diff --git a/skeletons/converter-example.c b/skeletons/converter-example.c
new file mode 100644
index 0000000..a1dc8f4
--- /dev/null
+++ b/skeletons/converter-example.c
@@ -0,0 +1,937 @@
+/*
+ * Generic converter template for a selected ASN.1 type.
+ * Copyright (c) 2005-2017 Lev Walkin <vlm@lionet.info>.
+ * All rights reserved.
+ * 
+ * To compile with your own ASN.1 type, redefine the PDU as shown:
+ * 
+ * cc -DPDU=MyCustomType -o myDecoder.o -c converter-example.c
+ */
+#ifdef    HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <stdio.h>
+#include <sys/types.h>
+#include <stdlib.h>    /* for atoi(3) */
+#include <unistd.h>    /* for getopt(3) */
+#include <string.h>    /* for strerror(3) */
+#include <sysexits.h>    /* for EX_* exit codes */
+#include <errno.h>    /* for errno */
+
+#include <asn_application.h>
+#include <asn_internal.h>    /* for ASN__DEFAULT_STACK_MAX */
+
+/* Convert "Type" defined by -DPDU into "asn_DEF_Type" */
+
+#ifndef NO_ASN_PDU
+#ifndef PDU
+#error Define -DPDU to compile this sample converter.
+#endif
+#ifdef    ASN_PDU_COLLECTION        /* Generated by asn1c: -pdu=... */
+extern asn_TYPE_descriptor_t *asn_pdu_collection[];
+#endif
+#define    ASN_DEF_PDU(t)    asn_DEF_ ## t
+#define    DEF_PDU_Type(t)    ASN_DEF_PDU(t)
+#define    PDU_Type    DEF_PDU_Type(PDU)
+
+extern asn_TYPE_descriptor_t PDU_Type;    /* ASN.1 type to be decoded */
+#define PDU_Type_Ptr (&PDU_Type)
+#else   /* NO_ASN_PDU */
+#define PDU_Type_Ptr    NULL
+#endif  /* NO_ASN_PDU */
+
+/*
+ * Open file and parse its contens.
+ */
+static void *data_decode_from_file(enum asn_transfer_syntax,
+                                   asn_TYPE_descriptor_t *asnTypeOfPDU,
+                                   FILE *file, const char *name,
+                                   ssize_t suggested_bufsize, int first_pdu);
+static int write_out(const void *buffer, size_t size, void *key);
+static FILE *argument_to_file(char *av[], int idx);
+static char *argument_to_name(char *av[], int idx);
+
+       int opt_debug;   /* -d (or -dd) */
+static int opt_check;   /* -c (constraints checking) */
+static int opt_stack;   /* -s (maximum stack size) */
+static int opt_nopad;   /* -per-nopad (PER input is not padded between msgs) */
+static int opt_onepdu;  /* -1 (decode single PDU) */
+
+#ifdef    JUNKTEST        /* Enable -J <probability> */
+#define    JUNKOPT    "J:"
+static double opt_jprob;    /* Junk bit probability */
+static int    junk_failures;
+static void   junk_bytes_with_probability(uint8_t *, size_t, double prob);
+#else
+#define    JUNKOPT
+#endif
+
+/* Debug output function */
+static void
+DEBUG(const char *fmt, ...) {
+    va_list ap;
+    if(!opt_debug) return;
+    fprintf(stderr, "AD: ");
+    va_start(ap, fmt);
+    vfprintf(stderr, fmt, ap);
+    va_end(ap);
+    fprintf(stderr, "\n");
+}
+
+static const char *
+ats_simple_name(enum asn_transfer_syntax syntax) {
+    switch(syntax) {
+    case ATS_INVALID:
+        return "/dev/null";
+    case ATS_NONSTANDARD_PLAINTEXT:
+        return "plaintext";
+    case ATS_BER:
+        return "BER";
+    case ATS_DER:
+        return "DER";
+    case ATS_CER:
+        return "CER";
+    case ATS_BASIC_OER:
+    case ATS_CANONICAL_OER:
+        return "OER";
+    case ATS_BASIC_XER:
+    case ATS_CANONICAL_XER:
+        return "XER";
