mirror of
https://github.com/koreader/koreader
synced 2024-11-11 19:11:14 +00:00
36 lines
1.2 KiB
Lua
36 lines
1.2 KiB
Lua
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local ffi = require("ffi")
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-- Utilities functions needed by this plugin, but that may be added to
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-- existing base/ffi/ files
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local xutil = {}
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-- Data compression/decompression of strings thru zlib (may be put in a new base/ffi/zlib.lua)
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-- from http://luajit.org/ext_ffi_tutorial.html
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ffi.cdef[[
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unsigned long compressBound(unsigned long sourceLen);
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int compress2(uint8_t *dest, unsigned long *destLen,
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const uint8_t *source, unsigned long sourceLen, int level);
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int uncompress(uint8_t *dest, unsigned long *destLen,
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const uint8_t *source, unsigned long sourceLen);
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]]
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local zlib = ffi.load(ffi.os == "Windows" and "zlib1" or "z")
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function xutil.zlib_compress(data)
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local n = zlib.compressBound(#data)
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local buf = ffi.new("uint8_t[?]", n)
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local buflen = ffi.new("unsigned long[1]", n)
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local res = zlib.compress2(buf, buflen, data, #data, 9)
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assert(res == 0)
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return ffi.string(buf, buflen[0])
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end
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function xutil.zlib_uncompress(zdata, datalen)
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local buf = ffi.new("uint8_t[?]", datalen)
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local buflen = ffi.new("unsigned long[1]", datalen)
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local res = zlib.uncompress(buf, buflen, zdata, #zdata)
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assert(res == 0)
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return ffi.string(buf, buflen[0])
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end
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return xutil
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