Add Sha2 functions

CMakeLists.txt

@@ -367,6 +367,7 @@ set(ZIG_STD_FILES
     "crypto/index.zig"
     "crypto/md5.zig"
     "crypto/sha1.zig"
+    "crypto/sha2.zig"
     "cstr.zig"
     "debug/failing_allocator.zig"
     "debug/index.zig"

std/crypto/index.zig

@@ -1,7 +1,14 @@
-pub const Sha1 = @import("md5.zig").Sha1;
 pub const Md5 = @import("sha1.zig").Md5;
+pub const Sha1 = @import("md5.zig").Sha1;
+
+const sha2 = @import("sha2.zig");
+pub const Sha224 = sha2.Sha224;
+pub const Sha256 = sha2.Sha256;
+pub const Sha384 = sha2.Sha384;
+pub const Sha512 = sha2.Sha512;
 
 test "crypto" {
     _ = @import("md5.zig");
     _ = @import("sha1.zig");
+    _ = @import("sha2.zig");
 }

std/crypto/md5.zig

@@ -4,11 +4,11 @@ const endian = @import("../endian.zig");
 const debug = @import("../debug/index.zig");
 
 const RoundParam = struct {
-    a: u32, b: u32, c: u32, d: u32,
-    k: u32, s: u32, t: u32
+    a: usize, b: usize, c: usize, d: usize,
+    k: usize, s: u32, t: u32
 };
 
-fn Rp(a: u32, b: u32, c: u32, d: u32, k: u32, s: u5, t: u32) -> RoundParam {
+fn Rp(a: usize, b: usize, c: usize, d: usize, k: usize, s: u32, t: u32) -> RoundParam {
     return RoundParam { .a = a, .b = b, .c = c, .d = d, .k = k, .s = s, .t = t };
 }
 
@@ -69,7 +69,8 @@ pub const Md5 = struct {
         mem.copy(u8, d.buf[d.buf_len..], b[off..]);
         d.buf_len += u8(b[off..].len);
 
-        d.total_len += b.len;
+        // Md5 uses the bottom 64-bits for length padding
+        d.total_len +%= b.len;
     }
 
     pub fn final(d: &Self) -> u128 {

std/crypto/sha1.zig

@@ -6,10 +6,10 @@ const debug = @import("../debug/index.zig");
 pub const u160 = @IntType(false, 160);
 
 const RoundParam = struct {
-    a: u32, b: u32, c: u32, d: u32, e: u32, i: u32,
+    a: usize, b: usize, c: usize, d: usize, e: usize, i: u32,
 };
 
-fn Rp(a: u32, b: u32, c: u32, d: u32, e: u32, i: u32) -> RoundParam {
+fn Rp(a: usize, b: usize, c: usize, d: usize, e: usize, i: u32) -> RoundParam {
     return RoundParam { .a = a, .b = b, .c = c, .d = d, .e = e, .i = i };
 }