Add an unpatched version of xz, XZ Utils, to /trunk/deps/third_party

xz/src/liblzma/common/vli_encoder.c

+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       vli_encoder.c
+/// \brief      Encodes 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_encode(lzma_vli vli, size_t *vli_pos,
+                uint8_t *restrict out, size_t *restrict out_pos,
+                size_t out_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;
+
+                // In single-call mode, we expect that the caller has
+                // reserved enough output space.
+                if (*out_pos >= out_size)
+                        return LZMA_PROG_ERROR;
+        } else {
+                // This never happens when we are called by liblzma, but
+                // may happen if called directly from an application.
+                if (*out_pos >= out_size)
+                        return LZMA_BUF_ERROR;
+        }
+
+        // Validate the arguments.
+        if (*vli_pos >= LZMA_VLI_BYTES_MAX || vli > LZMA_VLI_MAX)
+                return LZMA_PROG_ERROR;
+
+        // Shift vli so that the next bits to encode are the lowest. In
+        // single-call mode this never changes vli since *vli_pos is zero.
+        vli >>= *vli_pos * 7;
+
+        // Write the non-last bytes in a loop.
+        while (vli >= 0x80) {
+                // We don't need *vli_pos during this function call anymore,
+                // but update it here so that it is ready if we need to
+                // return before the whole integer has been decoded.
+                ++*vli_pos;
+                assert(*vli_pos < LZMA_VLI_BYTES_MAX);
+
+                // Write the next byte.
+                out[*out_pos] = (uint8_t)(vli) | 0x80;
+                vli >>= 7;
+
+                if (++*out_pos == out_size)
+                        return vli_pos == &vli_pos_internal
+                                        ? LZMA_PROG_ERROR : LZMA_OK;
+        }
+
+        // Write the last byte.
+        out[*out_pos] = (uint8_t)(vli);
+        ++*out_pos;
+        ++*vli_pos;
+
+        return vli_pos == &vli_pos_internal ? LZMA_OK : LZMA_STREAM_END;
+
+}