feat:add cid

Signed-off-by: Chen Kai <281165273grape@gmail.com>

Author: GrapeBaBa

src/cid.zig

@@ -0,0 +1,84 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+const testing = std.testing;
+
+pub const CidVersion = enum(u64) {
+    V0 = 0,
+    V1 = 1,
+};
+
+pub const Codec = enum(u64) {
+    Raw = 0x55,
+    DagPb = 0x70,
+    DagCbor = 0x71,
+};
+
+pub const Cid = struct {
+    version: CidVersion,
+    codec: Codec,
+    hash: []const u8,
+    allocator: Allocator,
+
+    pub fn init(allocator: Allocator, version: CidVersion, codec: Codec, hash: []const u8) !Cid {
+        const hash_copy = try allocator.dupe(u8, hash);
+        return Cid{
+            .version = version,
+            .codec = codec,
+            .hash = hash_copy,
+            .allocator = allocator,
+        };
+    }
+
+    pub fn deinit(self: *Cid) void {
+        self.allocator.free(self.hash);
+    }
+
+    pub fn format(self: Cid, comptime fmt: []const u8, options: std.fmt.FormatOptions, writer: anytype) !void {
+        _ = fmt;
+        _ = options;
+
+        switch (self.version) {
+            .V0 => {
+                if (self.codec != .DagPb) {
+                    return error.InvalidV0Codec;
+                }
+                try writer.writeAll(try std.fmt.allocPrint(self.allocator, "Qm{}", .{std.fmt.fmtSliceHexLower(self.hash)}));
+            },
+            .V1 => {
+                try writer.writeAll(try std.fmt.allocPrint(
+                    self.allocator,
+                    "b{}{}{}",
+                    .{
+                        @intFromEnum(self.version),
+                        @intFromEnum(self.codec),
+                        std.fmt.fmtSliceHexLower(self.hash),
+                    },
+                ));
+            },
+        }
+    }
+};
+
+test "CID v0" {
+    const allocator = testing.allocator;
+
+    var hash = [_]u8{ 1, 2, 3, 4, 5 };
+    var cid = try Cid.init(allocator, .V0, .DagPb, &hash);
+    defer cid.deinit();
+
+    try testing.expect(cid.version == .V0);
+    try testing.expect(cid.codec == .DagPb);
+    try testing.expectEqualSlices(u8, &hash, cid.hash);
+}
+
+test "CID v1" {
+    const allocator = testing.allocator;
+
+    var hash = [_]u8{ 1, 2, 3, 4, 5 };
+    var cid = try Cid.init(allocator, .V1, .DagCbor, &hash);
+    defer cid.deinit();
+
+    try testing.expect(cid.version == .V1);
+    try testing.expect(cid.codec == .DagCbor);
+    try testing.expectEqualSlices(u8, &hash, cid.hash);
+}

src/root.zig

@@ -8,6 +8,7 @@ const multihash_impls = @import("multihash.zig");
 const unsigned_varint = @import("unsigned_varint.zig");
 const multibase = @import("multibase.zig");
 const multiaddr = @import("multiaddr.zig");
+const cid = @import("cid.zig");
 
 test {
     @import("std").testing.refAllDeclsRecursive(@This());
@@ -16,4 +17,5 @@ test {
     _ = @import("multihash.zig");
     _ = @import("multibase.zig");
     _ = @import("multiaddr.zig");
+    _ = @import("cid.zig");
 }