disassembler/udis86/udis86_input.c

   1 /* udis86 - libudis86/input.c
   2  *
   3  * Copyright (c) 2002-2009 Vivek Thampi
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without modification,
   7  * are permitted provided that the following conditions are met:
   8  *
   9  *     * Redistributions of source code must retain the above copyright notice,
  10  *       this list of conditions and the following disclaimer.
  11  *     * Redistributions in binary form must reproduce the above copyright notice,
  12  *       this list of conditions and the following disclaimer in the documentation
  13  *       and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  18  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
  19  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  20  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  21  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  22  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  24  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26 #include "config.h"
  27
  28 #if USE(UDIS86)
  29
  30 #include "udis86_extern.h"
  31 #include "udis86_types.h"
  32 #include "udis86_input.h"
  33
  34 /* -----------------------------------------------------------------------------
  35  * inp_buff_hook() - Hook for buffered inputs.
  36  * -----------------------------------------------------------------------------
  37  */
  38 static int
  39 inp_buff_hook(struct ud* u)
  40 {
  41   if (u->inp_buff < u->inp_buff_end)
  42         return *u->inp_buff++;
  43   else  return -1;
  44 }
  45
  46 #ifndef __UD_STANDALONE__
  47 /* -----------------------------------------------------------------------------
  48  * inp_file_hook() - Hook for FILE inputs.
  49  * -----------------------------------------------------------------------------
  50  */
  51 static int
  52 inp_file_hook(struct ud* u)
  53 {
  54   return fgetc(u->inp_file);
  55 }
  56 #endif /* __UD_STANDALONE__*/
  57
  58 /* =============================================================================
  59  * ud_inp_set_hook() - Sets input hook.
  60  * =============================================================================
  61  */
  62 extern void
  63 ud_set_input_hook(register struct ud* u, int (*hook)(struct ud*))
  64 {
  65   u->inp_hook = hook;
  66   ud_inp_init(u);
  67 }
  68
  69 extern void
  70 ud_set_user_opaque_data( struct ud * u, void * opaque )
  71 {
  72   u->user_opaque_data = opaque;
  73 }
  74
  75 extern void *
  76 ud_get_user_opaque_data( struct ud * u )
  77 {
  78   return u->user_opaque_data;
  79 }
  80
  81 /* =============================================================================
  82  * ud_inp_set_buffer() - Set buffer as input.
  83  * =============================================================================
  84  */
  85 extern void
  86 ud_set_input_buffer(register struct ud* u, uint8_t* buf, size_t len)
  87 {
  88   u->inp_hook = inp_buff_hook;
  89   u->inp_buff = buf;
  90   u->inp_buff_end = buf + len;
  91   ud_inp_init(u);
  92 }
  93
  94 #ifndef __UD_STANDALONE__
  95 /* =============================================================================
  96  * ud_input_set_file() - Set buffer as input.
  97  * =============================================================================
  98  */
  99 extern void
 100 ud_set_input_file(register struct ud* u, FILE* f)
 101 {
 102   u->inp_hook = inp_file_hook;
 103   u->inp_file = f;
 104   ud_inp_init(u);
 105 }
 106 #endif /* __UD_STANDALONE__ */
 107
 108 /* =============================================================================
 109  * ud_input_skip() - Skip n input bytes.
 110  * =============================================================================
 111  */
 112 extern void
 113 ud_input_skip(struct ud* u, size_t n)
 114 {
 115   while (n--) {
 116         u->inp_hook(u);
 117   }
 118 }
 119
 120 /* =============================================================================
 121  * ud_input_end() - Test for end of input.
 122  * =============================================================================
 123  */
 124 extern int
 125 ud_input_end(struct ud* u)
 126 {
 127   return (u->inp_curr == u->inp_fill) && u->inp_end;
 128 }
 129
 130 /* -----------------------------------------------------------------------------
 131  * ud_inp_next() - Loads and returns the next byte from input.
 132  *
 133  * inp_curr and inp_fill are pointers to the cache. The program is written based
 134  * on the property that they are 8-bits in size, and will eventually wrap around
 135  * forming a circular buffer. So, the size of the cache is 256 in size, kind of
 136  * unnecessary yet optimized.
 137  *
 138  * A buffer inp_sess stores the bytes disassembled for a single session.
