QR code creator library

1 files changed, 149 insertions, 0 deletions

diff --git a/libs/libqrencode/src/rsecc.c b/libs/libqrencode/src/rsecc.c
new file mode 100644
index 0000000000..b88cae3071
--- /dev/null
+++ b/libs/libqrencode/src/rsecc.c
@@ -0,0 +1,149 @@
+/*
+ * qrencode - QR Code encoder
+ *
+ * Reed solomon error correction code encoder specialized for QR code.
+ * This code is rewritten by Kentaro Fukuchi, referring to the FEC library
+ * developed by Phil Karn (KA9Q).
+ *
+ * Copyright (C) 2002, 2003, 2004, 2006 Phil Karn, KA9Q
+ * Copyright (C) 2014-2017 Kentaro Fukuchi <kentaro@fukuchi.org>
+ *
+ * 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 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif
+#include <stdlib.h>
+#include <string.h>
+#if HAVE_LIBPTHREAD
+#include <pthread.h>
+#endif
+
+#include "rsecc.h"
+
+#if HAVE_LIBPTHREAD
+static pthread_mutex_t RSECC_mutex = PTHREAD_MUTEX_INITIALIZER;
+#endif
+
+static int initialized = 0;
+
+#define SYMBOL_SIZE (8)
+#define symbols ((1U << SYMBOL_SIZE) - 1)
+static const unsigned int proot = 0x11d; /* stands for x^8+x^4+x^3+x^2+1 (see pp.37 of JIS X0510:2004) */
+
+/* min/max codeword length of ECC, calculated from the specification. */
+#define min_length (2)
+#define max_length (30)
+#define max_generatorSize (max_length)
+
+static unsigned char alpha[symbols + 1];
+static unsigned char aindex[symbols + 1];
+static unsigned char generator[max_length - min_length + 1][max_generatorSize + 1];
+static unsigned char generatorInitialized[max_length - min_length + 1];
+
+static void RSECC_initLookupTable(void)
+{
+	unsigned int i, b;
+
+	alpha[symbols] = 0;
+	aindex[0] = symbols;
+
+	b = 1;
+	for(i = 0; i < symbols; i++) {
+		alpha[i] = b;
+		aindex[b] = i;
+		b <<= 1;
+		if(b & (symbols + 1)) {
+			b ^= proot;
+		}
+		b &= symbols;
+	}
+}
+
+static void RSECC_init(void)
+{
+	RSECC_initLookupTable();
+	memset(generatorInitialized, 0, (max_length - min_length + 1));
+	initialized = 1;
+}
+
+static void generator_init(size_t length)
+{
+	size_t i, j;
+	int g[max_generatorSize + 1];
+
+	g[0] = 1;
+	for(i = 0; i < length; i++) {
+		g[i + 1] = 1;
+		/* Because g[0] never be zero, skipped some conditional checks. */
+		for(j = i; j > 0; j--) {
+			g[j] = g[j - 1] ^  alpha[(aindex[g[j]] + i) % symbols];
+		}
+		g[0] = alpha[(aindex[g[0]] + i) % symbols];
+	}
+
+	for(i = 0; i <= length; i++) {
+		generator[length - min_length][i] = aindex[g[i]];
+	}
+
+	generatorInitialized[length - min_length] = 1;
+}
+
+int RSECC_encode(size_t data_length, size_t ecc_length, const unsigned char *data, unsigned char *ecc)
+{
+	size_t i, j;
+	unsigned char feedback;
+	unsigned char *gen;
+
+#if HAVE_LIBPTHREAD
+	pthread_mutex_lock(&RSECC_mutex);
+#endif
+	if(!initialized) {
+		RSECC_init();
+	}
+#if HAVE_LIBPTHREAD
+	pthread_mutex_unlock(&RSECC_mutex);
+#endif
+
+	if(ecc_length > max_length) return -1;
+
+	memset(ecc, 0, ecc_length);
+#if HAVE_LIBPTHREAD
+	pthread_mutex_lock(&RSECC_mutex);
+#endif
+	if(!generatorInitialized[ecc_length - min_length]) generator_init(ecc_length);
+#if HAVE_LIBPTHREAD
+	pthread_mutex_unlock(&RSECC_mutex);
+#endif
+	gen = generator[ecc_length - min_length];
+
+	for(i = 0; i < data_length; i++) {
+		feedback = aindex[data[i] ^ ecc[0]];
+		if(feedback != symbols) {
+			for(j = 1; j < ecc_length; j++) {
+				ecc[j] ^= alpha[(unsigned int)(feedback + gen[ecc_length - j]) % symbols];
+			}
+		}
+		memmove(&ecc[0], &ecc[1], ecc_length - 1);
+		if(feedback != symbols) {
+			ecc[ecc_length - 1] = alpha[(unsigned int)(feedback + gen[0]) % symbols];
+		} else {
+			ecc[ecc_length - 1] = 0;
+		}
+	}
+
+	return 0;
+}