Include C bindings of Snappy, contributed by Martin Gieseking.

I've made a few changes since Martin's version; mostly style nits, but also
a semantic change -- most functions that return bool in the C++ version now
return an enum, to better match typical C (and zlib) semantics.

I've kept the copyright notice, since Martin is obviously the author here;
he has signed the contributor license agreement, though, so this should not
hinder Google's use in the future.

We'll need to update the libtool version number to match the added interface,
but as of http://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html
I'm going to wait until public release.

R=csilvers
DELTA=238  (233 added, 0 deleted, 5 changed)


Revision created by MOE tool push_codebase.
MOE_MIGRATION=1294


git-svn-id: http://snappy.googlecode.com/svn/trunk@27 03e5f5b5-db94-4691-08a0-1a8bf15f6143

1 files changed, 138 insertions, 0 deletions

diff --git a/snappy-c.h b/snappy-c.h
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+/*
+ * Copyright 2011 Martin Gieseking <martin.gieseking@uos.de>.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Plain C interface (a wrapper around the C++ implementation).
+ */
+
+#ifndef UTIL_SNAPPY_OPENSOURCE_SNAPPY_C_H_
+#define UTIL_SNAPPY_OPENSOURCE_SNAPPY_C_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stddef.h>
+
+/*
+ * Return values; see the documentation for each function to know
+ * what each can return.
+ */
+typedef enum {
+  SNAPPY_OK = 0,
+  SNAPPY_INVALID_INPUT = 1,
+  SNAPPY_BUFFER_TOO_SMALL = 2,
+} snappy_status;
+
+/*
+ * Takes the data stored in "input[0..input_length-1]" and stores
+ * it in the array pointed to by "compressed".
+ *
+ * <compressed_length> signals the space available in "compressed".
+ * If it is not at least equal to "snappy_max_compressed_length(input_length)",
+ * SNAPPY_BUFFER_TOO_SMALL is returned. After successful compression,
+ * <compressed_length> contains the true length of the compressed output,
+ * and SNAPPY_OK is returned.
+ *
+ * Example:
+ *   size_t output_length = snappy_max_compressed_length(input_length);
+ *   char* output = (char*)malloc(output_length);
+ *   if (snappy_compress(input, input_length, output, &output_length)
+ *       == SNAPPY_OK) {
+ *     ... Process(output, output_length) ...
+ *   }
+ *   free(output);
+ */
+snappy_status snappy_compress(const char* input,
+                              size_t input_length,
+                              char* compressed,
+                              size_t* compressed_length);
+
+/*
+ * Given data in "compressed[0..compressed_length-1]" generated by
+ * calling the snappy_compress routine, this routine stores
+ * the uncompressed data to
+ *   uncompressed[0..uncompressed_length-1].
+ * Returns failure (a value not equal to SNAPPY_OK) if the message
+ * is corrupted and could not be decrypted.
+ *
+ * <uncompressed_length> signals the space available in "uncompressed".
+ * If it is not at least equal to the value returned by
+ * snappy_uncompressed_length for this stream, SNAPPY_BUFFER_TOO_SMALL
+ * is returned. After successful decompression, <uncompressed_length>
+ * contains the true length of the decompressed output.
+ *
+ * Example:
+ *   size_t output_length;
+ *   if (snappy_uncompressed_length(input, input_length, &output_length)
+ *       != SNAPPY_OK) {
+ *     ... fail ...
+ *   }
+ *   char* output = (char*)malloc(output_length);
+ *   if (snappy_uncompress(input, input_length, output, &output_length)
+ *       == SNAPPY_OK) {
+ *     ... Process(output, output_length) ...
+ *   }
+ *   free(output);
+ */
+snappy_status snappy_uncompress(const char* compressed,
+                                size_t compressed_length,
+                                char* uncompressed,
+                                size_t* uncompressed_length);
+
+/*
+ * Returns the maximal size of the compressed representation of
+ * input data that is "source_length" bytes in length.
+ */
+size_t snappy_max_compressed_length(size_t source_length);
+
+/*
+ * REQUIRES: "compressed[]" was produced by snappy_compress()
+ * Returns SNAPPY_OK and stores the length of the uncompressed data in
+ * *result normally. Returns SNAPPY_INVALID_INPUT on parsing error.
+ * This operation takes O(1) time.
+ */
+snappy_status snappy_uncompressed_length(const char* compressed,
+                                         size_t compressed_length,
+                                         size_t* result);
+
+/*
+ * Check if the contents of "compressed[]" can be uncompressed successfully.
+ * Does not return the uncompressed data; if so, returns SNAPPY_OK,
+ * or if not, returns SNAPPY_INVALID_INPUT.
+ * Takes time proportional to compressed_length, but is usually at least a
+ * factor of four faster than actual decompression.
+ */
+snappy_status snappy_validate_compressed_buffer(const char* compressed,
+                                                size_t compressed_length);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  /* UTIL_SNAPPY_OPENSOURCE_SNAPPY_C_H_ */