 139  * -----------------------------------------------------------------------------
 140  */
 141 extern uint8_t ud_inp_next(struct ud* u)
 142 {
 143   int c = -1;
 144   /* if current pointer is not upto the fill point in the
 145    * input cache.
 146    */
 147   if ( u->inp_curr != u->inp_fill ) {
 148         c = u->inp_cache[ ++u->inp_curr ];
 149   /* if !end-of-input, call the input hook and get a byte */
 150   } else if ( u->inp_end || ( c = u->inp_hook( u ) ) == -1 ) {
 151         /* end-of-input, mark it as an error, since the decoder,
 152          * expected a byte more.
 153          */
 154         u->error = 1;
 155         /* flag end of input */
 156         u->inp_end = 1;
 157         return 0;
 158   } else {
 159         /* increment pointers, we have a new byte.  */
 160         u->inp_curr = ++u->inp_fill;
 161         /* add the byte to the cache */
 162         u->inp_cache[ u->inp_fill ] = c;
 163   }
 164   /* record bytes input per decode-session. */
 165   u->inp_sess[ u->inp_ctr++ ] = c;
 166   /* return byte */
 167   return ( uint8_t ) c;
 168 }
 169
 170 /* -----------------------------------------------------------------------------
 171  * ud_inp_back() - Move back a single byte in the stream.
 172  * -----------------------------------------------------------------------------
 173  */
 174 extern void
 175 ud_inp_back(struct ud* u)
 176 {
 177   if ( u->inp_ctr > 0 ) {
 178         --u->inp_curr;
 179         --u->inp_ctr;
 180   }
 181 }
 182
 183 /* -----------------------------------------------------------------------------
 184  * ud_inp_peek() - Peek into the next byte in source.
 185  * -----------------------------------------------------------------------------
 186  */
 187 extern uint8_t
 188 ud_inp_peek(struct ud* u)
 189 {
 190   uint8_t r = ud_inp_next(u);
 191   if ( !u->error ) ud_inp_back(u); /* Don't backup if there was an error */
 192   return r;
 193 }
 194
 195 /* -----------------------------------------------------------------------------
 196  * ud_inp_move() - Move ahead n input bytes.
 197  * -----------------------------------------------------------------------------
 198  */
 199 extern void
 200 ud_inp_move(struct ud* u, size_t n)
 201 {
 202   while (n--)
 203         ud_inp_next(u);
 204 }
 205
 206 /*------------------------------------------------------------------------------
 207  *  ud_inp_uintN() - return uintN from source.
 208  *------------------------------------------------------------------------------
 209  */
 210 extern uint8_t
 211 ud_inp_uint8(struct ud* u)
 212 {
 213   return ud_inp_next(u);
 214 }
 215
 216 extern uint16_t
 217 ud_inp_uint16(struct ud* u)
 218 {
 219   uint16_t r, ret;
 220
 221   ret = ud_inp_next(u);
 222   r = ud_inp_next(u);
 223   return ret | (r << 8);
 224 }
 225
 226 extern uint32_t
 227 ud_inp_uint32(struct ud* u)
 228 {
 229   uint32_t r, ret;
 230
 231   ret = ud_inp_next(u);
 232   r = ud_inp_next(u);
 233   ret = ret | (r << 8);
 234   r = ud_inp_next(u);
 235   ret = ret | (r << 16);
 236   r = ud_inp_next(u);
 237   return ret | (r << 24);
 238 }
 239
 240 extern uint64_t
 241 ud_inp_uint64(struct ud* u)
 242 {
 243   uint64_t r, ret;
 244
 245   ret = ud_inp_next(u);
 246   r = ud_inp_next(u);
 247   ret = ret | (r << 8);
 248   r = ud_inp_next(u);
 249   ret = ret | (r << 16);
 250   r = ud_inp_next(u);
 251   ret = ret | (r << 24);
 252   r = ud_inp_next(u);
 253   ret = ret | (r << 32);
 254   r = ud_inp_next(u);
 255   ret = ret | (r << 40);
 256   r = ud_inp_next(u);
 257   ret = ret | (r << 48);
 258   r = ud_inp_next(u);
 259   return ret | (r << 56);
 260 }
 261
 262 #endif // USE(UDIS86)