Make mot-encoder C++, removes memory leaks

1 files changed, 816 insertions, 0 deletions

diff --git a/src/mot-encoder.cpp b/src/mot-encoder.cpp
new file mode 100644
index 0000000..e227412
--- /dev/null
+++ b/src/mot-encoder.cpp
@@ -0,0 +1,816 @@
+/*
+    Copyright (C) 2014 CSP Innovazione nelle ICT s.c.a r.l. (http://rd.csp.it/)
+
+    Copyright (C) 2014 Matthias P. Braendli (http://opendigitalradio.org)
+
+    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 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+    mot-encoder.c
+          Generete PAD data for MOT Slideshow and DLS
+
+    Authors:
+         Sergio Sagliocco <sergio.sagliocco@csp.it>
+         Matthias P. Braendli <matthias@mpb.li>
+*/
+
+#include <cstdio>
+#include <stdlib.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <cstring>
+#include <vector>
+#include <deque>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <wand/magick_wand.h>
+#include <getopt.h>
+
+extern "C" {
+#include "lib_crc.h"
+}
+
+#define MIN(a,b) (((a)<(b))?(a):(b))
+#define MAX(a,b) (((a)>(b))?(a):(b))
+
+#define MAXSEGLEN 8179
+#define MAXDLS 129
+
+typedef struct {
+    // MSC Data Group Header (extension field not supported)
+    unsigned char extflag;      //  1 bit
+    unsigned char crcflag;      //  1 bit
+    unsigned char segflag;      //  1 bit
+    unsigned char accflag;      //  1 bit
+    unsigned char dgtype;       //  4 bits
+    unsigned char cindex;       //  4 bits
+    unsigned char rindex;       //  4 bits
+    /// Session header - Segment field
+    unsigned char last;         //  1 bit
+    unsigned short int segnum;  // 16 bits
+    // Session header - User access field
+    unsigned char rfa;          //  3 bits
+    unsigned char tidflag;      //  1 bit
+    unsigned char lenid;        //  4 bits - Fixed to value 2 in this implemntation
+    unsigned short int tid;     // 16 bits
+    // MSC data group data field
+    //  Mot Segmentation header
+    unsigned char rcount;       //  3 bits
+    unsigned short int seglen;  // 13 bits
+    // Mot segment
+    unsigned char* segdata;
+    // MSC data group CRC
+    unsigned short int crc;     // 16 bits
+} MSCDG;
+/*
+   typedef struct {
+// MOT HEADER CUSTOMIZED FOR SLIDESHOW APP
+unsigned int bodysize;      // 28 bits
+unsigned short int headsize;    // 13 bits
+unsigned char ctype;        //  6 bits
+unsigned char sctype;       //  9 bits
+unsigned char triggertime[5];   // 0x85 0x00 0x00 0x00 0x00 => NOW
+unsigned char contname[14];     // 0xCC 0x0C 0x00 imgXXXX.jpg
+} MOTSLIDEHDR;
+*/
+int encodeFile(int output_fd, char* fname, int fidx, int padlen);
+void createMotHeader(size_t blobsize, int fidx, unsigned char* mothdr, int* mothdrlen);
+void createMscDG(MSCDG* msc, unsigned short int dgtype, unsigned short int cindex,
+        unsigned short int lastseg, unsigned short int tid, unsigned char* data,
+        unsigned short int datalen);
+
+void packMscDG(unsigned char* mscblob, MSCDG* msc, unsigned short int *bsize);
+void writeMotPAD(int output_fd,
+        unsigned char* mscdg,
+        unsigned short int mscdgsize,
+        unsigned short int padlen);
+
+void create_dls_datagroup(char* text, int padlen);
+void writeDLS(int output_fd, const char* dls_file, int padlen);
+
+int get_xpadlengthmask(int padlen);
+#define ALLOWED_PADLEN "23, 26, 34, 42, 58"
+
+// The toggle flag for the DLS
+static uint8_t dls_toggle = 0;
+
+// The DLS data groups
+std::deque<std::vector<uint8_t> > dlsdg;
+static int dlsfd = 0;
