]> git.stg.codes - stg.git/blobdiff - libs/smux/BIT_STRING.c
More std::jthread stuff.
[stg.git] / libs / smux / BIT_STRING.c
index 6469d4fd2c8782048e228c19e67950f3b2dc1305..0cff7706fae77685701ace324df8e68445195da8 100644 (file)
@@ -9,55 +9,72 @@
 /*
  * BIT STRING basic type description.
  */
-static ber_tlv_tag_t asn_DEF_BIT_STRING_tags[] = {
+static const ber_tlv_tag_t asn_DEF_BIT_STRING_tags[] = {
        (ASN_TAG_CLASS_UNIVERSAL | (3 << 2))
 };
-static asn_OCTET_STRING_specifics_t asn_DEF_BIT_STRING_specs = {
+asn_OCTET_STRING_specifics_t asn_SPC_BIT_STRING_specs = {
        sizeof(BIT_STRING_t),
        offsetof(BIT_STRING_t, _asn_ctx),
-       1,      /* Special indicator that this is a BIT STRING type */
+       ASN_OSUBV_BIT
 };
-asn_TYPE_descriptor_t asn_DEF_BIT_STRING = {
-       "BIT STRING",
-       "BIT_STRING",
+asn_TYPE_operation_t asn_OP_BIT_STRING = {
        OCTET_STRING_free,         /* Implemented in terms of OCTET STRING */
        BIT_STRING_print,
-       BIT_STRING_constraint,
+       BIT_STRING_compare,
        OCTET_STRING_decode_ber,   /* Implemented in terms of OCTET STRING */
        OCTET_STRING_encode_der,   /* Implemented in terms of OCTET STRING */
        OCTET_STRING_decode_xer_binary,
        BIT_STRING_encode_xer,
-       OCTET_STRING_decode_uper,       /* Unaligned PER decoder */
-       OCTET_STRING_encode_uper,       /* Unaligned PER encoder */
-       0, /* Use generic outmost tag fetcher */
+#ifdef ASN_DISABLE_OER_SUPPORT
+       0,
+       0,
+#else
+       BIT_STRING_decode_oer,
+       BIT_STRING_encode_oer,
+#endif  /* ASN_DISABLE_OER_SUPPORT */
+#ifdef ASN_DISABLE_PER_SUPPORT
+       0,
+       0,
+#else
+       BIT_STRING_decode_uper, /* Unaligned PER decoder */
+       BIT_STRING_encode_uper, /* Unaligned PER encoder */
+#endif  /* ASN_DISABLE_PER_SUPPORT */
+       BIT_STRING_random_fill,
+       0       /* Use generic outmost tag fetcher */
+};
+asn_TYPE_descriptor_t asn_DEF_BIT_STRING = {
+       "BIT STRING",
+       "BIT_STRING",
+       &asn_OP_BIT_STRING,
        asn_DEF_BIT_STRING_tags,
        sizeof(asn_DEF_BIT_STRING_tags)
          / sizeof(asn_DEF_BIT_STRING_tags[0]),
        asn_DEF_BIT_STRING_tags,        /* Same as above */
        sizeof(asn_DEF_BIT_STRING_tags)
          / sizeof(asn_DEF_BIT_STRING_tags[0]),
-       0,      /* No PER visible constraints */
+       { 0, 0, BIT_STRING_constraint },
        0, 0,   /* No members */
-       &asn_DEF_BIT_STRING_specs
+       &asn_SPC_BIT_STRING_specs
 };
 
