cairo-1.14.6

git-svn-id: svn://tug.org/texlive/trunk@39210 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 404 insertions, 0 deletions

diff --git a/Build/source/libs/cairo/cairo-src/src/cairo-lzw.c b/Build/source/libs/cairo/cairo-src/src/cairo-lzw.c
new file mode 100644
index 00000000000..de7f9998376
--- /dev/null
+++ b/Build/source/libs/cairo/cairo-src/src/cairo-lzw.c
@@ -0,0 +1,404 @@
+/* cairo - a vector graphics library with display and print output
+ *
+ * Copyright © 2006 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it either under the terms of the GNU Lesser General Public
+ * License version 2.1 as published by the Free Software Foundation
+ * (the "LGPL") or, at your option, under the terms of the Mozilla
+ * Public License Version 1.1 (the "MPL"). If you do not alter this
+ * notice, a recipient may use your version of this file under either
+ * the MPL or the LGPL.
+ *
+ * You should have received a copy of the LGPL along with this library
+ * in the file COPYING-LGPL-2.1; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
+ * You should have received a copy of the MPL along with this library
+ * in the file COPYING-MPL-1.1
+ *
+ * The contents of this file are subject to the Mozilla Public License
+ * Version 1.1 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
+ * OF ANY KIND, either express or implied. See the LGPL or the MPL for
+ * the specific language governing rights and limitations.
+ *
+ * The Original Code is the cairo graphics library.
+ *
+ * The Initial Developer of the Original Code is University of Southern
+ * California.
+ *
+ * Contributor(s):
+ *	Carl D. Worth <cworth@cworth.org>
+ */
+
+#include "cairoint.h"
+#include "cairo-error-private.h"
+
+typedef struct _lzw_buf {
+    cairo_status_t status;
+
+    unsigned char *data;
+    int data_size;
+    int num_data;
+    uint32_t pending;
+    unsigned int pending_bits;
+} lzw_buf_t;
+
+/* An lzw_buf_t is a simple, growable chunk of memory for holding
+ * variable-size objects of up to 16 bits each.
+ *
+ * Initialize an lzw_buf_t to the given size in bytes.
+ *
+ * To store objects into the lzw_buf_t, call _lzw_buf_store_bits and
+ * when finished, call _lzw_buf_store_pending, (which flushes out the
+ * last few bits that hadn't yet made a complete byte yet).
+ *
+ * Instead of returning failure from any functions, lzw_buf_t provides
+ * a status value that the caller can query, (and should query at
+ * least once when done with the object). The status value will be
+ * either %CAIRO_STATUS_SUCCESS or %CAIRO_STATUS_NO_MEMORY;
+ */
+static void
+_lzw_buf_init (lzw_buf_t *buf, int size)
+{
+    if (size == 0)
+	size = 16;
+
+    buf->status = CAIRO_STATUS_SUCCESS;
+    buf->data_size = size;
+    buf->num_data = 0;
+    buf->pending = 0;
+    buf->pending_bits = 0;
+
+    buf->data = malloc (size);
+    if (unlikely (buf->data == NULL)) {
+	buf->data_size = 0;
+	buf->status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
+	return;
+    }
+}
+
+/* Increase the buffer size by doubling.
+ *
+ * Returns %CAIRO_STATUS_SUCCESS or %CAIRO_STATUS_NO_MEMORY
+ */
+static cairo_status_t
+_lzw_buf_grow (lzw_buf_t *buf)
+{
+    int new_size = buf->data_size * 2;
+    unsigned char *new_data;
+
+    if (buf->status)
+	return buf->status;
+
+    new_data = NULL;
+    /* check for integer overflow */
+    if (new_size / 2 == buf->data_size)
+	new_data = realloc (buf->data, new_size);
+
+    if (unlikely (new_data == NULL)) {
+	free (buf->data);
+	buf->data_size = 0;
+	buf->status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
+	return buf->status;
+    }
+
+    buf->data = new_data;
+    buf->data_size = new_size;
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+/* Store the lowest num_bits bits of values into buf.
+ *
+ * Note: The bits of value above size_in_bits must be 0, (so don't lie
+ * about the size).
+ *
+ * See also _lzw_buf_store_pending which must be called after the last
+ * call to _lzw_buf_store_bits.
+ *
+ * Sets buf->status to either %CAIRO_STATUS_SUCCESS or %CAIRO_STATUS_NO_MEMORY.
+ */
+static void
+_lzw_buf_store_bits (lzw_buf_t *buf, uint16_t value, int num_bits)
+{
+    cairo_status_t status;
+
+    assert (value <= (1 << num_bits) - 1);
+
+    if (buf->status)
+	return;
+
+    buf->pending = (buf->pending << num_bits) | value;
+    buf->pending_bits += num_bits;
+
+    while (buf->pending_bits >= 8) {
+	if (buf->num_data >= buf->data_size) {
+	    status = _lzw_buf_grow (buf);
+	    if (unlikely (status))
+		return;
+	}
+	buf->data[buf->num_data++] = buf->pending >> (buf->pending_bits - 8);
+	buf->pending_bits -= 8;
+    }
+}
+
+/* Store the last remaining pending bits into the buffer.
