mirror of
https://github.com/koreader/koreader
synced 2024-11-18 03:25:46 +00:00
49 lines
1.8 KiB
Lua
49 lines
1.8 KiB
Lua
|
local ffi = require("ffi")
|
||
|
|
|
||
|
|
-- Utilities functions needed by this plugin, but that may be added to
|
||
|
|
-- existing base/ffi/ files
|
||
|
|
local xutil = {}
|
||
|
|
|
||
|
|
-- Data compression/decompression of strings thru zlib (may be put in a new base/ffi/zlib.lua)
|
||
|
|
-- from http://luajit.org/ext_ffi_tutorial.html
|
||
|
|
ffi.cdef[[
|
||
|
|
unsigned long compressBound(unsigned long sourceLen);
|
||
|
|
int compress2(uint8_t *dest, unsigned long *destLen,
|
||
|
|
const uint8_t *source, unsigned long sourceLen, int level);
|
||
|
|
int uncompress(uint8_t *dest, unsigned long *destLen,
|
||
|
|
const uint8_t *source, unsigned long sourceLen);
|
||
|
|
]]
|
||
|
|
local zlib = ffi.load(ffi.os == "Windows" and "zlib1" or "z")
|
||
|
|
|
||
|
|
function xutil.zlib_compress(data)
|
||
|
|
local n = zlib.compressBound(#data)
|
||
|
|
local buf = ffi.new("uint8_t[?]", n)
|
||
|
|
local buflen = ffi.new("unsigned long[1]", n)
|
||
|
|
local res = zlib.compress2(buf, buflen, data, #data, 9)
|
||
|
|
assert(res == 0)
|
||
|
|
return ffi.string(buf, buflen[0])
|
||
|
|
end
|
||
|
|
|
||
|
|
function xutil.zlib_uncompress(zdata, datalen)
|
||
|
|
local buf = ffi.new("uint8_t[?]", datalen)
|
||
|
|
local buflen = ffi.new("unsigned long[1]", datalen)
|
||
|
|
local res = zlib.uncompress(buf, buflen, zdata, #zdata)
|
||
|
|
assert(res == 0)
|
||
|
|
return ffi.string(buf, buflen[0])
|
||
|
|
end
|
||
|
|
|
||
|
|
-- Not provided by base/thirdparty/lua-ljsqlite3/init.lua
|
||
|
|
-- Add a timeout to a lua-ljsqlite3 connection
|
||
|
|
-- We need that if we have multiple processes accessing the same
|
||
|
|
-- SQLite db for reading or writting (read lock and write lock can't be
|
||
|
|
-- obtained at the same time, so waiting & retry is needed)
|
||
|
|
-- SQLite will retry getting a lock every 1ms to 100ms for
|
||
|
|
-- the timeout_ms given here
|
||
|
|
local sql = ffi.load("sqlite3")
|
||
|
|
function xutil.sqlite_set_timeout(conn, timeout_ms)
|
||
|
|
sql.sqlite3_busy_timeout(conn._ptr, timeout_ms)
|
||
|
|
end
|
||
|
|
-- For reference, SQ3 doc at: http://scilua.org/ljsqlite3.html
|
||
|
|
|
||
|
|
return xutil
|