 /*
  * BIT STRING generic constraint.
  */
 int
-BIT_STRING_constraint(asn_TYPE_descriptor_t *td, const void *sptr,
-               asn_app_constraint_failed_f *ctfailcb, void *app_key) {
-       const BIT_STRING_t *st = (const BIT_STRING_t *)sptr;
+BIT_STRING_constraint(const asn_TYPE_descriptor_t *td, const void *sptr,
+                      asn_app_constraint_failed_f *ctfailcb, void *app_key) {
+    const BIT_STRING_t *st = (const BIT_STRING_t *)sptr;
 
        if(st && st->buf) {
-               if(st->size == 1 && st->bits_unused) {
-                       _ASN_CTFAIL(app_key, td,
+               if((st->size == 0 && st->bits_unused)
+               || st->bits_unused < 0 || st->bits_unused > 7) {
+                       ASN__CTFAIL(app_key, td, sptr,
                                "%s: invalid padding byte (%s:%d)",
                                td->name, __FILE__, __LINE__);
                        return -1;
                }
        } else {
-               _ASN_CTFAIL(app_key, td,
+               ASN__CTFAIL(app_key, td, sptr,
                        "%s: value not given (%s:%d)",
                        td->name, __FILE__, __LINE__);
                return -1;
@@ -66,16 +83,16 @@ BIT_STRING_constraint(asn_TYPE_descriptor_t *td, const void *sptr,
        return 0;
 }
 
-static char *_bit_pattern[16] = {
+static const char *_bit_pattern[16] = {
        "0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111",
        "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"
 };
 
 asn_enc_rval_t
-BIT_STRING_encode_xer(asn_TYPE_descriptor_t *td, void *sptr,
-       int ilevel, enum xer_encoder_flags_e flags,
-               asn_app_consume_bytes_f *cb, void *app_key) {
-       asn_enc_rval_t er;
+BIT_STRING_encode_xer(const asn_TYPE_descriptor_t *td, const void *sptr,
+                      int ilevel, enum xer_encoder_flags_e flags,
+                      asn_app_consume_bytes_f *cb, void *app_key) {
+    asn_enc_rval_t er;
        char scratch[128];
        char *p = scratch;
        char *scend = scratch + (sizeof(scratch) - 10);
@@ -85,7 +102,7 @@ BIT_STRING_encode_xer(asn_TYPE_descriptor_t *td, void *sptr,
        uint8_t *end;
 
        if(!st || !st->buf)
-               _ASN_ENCODE_FAILED;
+               ASN__ENCODE_FAILED;
 
        er.encoded = 0;
 
@@ -99,10 +116,9 @@ BIT_STRING_encode_xer(asn_TYPE_descriptor_t *td, void *sptr,
                int v = *buf;
                int nline = xcan?0:(((buf - st->buf) % 8) == 0);
                if(p >= scend || nline) {
-                       er.encoded += p - scratch;
-                       _ASN_CALLBACK(scratch, p - scratch);
+                       ASN__CALLBACK(scratch, p - scratch);
                        p = scratch;
-                       if(nline) _i_ASN_TEXT_INDENT(1, ilevel);
+                       if(nline) ASN__TEXT_INDENT(1, ilevel);
                }
                memcpy(p + 0, _bit_pattern[v >> 4], 4);
                memcpy(p + 4, _bit_pattern[v & 0x0f], 4);
@@ -110,9 +126,8 @@ BIT_STRING_encode_xer(asn_TYPE_descriptor_t *td, void *sptr,
        }
 
        if(!xcan && ((buf - st->buf) % 8) == 0)
-               _i_ASN_TEXT_INDENT(1, ilevel);
-       er.encoded += p - scratch;
-       _ASN_CALLBACK(scratch, p - scratch);
+               ASN__TEXT_INDENT(1, ilevel);
+       ASN__CALLBACK(scratch, p - scratch);
        p = scratch;
 
        if(buf == end) {
@@ -121,15 +136,14 @@ BIT_STRING_encode_xer(asn_TYPE_descriptor_t *td, void *sptr,
                int i;
                for(i = 7; i >= ubits; i--)
                        *p++ = (v & (1 << i)) ? 0x31 : 0x30;
-               er.encoded += p - scratch;
-               _ASN_CALLBACK(scratch, p - scratch);
+               ASN__CALLBACK(scratch, p - scratch);
        }
 