+
+
+void usage(char* name)
+{
+    fprintf(stderr, "DAB MOT encoder %s for slideshow and DLS\n\n"
+                    "By CSP Innovazione nelle ICT s.c.a r.l. (http://rd.csp.it/)\n\n"
+                    "Reads image data from the specified directory, and outputs PAD data\n"
+                    "on standard output\n"
+                    "Reads DLS from /tmp/dls.file\n\n"
+                    "  http://opendigitalradio.org\n\n",
+#if defined(GITVERSION)
+                    GITVERSION
+#else
+                    PACKAGE_VERSION
+#endif
+                    );
+    fprintf(stderr, "Usage: %s [OPTIONS...]\n", name);
+    fprintf(stderr, " -d, --dir=DIRNAME      Directory to read images from.\n"
+                    "                        Mandatory.\n"
+                    " -o, --output=FILENAME  Fifo to write PAD data into.\n"
+                    "                        Default: /tmp/pad.fifo\n"
+                    " -t, --dls=FILENAME     Fifo or file to read DLS text from.\n"
+                    "                        Default: /tmp/dls.txt\n"
+                    " -p, --pad=LENGTH       Set the pad length.\n"
+                    "                        Possible values: " ALLOWED_PADLEN "\n"
+                    "                        Default: 58\n"
+           );
+}
+
+#define no_argument 0
+#define required_argument 1
+#define optional_argument 2
+int main(int argc, char *argv[])
+{
+    int len, fidx, ret;
+    struct dirent *pDirent;
+    DIR *pDir;
+    char imagepath[128];
+    char dlstext[MAXDLS];
+    int padlen=58;
+
+    char* dir = NULL;
+    char* output = "/tmp/pad.fifo";
+    char* dls_file = "/tmp/dls.txt";
+
+    const struct option longopts[] = {
+        {"dir",        required_argument,  0, 'd'},
+        {"output",     required_argument,  0, 'o'},
+        {"dls",        required_argument,  0, 't'},
+        {"pad",        required_argument,  0, 'p'},
+        {"help",       no_argument,        0, 'h'},
+        {0,0,0,0},
+    };
+
+    if (argc < 2) {
+        fprintf(stderr, "Error: too few arguments!\n");
+        usage(argv[0]);
+        return 2;
+    }
+
+    int ch=0;
+    int index;
+    while(ch != -1) {
+        ch = getopt_long(argc, argv, "hd:o:t:p:", longopts, &index);
+        switch (ch) {
+            case 'd':
+                dir = optarg;
+                break;
+            case 'o':
+                output = optarg;
+                break;
+            case 't':
+                dls_file = optarg;
+                break;
+            case 'p':
+                padlen = atoi(optarg);
+                break;
+            case '?':
+            case 'h':
+                usage(argv[0]);
+                return 0;
+        }
+    }
+
+    if (get_xpadlengthmask(padlen) == -1) {
+        fprintf(stderr, "Error: pad length %d invalid: Possible values: "
+                    ALLOWED_PADLEN "\n",
+                padlen);
+        return 2;
+    }
+
+    if (!dir) {
+        fprintf(stderr, "Error: image directory not defined!\n");
+        usage(argv[0]);
+        return 2;
+    }
+
+    int output_fd = open(output, O_WRONLY);
+    if (output_fd == -1) {
+        perror("Failed to open output");
+        return 3;
+    }
+
+    MagickWandGenesis();
+
+    fidx = 0;
+    while(1) {
+        pDir = opendir(dir);
+        if (pDir == NULL) {
+            printf ("Cannot open directory '%s'\n", dir);
+            return 1;
+        }
+        if (fidx == 9999) {
+            fidx = 0;
