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authorLasse Collin <lasse.collin@tukaani.org>2007-12-09 00:42:33 +0200
committerLasse Collin <lasse.collin@tukaani.org>2007-12-09 00:42:33 +0200
commit5d018dc03549c1ee4958364712fb0c94e1bf2741 (patch)
tree1b211911fb33fddb3f04b77f99e81df23623ffc4 /src/liblzma/common/vli_encoder.c
downloadxz-5d018dc03549c1ee4958364712fb0c94e1bf2741.tar.xz
Imported to git.
Diffstat (limited to 'src/liblzma/common/vli_encoder.c')
-rw-r--r--src/liblzma/common/vli_encoder.c81
1 files changed, 81 insertions, 0 deletions
diff --git a/src/liblzma/common/vli_encoder.c b/src/liblzma/common/vli_encoder.c
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+++ b/src/liblzma/common/vli_encoder.c
@@ -0,0 +1,81 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \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;
+}