+ *
+ * Note: This function must be called after the last call to
+ * _lzw_buf_store_bits.
+ *
+ * Sets buf->status to either %CAIRO_STATUS_SUCCESS or %CAIRO_STATUS_NO_MEMORY.
+ */
+static void
+_lzw_buf_store_pending  (lzw_buf_t *buf)
+{
+    cairo_status_t status;
+
+    if (buf->status)
+	return;
+
+    if (buf->pending_bits == 0)
+	return;
+
+    assert (buf->pending_bits < 8);
+
+    if (buf->num_data >= buf->data_size) {
+	status = _lzw_buf_grow (buf);
+	if (unlikely (status))
+	    return;
+    }
+
+    buf->data[buf->num_data++] = buf->pending << (8 - buf->pending_bits);
+    buf->pending_bits = 0;
+}
+
+/* LZW defines a few magic code values */
+#define LZW_CODE_CLEAR_TABLE	256
+#define LZW_CODE_EOD		257
+#define LZW_CODE_FIRST		258
+
+/* We pack three separate values into a symbol as follows:
+ *
+ * 12 bits (31 down to 20):	CODE: code value used to represent this symbol
+ * 12 bits (19 down to  8):	PREV: previous code value in chain
+ *  8 bits ( 7 down to  0):	NEXT: next byte value in chain
+ */
+typedef uint32_t lzw_symbol_t;
+
+#define LZW_SYMBOL_SET(sym, prev, next)			((sym) = ((prev) << 8)|(next))
+#define LZW_SYMBOL_SET_CODE(sym, code, prev, next)	((sym) = ((code << 20)|(prev) << 8)|(next))
+#define LZW_SYMBOL_GET_CODE(sym)			(((sym) >> 20))
+#define LZW_SYMBOL_GET_PREV(sym)			(((sym) >>  8) & 0x7ff)
+#define LZW_SYMBOL_GET_BYTE(sym)			(((sym) >>  0) & 0x0ff)
+
+/* The PREV+NEXT fields can be seen as the key used to fetch values
+ * from the hash table, while the code is the value fetched.
+ */
+#define LZW_SYMBOL_KEY_MASK	0x000fffff
+
+/* Since code values are only stored starting with 258 we can safely
+ * use a zero value to represent free slots in the hash table. */
+#define LZW_SYMBOL_FREE		0x00000000
+
+/* These really aren't very free for modifying. First, the PostScript
+ * specification sets the 9-12 bit range. Second, the encoding of
+ * lzw_symbol_t above also relies on 2 of LZW_BITS_MAX plus one byte
+ * fitting within 32 bits.
+ *
+ * But other than that, the LZW compression scheme could function with
+ * more bits per code.
+ */
+#define LZW_BITS_MIN		9
+#define LZW_BITS_MAX		12
+#define LZW_BITS_BOUNDARY(bits)	((1<<(bits))-1)
+#define LZW_MAX_SYMBOLS		(1<<LZW_BITS_MAX)
+
+#define LZW_SYMBOL_TABLE_SIZE	9013
+#define LZW_SYMBOL_MOD1		LZW_SYMBOL_TABLE_SIZE
+#define LZW_SYMBOL_MOD2		9011
+
+typedef struct _lzw_symbol_table {
+    lzw_symbol_t table[LZW_SYMBOL_TABLE_SIZE];
+} lzw_symbol_table_t;
+
+/* Initialize the hash table to entirely empty */
+static void
+_lzw_symbol_table_init (lzw_symbol_table_t *table)
+{
+    memset (table->table, 0, LZW_SYMBOL_TABLE_SIZE * sizeof (lzw_symbol_t));
+}
+
+/* Lookup a symbol in the symbol table. The PREV and NEXT fields of
+ * symbol form the key for the lookup.
+ *
+ * If successful, then this function returns %TRUE and slot_ret will be
+ * left pointing at the result that will have the CODE field of
+ * interest.
+ *
+ * If the lookup fails, then this function returns %FALSE and slot_ret
+ * will be pointing at the location in the table to which a new CODE
+ * value should be stored along with PREV and NEXT.
+ */
+static cairo_bool_t
+_lzw_symbol_table_lookup (lzw_symbol_table_t	 *table,
+			  lzw_symbol_t		  symbol,
+			  lzw_symbol_t		**slot_ret)
+{
+    /* The algorithm here is identical to that in cairo-hash.c. We
+     * copy it here to allow for a rather more efficient
+     * implementation due to several circumstances that do not apply
+     * to the more general case:
+     *
+     * 1) We have a known bound on the total number of symbols, so we
+     *    have a fixed-size table without any copying when growing
+     *
+     * 2) We never delete any entries, so we don't need to
+     *    support/check for DEAD entries during lookup.
+     *
+     * 3) The object fits in 32 bits so we store each object in its
+     *    entirety within the table rather than storing objects
+     *    externally and putting pointers in the table, (which here
+     *    would just double the storage requirements and have negative
+     *    impacts on memory locality).
