libs/smux/per_encoder.c

   1 #include <asn_application.h>
   2 #include <asn_internal.h>
   3 #include <per_encoder.h>
   4
   5 static asn_enc_rval_t uper_encode_internal(asn_TYPE_descriptor_t *td, asn_per_constraints_t *, void *sptr, asn_app_consume_bytes_f *cb, void *app_key);
   6
   7 asn_enc_rval_t
   8 uper_encode(asn_TYPE_descriptor_t *td, void *sptr, asn_app_consume_bytes_f *cb, void *app_key) {
   9         return uper_encode_internal(td, 0, sptr, cb, app_key);
  10 }
  11
  12 /*
  13  * Argument type and callback necessary for uper_encode_to_buffer().
  14  */
  15 typedef struct enc_to_buf_arg {
  16         void *buffer;
  17         size_t left;
  18 } enc_to_buf_arg;
  19 static int encode_to_buffer_cb(const void *buffer, size_t size, void *key) {
  20         enc_to_buf_arg *arg = (enc_to_buf_arg *)key;
  21
  22         if(arg->left < size)
  23                 return -1;      /* Data exceeds the available buffer size */
  24
  25         memcpy(arg->buffer, buffer, size);
  26         arg->buffer = ((char *)arg->buffer) + size;
  27         arg->left -= size;
  28
  29         return 0;
  30 }
  31
  32 asn_enc_rval_t
  33 uper_encode_to_buffer(asn_TYPE_descriptor_t *td, void *sptr, void *buffer, size_t buffer_size) {
  34         enc_to_buf_arg key;
  35
  36         key.buffer = buffer;
  37         key.left = buffer_size;
  38
  39         if(td) ASN_DEBUG("Encoding \"%s\" using UNALIGNED PER", td->name);
  40
  41         return uper_encode_internal(td, 0, sptr, encode_to_buffer_cb, &key);
  42 }
  43
  44 typedef struct enc_dyn_arg {
  45         void *buffer;
  46         size_t length;
  47         size_t allocated;
  48 } enc_dyn_arg;
  49 static int
  50 encode_dyn_cb(const void *buffer, size_t size, void *key) {
  51         enc_dyn_arg *arg = key;
  52         if(arg->length + size >= arg->allocated) {
  53                 void *p;
  54                 arg->allocated = arg->allocated ? (arg->allocated << 2) : size;
  55                 p = REALLOC(arg->buffer, arg->allocated);
  56                 if(!p) {
  57                         FREEMEM(arg->buffer);
  58                         memset(arg, 0, sizeof(*arg));
  59                         return -1;
  60                 }
  61                 arg->buffer = p;
  62         }
  63         memcpy(((char *)arg->buffer) + arg->length, buffer, size);
  64         arg->length += size;
  65         return 0;
  66 }
  67 ssize_t
  68 uper_encode_to_new_buffer(asn_TYPE_descriptor_t *td, asn_per_constraints_t *constraints, void *sptr, void **buffer_r) {
  69         asn_enc_rval_t er;
  70         enc_dyn_arg key;
  71
  72         memset(&key, 0, sizeof(key));
  73
  74         er = uper_encode_internal(td, constraints, sptr, encode_dyn_cb, &key);
  75         switch(er.encoded) {
  76         case -1:
  77                 FREEMEM(key.buffer);
  78                 return -1;
  79         case 0:
  80                 FREEMEM(key.buffer);
  81                 key.buffer = MALLOC(1);
  82                 if(key.buffer) {
  83                         *(char *)key.buffer = '\0';
  84                         *buffer_r = key.buffer;
  85                         return 1;
  86                 } else {
  87                         return -1;
  88                 }
  89         default:
  90                 *buffer_r = key.buffer;
  91                 ASN_DEBUG("Complete encoded in %ld bits", (long)er.encoded);
  92                 return ((er.encoded + 7) >> 3);
  93         }
  94 }
  95
  96 /*
  97  * Internally useful functions.
  98  */
  99
 100 /* Flush partially filled buffer */
 101 static int
 102 _uper_encode_flush_outp(asn_per_outp_t *po) {
 103         uint8_t *buf;
 104
 105         if(po->nboff == 0 && po->buffer == po->tmpspace)
 106                 return 0;
 107
 108         buf = po->buffer + (po->nboff >> 3);
 109         /* Make sure we account for the last, partially filled */
 110         if(po->nboff & 0x07) {
 111                 buf[0] &= 0xff << (8 - (po->nboff & 0x07));
 112                 buf++;
 113         }
 114
 115         return po->outper(po->tmpspace, buf - po->tmpspace, po->op_key);
 116 }
 117
 118 static asn_enc_rval_t
 119 uper_encode_internal(asn_TYPE_descriptor_t *td, asn_per_constraints_t *constraints, void *sptr, asn_app_consume_bytes_f *cb, void *app_key) {
 120         asn_per_outp_t po;
 121         asn_enc_rval_t er;
 122
 123         /*
 124          * Invoke type-specific encoder.
 125          */
 126         if(!td || !td->uper_encoder)
 127                 ASN__ENCODE_FAILED;     /* PER is not compiled in */
 128
 129         po.buffer = po.tmpspace;
 130         po.nboff = 0;
 131         po.nbits = 8 * sizeof(po.tmpspace);
 132         po.outper = cb;
 133         po.op_key = app_key;
 134         po.flushed_bytes = 0;
 135
 136         er = td->uper_encoder(td, constraints, sptr, &po);
 137         if(er.encoded != -1) {
 138                 size_t bits_to_flush;
 139
 140                 bits_to_flush = ((po.buffer - po.tmpspace) << 3) + po.nboff;
 141
 142                 /* Set number of bits encoded to a firm value */
 143                 er.encoded = (po.flushed_bytes << 3) + bits_to_flush;
 144
 145                 if(_uper_encode_flush_outp(&po))
 146                         ASN__ENCODE_FAILED;
 147         }
 148
 149         return er;
 150 }
 151