integrate lzma

[zpackage] / lzma / common / vli_encoder.c

diff --git a/lzma/common/vli_encoder.c b/lzma/common/vli_encoder.c
new file mode 100644 (file)
index 0000000..f864269
--- /dev/null
+++ b/lzma/common/vli_encoder.c
@@ -0,0 +1,69 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \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;
+
+}