+     */
+    int i, idx, step, hash = symbol & LZW_SYMBOL_KEY_MASK;
+    lzw_symbol_t candidate;
+
+    idx = hash % LZW_SYMBOL_MOD1;
+    step = 0;
+
+    *slot_ret = NULL;
+    for (i = 0; i < LZW_SYMBOL_TABLE_SIZE; i++)
+    {
+	candidate = table->table[idx];
+	if (candidate == LZW_SYMBOL_FREE)
+	{
+	    *slot_ret = &table->table[idx];
+	    return FALSE;
+	}
+	else /* candidate is LIVE */
+	{
+	    if ((candidate & LZW_SYMBOL_KEY_MASK) ==
+		(symbol & LZW_SYMBOL_KEY_MASK))
+	    {
+		*slot_ret = &table->table[idx];
+		return TRUE;
+	    }
+	}
+
+	if (step == 0) {
+	    step = hash % LZW_SYMBOL_MOD2;
+	    if (step == 0)
+		step = 1;
+	}
+
+	idx += step;
+	if (idx >= LZW_SYMBOL_TABLE_SIZE)
+	    idx -= LZW_SYMBOL_TABLE_SIZE;
+    }
+
+    return FALSE;
+}
+
+/* Compress a bytestream using the LZW algorithm.
+ *
+ * This is an original implementation based on reading the
+ * specification of the LZWDecode filter in the PostScript Language
+ * Reference. The free parameters in the LZW algorithm are set to the
+ * values mandated by PostScript, (symbols encoded with widths from 9
+ * to 12 bits).
+ *
+ * This function returns a pointer to a newly allocated buffer holding
+ * the compressed data, or %NULL if an out-of-memory situation
+ * occurs.
+ *
+ * Notice that any one of the _lzw_buf functions called here could
+ * trigger an out-of-memory condition. But lzw_buf_t uses cairo's
+ * shutdown-on-error idiom, so it's safe to continue to call into
+ * lzw_buf without having to check for errors, (until a final check at
+ * the end).
+ */
+unsigned char *
+_cairo_lzw_compress (unsigned char *data, unsigned long *size_in_out)
+{
+    int bytes_remaining = *size_in_out;
+    lzw_buf_t buf;
+    lzw_symbol_table_t table;
+    lzw_symbol_t symbol, *slot = NULL; /* just to squelch a warning */
+    int code_next = LZW_CODE_FIRST;
+    int code_bits = LZW_BITS_MIN;
+    int prev, next = 0; /* just to squelch a warning */
+
+    if (*size_in_out == 0)
+	return NULL;
+
+    _lzw_buf_init (&buf, *size_in_out);
+
+    _lzw_symbol_table_init (&table);
+
+    /* The LZW header is a clear table code. */
+    _lzw_buf_store_bits (&buf, LZW_CODE_CLEAR_TABLE, code_bits);
+
+    while (1) {
+
+	/* Find the longest existing code in the symbol table that
+	 * matches the current input, if any. */
+	prev = *data++;
+	bytes_remaining--;
+	if (bytes_remaining) {
+	    do
+	    {
+		next = *data++;
+		bytes_remaining--;
+		LZW_SYMBOL_SET (symbol, prev, next);
+		if (_lzw_symbol_table_lookup (&table, symbol, &slot))
+		    prev = LZW_SYMBOL_GET_CODE (*slot);
+	    } while (bytes_remaining && *slot != LZW_SYMBOL_FREE);
+	    if (*slot == LZW_SYMBOL_FREE) {
+		data--;
+		bytes_remaining++;
+	    }
+	}
+
+	/* Write the code into the output. This is either a byte read
+	 * directly from the input, or a code from the last successful
+	 * lookup. */
+	_lzw_buf_store_bits (&buf, prev, code_bits);
+
+	if (bytes_remaining == 0)
+	    break;
+
+	LZW_SYMBOL_SET_CODE (*slot, code_next++, prev, next);
+
+	if (code_next > LZW_BITS_BOUNDARY(code_bits))
+	{
+	    code_bits++;
+	    if (code_bits > LZW_BITS_MAX) {
+		_lzw_symbol_table_init (&table);
+		_lzw_buf_store_bits (&buf, LZW_CODE_CLEAR_TABLE, code_bits - 1);
+		code_bits = LZW_BITS_MIN;
+		code_next = LZW_CODE_FIRST;
+	    }
+	}
+    }
+
+    /* The LZW footer is an end-of-data code. */
+    _lzw_buf_store_bits (&buf, LZW_CODE_EOD, code_bits);
+
+    _lzw_buf_store_pending (&buf);
+
+    /* See if we ever ran out of memory while writing to buf. */
+    if (buf.status == CAIRO_STATUS_NO_MEMORY) {
+	*size_in_out = 0;
+	return NULL;
+    }
+
+    assert (buf.status == CAIRO_STATUS_SUCCESS);
+
+    *size_in_out = buf.num_data;
+    return buf.data;
+}