+    case ATS_UNALIGNED_BASIC_PER:
+    case ATS_UNALIGNED_CANONICAL_PER:
+        return "PER";
+    default:
+        return "<?>";
+    }
+}
+
+#define CODEC_OFFSET(fname)  ((ptrdiff_t)&(((asn_TYPE_operation_t *)0)->fname))
+typedef struct {
+    const char *name;
+    enum asn_transfer_syntax syntax;
+    ptrdiff_t codec_offset;
+    const char *full_name;
+} syntax_selector;
+
+static syntax_selector input_encodings[] = {
+    {"ber", ATS_BER, CODEC_OFFSET(ber_decoder),
+     "Input is in BER (Basic Encoding Rules) or DER"},
+    {"oer", ATS_BASIC_OER, CODEC_OFFSET(oer_decoder),
+     "Input is in OER (Octet Encoding Rules)"},
+    {"per", ATS_UNALIGNED_BASIC_PER, CODEC_OFFSET(uper_decoder),
+     "Input is in Unaligned PER (Packed Encoding Rules)"},
+    {"xer", ATS_BASIC_XER, CODEC_OFFSET(xer_decoder),
+     "Input is in XER (XML Encoding Rules)"},
+    {0, ATS_INVALID, 0, 0}};
+
+static syntax_selector output_encodings[] = {
+    {"der", ATS_DER, CODEC_OFFSET(der_encoder),
+     "Output as DER (Distinguished Encoding Rules)"},
+    {"oer", ATS_CANONICAL_OER, CODEC_OFFSET(oer_encoder),
+     "Output as Canonical OER (Octet Encoding Rules)"},
+    {"per", ATS_UNALIGNED_CANONICAL_PER, CODEC_OFFSET(uper_encoder),
+     "Output as Unaligned PER (Packed Encoding Rules)"},
+    {"xer", ATS_BASIC_XER, CODEC_OFFSET(xer_encoder),
+     "Output as XER (XML Encoding Rules)"},
+    {"text", ATS_NONSTANDARD_PLAINTEXT, CODEC_OFFSET(print_struct),
+     "Output as plain semi-structured text"},
+    {"null", ATS_INVALID, CODEC_OFFSET(print_struct),
+     "Verify (decode) input, but do not output"},
+    {0, ATS_INVALID, 0, 0}};
+
+static int
+has_codec_defined(const asn_TYPE_descriptor_t *td,
+                  const syntax_selector *element) {
+    return *(const void *const *)(const void *)((const char *)td->op
+                                                + element->codec_offset) != 0;
+}
+
+/*
+ * Select ASN.1 Transfer Enocoding Syntax by command line name.
+ */
+static const syntax_selector *
+ats_by_name(const char *name, const asn_TYPE_descriptor_t *td,
+            const syntax_selector *first_element) {
+    const syntax_selector *element;
+    for(element = first_element; element->name; element++) {
+        if(strcmp(element->name, name) == 0) {
+            if(td && td->op && has_codec_defined(td, element)) {
+                return element;
+            }
+        }
+    }
+    return NULL;
+}
+
+int
+main(int ac, char *av[]) {
+    FILE *binary_out;
+    static asn_TYPE_descriptor_t *pduType = PDU_Type_Ptr;
+    ssize_t suggested_bufsize = 8192;  /* close or equal to stdio buffer */
+    int number_of_iterations = 1;
+    int num;
+    int ch;
+    const syntax_selector *sel;
+    enum asn_transfer_syntax isyntax = ATS_INVALID;
+    enum asn_transfer_syntax osyntax = ATS_BASIC_XER;
+
+#ifndef  PDU
+    if(!pduType) {
+        fprintf(stderr, "No -DPDU defined during compilation.\n");
+#ifdef  NO_ASN_PDU
+        exit(0);
+#else
+        exit(EX_SOFTWARE);
+#endif
+    }
+#endif
+
+    /* Figure out if specialty decoder needs to be default */
+    if(ats_by_name("oer", pduType, input_encodings))
+        isyntax = ATS_BASIC_OER;
+    if(ats_by_name("per", pduType, input_encodings))
+        isyntax = ATS_UNALIGNED_BASIC_PER;
+
+    /*
+     * Pocess the command-line argments.
