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https://github.com/bungle/lua-resty-snappy

LuaJIT FFI bindings for Snappy, a fast compressor/decompressor (https://code.google.com/p/snappy/)
https://github.com/bungle/lua-resty-snappy

Last synced: about 1 month ago
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LuaJIT FFI bindings for Snappy, a fast compressor/decompressor (https://code.google.com/p/snappy/)

Host: GitHub
URL: https://github.com/bungle/lua-resty-snappy
Owner: bungle
License: bsd-2-clause
Created: 2014-09-23T19:05:50.000Z (almost 10 years ago)
Default Branch: master
Last Pushed: 2015-12-16T22:19:12.000Z (over 8 years ago)
Last Synced: 2024-02-15T02:32:22.091Z (4 months ago)
Language: Lua
Size: 5.86 KB
Stars: 16
Watchers: 6
Forks: 6
Open Issues: 1
Metadata Files:
- Readme: README.md
- Changelog: CHANGES
- License: LICENSE

Lists

awesome-resty - lua-resty-snappy
awesome-nginx - lua-resty-snappy - LuaJIT FFI bindings for Snappy, a fast compressor/decompressor. (Rust Modules / Lua Modules)
awesome-nginx - lua-resty-snappy - LuaJIT FFI bindings for Snappy, a fast compressor/decompressor. (Third Modules / C Modules)

README

lua-resty-snappy
================

`lua-resty-snappy` provides LuaJIT FFI bindings to Snappy, a fast compressor/decompressor (https://code.google.com/p/snappy/).

## Installation

Just place [`snappy.lua`](https://github.com/bungle/lua-resty-snappy/blob/master/lib/resty/snappy.lua) somewhere in your `package.path`, preferably under `resty` directory. If you are using OpenResty, the default location would be `/usr/local/openresty/lualib/resty`.

### Compiling and Installing Snappy C-library

1. Install snappy with your operating system's package management OR build it manually from the sources provided from
[Snappy repository](https://code.google.com/p/snappy/).
2. Check that you have `snappy.so` (or `.dylib`, or `.dll`) somewhere in the default search path for dynamic libraries of your operating system (or modify `snappy.lua` and point `ffi_load("snappy")`
with full path to `snappy.so`, e.g. `local json = ffi_load("/usr/local/lib/lua/5.1/snappy.so")`).

### Using LuaRocks or MoonRocks

This will only install the Lua module, not the Snappy C-library.

If you are using LuaRocks >= 2.2:

```Shell
$ luarocks install lua-resty-snappy
```

If you are using LuaRocks < 2.2:

```Shell
$ luarocks install --server=http://rocks.moonscript.org moonrocks
$ moonrocks install lua-resty-snappy
```

MoonRocks repository for `lua-resty-snappy` is located here: https://rocks.moonscript.org/modules/bungle/lua-resty-snappy.

## Lua API

#### Error Codes

```c
SNAPPY_OK = 0
SNAPPY_INVALID_INPUT = 1
SNAPPY_BUFFER_TOO_SMALL = 2
```

#### string, len snappy.compress(input)

Compresses `input` with Snappy algorithm, and returns compressed data and its length.
On error this will return nil and an error code.

##### Example

```lua
local snappy = require "resty.snappy"
local comp, err = snappy.compress("test")
if comp then
-- do something with compressed data and length
-- (length is stored in err value)...
else
if err = 1 then
print "Invalid input"
elseif err == 2 then
print "Buffer too small"
end
end
```

#### string, len snappy.uncompress(compressed)

Uncompresses `compressed` with Snappy algorithm, and returns uncompressed data and its length.
On error this will return nil and an error code.

##### Example

```lua
local snappy = require "resty.snappy"
local uncomp, err = snappy.uncompress(snappy.compress("test"))
```

#### number snappy.max_compressed_length(source_length)

Returns maximum-possible length as a number of bytes of compressed data when
uncompressed `source_length` is given. This is used to create buffer for compressing,
but can also be used in quick measurement (and it may have nothing to do with
final compressed output length, other than it cannot be larger than what this
function returns).

##### Example

```lua
local snappy = require "resty.snappy"
local number = snappy.max_compressed_length(1000)
```

#### number snappy.uncompressed_length(compressed)

This is quicker way (than using `snappy.uncompress` to determine how many bytes
the compressed data will be when it is uncompressed.

##### Example

```lua
local snappy = require "resty.snappy"
local number = snappy.uncompressed_length(snappy.compress("test"))
```

#### boolean snappy.validate_compressed_buffer(compressed)

This can be used to check if the compressed bytes are actually Snappy compressed
bytes or something else. I.e. something that can be uncompressed with Snappy.

##### Example

```lua
local snappy = require "resty.snappy"
local bool = snappy.validate_compressed_buffer(snappy.compress("test"))
```

## License

`lua-resty-snappy` uses two clause BSD license.

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.

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 HOLDER 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.
```