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#include <libpayload.h>
// This GETBIT is supposed to work on little endian
// 32bit systems. The algorithm will definitely need
// some fixing on other systems, but it might not be
// a problem since the nrv2b binary behaves the same..
#ifndef ENDIAN
#define ENDIAN 0
#endif
#ifndef BITSIZE
#define BITSIZE 32
#endif
#define GETBIT_8(bb, src, ilen) \
(((bb = bb & 0x7f ? bb*2 : ((unsigned)src[ilen++]*2+1)) >> 8) & 1)
#define GETBIT_LE16(bb, src, ilen) \
(bb*=2,bb&0xffff ? (bb>>16)&1 : (ilen+=2,((bb=(src[ilen-2]+src[ilen-1]*256u)*2+1)>>16)&1))
#define GETBIT_LE32(bb, src, ilen) \
(bc > 0 ? ((bb>>--bc)&1) : (bc=31,\
bb=*(const u32 *)((src)+ilen),ilen+=4,(bb>>31)&1))
#if ENDIAN == 0 && BITSIZE == 8
#define GETBIT(bb, src, ilen) GETBIT_8(bb, src, ilen)
#endif
#if ENDIAN == 0 && BITSIZE == 16
#define GETBIT(bb, src, ilen) GETBIT_LE16(bb, src, ilen)
#endif
#if ENDIAN == 0 && BITSIZE == 32
#define GETBIT(bb, src, ilen) GETBIT_LE32(bb, src, ilen)
#endif
unsigned long unrv2b(u8 *src, u8 *dst, unsigned long *ilen_p)
{
unsigned long ilen = 0, olen = 0, last_m_off = 1;
u32 bb = 0;
unsigned bc = 0;
const u8 *m_pos;
// skip length
src += 4;
/* FIXME: check olen with the length stored in first 4 bytes */
for (;;) {
unsigned int m_off, m_len;
while (GETBIT(bb, src, ilen)) {
dst[olen++] = src[ilen++];
}
m_off = 1;
do {
m_off = m_off * 2 + GETBIT(bb, src, ilen);
} while (!GETBIT(bb, src, ilen));
if (m_off == 2) {
m_off = last_m_off;
} else {
m_off = (m_off - 3) * 256 + src[ilen++];
if (m_off == 0xffffffffU)
break;
last_m_off = ++m_off;
}
m_len = GETBIT(bb, src, ilen);
m_len = m_len * 2 + GETBIT(bb, src, ilen);
if (m_len == 0) {
m_len++;
do {
m_len = m_len * 2 + GETBIT(bb, src, ilen);
} while (!GETBIT(bb, src, ilen));
m_len += 2;
}
m_len += (m_off > 0xd00);
m_pos = dst + olen - m_off;
dst[olen++] = *m_pos++;
do {
dst[olen++] = *m_pos++;
} while (--m_len > 0);
}
*ilen_p = ilen;
return olen;
}
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