+        }
+
+        while ((pDirent = readdir(pDir)) != NULL) {
+            if (pDirent->d_name[0] != '.') {
+                sprintf(imagepath, "%s/%s", dir, pDirent->d_name);
+                ret = encodeFile(output_fd, imagepath, fidx, padlen);
+                if (ret != 1) {
+                    fprintf(stderr, "Error - Cannot encode file %s\n", pDirent->d_name);
+                }
+                else {
+                    fidx++;
+                    writeDLS(output_fd, dls_file, padlen);
+                    sleep(10);
+                }
+            }
+        }
+        closedir(pDir);
+    }
+    return 1;
+}
+
+int encodeFile(int output_fd, char* fname, int fidx, int padlen)
+{
+    int fd=0, ret, mothdrlen, nseg, lastseglen, i, last, curseglen;
+    unsigned char mothdr[32];
+    MagickWand *m_wand = NULL;
+    PixelWand  *p_wand = NULL;
+    size_t blobsize, height, width;
+    unsigned char *blob = NULL, *curseg = NULL;
+    MagickBooleanType err;
+    MSCDG msc;
+    unsigned char mscblob[8200];
+    unsigned short int mscblobsize;
+    //float aspectRatio;
+
+    m_wand = NewMagickWand();
+    p_wand = NewPixelWand();
+    PixelSetColor(p_wand, "black");
+
+    err = MagickReadImage(m_wand, fname);
+    if (err == MagickFalse) {
+        fprintf(stderr, "Error - Unable to load image %s\n", fname);
+        ret = 0;
+        goto RETURN;
+    }
+
+    height = MagickGetImageHeight(m_wand);
+    width  = MagickGetImageWidth(m_wand);
+    //aspectRatio = (width * 1.0)/height;
+
+    fprintf(stderr, "Image: %s (id=%d). Original size: %zu x %zu. ",
+            fname, fidx, width, height);
+
+    while (height > 240 || width > 320) {
+        if (height/240.0 > width/320.0) {
+            //width = height * aspectRatio;
+            width = width * 240.0 / height;
+            height = 240;
+        }
+        else {
+            //height = width * (1.0/aspectRatio);
+            height = height * 320.0 / width;
+            width = 320;
+        }
+        MagickResizeImage(m_wand, width, height, LanczosFilter, 1);
+    }
+
+
+
+    height = MagickGetImageHeight(m_wand);
+    width  = MagickGetImageWidth(m_wand);
+
+    MagickBorderImage(m_wand, p_wand, (320-width)/2, (240-height)/2);
+
+    MagickSetImageCompressionQuality(m_wand, 75);
+    MagickSetImageFormat(m_wand, "jpg");
+    blob = MagickGetImagesBlob(m_wand, &blobsize);
+    fprintf(stderr, "Resized to %zu x %zu. Size after compression %zu bytes\n",
+            width, height, blobsize);
+
+    nseg = blobsize / MAXSEGLEN;
+    lastseglen = blobsize % MAXSEGLEN;
+    if (lastseglen != 0) {
+        nseg++;
+    }
+
+    createMotHeader(blobsize, fidx, mothdr, &mothdrlen);
+    // Create the MSC Data Group C-Structure
+    createMscDG(&msc, 3, 0, 1, fidx, mothdr, mothdrlen);
+    // Generate the MSC DG frame (Figure 9 en 300 401)
+    packMscDG(mscblob, &msc, &mscblobsize);
+    writeMotPAD(output_fd, mscblob, mscblobsize, padlen);
+
+    for (i = 0; i < nseg; i++) {
+        curseg = blob + i * MAXSEGLEN;
+        if (i == nseg-1) {
+            curseglen = lastseglen;
+            last = 1;
+        }
+        else {
+            curseglen = MAXSEGLEN;
+            last = 0;
+        }
+
+        createMscDG(&msc, 4, i, last, fidx, curseg, curseglen);
+        packMscDG(mscblob, &msc, &mscblobsize);
+        writeMotPAD(output_fd, mscblob, mscblobsize, padlen);
+    }
+
+    ret = 1;
+
+RETURN:
+    if (m_wand) {
+        m_wand = DestroyMagickWand(m_wand);
