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-rw-r--r--Build/source/extra/xz-4.999.9beta/src/liblzma/common/vli_decoder.c86
1 files changed, 86 insertions, 0 deletions
diff --git a/Build/source/extra/xz-4.999.9beta/src/liblzma/common/vli_decoder.c b/Build/source/extra/xz-4.999.9beta/src/liblzma/common/vli_decoder.c
new file mode 100644
index 00000000000..ffb27cadc53
--- /dev/null
+++ b/Build/source/extra/xz-4.999.9beta/src/liblzma/common/vli_decoder.c
@@ -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 *restrict 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 immediatelly.
+ 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;
+}