/* -----------------------------------------------------------------------------
* input.c
*
* Copyright (c) 2004, 2005, 2006, Vivek Mohan <vivek@sig9.com>
* All rights reserved. See LICENSE
* -----------------------------------------------------------------------------
*/
#include "extern.h"
#include "types.h"
#include "input.h"
/* -----------------------------------------------------------------------------
* 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.
* =============================================================================
*/
extern 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.
* =============================================================================
*/
extern void
ud_set_input_buffer(register struct ud* u, 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.
* =============================================================================
*/
extern 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.
* =============================================================================
*/
extern void
ud_input_skip(struct ud* u, size_t n)
{
while (n--) {
u->inp_hook(u);
}
}
/* =============================================================================
* ud_input_end() - Test for end of input.
* =============================================================================
*/
extern int
ud_input_end(struct ud* u)
{
return (u->inp_curr == u->inp_fill) && u->inp_end;
}
/* -----------------------------------------------------------------------------
* 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 optimized.
*
* A buffer inp_sess stores the bytes disassembled for a single session.
* -----------------------------------------------------------------------------
*/
extern uint8_t 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.
*/
u->error = 1;
/* 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;
}
/* -----------------------------------------------------------------------------
* inp_back() - Move back a single byte in the stream.
* -----------------------------------------------------------------------------
*/
extern void
inp_back(struct ud* u)
{
if ( u->inp_ctr > 0 ) {
--u->inp_curr;
--u->inp_ctr;
}
}
/* -----------------------------------------------------------------------------
* inp_peek() - Peek into the next byte in source.
* -----------------------------------------------------------------------------
*/
extern uint8_t
inp_peek(struct ud* u)
{
uint8_t r = inp_next(u);
if ( !u->error ) inp_back(u); /* Don't backup if there was an error */
return r;
}
/* -----------------------------------------------------------------------------
* inp_move() - Move ahead n input bytes.
* -----------------------------------------------------------------------------
*/
extern void
inp_move(struct ud* u, size_t n)
{
while (n--)
inp_next(u);
}
/*------------------------------------------------------------------------------
* inp_uintN() - return uintN from source.
*------------------------------------------------------------------------------
*/
extern uint8_t
inp_uint8(struct ud* u)
{
return inp_next(u);
}
extern uint16_t
inp_uint16(struct ud* u)
{
uint16_t r, ret;
ret = inp_next(u);
r = inp_next(u);
return ret | (r << 8);
}
extern uint32_t
inp_uint32(struct ud* u)
{
uint32_t r, ret;
ret = inp_next(u);
r = inp_next(u);
ret = ret | (r << 8);
r = inp_next(u);
ret = ret | (r << 16);
r = inp_next(u);
return ret | (r << 24);
}
extern uint64_t
inp_uint64(struct ud* u)
{
uint64_t r, ret;
ret = inp_next(u);
r = inp_next(u);
ret = ret | (r << 8);
r = inp_next(u);
ret = ret | (r << 16);
r = inp_next(u);
ret = ret | (r << 24);
r = inp_next(u);
ret = ret | (r << 32);
r = inp_next(u);
ret = ret | (r << 40);
r = inp_next(u);
ret = ret | (r << 48);
r = inp_next(u);
return ret | (r << 56);
}