+    }
+    if (blob) {
+        free(blob);
+    }
+    return ret;
+}
+
+
+void createMotHeader(size_t blobsize, int fidx, unsigned char* mothdr, int* mothdrlen)
+{
+    int ret;
+    struct stat s;
+    char MotHeaderCore[7] = {0x00,0x00,0x00,0x00,0x0D,0x04,0x01};
+    char MotHeaderExt[19] = {0x85,0x00,0x00,0x00,0x00,0xcc,0x0c,
+        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
+    char cntemp[12];
+    int i;
+
+    MotHeaderCore[0] = (blobsize<<4 & 0xFF000000) >> 24;
+    MotHeaderCore[1] = (blobsize<<4 & 0x00FF0000) >> 16;
+    MotHeaderCore[2] = (blobsize<<4 & 0x0000FF00) >> 8;
+    MotHeaderCore[3] = (blobsize<<4 & 0x000000FF);
+
+    sprintf(cntemp, "img%04d.jpg", fidx);
+    for (i = 0; i < strlen(cntemp); i++) {
+        MotHeaderExt[8+i] = cntemp[i];
+    }
+    *mothdrlen = 26;
+    for (i = 0; i < 7; i++)
+        mothdr[i] = MotHeaderCore[i];
+    for (i = 0; i < 19; i++)
+        mothdr[7+i] = MotHeaderExt[i];
+
+    return;
+}
+
+void createMscDG(MSCDG* msc, unsigned short int dgtype,
+        unsigned short int cindex, unsigned short int lastseg,
+        unsigned short int tid, unsigned char* data,
+        unsigned short int datalen)
+{
+    msc->extflag = 0;
+    msc->crcflag = 1;
+    msc->segflag = 1;
+    msc->accflag = 1;
+    msc->dgtype = dgtype;
+    msc->cindex = cindex;
+    msc->rindex = 0;
+    msc->last = lastseg;
+    msc->segnum = cindex;
+    msc->rfa = 0;
+    msc->tidflag = 1;
+    msc->lenid = 2;
+    msc->tid = tid;
+    msc->segdata = data;
+    msc->rcount = 0;
+    msc->seglen = datalen;
+}
+
+
+void packMscDG(unsigned char* b, MSCDG* msc, unsigned short int* bsize)
+{
+    int i;
+    unsigned short int crc=0xFFFF;
+
+    b[0] = (msc->extflag<<7) | (msc->crcflag<<6) | (msc->segflag<<5) |
+           (msc->accflag<<4) | msc->dgtype;
+
+    b[1] = (msc->cindex<<4) | msc->rindex;
+    b[2] = (msc->last<<7) | ((msc->segnum & 0x7F00) >> 8);
+    b[3] =  msc->segnum & 0x00FF;
+    b[4] = 0;
+    b[4] = (msc->rfa << 5) | (msc->tidflag << 4) | msc->lenid;
+    b[5] = (msc->tid & 0xFF00) >> 8;
+    b[6] =  msc->tid & 0x00FF;
+    b[7] = (msc->rcount << 5) | ((msc->seglen & 0x1F00)>>8);
+    b[8] =  msc->seglen & 0x00FF;
+
+    for (i = 0; i<9; i++) {
+        crc = update_crc_ccitt(crc, b[i]);
+    }
+
+    for(i = 0; i < msc->seglen; i++) {
+        b[i+9] = (msc->segdata)[i];
+        crc = update_crc_ccitt(crc, b[i+9]);
+    }
+
+    crc = ~crc;
+    b[9+msc->seglen]   = (crc & 0xFF00) >> 8;     // HI CRC
+    b[9+msc->seglen+1] =  crc & 0x00FF;          // LO CRC
+
+    *bsize = 9 + msc->seglen + 1 + 1;
+
+    //write(1,b,9+msc->seglen+1+1);
+
+}
+
+
+
+void writeDLS(int output_fd, const char* dls_file, int padlen) {
+    char dlstext[MAXDLS];
+    int dlslen;
+    int i;
+
+    if (dlsfd != 0) {
+        close(dlsfd);
+    }
+
+    dlsfd = open(dls_file, O_RDONLY);
+    if (dlsfd == -1) {
+        fprintf(stderr,"Error - Cannot open dls file\n");
+        return;
+    }
+
+    dlslen = read(dlsfd, dlstext, MAXDLS);
+    dlstext[dlslen] = 0x00;
+    create_dls_datagroup(dlstext, padlen);
+    for (i = 0; i < dlsdg.size(); i++) {
+        write(output_fd, &dlsdg[i].front(), dlsdg[i].size());
+    }
+
+}
+
+void create_dls_datagroup(char* text, int padlen) {
+
+    int numdg = 0;            // Number of data groups
+    int numseg;               // Number of DSL segments
+    int lastseglen;           // Length of the last segment
+    int xpadlengthmask;
+    int i, j, k, z, idx_start_crc, idx_stop_crc;