+     */
+    while((ch = getopt(ac, av, "i:o:1b:cdn:p:hs:" JUNKOPT)) != -1)
+    switch(ch) {
+    case 'i':
+        sel = ats_by_name(optarg, pduType, input_encodings);
+        if(sel) {
+            isyntax = sel->syntax;
+        } else {
+            fprintf(stderr, "-i<format>: '%s': improper format selector\n",
+                    optarg);
+            exit(EX_UNAVAILABLE);
+        }
+        break;
+    case 'o':
+        sel = ats_by_name(optarg, pduType, output_encodings);
+        if(sel) {
+            osyntax = sel->syntax;
+        } else {
+            fprintf(stderr, "-o<format>: '%s': improper format selector\n",
+                    optarg);
+            exit(EX_UNAVAILABLE);
+        }
+        break;
+    case '1':
+        opt_onepdu = 1;
+        break;
+    case 'b':
+        suggested_bufsize = atoi(optarg);
+        if(suggested_bufsize < 1
+            || suggested_bufsize > 16 * 1024 * 1024) {
+            fprintf(stderr,
+                "-b %s: Improper buffer size (1..16M)\n",
+                optarg);
+            exit(EX_UNAVAILABLE);
+        }
+        break;
+    case 'c':
+        opt_check = 1;
+        break;
+    case 'd':
+        opt_debug++;    /* Double -dd means ASN.1 debug */
+        break;
+    case 'n':
+        number_of_iterations = atoi(optarg);
+        if(number_of_iterations < 1) {
+            fprintf(stderr,
+                "-n %s: Improper iterations count\n", optarg);
+            exit(EX_UNAVAILABLE);
+        }
+        break;
+    case 'p':
+        if(strcmp(optarg, "er-nopad") == 0) {
+            opt_nopad = 1;
+            break;
+        }
+#ifdef    ASN_PDU_COLLECTION
+        if(strcmp(optarg, "list") == 0) {
+            asn_TYPE_descriptor_t **pdu = asn_pdu_collection;
+            fprintf(stderr, "Available PDU types:\n");
+            for(; *pdu; pdu++) printf("%s\n", (*pdu)->name);
+            exit(0);
+        } else if(optarg[0] >= 'A' && optarg[0] <= 'Z') {
+            asn_TYPE_descriptor_t **pdu = asn_pdu_collection;
+            while(*pdu && strcmp((*pdu)->name, optarg)) pdu++;
+            if(*pdu) { pduType = *pdu; break; }
+            fprintf(stderr, "-p %s: Unrecognized PDU\n", optarg);
+            exit(EX_USAGE);
+        }
+#else   /* Without -pdu=auto there's just a single type */
+        if(strcmp(optarg, "list") == 0) {
+            fprintf(stderr, "Available PDU types:\n");
+            printf("%s\n", pduType->name);
+            exit(0);
+        } else if(optarg[0] >= 'A' && optarg[0] <= 'Z') {
+            if(strcmp(optarg, pduType->name) == 0) {
+                break;
+            }
+            fprintf(stderr, "-p %s: Unrecognized PDU\n", optarg);
+            exit(EX_USAGE);
+        }
+#endif    /* ASN_PDU_COLLECTION */
+        fprintf(stderr, "-p %s: Unrecognized option\n", optarg);
+        exit(EX_UNAVAILABLE);
+    case 's':
+        opt_stack = atoi(optarg);
+        if(opt_stack < 0) {
+            fprintf(stderr,
+                "-s %s: Non-negative value expected\n",
+                optarg);
+            exit(EX_UNAVAILABLE);
+        }
+        break;
+#ifdef    JUNKTEST
+    case 'J':
+        opt_jprob = strtod(optarg, 0);
+        if(opt_jprob <= 0.0 || opt_jprob > 1.0) {
+            fprintf(stderr,
+                "-J %s: Probability range 0..1 expected \n",
+                optarg);
+            exit(EX_UNAVAILABLE);
+        }
+        break;
+#endif    /* JUNKTEST */
+    case 'h':
+    default:
+#ifdef    ASN_CONVERTER_TITLE
+#define    _AXS(x)    #x
+#define    _ASX(x)    _AXS(x)
+        fprintf(stderr, "%s\n", _ASX(ASN_CONVERTER_TITLE));
+#endif
+        fprintf(stderr, "Usage: %s [options] <datafile> ...\n", av[0]);
+        fprintf(stderr, "Where options are:\n");
+        for(sel = input_encodings; sel->name; sel++) {
+            if(ats_by_name(sel->name, pduType, sel)) {
+                fprintf(stderr, "  -i%s        %s%s\n", sel->name,
+                        sel->full_name,
+                        (sel->syntax == isyntax) ? " (DEFAULT)" : "");
+            }
+        }
+        for(sel = output_encodings; sel->name; sel++) {
