| /* udis86 - libudis86/input.c |
| * |
| * Copyright (c) 2002-2009 Vivek Thampi |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without modification, |
| * are permitted provided that the following conditions are met: |
| * |
| * * Redistributions of source code must retain the above copyright notice, |
| * this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above copyright notice, |
| * this list of conditions and the following disclaimer in the documentation |
| * and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR |
| * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON |
| * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| #include "extern.h" |
| #include "types.h" |
| #include "input.h" |
| #include "udint.h" |
| |
| /* |
| * inp_init |
| * Initializes the input system. |
| */ |
| static void |
| inp_init(struct ud *u) |
| { |
| u->inp_curr = 0; |
| u->inp_fill = 0; |
| u->inp_ctr = 0; |
| u->inp_end = 0; |
| } |
| |
| |
| /* ----------------------------------------------------------------------------- |
| * inp_buff_hook() - Hook for buffered inputs. |
| * ----------------------------------------------------------------------------- |
| */ |
| static int |
| inp_buff_hook(struct ud* u) |
| { |
| if (u->inp_buff < u->inp_buff_end) |
| return *u->inp_buff++; |
| else return -1; |
| } |
| |
| #ifndef __UD_STANDALONE__ |
| /* ----------------------------------------------------------------------------- |
| * inp_file_hook() - Hook for FILE inputs. |
| * ----------------------------------------------------------------------------- |
| */ |
| static int |
| inp_file_hook(struct ud* u) |
| { |
| return fgetc(u->inp_file); |
| } |
| #endif /* __UD_STANDALONE__*/ |
| |
| /* ============================================================================= |
| * ud_inp_set_hook() - Sets input hook. |
| * ============================================================================= |
| */ |
| void |
| ud_set_input_hook(register struct ud* u, int (*hook)(struct ud*)) |
| { |
| u->inp_hook = hook; |
| inp_init(u); |
| } |
| |
| /* ============================================================================= |
| * ud_inp_set_buffer() - Set buffer as input. |
| * ============================================================================= |
| */ |
| void |
| ud_set_input_buffer(register struct ud* u, const uint8_t* buf, size_t len) |
| { |
| u->inp_hook = inp_buff_hook; |
| u->inp_buff = buf; |
| u->inp_buff_end = buf + len; |
| inp_init(u); |
| } |
| |
| #ifndef __UD_STANDALONE__ |
| /* ============================================================================= |
| * ud_input_set_file() - Set buffer as input. |
| * ============================================================================= |
| */ |
| void |
| ud_set_input_file(register struct ud* u, FILE* f) |
| { |
| u->inp_hook = inp_file_hook; |
| u->inp_file = f; |
| inp_init(u); |
| } |
| #endif /* __UD_STANDALONE__ */ |
| |
| /* ============================================================================= |
| * ud_input_skip() - Skip n input bytes. |
| * ============================================================================= |
| */ |
| void |
| ud_input_skip(struct ud* u, size_t n) |
| { |
| while (n--) { |
| u->inp_hook(u); |
| } |
| } |
| |
| /* ============================================================================= |
| * ud_input_end() - Test for end of input. |
| * ============================================================================= |
| */ |
| int |
| ud_input_end(const struct ud* u) |
| { |
| return (u->inp_curr == u->inp_fill) && u->inp_end; |
| } |
| |
| |
| /* |
| * ud_inp_next |
| * Loads and returns the next byte from input. |
| * |
| * inp_curr and inp_fill are pointers to the cache. The program is |
| * written based on the property that they are 8-bits in size, and |
| * will eventually wrap around forming a circular buffer. So, the |
| * size of the cache is 256 in size, kind of unnecessary yet |
| * optimal. |
| * |
| * A buffer inp_sess stores the bytes disassembled for a single |
| * session. |
| */ |
| uint8_t |
| ud_inp_next(struct ud* u) |
| { |
| int c = -1; |
| /* if current pointer is not upto the fill point in the |
| * input cache. |
| */ |
| if (u->inp_curr != u->inp_fill) { |
| c = u->inp_cache[ ++u->inp_curr ]; |
| /* if !end-of-input, call the input hook and get a byte */ |
| } else if (u->inp_end || (c = u->inp_hook(u)) == -1) { |
| /* end-of-input, mark it as an error, since the decoder, |
| * expected a byte more. |
| */ |
| UDERR(u, "byte expected, eoi received"); |
| /* flag end of input */ |
| u->inp_end = 1; |
| return 0; |
| } else { |
| /* increment pointers, we have a new byte. */ |
| u->inp_curr = ++u->inp_fill; |
| /* add the byte to the cache */ |
| u->inp_cache[u->inp_fill] = c; |
| } |
| /* record bytes input per decode-session. */ |
| u->inp_sess[u->inp_ctr++] = c; |
| /* return byte */ |
| return (uint8_t) c; |
| } |
| |
| /* |
| vim: set ts=2 sw=2 expandtab |
| */ |