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author | Lasse Collin <lasse.collin@tukaani.org> | 2007-12-09 00:42:33 +0200 |
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committer | Lasse Collin <lasse.collin@tukaani.org> | 2007-12-09 00:42:33 +0200 |
commit | 5d018dc03549c1ee4958364712fb0c94e1bf2741 (patch) | |
tree | 1b211911fb33fddb3f04b77f99e81df23623ffc4 /src/liblzma/common/vli_decoder.c | |
download | xz-5d018dc03549c1ee4958364712fb0c94e1bf2741.tar.xz |
Imported to git.
Diffstat (limited to '')
-rw-r--r-- | src/liblzma/common/vli_decoder.c | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/src/liblzma/common/vli_decoder.c b/src/liblzma/common/vli_decoder.c new file mode 100644 index 00000000..2b89c1a7 --- /dev/null +++ b/src/liblzma/common/vli_decoder.c @@ -0,0 +1,69 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \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; +} |