+            if(ats_by_name(sel->name, pduType, sel)) {
+                fprintf(stderr, "  -o%s%s       %s%s\n", sel->name,
+                        strlen(sel->name) > 3 ? "" : " ",
+                        sel->full_name,
+                        (sel->syntax == osyntax) ? " (DEFAULT)" : "");
+            }
+        }
+        if(pduType->op->uper_decoder) {
+            fprintf(stderr,
+                    "  -per-nopad   Assume PER PDUs are not padded (-iper)\n");
+        }
+#ifdef    ASN_PDU_COLLECTION
+        fprintf(stderr,
+        "  -p <PDU>     Specify PDU type to decode\n"
+        "  -p list      List available PDUs\n");
+#endif    /* ASN_PDU_COLLECTION */
+        fprintf(stderr,
+        "  -1           Decode only the first PDU in file\n"
+        "  -b <size>    Set the i/o buffer size (default is %ld)\n"
+        "  -c           Check ASN.1 constraints after decoding\n"
+        "  -d           Enable debugging (-dd is even better)\n"
+        "  -n <num>     Process files <num> times\n"
+        "  -s <size>    Set the stack usage limit (default is %d)\n"
+#ifdef    JUNKTEST
+        "  -J <prob>    Set random junk test bit garbaging probability\n"
+#endif
+        , (long)suggested_bufsize, ASN__DEFAULT_STACK_MAX);
+        exit(EX_USAGE);
+    }
+
+    ac -= optind;
+    av += optind;
+
+    if(ac < 1) {
+        fprintf(stderr, "%s: No input files specified. "
+                "Try '-h' for more information\n",
+                av[-optind]);
+        exit(EX_USAGE);
+    }
+
+    if(isatty(1)) {
+        const int is_text_output = osyntax == ATS_NONSTANDARD_PLAINTEXT
+                                   || osyntax == ATS_BASIC_XER
+                                   || osyntax == ATS_CANONICAL_XER;
+        if(is_text_output) {
+            binary_out = stdout;
+        } else {
+            fprintf(stderr, "(Suppressing binary output to a terminal.)\n");
+            binary_out = fopen("/dev/null", "wb");
+            if(!binary_out) {
+                fprintf(stderr, "Can't open /dev/null: %s\n", strerror(errno));
+                exit(EX_OSERR);
+            }
+        }
+    } else {
+        binary_out = stdout;
+    }
+    setvbuf(stdout, 0, _IOLBF, 0);
+
+    for(num = 0; num < number_of_iterations; num++) {
+      int ac_i;
+      /*
+       * Process all files in turn.
+       */
+      for(ac_i = 0; ac_i < ac; ac_i++) {
+        asn_enc_rval_t erv;
+        void *structure;    /* Decoded structure */
+        FILE *file = argument_to_file(av, ac_i);
+        char *name = argument_to_name(av, ac_i);
+        int first_pdu;
+
+        for(first_pdu = 1; (first_pdu || !opt_onepdu); first_pdu = 0) {
+            /*
+             * Decode the encoded structure from file.
+             */
+            structure = data_decode_from_file(isyntax, pduType, file, name,
+                                              suggested_bufsize, first_pdu);
+            if(!structure) {
+                if(errno) {
+                    /* Error message is already printed */
+                    exit(EX_DATAERR);
+                } else {
+                    /* EOF */
+                    break;
+                }
+            }
+
+            /* Check ASN.1 constraints */
+            if(opt_check) {
+                char errbuf[128];
+                size_t errlen = sizeof(errbuf);
+                if(asn_check_constraints(pduType, structure, errbuf, &errlen)) {
+                    fprintf(stderr,
+                            "%s: ASN.1 constraint "
+                            "check failed: %s\n",
+                            name, errbuf);
+                    exit(EX_DATAERR);
+                }
+            }
+
+            if(osyntax == ATS_INVALID) {
+#ifdef JUNKTEST
+                if(opt_jprob == 0.0) {
+                    fprintf(stderr, "%s: decoded successfully\n", name);
+                }
+#else
+                fprintf(stderr, "%s: decoded successfully\n", name);
+#endif
+            } else {
+                erv = asn_encode(NULL, osyntax, pduType, structure, write_out,
