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

xz/src/liblzma/delta/delta_encoder.c

+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       delta_encoder.c
+/// \brief      Delta filter encoder
+//
+//  Author:     Lasse Collin
+//
+//  This file has been put into the public domain.
+//  You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "delta_encoder.h"
+#include "delta_private.h"
+
+
+/// Copies and encodes the data at the same time. This is used when Delta
+/// is the first filter in the chain (and thus the last filter in the
+/// encoder's filter stack).
+static void
+copy_and_encode(lzma_coder *coder,
+                const uint8_t *restrict in, uint8_t *restrict out, size_t size)
+{
+        const size_t distance = coder->distance;
+
+        for (size_t i = 0; i < size; ++i) {
+                const uint8_t tmp = coder->history[
+                                (distance + coder->pos) & 0xFF];
+                coder->history[coder->pos-- & 0xFF] = in[i];
+                out[i] = in[i] - tmp;
+        }
+}
+
+
+/// Encodes the data in place. This is used when we are the last filter
+/// in the chain (and thus non-last filter in the encoder's filter stack).
+static void
+encode_in_place(lzma_coder *coder, uint8_t *buffer, size_t size)
+{
+        const size_t distance = coder->distance;
+
+        for (size_t i = 0; i < size; ++i) {
+                const uint8_t tmp = coder->history[
+                                (distance + coder->pos) & 0xFF];
+                coder->history[coder->pos-- & 0xFF] = buffer[i];
+                buffer[i] -= tmp;
+        }
+}
+
+
+static lzma_ret
+delta_encode(lzma_coder *coder, lzma_allocator *allocator,
+                const uint8_t *restrict in, size_t *restrict in_pos,
+                size_t in_size, uint8_t *restrict out,
+                size_t *restrict out_pos, size_t out_size, lzma_action action)
+{
+        lzma_ret ret;
+
+        if (coder->next.code == NULL) {
+                const size_t in_avail = in_size - *in_pos;
+                const size_t out_avail = out_size - *out_pos;
+                const size_t size = my_min(in_avail, out_avail);
+
+                copy_and_encode(coder, in + *in_pos, out + *out_pos, size);
+
+                *in_pos += size;
+                *out_pos += size;
+
+                ret = action != LZMA_RUN && *in_pos == in_size
+                                ? LZMA_STREAM_END : LZMA_OK;
+
+        } else {
+                const size_t out_start = *out_pos;
+
+                ret = coder->next.code(coder->next.coder, allocator,
+                                in, in_pos, in_size, out, out_pos, out_size,
+                                action);
+
+                encode_in_place(coder, out + out_start, *out_pos - out_start);
+        }
+
+        return ret;
+}
+
+
+static lzma_ret
+delta_encoder_update(lzma_coder *coder, lzma_allocator *allocator,
+                const lzma_filter *filters_null lzma_attribute((unused)),
+                const lzma_filter *reversed_filters)
+{
+        // Delta doesn't and will never support changing the options in
+        // the middle of encoding. If the app tries to change them, we
+        // simply ignore them.
+        return lzma_next_filter_update(
+                        &coder->next, allocator, reversed_filters + 1);
+}
+
+
+extern lzma_ret
+lzma_delta_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+                const lzma_filter_info *filters)
+{
+        next->code = &delta_encode;
+        next->update = &delta_encoder_update;
+        return lzma_delta_coder_init(next, allocator, filters);
+}
+
+
+extern lzma_ret
+lzma_delta_props_encode(const void *options, uint8_t *out)
+{
+        // The caller must have already validated the options, so it's
+        // LZMA_PROG_ERROR if they are invalid.
+        if (lzma_delta_coder_memusage(options) == UINT64_MAX)
+                return LZMA_PROG_ERROR;
+
+        const lzma_options_delta *opt = options;
+        out[0] = opt->dist - LZMA_DELTA_DIST_MIN;
+
+        return LZMA_OK;
+}