+    uint16_t dlscrc;
+
+    if (dls_toggle == 0)
+        dls_toggle = 1;
+    else
+        dls_toggle = 0;
+
+    numseg = strlen(text) / 16;
+    lastseglen = strlen(text) % 16;
+    if (padlen-9 >= 16) {
+        if (lastseglen > 0) {
+            numseg++;   // The last incomplete segment
+        }
+
+        // The PAD can contain the full segmnet and overhead (9 bytes)
+        numdg = numseg;
+
+    }
+    else {
+        // Each 16 char segment span over 2 dg
+        numdg = numseg * 2;
+
+        if (lastseglen > 0) {
+            numseg++;              // The last incomplete segment
+
+            if (lastseglen <= padlen-9) {
+                numdg += 1;
+            }
+            else {
+                numdg += 2;
+            }
+        }
+    }
+
+    fprintf(stderr, "PAD Length: %d\n", padlen);
+    fprintf(stderr, "DLS text: %s\n", text);
+    fprintf(stderr, "Number of DLS segments: %d\n", numseg);
+    fprintf(stderr, "Number of DLS data groups: %d\n", numdg);
+
+    xpadlengthmask = get_xpadlengthmask(padlen);
+
+    dlsdg.resize(0);
+    dlsdg.resize(numdg);
+
+    i = 0;
+    for (z=0; z < numseg; z++) {
+        char* curseg;
+        int curseglen;
+        uint8_t firstseg, lastseg;
+
+        curseg = &text[z * 16];
+        fprintf(stderr, "Segment number %d\n", z+1);
+
+        if (z == 0) {             // First segment
+            firstseg = 1;
+        }
+        else {
+            firstseg = 0;
+        }
+
+        if (z == numseg-1) {      //Last segment
+            if (lastseglen != 0) {
+                curseglen = lastseglen;
+            }
+            else {
+                curseglen = 16;
+            }
+            lastseg = 1;
+        }
+        else {
+            curseglen = 16;
+            lastseg = 0;
+        }
+
+        if (curseglen <= padlen-9) {  // Segment is composed of 1 data group
+            dlsdg[i].resize(padlen);
+
+            // FF-PAD Byte L (CI=1)
+            dlsdg[i][padlen-1]=0x02;
+
+            // FF-PAD Byte L-1 (Variable size X_PAD)
+            dlsdg[i][padlen-2]=0x20;
+
+            // CI => data length = 12 (011) - Application Type=2
+            // (DLS - start of X-PAD data group)
+            dlsdg[i][padlen-3]=(xpadlengthmask<<5) | 0x02;
+
+            // End of CI list
+            dlsdg[i][padlen-4]=0x00;
+
+            // DLS Prefix (T=1,Only one segment,segment length-1)
+            dlsdg[i][padlen-5]=((dls_toggle*8+firstseg*4+lastseg*2+0)<<4) | 
+                (curseglen-1);
+
+            if (firstseg==1) {
+                // DLS Prefix (Charset standard)
+                dlsdg[i][padlen-6]=0x00;
+            }
+            else {
+                // DLS SegNum
+                dlsdg[i][padlen-6]=z<<4;
+            }
+
+            // CRC start from prefix
+            idx_start_crc = padlen-5;
+
+            // DLS text
+            for (j = 0; j < curseglen; j++) {
+                dlsdg[i][padlen-7-j] = curseg[j];
+            }
+
+            idx_stop_crc = padlen - 7 - curseglen+1;
+
+            dlscrc = 0xffff;
+            for (j = idx_start_crc; j >= idx_stop_crc; j--) {
+                dlscrc = update_crc_ccitt(dlscrc, dlsdg[i][j]);
+            }
+
+            dlscrc = ~dlscrc;
+            fprintf(stderr, "crc=%x ~crc=%x\n", ~dlscrc, dlscrc);
+
+            dlsdg[i][padlen-7-curseglen]   = (dlscrc & 0xFF00) >> 8;  // HI CRC
+            dlsdg[i][padlen-7-curseglen-1] = dlscrc & 0x00FF;         // LO CRC
+
