New: CRC-32 functions.

* Makefile (OBJS): Add chksums/crc32.o.

* chksum.c (crc32_stream, crc32): New functions.
(chksum_init): Register crc32-stream and crc32 intrinsic
functions.

* chksums/crc32.c, chksums/crc32.h: New files.

* txr.1: Documented.

5 files changed, 243 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index a4395aec..81a09551 100644
--- a/Makefile
+++ b/Makefile
@@ -52,7 +52,7 @@ EXTRA_OBJS-y :=
 OBJS := txr.o lex.yy.o y.tab.o match.o lib.o regex.o gc.o unwind.o stream.o
 OBJS += arith.o hash.o utf8.o filter.o eval.o parser.o rand.o combi.o sysif.o
 OBJS += args.o lisplib.o cadr.o struct.o itypes.o buf.o jmp.o protsym.o ffi.o
-OBJS += strudel.o vm.o chksum.o chksums/sha256.o
+OBJS += strudel.o vm.o chksum.o chksums/sha256.o chksums/crc32.o
 OBJS-$(debug_support) += debug.o
 OBJS-$(have_syslog) += syslog.o
 OBJS-$(have_glob) += glob.o
diff --git a/chksum.c b/chksum.c
index 78af6b8d..588bdf92 100644
--- a/chksum.c
+++ b/chksum.c
@@ -44,6 +44,7 @@
 #include "utf8.h"
 #include "buf.h"
 #include "chksums/sha256.h"
+#include "chksums/crc32.h"
 #include "chksum.h"
 
 val sha256_stream(val stream, val nbytes)
@@ -135,8 +136,94 @@ val sha256(val obj)
   }
 }
 
+val crc32_stream(val stream, val nbytes)
+{
+  u32_t crc = 0;
+  val bfsz = num_fast(BUFSIZ);
+  val buf = make_buf(bfsz, nil, nil);
+
+  if (null_or_missing_p(nbytes)) {
+    for (;;) {
+      val read = fill_buf(buf, zero, stream);
+      cnum rd = c_num(read);
+
+      if (!rd)
+        break;
+
+      crc = crc32_cont(buf->b.data, rd, crc);
+    }
+  } else {
+    while (ge(nbytes, bfsz)) {
+      val read = fill_buf(buf, zero, stream);
+      cnum rd = c_num(read);
+
+      if (zerop(read))
+        break;
+
+      crc = crc32_cont(buf->b.data, rd, crc);
+      nbytes = minus(nbytes, read);
+    }
+
+    buf_set_length(buf, nbytes, nil);
+
+    {
+      val read = fill_buf(buf, zero, stream);
+      cnum rd = c_num(read);
+      if (rd)
+        crc = crc32_cont(buf->b.data, rd, crc);
+    }
+  }
+
+  return unum(crc);
+}
+
+static val crc32_buf(val buf, val self)
+{
+  ucnum len = c_unum(buf->b.len);
+  mem_t *data = buf->b.data;
+  const size_t szmax = convert(size_t, -1) / 4 + 1;
+  u32_t crc = 0;
+
+  while (len >= szmax) {
+    crc = crc32_cont(data, szmax, crc);
+    data += szmax;
+    len -= szmax;
+  }
+
+  if (len > 0)
+    crc = crc32_cont(data, len, crc);
+
+  return unum(crc);
+}
+
+static val crc32_str(val str, val self)
+{
+  val s = make_byte_input_stream(str);
+  return crc32_stream(s, nil);
+}
+
+
+val crc32(val obj)
+{
+  val self = lit("sha256");
+
+  switch (type(obj)) {
+  case STR:
+  case LSTR:
+  case LIT:
+    return crc32_str(obj, self);
+  case BUF:
+    return crc32_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));
+  reg_fun(intern(lit("crc32-stream"), user_package), func_n2o(crc32_stream, 1));
+  reg_fun(intern(lit("crc32"), user_package), func_n1(crc32));
 }
diff --git a/chksums/crc32.c b/chksums/crc32.c
new file mode 100644
index 00000000..b8764d1d
--- /dev/null
+++ b/chksums/crc32.c
@@ -0,0 +1,86 @@
+/* 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 <string.h>
+#include <limits.h>
+#include <wchar.h>
+#include "config.h"
+#include "lib.h"
+#include "itypes.h"
+#include "crc32.h"
+
+static u32_t crc32_tab[] = {
+  0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
+  0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+  0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
+  0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+  0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
+  0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+  0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
+  0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+  0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
+  0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+  0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
+  0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+  0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
+  0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+  0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+  0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+  0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
+  0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+  0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
+  0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+  0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
+  0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+  0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
+  0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+  0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+  0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+  0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
+  0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+  0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
+  0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+  0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
+  0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+  0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
+  0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+  0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+  0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+  0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
+  0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+  0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
+  0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+  0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
+  0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+  0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
+};
+
+u32_t crc32_cont(const u8_t *p, size_t size, u32_t crc_prev)
+{
+  u32_t crc = ~crc_prev;
+  while (size--)
+    crc = crc32_tab[(crc ^ *p++) & 0xff] ^ (crc >> 8);
+  return ~crc;
+}
diff --git a/chksums/crc32.h b/chksums/crc32.h
new file mode 100644
index 00000000..c10f3f3e
--- /dev/null
+++ b/chksums/crc32.h
@@ -0,0 +1,26 @@
+/* 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.
+ */
+
+u32_t crc32_cont(const u8_t *p, size_t size, u32_t crc_prev);
diff --git a/txr.1 b/txr.1
index 940e133f..a7df3a1f 100644
--- a/txr.1
+++ b/txr.1
@@ -51825,6 +51825,49 @@ savings time).
 
 .SS* Data Integrity
 
+.coNP Function @ crc32-stream
+.synb
+.mets (crc32-stream < stream <> [ nbytes ])
+.syne
+.desc
+The
+.code crc32-stream
+calculates the CRC-32 sum over the bytes read from
+.metn stream ,
+starting at the stream's current position.
+
+If the
+.meta nbytes
+argument is specified, it should be a nonnegative
+integer. It gives the number of bytes which should be read
+and included in the sum. If the argument is omitted, then bytes are read
+until the end of the stream.
+
+The CRC-32 is returned as a non-negative integer.
+
+.coNP Function @ crc32
+.synb
+.mets (crc32 << obj )
+.syne
+.desc
+The
+.code crc32
+function calculates the CRC-32 sum over
+.metn obj ,
+which may be a character string or a buffer.
+
+If
+.meta obj
+is a buffer, then the sum is calculated over all of the bytes contained
+in that buffer, according to its current length.
+
+If
+.meta obj
+is a character string, then the sum is calculated over the bytes
+which constitute its UTF-8 representation.
+
+The CRC-32 is returned as a non-negative integer.
+
 .coNP Function @ sha256-stream
 .synb
 .mets (sha256-stream < stream <> [ nbytes ])