-       if(!xcan) _i_ASN_TEXT_INDENT(1, ilevel - 1);
+       if(!xcan) ASN__TEXT_INDENT(1, ilevel - 1);
 
-       _ASN_ENCODED_OK(er);
+       ASN__ENCODED_OK(er);
 cb_failed:
-       _ASN_ENCODE_FAILED;
+       ASN__ENCODE_FAILED;
 }
 
 
@@ -137,9 +151,9 @@ cb_failed:
  * BIT STRING specific contents printer.
  */
 int
-BIT_STRING_print(asn_TYPE_descriptor_t *td, const void *sptr, int ilevel,
-               asn_app_consume_bytes_f *cb, void *app_key) {
-       static const char *h2c = "0123456789ABCDEF";
+BIT_STRING_print(const asn_TYPE_descriptor_t *td, const void *sptr, int ilevel,
+                 asn_app_consume_bytes_f *cb, void *app_key) {
+    const char * const h2c = "0123456789ABCDEF";
        char scratch[64];
        const BIT_STRING_t *st = (const BIT_STRING_t *)sptr;
        uint8_t *buf;
@@ -183,6 +197,456 @@ BIT_STRING_print(asn_TYPE_descriptor_t *td, const void *sptr, int ilevel,
                        return -1;
        }
 
+    if(st->bits_unused) {
+        int ret = snprintf(scratch, sizeof(scratch), " (%d bit%s unused)",
+                           st->bits_unused, st->bits_unused == 1 ? "" : "s");
+        assert(ret > 0 && ret < (ssize_t)sizeof(scratch));
+        if(ret > 0 && ret < (ssize_t)sizeof(scratch)
+           && cb(scratch, ret, app_key) < 0)
+            return -1;
+    }
+
        return 0;
 }
 
