range_check| {
+                if (a.numBits() >= range_check.N_PARTS * range_check.INNER_RC_BOUND_SHIFT) {
+                    return std.fmt.errorf("Assertion failed, 0 <= ids.a %% PRIME < range_check_builtin.bound\n a = {s} is out of range", .{a.toHexString()});
+                }
+            },
+            else => {},
+        }
+    }
+}

src/lib.zig

@@ -41,6 +41,8 @@ pub const build_options = @import("build_options.zig");
 
 pub const hint_processor = struct {
     pub usingnamespace @import("hint_processor/hint_processor_def.zig");
+    pub usingnamespace @import("hint_processor/hint_utils.zig");
+    pub usingnamespace @import("hint_processor/math_hints.zig");
 };
 
 pub const parser = struct {