| Index: xz/src/liblzma/common/vli_decoder.c
|
| ===================================================================
|
| --- xz/src/liblzma/common/vli_decoder.c (revision 0)
|
| +++ xz/src/liblzma/common/vli_decoder.c (revision 0)
|
| @@ -0,0 +1,86 @@
|
| +///////////////////////////////////////////////////////////////////////////////
|
| +//
|
| +/// \file vli_decoder.c
|
| +/// \brief Decodes variable-length integers
|
| +//
|
| +// Author: Lasse Collin
|
| +//
|
| +// This file has been put into the public domain.
|
| +// You can do whatever you want with this file.
|
| +//
|
| +///////////////////////////////////////////////////////////////////////////////
|
| +
|
| +#include "common.h"
|
| +
|
| +
|
| +extern LZMA_API(lzma_ret)
|
| +lzma_vli_decode(lzma_vli *restrict vli, size_t *vli_pos,
|
| + const uint8_t *restrict in, size_t *restrict in_pos,
|
| + size_t in_size)
|
| +{
|
| + // If we haven't been given vli_pos, work in single-call mode.
|
| + size_t vli_pos_internal = 0;
|
| + if (vli_pos == NULL) {
|
| + vli_pos = &vli_pos_internal;
|
| + *vli = 0;
|
| +
|
| + // If there's no input, use LZMA_DATA_ERROR. This way it is
|
| + // easy to decode VLIs from buffers that have known size,
|
| + // and get the correct error code in case the buffer is
|
| + // too short.
|
| + if (*in_pos >= in_size)
|
| + return LZMA_DATA_ERROR;
|
| +
|
| + } else {
|
| + // Initialize *vli when starting to decode a new integer.
|
| + if (*vli_pos == 0)
|
| + *vli = 0;
|
| +
|
| + // Validate the arguments.
|
| + if (*vli_pos >= LZMA_VLI_BYTES_MAX
|
| + || (*vli >> (*vli_pos * 7)) != 0)
|
| + return LZMA_PROG_ERROR;;
|
| +
|
| + if (*in_pos >= in_size)
|
| + return LZMA_BUF_ERROR;
|
| + }
|
| +
|
| + do {
|
| + // Read the next byte. Use a temporary variable so that we
|
| + // can update *in_pos immediately.
|
| + const uint8_t byte = in[*in_pos];
|
| + ++*in_pos;
|
| +
|
| + // Add the newly read byte to *vli.
|
| + *vli += (lzma_vli)(byte & 0x7F) << (*vli_pos * 7);
|
| + ++*vli_pos;
|
| +
|
| + // Check if this is the last byte of a multibyte integer.
|
| + if ((byte & 0x80) == 0) {
|
| + // We don't allow using variable-length integers as
|
| + // padding i.e. the encoding must use the most the
|
| + // compact form.
|
| + if (byte == 0x00 && *vli_pos > 1)
|
| + return LZMA_DATA_ERROR;
|
| +
|
| + return vli_pos == &vli_pos_internal
|
| + ? LZMA_OK : LZMA_STREAM_END;
|
| + }
|
| +
|
| + // There is at least one more byte coming. If we have already
|
| + // read maximum number of bytes, the integer is considered
|
| + // corrupt.
|
| + //
|
| + // If we need bigger integers in future, old versions liblzma
|
| + // will confusingly indicate the file being corrupt istead of
|
| + // unsupported. I suppose it's still better this way, because
|
| + // in the foreseeable future (writing this in 2008) the only
|
| + // reason why files would appear having over 63-bit integers
|
| + // is that the files are simply corrupt.
|
| + if (*vli_pos == LZMA_VLI_BYTES_MAX)
|
| + return LZMA_DATA_ERROR;
|
| +
|
| + } while (*in_pos < in_size);
|
| +
|
| + return vli_pos == &vli_pos_internal ? LZMA_DATA_ERROR : LZMA_OK;
|
| +}
|
|
|
| Property changes on: xz/src/liblzma/common/vli_decoder.c
|
| ___________________________________________________________________
|
| Added: svn:eol-style
|
| + LF
|
|
|
|
|