+                                 binary_out);
+
+                if(erv.encoded == -1) {
+                    fprintf(stderr, "%s: Cannot convert %s into %s\n", name,
+                            pduType->name, ats_simple_name(osyntax));
+                    exit(EX_UNAVAILABLE);
+                }
+                DEBUG("Encoded in %zd bytes of %s", erv.encoded,
+                      ats_simple_name(osyntax));
+            }
+
+            ASN_STRUCT_FREE(*pduType, structure);
+        }
+
+        if(file && file != stdin) {
+            fclose(file);
+        }
+      }
+    }
+
+#ifdef    JUNKTEST
+    if(opt_jprob > 0.0) {
+        fprintf(stderr, "Junked %f OK (%d/%d)\n",
+            opt_jprob, junk_failures, number_of_iterations);
+    }
+#endif    /* JUNKTEST */
+
+    return 0;
+}
+
+static struct dynamic_buffer {
+    uint8_t *data;        /* Pointer to the data bytes */
+    size_t offset;        /* Offset from the start */
+    size_t length;        /* Length of meaningful contents */
+    size_t unbits;        /* Unused bits in the last byte */
+    size_t allocated;    /* Allocated memory for data */
+    int    nreallocs;    /* Number of data reallocations */
+    off_t  bytes_shifted;    /* Number of bytes ever shifted */
+} DynamicBuffer;
+
+static void
+buffer_dump() {
+    uint8_t *p = DynamicBuffer.data + DynamicBuffer.offset;
+    uint8_t *e = p + DynamicBuffer.length - (DynamicBuffer.unbits ? 1 : 0);
+    if(!opt_debug) return;
+    DEBUG("Buffer: { d=%p, o=%ld, l=%ld, u=%ld, a=%ld, s=%ld }",
+        DynamicBuffer.data,
+        (long)DynamicBuffer.offset,
+        (long)DynamicBuffer.length,
+        (long)DynamicBuffer.unbits,
+        (long)DynamicBuffer.allocated,
+        (long)DynamicBuffer.bytes_shifted);
+    for(; p < e; p++) {
+        fprintf(stderr, " %c%c%c%c%c%c%c%c",
+            ((*p >> 7) & 1) ? '1' : '0',
+            ((*p >> 6) & 1) ? '1' : '0',
+            ((*p >> 5) & 1) ? '1' : '0',
+            ((*p >> 4) & 1) ? '1' : '0',
+            ((*p >> 3) & 1) ? '1' : '0',
+            ((*p >> 2) & 1) ? '1' : '0',
+            ((*p >> 1) & 1) ? '1' : '0',
+            ((*p >> 0) & 1) ? '1' : '0');
+    }
+    if(DynamicBuffer.unbits) {
+        unsigned int shift;
+        fprintf(stderr, " ");
+        for(shift = 7; shift >= DynamicBuffer.unbits; shift--)
+            fprintf(stderr, "%c", ((*p >> shift) & 1) ? '1' : '0');
+        fprintf(stderr, " %ld:%ld\n",
+            (long)DynamicBuffer.length - 1,
+            (long)8 - DynamicBuffer.unbits);
+    } else {
+        fprintf(stderr, " %ld\n", (long)DynamicBuffer.length);
+    }
+}
+
+/*
+ * Move the buffer content left N bits, possibly joining it with
+ * preceeding content.
+ */
+static void
+buffer_shift_left(size_t offset, int bits) {
+    uint8_t *ptr = DynamicBuffer.data + DynamicBuffer.offset + offset;
+    uint8_t *end = DynamicBuffer.data + DynamicBuffer.offset
+            + DynamicBuffer.length - 1;
+    
+    if(!bits) return;
+
+    DEBUG("Shifting left %d bits off %ld (o=%ld, u=%ld, l=%ld)",
+        bits, (long)offset,
+        (long)DynamicBuffer.offset,
+        (long)DynamicBuffer.unbits,
+        (long)DynamicBuffer.length);
+
+    if(offset) {
+        int right;
+        right = ptr[0] >> (8 - bits);
+
+        DEBUG("oleft: %c%c%c%c%c%c%c%c",
+            ((ptr[-1] >> 7) & 1) ? '1' : '0',
+            ((ptr[-1] >> 6) & 1) ? '1' : '0',
+            ((ptr[-1] >> 5) & 1) ? '1' : '0',
+            ((ptr[-1] >> 4) & 1) ? '1' : '0',
+            ((ptr[-1] >> 3) & 1) ? '1' : '0',
+            ((ptr[-1] >> 2) & 1) ? '1' : '0',
+            ((ptr[-1] >> 1) & 1) ? '1' : '0',
+            ((ptr[-1] >> 0) & 1) ? '1' : '0');
+
+        DEBUG("oriht: %c%c%c%c%c%c%c%c",
+            ((ptr[0] >> 7) & 1) ? '1' : '0',
+            ((ptr[0] >> 6) & 1) ? '1' : '0',
+            ((ptr[0] >> 5) & 1) ? '1' : '0',
+            ((ptr[0] >> 4) & 1) ? '1' : '0',
+            ((ptr[0] >> 3) & 1) ? '1' : '0',
+            ((ptr[0] >> 2) & 1) ? '1' : '0',
+            ((ptr[0] >> 1) & 1) ? '1' : '0',
+            ((ptr[0] >> 0) & 1) ? '1' : '0');
+
+        DEBUG("mriht: %c%c%c%c%c%c%c%c",
