Build: Build LZMA1/2 presets also when only decoder is wanted.

People shouldn't rely on the presets when decoding raw streams,
but xz uses the presets as the starting point for raw decoder
options anyway.

lzma_encocder_presets.c was renamed to lzma_presets.c to
make it clear it's not used solely by the encoder code.

1 files changed, 64 insertions, 0 deletions

diff --git a/src/liblzma/lzma/lzma_presets.c b/src/liblzma/lzma/lzma_presets.c
new file mode 100644
index 00000000..d49d2427
--- /dev/null
+++ b/src/liblzma/lzma/lzma_presets.c
@@ -0,0 +1,64 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       lzma_presets.c
+/// \brief      Encoder presets
+/// \note       xz needs this even when only decoding is enabled.
+//
+//  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_bool)
+lzma_lzma_preset(lzma_options_lzma *options, uint32_t preset)
+{
+	const uint32_t level = preset & LZMA_PRESET_LEVEL_MASK;
+	const uint32_t flags = preset & ~LZMA_PRESET_LEVEL_MASK;
+	const uint32_t supported_flags = LZMA_PRESET_EXTREME;
+
+	if (level > 9 || (flags & ~supported_flags))
+		return true;
+
+	options->preset_dict = NULL;
+	options->preset_dict_size = 0;
+
+	options->lc = LZMA_LC_DEFAULT;
+	options->lp = LZMA_LP_DEFAULT;
+	options->pb = LZMA_PB_DEFAULT;
+
+	static const uint8_t dict_pow2[]
+			= { 18, 20, 21, 22, 22, 23, 23, 24, 25, 26 };
+	options->dict_size = UINT32_C(1) << dict_pow2[level];
+
+	if (level <= 3) {
+		options->mode = LZMA_MODE_FAST;
+		options->mf = level == 0 ? LZMA_MF_HC3 : LZMA_MF_HC4;
+		options->nice_len = level <= 1 ? 128 : 273;
+		static const uint8_t depths[] = { 4, 8, 24, 48 };
+		options->depth = depths[level];
+	} else {
+		options->mode = LZMA_MODE_NORMAL;
+		options->mf = LZMA_MF_BT4;
+		options->nice_len = level == 4 ? 16 : level == 5 ? 32 : 64;
+		options->depth = 0;
+	}
+
+	if (flags & LZMA_PRESET_EXTREME) {
+		options->mode = LZMA_MODE_NORMAL;
+		options->mf = LZMA_MF_BT4;
+		if (level == 3 || level == 5) {
+			options->nice_len = 192;
+			options->depth = 0;
+		} else {
+			options->nice_len = 273;
+			options->depth = 512;
+		}
+	}
+
+	return false;
+}