+/*
+ * Non-destructively remove the trailing 0-bits from the given bit string.
+ */
+static const BIT_STRING_t *
+BIT_STRING__compactify(const BIT_STRING_t *st, BIT_STRING_t *tmp) {
+    const uint8_t *b;
+    union {
+        const uint8_t *c_buf;
+        uint8_t *nc_buf;
+    } unconst;
+
+    if(st->size == 0) {
+        assert(st->bits_unused == 0);
+        return st;
+    } else {
+        for(b = &st->buf[st->size - 1]; b > st->buf && *b == 0; b--) {
+            ;
+        }
+        /* b points to the last byte which may contain data */
+        if(*b) {
+            int unused = 7;
+            uint8_t v = *b;
+            v &= -(int8_t)v;
+            if(v & 0x0F) unused -= 4;
+            if(v & 0x33) unused -= 2;
+            if(v & 0x55) unused -= 1;
+            tmp->size = b-st->buf + 1;
+            tmp->bits_unused = unused;
+        } else {
+            tmp->size = b-st->buf;
+            tmp->bits_unused = 0;
+        }
+
+        assert(b >= st->buf);
+    }
+
+    unconst.c_buf = st->buf;
+    tmp->buf = unconst.nc_buf;
+    return tmp;
+}
+
+/*
+ * Lexicographically compare the common prefix of both strings,
+ * and if it is the same return -1 for the smallest string.
+ */
+int
+BIT_STRING_compare(const asn_TYPE_descriptor_t *td, const void *aptr,
+                   const void *bptr) {
+    /*
+     * Remove information about trailing bits, since
+     * X.680 (08/2015) #22.7 "ensure that different semantics are not"
+     * "associated with [values that differ only in] the trailing 0 bits."
+     */
+    BIT_STRING_t compact_a, compact_b;
+    const BIT_STRING_t *a = BIT_STRING__compactify(aptr, &compact_a);
+    const BIT_STRING_t *b = BIT_STRING__compactify(bptr, &compact_b);
+    const asn_OCTET_STRING_specifics_t *specs = td->specifics;
+
+    assert(specs && specs->subvariant == ASN_OSUBV_BIT);
+
+    if(a && b) {
+        size_t common_prefix_size = a->size <= b->size ? a->size : b->size;
+        int ret = memcmp(a->buf, b->buf, common_prefix_size);
+        if(ret == 0) {
+            /* Figure out which string with equal prefixes is longer. */
+            if(a->size < b->size) {
+                return -1;
+            } else if(a->size > b->size) {
+                return 1;
+            } else {
+                /* Figure out how many unused bits */
+                if(a->bits_unused > b->bits_unused) {
+                    return -1;
+                } else if(a->bits_unused < b->bits_unused) {
+                    return 1;
+                } else {
+                    return 0;
+                }
+            }
+        } else {
+            return ret;
+        }
+    } else if(!a && !b) {
+        return 0;
+    } else if(!a) {
+        return -1;
+    } else {
+        return 1;
+    }
+}
+
+#ifndef  ASN_DISABLE_PER_SUPPORT
+
+#undef  RETURN
+#define RETURN(_code)                       \
+    do {                                    \
+        asn_dec_rval_t tmprval;             \
+        tmprval.code = _code;               \
+        tmprval.consumed = consumed_myself; \
+        return tmprval;                     \
+    } while(0)
+
+static asn_per_constraint_t asn_DEF_BIT_STRING_constraint_size = {
+    APC_SEMI_CONSTRAINED, -1, -1, 0, 0};
+
+asn_dec_rval_t
+BIT_STRING_decode_uper(const asn_codec_ctx_t *opt_codec_ctx,
+                       const asn_TYPE_descriptor_t *td,
+                       const asn_per_constraints_t *constraints, void **sptr,
+                       asn_per_data_t *pd) {
+    const asn_OCTET_STRING_specifics_t *specs = td->specifics
+               ? (const asn_OCTET_STRING_specifics_t *)td->specifics
+               : &asn_SPC_BIT_STRING_specs;
+    const asn_per_constraints_t *pc =
+        constraints ? constraints : td->encoding_constraints.per_constraints;
+       const asn_per_constraint_t *csiz;
+       asn_dec_rval_t rval = { RC_OK, 0 };