+            ((right >> 7) & 1) ? '1' : '0',
+            ((right >> 6) & 1) ? '1' : '0',
+            ((right >> 5) & 1) ? '1' : '0',
+            ((right >> 4) & 1) ? '1' : '0',
+            ((right >> 3) & 1) ? '1' : '0',
+            ((right >> 2) & 1) ? '1' : '0',
+            ((right >> 1) & 1) ? '1' : '0',
+            ((right >> 0) & 1) ? '1' : '0');
+
+        ptr[-1] = (ptr[-1] & (0xff << bits)) | right;
+
+        DEBUG("after: %c%c%c%c%c%c%c%c",
+            ((ptr[-1] >> 7) & 1) ? '1' : '0',
+            ((ptr[-1] >> 6) & 1) ? '1' : '0',
+            ((ptr[-1] >> 5) & 1) ? '1' : '0',
+            ((ptr[-1] >> 4) & 1) ? '1' : '0',
+            ((ptr[-1] >> 3) & 1) ? '1' : '0',
+            ((ptr[-1] >> 2) & 1) ? '1' : '0',
+            ((ptr[-1] >> 1) & 1) ? '1' : '0',
+            ((ptr[-1] >> 0) & 1) ? '1' : '0');
+    }
+
+    buffer_dump();
+
+    for(; ptr < end; ptr++) {
+        int right = ptr[1] >> (8 - bits);
+        *ptr = (*ptr << bits) | right;
+    }
+    *ptr <<= bits;
+
+    DEBUG("Unbits [%d=>", (int)DynamicBuffer.unbits);
+    if(DynamicBuffer.unbits == 0) {
+        DynamicBuffer.unbits += bits;
+    } else {
+        DynamicBuffer.unbits += bits;
+        if(DynamicBuffer.unbits > 7) {
+            DynamicBuffer.unbits -= 8;
+            DynamicBuffer.length--;
+            DynamicBuffer.bytes_shifted++;
+        }
+    }
+    DEBUG("Unbits =>%d]", (int)DynamicBuffer.unbits);
+
+    buffer_dump();
+
+    DEBUG("Shifted. Now (o=%ld, u=%ld l=%ld)",
+        (long)DynamicBuffer.offset,
+        (long)DynamicBuffer.unbits,
+        (long)DynamicBuffer.length);
+    
+
+}
+
+/*
+ * Ensure that the buffer contains at least this amount of free space.
+ */
+static void add_bytes_to_buffer(const void *data2add, size_t bytes) {
+
+    if(bytes == 0) return;
+
+    DEBUG("=> add_bytes(%ld) { o=%ld l=%ld u=%ld, s=%ld }",
+        (long)bytes,
+        (long)DynamicBuffer.offset,
+        (long)DynamicBuffer.length,
+        (long)DynamicBuffer.unbits,
+        (long)DynamicBuffer.allocated);
+
+    if(DynamicBuffer.allocated
+    >= (DynamicBuffer.offset + DynamicBuffer.length + bytes)) {
+        DEBUG("\tNo buffer reallocation is necessary");
+    } else if(bytes <= DynamicBuffer.offset) {
+        DEBUG("\tContents shifted by %ld", DynamicBuffer.offset);
+
+        /* Shift the buffer contents */
+        memmove(DynamicBuffer.data,
+                DynamicBuffer.data + DynamicBuffer.offset,
+            DynamicBuffer.length);
+        DynamicBuffer.bytes_shifted += DynamicBuffer.offset;
+        DynamicBuffer.offset = 0;
+    } else {
+        size_t newsize = (DynamicBuffer.allocated << 2) + bytes;
+        void *p = MALLOC(newsize);
+        if(!p) {
+            perror("malloc()");
+            exit(EX_OSERR);
+        }
+        memcpy(p,
+            DynamicBuffer.data + DynamicBuffer.offset,
+            DynamicBuffer.length);
+        FREEMEM(DynamicBuffer.data);
+        DynamicBuffer.data = (uint8_t *)p;
+        DynamicBuffer.offset = 0;
+        DynamicBuffer.allocated = newsize;
+        DynamicBuffer.nreallocs++;
+        DEBUG("\tBuffer reallocated to %ld (%d time)",
+            newsize, DynamicBuffer.nreallocs);
+    }
+
+    memcpy(DynamicBuffer.data
+        + DynamicBuffer.offset + DynamicBuffer.length,
+        data2add, bytes);
+    DynamicBuffer.length += bytes;
+    if(DynamicBuffer.unbits) {
+        int bits = DynamicBuffer.unbits;
+        DynamicBuffer.unbits = 0;
+        buffer_shift_left(DynamicBuffer.length - bytes, bits);
+    }
+
+    DEBUG("<= add_bytes(%ld) { o=%ld l=%ld u=%ld, s=%ld }",
+        (long)bytes,
+        (long)DynamicBuffer.offset,
+        (long)DynamicBuffer.length,
+        (long)DynamicBuffer.unbits,
+        (long)DynamicBuffer.allocated);
+}
+
+static int
+is_syntax_PER(enum asn_transfer_syntax syntax) {
+    return (syntax != ATS_UNALIGNED_BASIC_PER
+            && syntax != ATS_UNALIGNED_CANONICAL_PER);
+}
+
+static int
+restartability_supported(enum asn_transfer_syntax syntax) {
+    return is_syntax_PER(syntax);
+}
+
+static void *