+            // NULL PADDING
+            for (j = padlen-7-curseglen-2; j >= 0; j--) {
+                dlsdg[i][j]=0x00;
+            }
+
+            fprintf(stderr, "Data group: ");
+            for (j = 0; j < padlen; j++)
+                fprintf(stderr, "%x ", dlsdg[i][j]);
+            fprintf(stderr, "\n");
+            i++;
+
+        }
+        else {   // Segment is composed of 2 data groups
+
+            // FIRST DG (NO CRC)
+            dlscrc = 0xffff;
+
+            dlsdg[i].resize(padlen);
+
+            // FF-PAD Byte L (CI=1)
+            dlsdg[i][padlen-1]=0x02;
+
+            // FF-PAD Byte L-1 (Variable size X_PAD)
+            dlsdg[i][padlen-2]=0x20;
+
+            // CI => data length = 12 (011) - Application Type=2
+            // (DLS - start of X-PAD data group)
+            dlsdg[i][padlen-3]=(xpadlengthmask<<5) | 0x02;
+
+            // End of CI list
+            dlsdg[i][padlen-4]=0x00;
+
+            // DLS Prefix (T=1,Only one segment,segment length-1)
+            dlsdg[i][padlen-5]=((dls_toggle*8+firstseg*4+lastseg*2+0)<<4) |
+                (curseglen-1);
+
+
+            if (firstseg == 1) {
+                // DLS Prefix (Charset standard)
+                dlsdg[i][padlen-6] = 0x00;
+            }
+            else {
+                // DLS SegNum
+                dlsdg[i][padlen-6]=(i-1)<<4;
+            }
+
+            dlscrc = update_crc_ccitt(dlscrc, dlsdg[i][padlen-5]);
+            dlscrc = update_crc_ccitt(dlscrc, dlsdg[i][padlen-6]);
+
+            // DLS text
+            for (j=0; j < MIN(curseglen, padlen-7); j++) {
+                dlsdg[i][padlen-7-j] = curseg[j];
+                dlscrc = update_crc_ccitt(dlscrc, dlsdg[i][padlen-7-j]);
+            }
+            k = j;
+
+            // end of segment
+            if (curseglen == padlen-8) {
+                dlscrc = ~dlscrc;
+                dlsdg[i][1] = (dlscrc & 0xFF00) >> 8;     // HI CRC
+                fprintf(stderr, "crc=%x ~crc=%x\n", ~dlscrc, dlscrc);
+            }
+            else if (curseglen == padlen-7) {
+                dlscrc = ~dlscrc;
+                fprintf(stderr, "crc=%x ~crc=%x\n", ~dlscrc, dlscrc);
+            }
+            dlsdg[i][0]=0x00;
+
+            fprintf(stderr, "First Data group: ");
+            for (j = 0; j < padlen; j++) {
+                fprintf(stderr, "%x ", dlsdg[i][j]);
+            }
+            fprintf(stderr,"\n");
+
+            // SECOND DG (NO CI, NO PREFIX)
+            i++;
+
+            dlsdg[i].resize(padlen);
+
+            // FF-PAD Byte L (CI=0)
+            dlsdg[i][padlen-1] = 0x00;
+
+            // FF-PAD Byte L-1 (Variable size X_PAD)
+            dlsdg[i][padlen-2] = 0x20;
+
+            if (curseglen == padlen-8) {
+                dlsdg[i][padlen-3] = dlscrc & 0x00FF;          // LO CRC
+            }
+            else if (curseglen==padlen-7) {
+                dlsdg[i][padlen-3] = (dlscrc & 0xFF00) >> 8;    // HI CRC
+                dlsdg[i][padlen-4] =  dlscrc & 0x00FF;          // LO CRC
+            }
+            else {
+                // DLS text
+                for (j = 0; j < curseglen-k; j++) {
+                    dlsdg[i][padlen-3-j] = curseg[k+j];
+                    dlscrc = update_crc_ccitt(dlscrc, dlsdg[i][padlen-3-j]);
+                }
+                dlscrc = ~dlscrc;
+                dlsdg[i][padlen-3-curseglen+k] =  (dlscrc & 0xFF00) >> 8;    // HI CRC
+                dlsdg[i][padlen-3-curseglen+k-1] = dlscrc & 0x00FF;          // LO CRC
