source/include/snappy-c.h

0001 /*
0002  * Copyright 2011 Martin Gieseking <martin.gieseking@uos.de>.
0003  *
0004  * Redistribution and use in source and binary forms, with or without
0005  * modification, are permitted provided that the following conditions are
0006  * met:
0007  *
0008  *     * Redistributions of source code must retain the above copyright
0009  * notice, this list of conditions and the following disclaimer.
0010  *     * Redistributions in binary form must reproduce the above
0011  * copyright notice, this list of conditions and the following disclaimer
0012  * in the documentation and/or other materials provided with the
0013  * distribution.
0014  *     * Neither the name of Google Inc. nor the names of its
0015  * contributors may be used to endorse or promote products derived from
0016  * this software without specific prior written permission.
0017  *
0018  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
0019  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
0020  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
0021  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
0022  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
0023  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
0024  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
0025  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
0026  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
0027  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
0028  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
0029  *
0030  * Plain C interface (a wrapper around the C++ implementation).
0031  */
0032
0033 #ifndef THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_C_H_
0034 #define THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_C_H_
0035
0036 #ifdef __cplusplus
0037 extern "C" {
0038 #endif
0039
0040 #include <stddef.h>
0041
0042 /*
0043  * Return values; see the documentation for each function to know
0044  * what each can return.
0045  */
0046 typedef enum {
0047   SNAPPY_OK = 0,
0048   SNAPPY_INVALID_INPUT = 1,
0049   SNAPPY_BUFFER_TOO_SMALL = 2
0050 } snappy_status;
0051
0052 /*
0053  * Takes the data stored in "input[0..input_length-1]" and stores
0054  * it in the array pointed to by "compressed".
0055  *
0056  * <compressed_length> signals the space available in "compressed".
0057  * If it is not at least equal to "snappy_max_compressed_length(input_length)",
0058  * SNAPPY_BUFFER_TOO_SMALL is returned. After successful compression,
0059  * <compressed_length> contains the true length of the compressed output,
0060  * and SNAPPY_OK is returned.
0061  *
0062  * Example:
0063  *   size_t output_length = snappy_max_compressed_length(input_length);
0064  *   char* output = (char*)malloc(output_length);
0065  *   if (snappy_compress(input, input_length, output, &output_length)
0066  *       == SNAPPY_OK) {
0067  *     ... Process(output, output_length) ...
0068  *   }
0069  *   free(output);
0070  */
0071 snappy_status snappy_compress(const char* input,
0072                               size_t input_length,
0073                               char* compressed,
0074                               size_t* compressed_length);
0075
0076 /*
0077  * Given data in "compressed[0..compressed_length-1]" generated by
0078  * calling the snappy_compress routine, this routine stores
0079  * the uncompressed data to
0080  *   uncompressed[0..uncompressed_length-1].
0081  * Returns failure (a value not equal to SNAPPY_OK) if the message
0082  * is corrupted and could not be decrypted.
0083  *
0084  * <uncompressed_length> signals the space available in "uncompressed".
0085  * If it is not at least equal to the value returned by
0086  * snappy_uncompressed_length for this stream, SNAPPY_BUFFER_TOO_SMALL
0087  * is returned. After successful decompression, <uncompressed_length>
0088  * contains the true length of the decompressed output.
0089  *
0090  * Example:
0091  *   size_t output_length;
0092  *   if (snappy_uncompressed_length(input, input_length, &output_length)
0093  *       != SNAPPY_OK) {
0094  *     ... fail ...
0095  *   }
0096  *   char* output = (char*)malloc(output_length);
0097  *   if (snappy_uncompress(input, input_length, output, &output_length)
0098  *       == SNAPPY_OK) {
0099  *     ... Process(output, output_length) ...
0100  *   }
0101  *   free(output);
0102  */
0103 snappy_status snappy_uncompress(const char* compressed,
0104                                 size_t compressed_length,
0105                                 char* uncompressed,
0106                                 size_t* uncompressed_length);
0107
0108 /*
0109  * Returns the maximal size of the compressed representation of
0110  * input data that is "source_length" bytes in length.
0111  */
0112 size_t snappy_max_compressed_length(size_t source_length);
0113
0114 /*
0115  * REQUIRES: "compressed[]" was produced by snappy_compress()
0116  * Returns SNAPPY_OK and stores the length of the uncompressed data in
0117  * *result normally. Returns SNAPPY_INVALID_INPUT on parsing error.
0118  * This operation takes O(1) time.
0119  */
0120 snappy_status snappy_uncompressed_length(const char* compressed,
0121                                          size_t compressed_length,
0122                                          size_t* result);
0123
0124 /*
0125  * Check if the contents of "compressed[]" can be uncompressed successfully.
0126  * Does not return the uncompressed data; if so, returns SNAPPY_OK,
0127  * or if not, returns SNAPPY_INVALID_INPUT.
0128  * Takes time proportional to compressed_length, but is usually at least a
0129  * factor of four faster than actual decompression.
0130  */
0131 snappy_status snappy_validate_compressed_buffer(const char* compressed,
0132                                                 size_t compressed_length);
0133
0134 #ifdef __cplusplus
0135 }  // extern "C"
0136 #endif
0137
0138 #endif  /* THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_C_H_ */