add parameter loading

Signed-off-by: Ignacio Hagopian <jsign.uy@gmail.com>
jsign · Aug 26, 2023 · b1d6ac4 · b1d6ac4
1 parent 8455b87
commit b1d6ac4
Showing 1 changed file with 151 additions and 0 deletions.
diff --git a/src/parameters.zig b/src/parameters.zig
@@ -0,0 +1,151 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+const BabyJubJubFr = @import("bn254/fr.zig");
+
+// PoseidonParameters describes a set of configuration parameters for Poseidon setups for different `WIDTH`s.
+pub fn PoseidonFamilyParameters(comptime Fr: type) type {
+    return struct {
+        const Parameters = struct {
+            C: [][]Fr.MontgomeryDomainFieldElement,
+            M: [][][]Fr.MontgomeryDomainFieldElement,
+            P: [][][]Fr.MontgomeryDomainFieldElement,
+            S: [][]Fr.MontgomeryDomainFieldElement,
+        };
+
+        allocator: Allocator,
+        parameters: Parameters,
+
+        pub fn init(allocator: Allocator, json_spec: []const u8) !@This() {
+            const ParametersJSON = struct {
+                C: [][][]const u8,
+                M: [][][][]const u8,
+                P: [][][][]const u8,
+                S: [][][]const u8,
+            };
+            var parameters = try std.json.parseFromSlice(
+                ParametersJSON,
+                allocator,
+                json_spec,
+                .{ .allocate = std.json.AllocWhen.alloc_always },
+            );
+            defer parameters.deinit();
+
+            var ret = Parameters{
+                .C = try allocator.alloc([]Fr.MontgomeryDomainFieldElement, parameters.value.C.len),
+                .M = try allocator.alloc([][]Fr.MontgomeryDomainFieldElement, parameters.value.M.len),
+                .P = try allocator.alloc([][]Fr.MontgomeryDomainFieldElement, parameters.value.P.len),
+                .S = try allocator.alloc([]Fr.MontgomeryDomainFieldElement, parameters.value.S.len),
+            };
+
+            for (0..parameters.value.C.len) |i| {
+                ret.C[i] = try allocator.alloc(Fr.MontgomeryDomainFieldElement, parameters.value.C[i].len);
+                for (0..parameters.value.C[i].len) |j| {
+                    var fe = try std.fmt.parseInt(u256, parameters.value.C[i][j], 0);
+                    var buf: [32]u8 = undefined;
+                    std.mem.writeIntLittle(@TypeOf(fe), &buf, fe);
+                    Fr.fromBytes(&ret.C[i][j], buf);
+                    Fr.toMontgomery(&ret.C[i][j], ret.C[i][j]);
+                }
+            }
+
+            for (0..parameters.value.M.len) |i| {
+                ret.M[i] = try allocator.alloc([]Fr.MontgomeryDomainFieldElement, parameters.value.M[i].len);
+                for (0..parameters.value.M[i].len) |j| {
+                    ret.M[i][j] = try allocator.alloc(Fr.MontgomeryDomainFieldElement, parameters.value.M[i][j].len);
+                    for (0..parameters.value.M[i][j].len) |k| {
+                        var fe = try std.fmt.parseInt(u256, parameters.value.M[i][j][k], 0);
+                        var buf: [32]u8 = undefined;
+                        std.mem.writeIntLittle(@TypeOf(fe), &buf, fe);
+                        Fr.fromBytes(&ret.M[i][j][k], buf);
+                        Fr.toMontgomery(&ret.M[i][j][k], ret.M[i][j][k]);
+                    }
+                }
+            }
+
+            for (0..parameters.value.P.len) |i| {
+                ret.P[i] = try allocator.alloc([]Fr.MontgomeryDomainFieldElement, parameters.value.P[i].len);
+                for (0..parameters.value.P[i].len) |j| {
+                    ret.P[i][j] = try allocator.alloc(Fr.MontgomeryDomainFieldElement, parameters.value.P[i][j].len);
+                    for (0..parameters.value.P[i][j].len) |k| {
+                        var fe = try std.fmt.parseInt(u256, parameters.value.P[i][j][k], 0);
+                        var buf: [32]u8 = undefined;
+                        std.mem.writeIntLittle(@TypeOf(fe), &buf, fe);
+                        Fr.fromBytes(&ret.P[i][j][k], buf);
+                        Fr.toMontgomery(&ret.P[i][j][k], ret.P[i][j][k]);
+                    }
+                }
+            }
+
+            for (0..parameters.value.S.len) |i| {
+                ret.S[i] = try allocator.alloc(Fr.MontgomeryDomainFieldElement, parameters.value.S[i].len);
+                for (0..parameters.value.S[i].len) |j| {
+                    var fe = try std.fmt.parseInt(u256, parameters.value.S[i][j], 0);
+                    var buf: [32]u8 = undefined;
+                    std.mem.writeIntLittle(@TypeOf(fe), &buf, fe);
+                    Fr.fromBytes(&ret.S[i][j], buf);
+                    Fr.toMontgomery(&ret.S[i][j], ret.S[i][j]);
+                }
+            }
+
+            return .{
+                .allocator = allocator,
+                .parameters = ret,
+            };
+        }
+
+        pub fn deinit(self: *@This()) void {
+            for (self.parameters.C) |c| {
+                self.allocator.free(c);
+            }
+            self.allocator.free(self.parameters.C);
+
+            for (self.parameters.M) |m1| {
+                for (m1) |m2| {
+                    self.allocator.free(m2);
+                }
+                self.allocator.free(m1);
+            }
+            self.allocator.free(self.parameters.M);
+
+            for (self.parameters.P) |p1| {
+                for (p1) |p2| {
+                    self.allocator.free(p2);
+                }
+                self.allocator.free(p1);
+            }
+            self.allocator.free(self.parameters.P);
+
+            for (self.parameters.S) |s| {
+                self.allocator.free(s);
+            }
+            self.allocator.free(self.parameters.S);
+        }
+
+        pub fn get_params_for_width(self: *@This(), w: u8) struct {
+            C: []Fr.MontgomeryDomainFieldElement,
+            M: [][]Fr.MontgomeryDomainFieldElement,
+            P: [][]Fr.MontgomeryDomainFieldElement,
+            S: []Fr.MontgomeryDomainFieldElement,
+            R_f: u8,
+            R_P: u8,
+        } {
+            return .{
+                .C = self.parameters.C[w - 2],
+                .M = self.parameters.M[w - 2],
+                .P = self.parameters.P[w - 2],
+                .S = self.parameters.S[w - 2],
+                .R_f = 8 / 2,
+                .R_P = 56,
+            };
+        }
+    };
+}
+
+// get_babyjubjub_parameters returns the parameters for the BabyJubJub curve.
+// The caller is responsible for calling `deinit` on the returned parameters.
+pub fn get_babyjubjub_parameters(allocator: Allocator) !PoseidonFamilyParameters(BabyJubJubFr) {
+    return try PoseidonFamilyParameters(BabyJubJubFr).init(
+        allocator,
+        @embedFile("bn254/optimized_poseidon_constants.json"),
+    );
+}