+data_decode_from_file(enum asn_transfer_syntax isyntax, asn_TYPE_descriptor_t *pduType, FILE *file, const char *name, ssize_t suggested_bufsize, int on_first_pdu) {
+    static uint8_t *fbuf;
+    static ssize_t fbuf_size;
+    static asn_codec_ctx_t s_codec_ctx;
+    asn_codec_ctx_t *opt_codec_ctx = 0;
+    void *structure = 0;
+    asn_dec_rval_t rval;
+    size_t old_offset;    
+    size_t new_offset;
+    int tolerate_eof;
+    size_t rd;
+
+    if(!file) {
+        fprintf(stderr, "%s: %s\n", name, strerror(errno));
+        errno = EINVAL;
+        return 0;
+    }
+
+    if(opt_stack) {
+        s_codec_ctx.max_stack_size = opt_stack;
+        opt_codec_ctx = &s_codec_ctx;
+    }
+
+    DEBUG("Processing %s", name);
+
+    /* prepare the file buffer */
+    if(fbuf_size != suggested_bufsize) {
+        fbuf = (uint8_t *)REALLOC(fbuf, suggested_bufsize);
+        if(!fbuf) {
+            perror("realloc()");
+            exit(EX_OSERR);
+        }
+        fbuf_size = suggested_bufsize;
+    }
+
+    if(on_first_pdu) {
+        DynamicBuffer.offset = 0;
+        DynamicBuffer.length = 0;
+        DynamicBuffer.unbits = 0;
+        DynamicBuffer.allocated = 0;
+        DynamicBuffer.bytes_shifted = 0;
+        DynamicBuffer.nreallocs = 0;
+    }
+
+    old_offset = DynamicBuffer.bytes_shifted + DynamicBuffer.offset;
+
+    /* Pretend immediate EOF */
+    rval.code = RC_WMORE;
+    rval.consumed = 0;
+
+    for(tolerate_eof = 1;    /* Allow EOF first time buffer is non-empty */
+        (rd = fread(fbuf, 1, fbuf_size, file))
+        || feof(file) == 0
+        || (tolerate_eof && DynamicBuffer.length)
+        ;) {
+        int      ecbits = 0;    /* Extra consumed bits in case of PER */
+        uint8_t *i_bptr;
+        size_t   i_size;
+
+        /*
+         * Copy the data over, or use the original buffer.
+         */
+        if(DynamicBuffer.allocated) {
+            /* Append new data into the existing dynamic buffer */
+            add_bytes_to_buffer(fbuf, rd);
+            i_bptr = DynamicBuffer.data + DynamicBuffer.offset;
+            i_size = DynamicBuffer.length;
+        } else {
+            i_bptr = fbuf;
+            i_size = rd;
+        }
+
+        DEBUG("Decoding %ld bytes", (long)i_size);
+
+#ifdef    JUNKTEST
+        junk_bytes_with_probability(i_bptr, i_size, opt_jprob);
+#endif
+
+        if(is_syntax_PER(isyntax) && opt_nopad) {
+#ifdef  ASN_DISABLE_PER_SUPPORT
+            rval.code = RC_FAIL;
+            rval.consumed = 0;
+#else
+            rval = uper_decode(opt_codec_ctx, pduType, (void **)&structure,
+                               i_bptr, i_size, 0, DynamicBuffer.unbits);
+            /* uper_decode() returns bits! */
+            ecbits = rval.consumed % 8; /* Bits consumed from the last byte */
+            rval.consumed >>= 3;    /* Convert bits into bytes. */
+#endif
+            /* Non-padded PER decoder */
+        } else {
+            rval = asn_decode(opt_codec_ctx, isyntax, pduType,
+                              (void **)&structure, i_bptr, i_size);
+        }
+        if(rval.code == RC_WMORE && !restartability_supported(isyntax)) {
+            /* PER does not support restartability */
+            ASN_STRUCT_FREE(*pduType, structure);
+            structure = 0;
+            rval.consumed = 0;
+            /* Continue accumulating data */
+        }
+
+        DEBUG("decode(%ld) consumed %ld+%db (%ld), code %d",
+            (long)DynamicBuffer.length,
+            (long)rval.consumed, ecbits, (long)i_size,
+            rval.code);
+
+        if(DynamicBuffer.allocated == 0) {
+            /*
+             * Flush remainder into the intermediate buffer.
+             */
+            if(rval.code != RC_FAIL && rval.consumed < rd) {
+                add_bytes_to_buffer(fbuf + rval.consumed,
+                    rd - rval.consumed);
+                buffer_shift_left(0, ecbits);
+                DynamicBuffer.bytes_shifted = rval.consumed;
+                rval.consumed = 0;
+                ecbits = 0;
+            }
+        }
+
+        /*
+         * Adjust position inside the source buffer.