+            }
+
+            fprintf(stderr, "Second Data group: ");
+            for (j = 0; j < padlen; j++) {
+                fprintf(stderr, "%x ", dlsdg[i][j]);
+            }
+
+            fprintf(stderr, "\n");
+            fprintf(stderr, "**** crc=%x ~crc=%x\n", ~dlscrc, dlscrc);
+            i++;
+        }
+    }
+}
+
+void writeMotPAD(int output_fd,
+        unsigned char* mscdg,
+        unsigned short int mscdgsize,
+        unsigned short int padlen)
+{
+
+    unsigned char pad[128];
+    int xpadlengthmask, i, j,k, numseg, lastseglen;
+    unsigned short int crc;
+
+    xpadlengthmask = get_xpadlengthmask(padlen);
+
+    // Write MSC Data Groups
+    int curseglen, non_ci_seglen;
+    for (i = 0; i < mscdgsize; i += curseglen) {
+        uint8_t* curseg;
+        uint8_t  firstseg;
+
+        curseg = &mscdg[i];
+        //fprintf(stderr,"Segment offset %d\n",i);
+
+        if (i == 0) {             // First segment
+            firstseg = 1;
+            curseglen = padlen-10;
+
+            // size of first X-PAD = MSC-DG + DGLI-DG + End of CI list + 2x CI = size of subsequent non-CI X-PADs
+            non_ci_seglen = curseglen + 4 + 1 + 2;
+        }
+        else {
+            firstseg = 0;
+            curseglen = MIN(non_ci_seglen,mscdgsize-i);
+        }
+
+        if (firstseg == 1) {
+            // FF-PAD Byte L (CI=1)
+            pad[padlen-1] = 0x02;
+
+            // FF-PAD Byte L-1 (Variable size X_PAD)
+            pad[padlen-2] = 0x20;
+
+            // Write Data Group Length Indicator
+            crc = 0xffff;
+            // CI for data group length indicator: data length=4, Application Type=1
+            pad[padlen-3]=0x01;
+            // CI for data group length indicator: Application Type=12 (Start of MOT)
+            pad[padlen-4]=(xpadlengthmask<<5) | 12; 
+            // End of CI list
+            pad[padlen-5]=0x00;
+            // RFA+HI Data group length
+            pad[padlen-6]=(mscdgsize & 0x3F00)>>8;
+            pad[padlen-7]=(mscdgsize & 0x00FF);
+            crc = update_crc_ccitt(crc, pad[padlen-6]);
+            crc = update_crc_ccitt(crc, pad[padlen-7]);
+            crc = ~crc;
+            // HI CRC
+            pad[padlen-8]=(crc & 0xFF00) >> 8;
+            // LO CRC
+            pad[padlen-9]=(crc & 0x00FF);
+            k=10;
+        }
+        else {
+            // FF-PAD Byte L (CI=0)
+            pad[padlen-1] = 0x00;
+
+            // FF-PAD Byte L-1 (Variable size X_PAD)
+            pad[padlen-2] = 0x20;
+            k=3;
+        }
+
+        for (j = 0; j < curseglen; j++) {
+            pad[padlen-k-j] = curseg[j];
+        }
+        for (j = padlen-k-curseglen; j >= 0; j--) {
+            pad[j] = 0x00;
+        }
+
+        write(output_fd, pad, padlen);
+        //fprintf(stderr,"MSC Data Group - Segment %d: ",i);
+        //for (j=0;j<padlen;j++) fprintf(stderr,"%02x ",pad[j]);
+        //        fprintf(stderr,"\n");
+
+    }
+}
+
+
+int get_xpadlengthmask(int padlen)
+{
+    int xpadlengthmask;
+
+    /* Don't forget to change ALLOWED_PADLEN
+     * if you change this check
+     */
+    if (padlen == 23)
+        xpadlengthmask = 3;
+    else if (padlen == 26)
+        xpadlengthmask = 4;
+    else if (padlen == 34)
+        xpadlengthmask = 5;
+    else if (padlen == 42)
+        xpadlengthmask = 6;
+    else if (padlen == 58)
+        xpadlengthmask = 7;
+    else
+        xpadlengthmask = -1; // Error
+
+    return xpadlengthmask;
+}
+