RS encode (not working yet)

5 files changed, 69 insertions, 2 deletions

diff --git a/lpg/libqr/Makefile b/lpg/libqr/Makefile
index e36b09f..1f34caf 100644
--- a/lpg/libqr/Makefile
+++ b/lpg/libqr/Makefile
@@ -5,7 +5,8 @@ OBJECTS :=      bitstream.o     \
                 code-render.o   \
                 data-common.o   \
                 data-create.o   \
-                data-parse.o
+                data-parse.o	\
+                rs-encode.o
 
 CFLAGS := -std=c89 -pedantic -I. -Wall
 CFLAGS += -g
diff --git a/lpg/libqr/code-create.c b/lpg/libqr/code-create.c
index d09c2fe..484dbe3 100644
--- a/lpg/libqr/code-create.c
+++ b/lpg/libqr/code-create.c
@@ -5,6 +5,7 @@
 
 #include "code-common.h"
 #include "data-common.h"
+#include "rs.h"
 
 #define MIN(a, b) ((b) < (a) ? (b) : (a))
 
@@ -29,7 +30,15 @@ static int add_ecc(struct bitstream * bits, int format, enum qr_ec_level ec)
 {
         puts("Before ecc:");
         x_dump(bits);
-
+        {
+                const int g[10] = { 251, 67, 61, 118, 70, 64, 94, 32, 45 };
+                int rs_words = 10; /* 1-M */
+                struct bitstream * rs;
+
+                rs = rs_generate_words(rs_words, g, bits);
+                puts("ecc part:");
+                x_dump(rs);
+        }
         return -1;
 }
 
diff --git a/lpg/libqr/rs-encode.c b/lpg/libqr/rs-encode.c
new file mode 100644
index 0000000..ec99c6b
--- /dev/null
+++ b/lpg/libqr/rs-encode.c
@@ -0,0 +1,47 @@
+#include <assert.h>
+#include <stdlib.h>
+#include "bitstream.h"
+#include "rs.h"
+
+struct bitstream * rs_generate_words(int k, const int * coeff, struct bitstream * data)
+{
+        struct bitstream * ec = 0;
+        unsigned int * b = 0;
+        size_t n, i, dlen;
+
+        dlen = bitstream_size(data);
+        assert(dlen % 8 == 0);
+        dlen /= 8;
+
+        ec = bitstream_create();
+        if (!ec)
+                return 0;
+
+        if (bitstream_resize(ec, k * 8) != 0)
+                goto fail;
+
+        b = calloc(k, sizeof(*b));
+        if (!b)
+                goto fail;
+
+        /* First, prepare the registers (b) with data bits. Note that
+         * the registers are in reverse of the normal order
+         */
+        bitstream_seek(data, 0);
+        for (n = 0; n < dlen; ++n) {
+                unsigned int x = b[0] + bitstream_read(data, 8);
+                for (i = 0; i < k-1; ++i)
+                        b[i] = b[i+1] + coeff[(k-1) - i] * x;
+                b[k-1] = coeff[0] * x;
+        }
+
+        /* Read off the registers */
+        bitstream_pack(ec, b, k, 8);
+
+        free(b);
+        return ec;
+fail:
+        bitstream_destroy(ec);
+        return 0;
+}
+
diff --git a/lpg/libqr/rs.h b/lpg/libqr/rs.h
new file mode 100644
index 0000000..98e3aa0
--- /dev/null
+++ b/lpg/libqr/rs.h
@@ -0,0 +1,9 @@
+#ifndef RS_H
+#define RS_H
+
+#include "bitstream.h"
+
+struct bitstream * rs_generate_words(int k, const int * coeff, struct bitstream * data);
+
+#endif
+
diff --git a/lpg/libqr/test.c b/lpg/libqr/test.c
index 76d0b97..ec77bfe 100644
--- a/lpg/libqr/test.c
+++ b/lpg/libqr/test.c
@@ -5,6 +5,7 @@
 #include <qr/data.h>
 
 #include "bitstream.h"
+#include "code-common.h"
 
 int main() {