+       BIT_STRING_t *st = (BIT_STRING_t *)*sptr;
+       ssize_t consumed_myself = 0;
+       int repeat;
+
+       (void)opt_codec_ctx;
+
+       if(pc) {
+               csiz = &pc->size;
+       } else {
+               csiz = &asn_DEF_BIT_STRING_constraint_size;
+       }
+
+       if(specs->subvariant != ASN_OSUBV_BIT) {
+               ASN_DEBUG("Subvariant %d is not BIT OSUBV_BIT", specs->subvariant);
+               RETURN(RC_FAIL);
+    }
+
+       /*
+        * Allocate the string.
+        */
+       if(!st) {
+               st = (BIT_STRING_t *)(*sptr = CALLOC(1, specs->struct_size));
+               if(!st) RETURN(RC_FAIL);
+       }
+
+       ASN_DEBUG("PER Decoding %s size %ld .. %ld bits %d",
+               csiz->flags & APC_EXTENSIBLE ? "extensible" : "non-extensible",
+               csiz->lower_bound, csiz->upper_bound, csiz->effective_bits);
+
+       if(csiz->flags & APC_EXTENSIBLE) {
+               int inext = per_get_few_bits(pd, 1);
+               if(inext < 0) RETURN(RC_WMORE);
+               if(inext) {
+                       csiz = &asn_DEF_BIT_STRING_constraint_size;
+               }
+       }
+
+       if(csiz->effective_bits >= 0) {
+               FREEMEM(st->buf);
+        st->size = (csiz->upper_bound + 7) >> 3;
+        st->buf = (uint8_t *)MALLOC(st->size + 1);
+               if(!st->buf) { st->size = 0; RETURN(RC_FAIL); }
+       }
+
+       /* X.691, #16.5: zero-length encoding */
+       /* X.691, #16.6: short fixed length encoding (up to 2 octets) */
+       /* X.691, #16.7: long fixed length encoding (up to 64K octets) */
+       if(csiz->effective_bits == 0) {
+               int ret;
+        ASN_DEBUG("Encoding BIT STRING size %ld", csiz->upper_bound);
+        ret = per_get_many_bits(pd, st->buf, 0, csiz->upper_bound);
+               if(ret < 0) RETURN(RC_WMORE);
+               consumed_myself += csiz->upper_bound;
+               st->buf[st->size] = 0;
+        st->bits_unused = (8 - (csiz->upper_bound & 0x7)) & 0x7;
+        RETURN(RC_OK);
+       }
+
+       st->size = 0;
+       do {
+               ssize_t raw_len;
+               ssize_t len_bytes;
+               ssize_t len_bits;
+               void *p;
+               int ret;
+
+               /* Get the PER length */
+               raw_len = uper_get_length(pd, csiz->effective_bits, csiz->lower_bound,
+                                         &repeat);
+               if(raw_len < 0) RETURN(RC_WMORE);
+        if(raw_len == 0 && st->buf) break;
+
+               ASN_DEBUG("Got PER length eb %ld, len %ld, %s (%s)",
+                       (long)csiz->effective_bits, (long)raw_len,
+                       repeat ? "repeat" : "once", td->name);
+        len_bits = raw_len;
+        len_bytes = (len_bits + 7) >> 3;
+        if(len_bits & 0x7) st->bits_unused = 8 - (len_bits & 0x7);
+        /* len_bits be multiple of 16K if repeat is set */
+        p = REALLOC(st->buf, st->size + len_bytes + 1);
+               if(!p) RETURN(RC_FAIL);
+               st->buf = (uint8_t *)p;
+
+        ret = per_get_many_bits(pd, &st->buf[st->size], 0, len_bits);
+        if(ret < 0) RETURN(RC_WMORE);
+               st->size += len_bytes;
+       } while(repeat);
+       st->buf[st->size] = 0;  /* nul-terminate */
+
+       return rval;
+}
+
+asn_enc_rval_t
+BIT_STRING_encode_uper(const asn_TYPE_descriptor_t *td,
+                       const asn_per_constraints_t *constraints,
+                       const void *sptr, asn_per_outp_t *po) {
+    const asn_OCTET_STRING_specifics_t *specs =
+        td->specifics ? (const asn_OCTET_STRING_specifics_t *)td->specifics
+                      : &asn_SPC_BIT_STRING_specs;
+    const asn_per_constraints_t *pc =
+        constraints ? constraints : td->encoding_constraints.per_constraints;
+       const asn_per_constraint_t *csiz;
+       const BIT_STRING_t *st = (const BIT_STRING_t *)sptr;
