From fc0b68f105a191c7cd4dbb85251ada870119d470 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Sun, 23 Jun 2019 21:36:16 -0700
Subject: * Makefile (OBJS): New objects chksum.o and chksums/sha256.o.

* chksum.c, chksum.h, chksums/sha256.c, chksums/sha256.h: New files.

* lib.c (init): Call chksum_init.

* txr.1: Documented.

* LICENSE: Add SHA-256 copyright notice.
---
 chksum.c | 142 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 chksum.c

(limited to 'chksum.c')

diff --git a/chksum.c b/chksum.c
new file mode 100644
index 00000000..78af6b8d
--- /dev/null
+++ b/chksum.c
@@ -0,0 +1,142 @@
+/* Copyright 2019
+ * Kaz Kylheku <kaz@kylheku.com>
+ * Vancouver, Canada
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice, *    this list of conditions and the following disclaimer in the documentation *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stddef.h>
+#include <wchar.h>
+#include <limits.h>
+#include <float.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <signal.h>
+#include <stdio.h>
+#include "config.h"
+#include "lib.h"
+#include "gc.h"
+#include "itypes.h"
+#include "signal.h"
+#include "unwind.h"
+#include "eval.h"
+#include "stream.h"
+#include "arith.h"
+#include "utf8.h"
+#include "buf.h"
+#include "chksums/sha256.h"
+#include "chksum.h"
+
+val sha256_stream(val stream, val nbytes)
+{
+  SHA256_t s256;
+  unsigned char *hash = chk_malloc(SHA256_DIGEST_LENGTH);
+  val bfsz = num_fast(BUFSIZ);
+  val buf = make_buf(bfsz, nil, nil);
+  SHA256_init(&s256);
+
+  if (null_or_missing_p(nbytes)) {
+    for (;;) {
+      val read = fill_buf(buf, zero, stream);
+      cnum rd = c_num(read);
+
+      if (!rd)
+        break;
+
+      SHA256_update(&s256, buf->b.data, rd);
+    }
+  } else {
+    while (ge(nbytes, bfsz)) {
+      val read = fill_buf(buf, zero, stream);
+      cnum rd = c_num(read);
+
+      if (zerop(read))
+        break;
+
+      SHA256_update(&s256, buf->b.data, rd);
+      nbytes = minus(nbytes, read);
+    }
+
+    buf_set_length(buf, nbytes, nil);
+
+    {
+      val read = fill_buf(buf, zero, stream);
+      cnum rd = c_num(read);
+      if (rd)
+        SHA256_update(&s256, buf->b.data, rd);
+    }
+  }
+
+  SHA256_final(&s256, hash);
+  return make_borrowed_buf(num_fast(SHA256_DIGEST_LENGTH), hash);
+}
+
+static val sha256_buf(val buf, val self)
+{
+  SHA256_t s256;
+  unsigned char *hash = chk_malloc(SHA256_DIGEST_LENGTH);
+  SHA256_init(&s256);
+  ucnum len = c_unum(buf->b.len);
+  mem_t *data = buf->b.data;
+  const size_t szmax = convert(size_t, -1) / 4 + 1;
+
+  while (len >= szmax) {
+    SHA256_update(&s256, data, szmax);
+    data += szmax;
+    len -= szmax;
+  }
+
+  if (len > 0)
+    SHA256_update(&s256, data, len);
+
+  SHA256_final(&s256, hash);
+  return make_borrowed_buf(num_fast(SHA256_DIGEST_LENGTH), hash);
+}
+
+static val sha256_str(val str, val self)
+{
+  val s = make_byte_input_stream(str);
+  return sha256_stream(s, nil);
+}
+
+val sha256(val obj)
+{
+  val self = lit("sha256");
+
+  switch (type(obj)) {
+  case STR:
+  case LSTR:
+  case LIT:
+    return sha256_str(obj, self);
+  case BUF:
+    return sha256_buf(obj, self);
+  default:
+    uw_throwf(error_s, lit("~a: cannot hash ~s, only buffer and strings"),
+              self, obj, nao);
+  }
+}
+
+void chksum_init(void)
+{
+  reg_fun(intern(lit("sha256-stream"), user_package), func_n2o(sha256_stream, 1));
+  reg_fun(intern(lit("sha256"), user_package), func_n1(sha256));
+}
-- 
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