Add CRC32 (ISO).

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 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 library.h)

crc32.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 "crc32.h"
+
+#include "library.h"
+
+crc32_ctx* crc32_init(void)
+{
+    crc32_ctx* ctx = (crc32_ctx*)malloc(sizeof(crc32_ctx));
+
+    if(!ctx) return NULL;
+
+    ctx->crc = CRC32_ISO_SEED;
+
+    for(int i = 0; i < 256; i++)
+    {
+        uint32_t entry = (uint32_t)i;
+
+        for(int j = 0; j < 8; j++)
+            if(entry & 1) ctx->table[i] = (entry >> 1) ^ CRC32_ISO_POLY;
+            else
+                ctx->table[i] >>= 1;
+    }
+
+    return ctx;
+}
+
+int crc32_update(crc32_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 crc32_final(crc32_ctx* ctx, uint32_t* crc)
+{
+    if(!ctx) return -1;
+
+    *crc = ctx->crc ^ CRC32_ISO_SEED;
+
+    return 0;
+}
+
+void crc32_free(crc32_ctx* ctx)
+{
+    if(ctx) free(ctx);
+}

crc32.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
+{
+    uint32_t crc;
+    uint32_t table[256];
+} crc32_ctx;
+
+#define CRC32_ISO_POLY 0xEDB88320
+#define CRC32_ISO_SEED 0xFFFFFFFF
+
+crc32_ctx* crc32_init();
+int crc32_update(crc32_ctx* ctx, const uint8_t* data, uint32_t len);
+int crc32_final(crc32_ctx* ctx, uint32_t* crc);
+void crc32_free(crc32_ctx* ctx);