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///////////////////////////////////////////////////////////////////////////////
//
/// \file vli_decoder.c
/// \brief Decodes variable-length integers
//
// Copyright (C) 2007 Lasse Collin
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
///////////////////////////////////////////////////////////////////////////////
#include "common.h"
extern LZMA_API lzma_ret
lzma_vli_decode(lzma_vli *restrict vli, size_t *restrict vli_pos,
const uint8_t *restrict in, size_t *restrict in_pos,
size_t in_size)
{
if (*vli > LZMA_VLI_VALUE_MAX || *vli_pos >= 9
|| (*vli >> (7 * *vli_pos)) != 0)
return LZMA_PROG_ERROR;
if (*in_pos >= in_size)
return LZMA_BUF_ERROR;
if (*vli_pos == 0) {
*vli_pos = 1;
if (in[*in_pos] <= 0x7F) {
// Single-byte integer
*vli = in[*in_pos];
++*in_pos;
return LZMA_STREAM_END;
}
*vli = in[*in_pos] & 0x7F;
++*in_pos;
}
while (*in_pos < in_size) {
// Read in the next byte.
*vli |= (lzma_vli)(in[*in_pos] & 0x7F) << (*vli_pos * 7);
++*vli_pos;
// Check if this is the last byte of a multibyte integer.
if (in[*in_pos] & 0x80) {
++*in_pos;
return LZMA_STREAM_END;
}
// Limit variable-length representation to nine bytes.
if (*vli_pos == 9)
return LZMA_DATA_ERROR;
// Increment input position only when the byte was accepted.
++*in_pos;
}
return LZMA_OK;
}
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