+       BIT_STRING_t compact_bstr;  /* Do not modify this directly! */
+       asn_enc_rval_t er = { 0, 0, 0 };
+       int inext = 0;          /* Lies not within extension root */
+       size_t size_in_bits;
+       const uint8_t *buf;
+       int ret;
+       int ct_extensible;
+
+       if(!st || (!st->buf && st->size))
+               ASN__ENCODE_FAILED;
+
+       if(specs->subvariant == ASN_OSUBV_BIT) {
+        if((st->size == 0 && st->bits_unused) || (st->bits_unused & ~7))
+            ASN__ENCODE_FAILED;
+    } else {
+               ASN__ENCODE_FAILED;
+    }
+
+       if(pc) {
+        csiz = &pc->size;
+    } else {
+               csiz = &asn_DEF_BIT_STRING_constraint_size;
+       }
+       ct_extensible = csiz->flags & APC_EXTENSIBLE;
+
+    /* Figure out the size without the trailing bits */
+    st = BIT_STRING__compactify(st, &compact_bstr);
+    size_in_bits = 8 * st->size - st->bits_unused;
+
+    ASN_DEBUG(
+        "Encoding %s into %" ASN_PRI_SIZE " bits"
+        " (%ld..%ld, effective %d)%s",
+        td->name, size_in_bits, csiz->lower_bound, csiz->upper_bound,
+        csiz->effective_bits, ct_extensible ? " EXT" : "");
+
+    /* Figure out whether size lies within PER visible constraint */
+
+    if(csiz->effective_bits >= 0) {
+        if((ssize_t)size_in_bits > csiz->upper_bound) {
+            if(ct_extensible) {
+                csiz = &asn_DEF_BIT_STRING_constraint_size;
+                inext = 1;
+            } else {
+                ASN__ENCODE_FAILED;
+            }
+        }
+    } else {
+        inext = 0;
+    }
+
+    if(ct_extensible) {
+               /* Declare whether length is [not] within extension root */
+               if(per_put_few_bits(po, inext, 1))
+                       ASN__ENCODE_FAILED;
+       }
+
+    if(csiz->effective_bits >= 0 && !inext) {
+        int add_trailer = (ssize_t)size_in_bits < csiz->lower_bound;
+        ASN_DEBUG(
+            "Encoding %" ASN_PRI_SIZE " bytes (%ld), length (in %d bits) trailer %d; actual "
+            "value %" ASN_PRI_SSIZE "",
+            st->size, size_in_bits - csiz->lower_bound, csiz->effective_bits,
+            add_trailer,
+            add_trailer ? 0 : (ssize_t)size_in_bits - csiz->lower_bound);
+        ret = per_put_few_bits(
+            po, add_trailer ? 0 : (ssize_t)size_in_bits - csiz->lower_bound,
+            csiz->effective_bits);
+        if(ret) ASN__ENCODE_FAILED;
+        ret = per_put_many_bits(po, st->buf, size_in_bits);
+        if(ret) ASN__ENCODE_FAILED;
+        if(add_trailer) {
+            static const uint8_t zeros[16];
+            size_t trailing_zero_bits = csiz->lower_bound - size_in_bits;
+            while(trailing_zero_bits > 0) {
+                if(trailing_zero_bits > 8 * sizeof(zeros)) {
+                    ret = per_put_many_bits(po, zeros, 8 * sizeof(zeros));
+                    trailing_zero_bits -= 8 * sizeof(zeros);
+                } else {
+                    ret = per_put_many_bits(po, zeros, trailing_zero_bits);
+                    trailing_zero_bits = 0;
+                }
+                if(ret) ASN__ENCODE_FAILED;
+            }
+        }
+        ASN__ENCODED_OK(er);
+    }
+
+    ASN_DEBUG("Encoding %" ASN_PRI_SIZE " bytes", st->size);
+
+    buf = st->buf;
+    do {
+        int need_eom = 0;
+        ssize_t maySave = uper_put_length(po, size_in_bits, &need_eom);
+        if(maySave < 0) ASN__ENCODE_FAILED;
+
+        ASN_DEBUG("Encoding %" ASN_PRI_SSIZE " of %" ASN_PRI_SIZE "", maySave, size_in_bits);
+
+        ret = per_put_many_bits(po, buf, maySave);
+        if(ret) ASN__ENCODE_FAILED;
+
+        buf += maySave >> 3;
+        size_in_bits -= maySave;
+        assert(!(maySave & 0x07) || !size_in_bits);
+        if(need_eom && uper_put_length(po, 0, 0))
+            ASN__ENCODE_FAILED; /* End of Message length */
+    } while(size_in_bits);
+
+    ASN__ENCODED_OK(er);
+}
