Extended crypto API by variants that write the result into a destination buffer, instead of returning it

core/crypto/md5/md5.odin

@@ -20,16 +20,18 @@ import "../util"
     High level API
 */
 
+DIGEST_SIZE :: 16
+
 // hash_string will hash the given input and return the
 // computed hash
-hash_string :: proc(data: string) -> [16]byte {
+hash_string :: proc(data: string) -> [DIGEST_SIZE]byte {
     return hash_bytes(transmute([]byte)(data))
 }
 
 // hash_bytes will hash the given input and return the
 // computed hash
-hash_bytes :: proc(data: []byte) -> [16]byte {
-    hash: [16]byte
+hash_bytes :: proc(data: []byte) -> [DIGEST_SIZE]byte {
+    hash: [DIGEST_SIZE]byte
     ctx: Md5_Context
     init(&ctx)
     update(&ctx, data)
@@ -37,10 +39,28 @@ hash_bytes :: proc(data: []byte) -> [16]byte {
     return hash
 }
 
+// hash_string_to_buffer will hash the given input and assign the
+// computed hash to the second parameter.
+// It requires that the destination buffer is at least as big as the digest size
+hash_string_to_buffer :: proc(data: string, hash: []byte) {
+    hash_bytes_to_buffer(transmute([]byte)(data), hash);
+}
+
+// hash_bytes_to_buffer will hash the given input and write the
+// computed hash into the second parameter.
+// It requires that the destination buffer is at least as big as the digest size
+hash_bytes_to_buffer :: proc(data, hash: []byte) {
+    assert(len(hash) >= DIGEST_SIZE, "Size of destination buffer is smaller than the digest size")
+    ctx: Md5_Context
+    init(&ctx)
+    update(&ctx, data)
+    final(&ctx, hash)
+}
+
 // hash_stream will read the stream in chunks and compute a
 // hash from its contents
-hash_stream :: proc(s: io.Stream) -> ([16]byte, bool) {
-    hash: [16]byte
+hash_stream :: proc(s: io.Stream) -> ([DIGEST_SIZE]byte, bool) {
+    hash: [DIGEST_SIZE]byte
     ctx: Md5_Context
     init(&ctx)
     buf := make([]byte, 512)
@@ -58,7 +78,7 @@ hash_stream :: proc(s: io.Stream) -> ([16]byte, bool) {
 
 // hash_file will read the file provided by the given handle
 // and compute a hash
-hash_file :: proc(hd: os.Handle, load_at_once := false) -> ([16]byte, bool) {
+hash_file :: proc(hd: os.Handle, load_at_once := false) -> ([DIGEST_SIZE]byte, bool) {
     if !load_at_once {
         return hash_stream(os.stream_from_handle(hd))
     } else {
@@ -66,7 +86,7 @@ hash_file :: proc(hd: os.Handle, load_at_once := false) -> ([16]byte, bool) {
             return hash_bytes(buf[:]), ok
         }
     }
-    return [16]byte{}, false
+    return [DIGEST_SIZE]byte{}, false
 }
 
 hash :: proc {
@@ -74,6 +94,8 @@ hash :: proc {
     hash_file,
     hash_bytes,
     hash_string,
+    hash_bytes_to_buffer,
+    hash_string_to_buffer,
 }
 
 /*
@@ -176,9 +198,9 @@ II :: #force_inline proc "contextless" (a, b, c, d, m: u32, s: int, t: u32) -> u
 
 transform :: proc(ctx: ^Md5_Context, data: []byte) {
     i, j: u32
-    m: [16]u32
+    m: [DIGEST_SIZE]u32
 
-    for i, j = 0, 0; i < 16; i+=1 {
+    for i, j = 0, 0; i < DIGEST_SIZE; i+=1 {
         m[i] = u32(data[j]) + u32(data[j + 1]) << 8 + u32(data[j + 2]) << 16 + u32(data[j + 3]) << 24
         j += 4
     }