+         */
+        if(DynamicBuffer.allocated) {
+            DynamicBuffer.offset += rval.consumed;
+            DynamicBuffer.length -= rval.consumed;
+        } else {
+            DynamicBuffer.bytes_shifted += rval.consumed;
+        }
+
+        switch(rval.code) {
+        case RC_OK:
+            if(ecbits) buffer_shift_left(0, ecbits);
+            DEBUG("RC_OK, finishing up with %ld+%d",
+                (long)rval.consumed, ecbits);
+            return structure;
+        case RC_WMORE:
+            DEBUG("RC_WMORE, continuing read=%ld, cons=%ld "
+                " with %ld..%ld-%ld..%ld",
+                (long)rd,
+                (long)rval.consumed,
+                (long)DynamicBuffer.offset,
+                (long)DynamicBuffer.length,
+                (long)DynamicBuffer.unbits,
+                (long)DynamicBuffer.allocated);
+            if(!rd) tolerate_eof--;
+            continue;
+        case RC_FAIL:
+            break;
+        }
+        break;
+    }
+
+    DEBUG("Clean up partially decoded %s", pduType->name);
+    ASN_STRUCT_FREE(*pduType, structure);
+
+    new_offset = DynamicBuffer.bytes_shifted + DynamicBuffer.offset;
+
+    /*
+     * Print a message and return failure only if not EOF,
+     * unless this is our first PDU (empty file).
+     */
+    if(on_first_pdu
+    || DynamicBuffer.length
+    || new_offset - old_offset > ((isyntax == ATS_BASIC_XER)?sizeof("\r\n")-1:0)
+    ) {
+
+#ifdef    JUNKTEST
+        /*
+         * Nothing's wrong with being unable to decode junk.
+         * Simulate EOF.
+         */
+        if(opt_jprob != 0.0) {
+            junk_failures++;
+            errno = 0;
+            return 0;
+        }
+#endif
+
+        DEBUG("ofp %d, no=%ld, oo=%ld, dbl=%ld",
+            on_first_pdu, (long)new_offset, (long)old_offset,
+            (long)DynamicBuffer.length);
+        fprintf(stderr, "%s: "
+            "Decode failed past byte %ld: %s\n",
+            name, (long)new_offset,
+            (rval.code == RC_WMORE)
+                ? "Unexpected end of input"
+                : "Input processing error");
+#ifndef    ENOMSG
+#define    ENOMSG EINVAL
+#endif
+#ifndef    EBADMSG
+#define    EBADMSG EINVAL
+#endif
+        errno = (rval.code == RC_WMORE) ? ENOMSG : EBADMSG;
+    } else {
+        /* Got EOF after a few successful PDUs */
+        errno = 0;
+    }
+
+    return 0;
+}
+
+/* Dump the buffer out to the specified FILE */
+static int write_out(const void *buffer, size_t size, void *key) {
+    FILE *fp = (FILE *)key;
+    return (fwrite(buffer, 1, size, fp) == size) ? 0 : -1;
+}
+
+static int argument_is_stdin(char *av[], int idx) {
+    if(strcmp(av[idx], "-")) {
+        return 0; /* Certainly not <stdin> */
+    } else {
+        /* This might be <stdin>, unless `./program -- -` */
+        if(strcmp(av[-1], "--"))
+            return 1;
+        else
+            return 0;
+    }
+}
+
+static FILE *argument_to_file(char *av[], int idx) {
+    return argument_is_stdin(av, idx) ? stdin : fopen(av[idx], "rb");
+}
+
+static char *argument_to_name(char *av[], int idx) {
+    return argument_is_stdin(av, idx) ? "standard input" : av[idx];
+}
+
+#ifdef    JUNKTEST
+/*
+ * Fill bytes with some garbage with specified probability (more or less).
+ */
+static void
+junk_bytes_with_probability(uint8_t *buf, size_t size, double prob) {
+    static int junkmode;
+    uint8_t *ptr;
+    uint8_t *end;
+    if(opt_jprob <= 0.0) return;
+    for(ptr = buf, end = ptr + size; ptr < end; ptr++) {
+        int byte = *ptr;
+        if(junkmode++ & 1) {
+            if((((double)random() / RAND_MAX) < prob))
+                byte = random() & 0xff;
+        } else {
+#define    BPROB(b)    ((((double)random() / RAND_MAX) < prob) ? b : 0)
+            byte ^= BPROB(0x80);
+            byte ^= BPROB(0x40);
+            byte ^= BPROB(0x20);
+            byte ^= BPROB(0x10);
+            byte ^= BPROB(0x08);
+            byte ^= BPROB(0x04);
+            byte ^= BPROB(0x02);
+            byte ^= BPROB(0x01);
+        }
+        if(byte != *ptr) {
+            DEBUG("Junk buf[%d] %02x -> %02x", ptr - buf, *ptr, byte);
+            *ptr = byte;
+        }
+    }
+}
+#endif    /* JUNKTEST */
+