+
+#endif  /* ASN_DISABLE_PER_SUPPORT */
+
+asn_random_fill_result_t
+BIT_STRING_random_fill(const asn_TYPE_descriptor_t *td, void **sptr,
+                       const asn_encoding_constraints_t *constraints,
+                       size_t max_length) {
+    const asn_OCTET_STRING_specifics_t *specs =
+        td->specifics ? (const asn_OCTET_STRING_specifics_t *)td->specifics
+                      : &asn_SPC_BIT_STRING_specs;
+    asn_random_fill_result_t result_ok = {ARFILL_OK, 1};
+    asn_random_fill_result_t result_failed = {ARFILL_FAILED, 0};
+    asn_random_fill_result_t result_skipped = {ARFILL_SKIPPED, 0};
+    static unsigned lengths[] = {0,     1,     2,     3,     4,     8,
+                                 126,   127,   128,   16383, 16384, 16385,
+                                 65534, 65535, 65536, 65537};
+    uint8_t *buf;
+    uint8_t *bend;
+    uint8_t *b;
+    size_t rnd_bits, rnd_len;
+    BIT_STRING_t *st;
+
+    if(max_length == 0) return result_skipped;
+
+    switch(specs->subvariant) {
+    case ASN_OSUBV_ANY:
+        return result_failed;
+    case ASN_OSUBV_BIT:
+        break;
+    default:
+        break;
+    }
+
+    /* Figure out how far we should go */
+    rnd_bits = lengths[asn_random_between(
+        0, sizeof(lengths) / sizeof(lengths[0]) - 1)];
+    if(!constraints || !constraints->per_constraints)
+        constraints = &td->encoding_constraints;
+    if(constraints->per_constraints) {
+        const asn_per_constraint_t *pc = &constraints->per_constraints->size;
+        if(pc->flags & APC_CONSTRAINED) {
+            long suggested_upper_bound = pc->upper_bound < (ssize_t)max_length
+                                             ? pc->upper_bound
+                                             : (ssize_t)max_length;
+            if(max_length < (size_t)pc->lower_bound) {
+                return result_skipped;
+            }
+            if(pc->flags & APC_EXTENSIBLE) {
+                switch(asn_random_between(0, 5)) {
+                case 0:
+                    if(pc->lower_bound > 0) {
+                        rnd_bits = pc->lower_bound - 1;
+                        break;
+                    }
+                    /* Fall through */
+                case 1:
+                    rnd_bits = pc->upper_bound + 1;
+                    break;
+                case 2:
+                    /* Keep rnd_bits from the table */
+                    if(rnd_bits < max_length) {
+                        break;
+                    }
+                    /* Fall through */
+                default:
+                    rnd_bits = asn_random_between(pc->lower_bound,
+                                                  suggested_upper_bound);
+                }
+            } else {
+                rnd_bits =
+                    asn_random_between(pc->lower_bound, suggested_upper_bound);
+            }
+        } else {
+            rnd_bits = asn_random_between(0, max_length - 1);
+        }
+    } else if(rnd_bits >= max_length) {
+        rnd_bits = asn_random_between(0, max_length - 1);
+    }
+
+    rnd_len = (rnd_bits + 7) / 8;
+    buf = CALLOC(1, rnd_len + 1);
+    if(!buf) return result_failed;
+
+    bend = &buf[rnd_len];
+
+    for(b = buf; b < bend; b++) {
+        *(uint8_t *)b = asn_random_between(0, 255);
+    }
+    *b = 0; /* Zero-terminate just in case. */
+
+    if(*sptr) {
+        st = *sptr;
+        FREEMEM(st->buf);
+    } else {
+        st = (BIT_STRING_t *)(*sptr = CALLOC(1, specs->struct_size));
+        if(!st) {
+            FREEMEM(buf);
+            return result_failed;
+        }
+    }
+
+    st->buf = buf;
+    st->size = rnd_len;
+    st->bits_unused = (8 - (rnd_bits & 0x7)) & 0x7;
+    if(st->bits_unused) {
+        assert(st->size > 0);
+        st->buf[st->size-1] &= 0xff << st->bits_unused;
+    }
+
+    result_ok.length = st->size;
+    return result_ok;
+}