From d9b53ed189b99cea08c4bd7e0088de1e07c36f7e Mon Sep 17 00:00:00 2001
From: Natalia Portillo <claunia@claunia.com>
Date: Tue, 21 Sep 2021 23:54:09 +0100
Subject: [PATCH] Add CRC64 (ECMA).

---
 CMakeLists.txt |  2 +-
 crc64.c        | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++
 crc64.h        | 31 +++++++++++++++++++++++
 3 files changed, 100 insertions(+), 1 deletion(-)
 create mode 100644 crc64.c
 create mode 100644 crc64.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 93e31c6..ea0c560 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,4 +3,4 @@ project("Aaru.Checksums.Native" C)
 
 set(CMAKE_C_STANDARD 90)
 
-add_library("Aaru.Checksums.Native" SHARED adler32.h adler32.c crc16.h crc16.c crc16_ccitt.h crc16_ccitt.c crc32.c crc32.h library.h)
+add_library("Aaru.Checksums.Native" SHARED adler32.h adler32.c crc16.h crc16.c crc16_ccitt.h crc16_ccitt.c crc32.c crc32.h crc64.c crc64.h library.h)
diff --git a/crc64.c b/crc64.c
new file mode 100644
index 0000000..cdeb6c0
--- /dev/null
+++ b/crc64.c
@@ -0,0 +1,68 @@
+/*
+ * This file is part of the Aaru Data Preservation Suite.
+ * Copyright (c) 2019-2021 Natalia Portillo.
+ *
+ * This library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of the
+ * License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "crc64.h"
+
+#include "library.h"
+
+crc64_ctx* crc64_init(void)
+{
+    crc64_ctx* ctx = (crc64_ctx*)malloc(sizeof(crc64_ctx));
+
+    if(!ctx) return NULL;
+
+    ctx->crc = CRC64_ECMA_SEED;
+
+    for(int i = 0; i < 256; i++)
+    {
+        uint64_t entry = (uint64_t)i;
+
+        for(int j = 0; j < 8; j++)
+            if(entry & 1) ctx->table[i] = (entry >> 1) ^ CRC64_ECMA_POLY;
+            else
+                ctx->table[i] >>= 1;
+    }
+
+    return ctx;
+}
+
+int crc64_update(crc64_ctx* ctx, const uint8_t* data, uint32_t len)
+{
+    if(!ctx || !data) return -1;
+
+    for(uint32_t i = 0; i < len; i++) ctx->crc = (ctx->crc >> 8) ^ ctx->table[data[i] ^ (ctx->crc & 0xff)];
+
+    return 0;
+}
+
+int crc64_final(crc64_ctx* ctx, uint64_t* crc)
+{
+    if(!ctx) return -1;
+
+    *crc = ctx->crc ^ CRC64_ECMA_SEED;
+
+    return 0;
+}
+
+void crc64_free(crc64_ctx* ctx)
+{
+    if(ctx) free(ctx);
+}
\ No newline at end of file
diff --git a/crc64.h b/crc64.h
new file mode 100644
index 0000000..18e4920
--- /dev/null
+++ b/crc64.h
@@ -0,0 +1,31 @@
+/*
+ * This file is part of the Aaru Data Preservation Suite.
+ * Copyright (c) 2019-2021 Natalia Portillo.
+ *
+ * This library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of the
+ * License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+typedef struct
+{
+    uint64_t crc;
+    uint64_t table[256];
+} crc64_ctx;
+
+#define CRC64_ECMA_POLY 0xC96C5795D7870F42
+#define CRC64_ECMA_SEED 0xFFFFFFFFFFFFFFFF
+
+crc64_ctx* crc64_init();
+int crc64_update(crc64_ctx* ctx, const uint8_t* data, uint32_t len);
+int crc64_final(crc64_ctx* ctx, uint64_t* crc);
+void crc64_free(crc64_ctx* ctx);
\ No newline at end of file