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 */
38static int
39inp_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 */
51static int
52inp_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 */
62extern void
63ud_set_input_hook(register struct ud* u, int (*hook)(struct ud*))
64{
65  u->inp_hook = hook;
66  ud_inp_init(u);
67}
68
69extern void
70ud_set_user_opaque_data( struct ud * u, void * opaque )
71{
72  u->user_opaque_data = opaque;
73}
74
75extern void *
76ud_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 */
85extern void
86ud_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 */
99extern void
100ud_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 */
112extern void
113ud_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 */
124extern int
125ud_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 */
141extern 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 */
174extern void
175ud_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 */
187extern uint8_t
188ud_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 */
199extern void
200ud_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 */
210extern uint8_t
211ud_inp_uint8(struct ud* u)
212{
213  return ud_inp_next(u);
214}
215
216extern uint16_t
217ud_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
226extern uint32_t
227ud_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
240extern uint64_t
241ud_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)
263