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///////////////////////////////////////////////////////////////////////////////
//
/// \file vli_encoder.c
/// \brief Encodes 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_encode(lzma_vli vli, size_t *restrict vli_pos, size_t vli_size,
uint8_t *restrict out, size_t *restrict out_pos,
size_t out_size)
{
if (vli > LZMA_VLI_VALUE_MAX || *vli_pos >= 9 || vli_size > 9
|| (vli != 0 && (vli >> (7 * *vli_pos)) == 0))
return LZMA_PROG_ERROR;
if (*out_pos >= out_size)
return LZMA_BUF_ERROR;
if (*vli_pos == 0) {
*vli_pos = 1;
if (vli <= 0x7F && *vli_pos >= vli_size) {
// Single-byte integer
out[(*out_pos)++] = vli;
return LZMA_STREAM_END;
}
// First byte of a multibyte integer
out[(*out_pos)++] = (vli & 0x7F) | 0x80;
}
while (*out_pos < out_size) {
const lzma_vli b = vli >> (7 * *vli_pos);
++*vli_pos;
if (b <= 0x7F && *vli_pos >= vli_size) {
// Last byte of a multibyte integer
out[(*out_pos)++] = (b & 0xFF) | 0x80;
return LZMA_STREAM_END;
}
// Middle byte of a multibyte integer
out[(*out_pos)++] = b & 0x7F;
}
// vli is not yet completely written out.
return LZMA_OK;
}
extern LZMA_API size_t
lzma_vli_size(lzma_vli vli)
{
if (vli > LZMA_VLI_VALUE_MAX)
return 0;
size_t i = 0;
do {
vli >>= 7;
++i;
} while (vli != 0);
assert(i <= 9);
return i;
}
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