Patch from Aurelien Jacobs to add unlzma. (A new decompression type,

see www.7-zip.org)
2006-01-20 18:28:50 +00:00
parent 7a43bd07e6
commit c1d69906a0
12 changed files with 691 additions and 5 deletions
--- a/archival/libunarchive/rangecoder.h
+++ b/archival/libunarchive/rangecoder.h
@ -0,0 +1,158 @@
+/*
+ * Small range coder implementation for lzma.
+ * Copyright (C) 2006  Aurelien Jacobs <aurel@gnuage.org>
+ *
+ * Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
+ * Copyright (c) 1999-2005  Igor Pavlov
+ *
+ * This program 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 program 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.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <stdint.h>
+
+#include "libbb.h"
+
+#ifndef always_inline
+#  if defined(__GNUC__) && (__GNUC__ > 3 || __GNUC__ == 3 && __GNUC_MINOR__ >0)
+#    define always_inline __attribute__((always_inline)) inline
+#  else
+#    define always_inline inline
+#  endif
+#endif
+
+#ifdef CONFIG_FEATURE_LZMA_FAST
+#  define speed_inline always_inline
+#else
+#  define speed_inline
+#endif
+
+
+typedef struct {
+	int fd;
+	uint8_t *ptr;
+	uint8_t *buffer;
+	uint8_t *buffer_end;
+	int buffer_size;
+	uint32_t code;
+	uint32_t range;
+	uint32_t bound;
+} rc_t;
+
+
+#define RC_TOP_BITS 24
+#define RC_MOVE_BITS 5
+#define RC_MODEL_TOTAL_BITS 11
+
+
+static speed_inline void rc_read(rc_t * rc)
+{
+	rc->buffer_size = read(rc->fd, rc->buffer, rc->buffer_size);
+	if (rc->buffer_size <= 0)
+		bb_error_msg_and_die("unexpected EOF");
+	rc->ptr = rc->buffer;
+	rc->buffer_end = rc->buffer + rc->buffer_size;
+}
+
+static always_inline void rc_init(rc_t * rc, int fd, int buffer_size)
+{
+	int i;
+
+	rc->fd = fd;
+	rc->buffer = malloc(buffer_size);
+	rc->buffer_size = buffer_size;
+	rc->buffer_end = rc->buffer + rc->buffer_size;
+	rc->ptr = rc->buffer_end;
+
+	rc->code = 0;
+	rc->range = 0xFFFFFFFF;
+	for (i = 0; i < 5; i++) {
+		if (rc->ptr >= rc->buffer_end)
+			rc_read(rc);
+		rc->code = (rc->code << 8) | *rc->ptr++;
+	}
+}
+
+static always_inline void rc_free(rc_t * rc)
+{
+	if (ENABLE_FEATURE_CLEAN_UP)
+		free(rc->buffer);
+}
+
+static always_inline void rc_normalize(rc_t * rc)
+{
+	if (rc->range < (1 << RC_TOP_BITS)) {
+		if (rc->ptr >= rc->buffer_end)
+			rc_read(rc);
+		rc->range <<= 8;
+		rc->code = (rc->code << 8) | *rc->ptr++;
+	}
+}
+
+static speed_inline int rc_is_bit_0(rc_t * rc, uint16_t * p)
+{
+	rc_normalize(rc);
+	rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS);
+	return rc->code < rc->bound;
+}
+
+static speed_inline void rc_update_bit_0(rc_t * rc, uint16_t * p)
+{
+	rc->range = rc->bound;
+	*p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
+}
+
+static speed_inline void rc_update_bit_1(rc_t * rc, uint16_t * p)
+{
+	rc->range -= rc->bound;
+	rc->code -= rc->bound;
+	*p -= *p >> RC_MOVE_BITS;
+}
+
+static speed_inline int rc_get_bit(rc_t * rc, uint16_t * p, int *symbol)
+{
+	if (rc_is_bit_0(rc, p)) {
+		rc_update_bit_0(rc, p);
+		*symbol *= 2;
+		return 0;
+	} else {
+		rc_update_bit_1(rc, p);
+		*symbol = *symbol * 2 + 1;
+		return 1;
+	}
+}
+
+static always_inline int rc_direct_bit(rc_t * rc)
+{
+	rc_normalize(rc);
+	rc->range >>= 1;
+	if (rc->code >= rc->range) {
+		rc->code -= rc->range;
+		return 1;
+	}
+	return 0;
+}
+
+static speed_inline void
+rc_bit_tree_decode(rc_t * rc, uint16_t * p, int num_levels, int *symbol)
+{
+	int i = num_levels;
+
+	*symbol = 1;
+	while (i--)
+		rc_get_bit(rc, p + *symbol, symbol);
+	*symbol -= 1 << num_levels;
+}
+
+/* vi:set ts=4: */