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authorJames Buren <braewoods+rb@braewoods.net>2021-07-30 23:11:49 +0000
committerJames Buren <braewoods+rb@braewoods.net>2021-07-30 23:11:49 +0000
commitf32fc84ef6c0b95eec85b4436623a04d0b0bd6cb (patch)
treea5d6ca620ac6ce07b93b74f386ce21492b56595b
parentee05b8574a84fa7a46d6f0453b60a611c1bcc813 (diff)
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adler32: import adapted implementation from tinf/zlib
This adds an adapted version of the adler32 algorithm from tinf/zlib which will be necessary to support ZLIB deflate streams in the future. Change-Id: Ie60e15acb288acf56a2d44e3d3e912e1b3eb2216
-rw-r--r--firmware/SOURCES1
-rw-r--r--firmware/common/adler32.c75
-rw-r--r--firmware/include/adler32.h29
3 files changed, 105 insertions, 0 deletions
diff --git a/firmware/SOURCES b/firmware/SOURCES
index fc194fe640..71a11429cd 100644
--- a/firmware/SOURCES
+++ b/firmware/SOURCES
@@ -269,6 +269,7 @@ common/timefuncs.c
common/unicode.c
common/vuprintf.c
common/zip.c
+common/adler32.c
/* Display */
scroll_engine.c
diff --git a/firmware/common/adler32.c b/firmware/common/adler32.c
new file mode 100644
index 0000000000..8f5f85b453
--- /dev/null
+++ b/firmware/common/adler32.c
@@ -0,0 +1,75 @@
+/***************************************************************************
+ * __________ __ ___.
+ * Open \______ \ ____ ____ | | _\_ |__ _______ ___
+ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
+ * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
+ * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
+ * \/ \/ \/ \/ \/
+ * $Id$
+ *
+ * Copyright (C) 2021 James Buren (adaptations from tinf/zlib)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include "adler32.h"
+#include "system.h"
+
+/* adler_32 (derived from tinf adler32 which was taken from zlib)
+ * Adler-32 algorithm taken from the zlib source, which is
+ * Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler
+ */
+uint32_t adler_32(const void *src, uint32_t len, uint32_t adler32)
+{
+ const unsigned char *buf = (const unsigned char *)src;
+ uint32_t s1 = (adler32 & 0xffff);
+ uint32_t s2 = (adler32 >> 16);
+
+ enum {
+ A32_BASE = 65521,
+ A32_NMAX = 5552,
+ };
+
+ while (len > 0) {
+ uint32_t k = MIN(len, A32_NMAX);
+ uint32_t i;
+
+ for (i = k / 16; i; --i, buf += 16) {
+ s2 += s1 += buf[0];
+ s2 += s1 += buf[1];
+ s2 += s1 += buf[2];
+ s2 += s1 += buf[3];
+ s2 += s1 += buf[4];
+ s2 += s1 += buf[5];
+ s2 += s1 += buf[6];
+ s2 += s1 += buf[7];
+ s2 += s1 += buf[8];
+ s2 += s1 += buf[9];
+ s2 += s1 += buf[10];
+ s2 += s1 += buf[11];
+ s2 += s1 += buf[12];
+ s2 += s1 += buf[13];
+ s2 += s1 += buf[14];
+ s2 += s1 += buf[15];
+ }
+
+ for (i = k % 16; i; --i) {
+ s1 += *buf++;
+ s2 += s1;
+ }
+
+ s1 %= A32_BASE;
+ s2 %= A32_BASE;
+
+ len -= k;
+ }
+
+ return (s1 | (s2 << 16));
+}
diff --git a/firmware/include/adler32.h b/firmware/include/adler32.h
new file mode 100644
index 0000000000..cd5302e869
--- /dev/null
+++ b/firmware/include/adler32.h
@@ -0,0 +1,29 @@
+/***************************************************************************
+ * __________ __ ___.
+ * Open \______ \ ____ ____ | | _\_ |__ _______ ___
+ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
+ * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
+ * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
+ * \/ \/ \/ \/ \/
+ * $Id$
+ *
+ * Copyright (C) 2021 James Buren (adaptations from tinf/zlib)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include <stdint.h>
+
+#ifndef _ADLER32_H
+#define _ADLER32_H
+
+uint32_t adler_32(const void *src, uint32_t len, uint32_t adler32);
+
+#endif