d1b0909894
This allows readFile() to indicate that a file doesn't exist, and might eliminate some large string copying.
96 lines
2.4 KiB
C++
96 lines
2.4 KiB
C++
#include "compression.hh"
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#include "types.hh"
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#include <lzma.h>
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#include <cstdio>
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namespace nix {
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/* RAII wrapper around lzma_stream. */
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struct LzmaStream
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{
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lzma_stream strm;
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LzmaStream() : strm(LZMA_STREAM_INIT) { };
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~LzmaStream() { lzma_end(&strm); };
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lzma_stream & operator()() { return strm; }
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};
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std::string compressXZ(const std::string & in)
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{
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LzmaStream strm;
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// FIXME: apply the x86 BCJ filter?
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lzma_ret ret = lzma_easy_encoder(
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&strm(), 6, LZMA_CHECK_CRC64);
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if (ret != LZMA_OK)
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throw Error("unable to initialise lzma encoder");
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lzma_action action = LZMA_RUN;
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uint8_t outbuf[BUFSIZ];
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string res;
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strm().next_in = (uint8_t *) in.c_str();
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strm().avail_in = in.size();
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strm().next_out = outbuf;
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strm().avail_out = sizeof(outbuf);
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while (true) {
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if (strm().avail_in == 0)
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action = LZMA_FINISH;
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lzma_ret ret = lzma_code(&strm(), action);
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if (strm().avail_out == 0 || ret == LZMA_STREAM_END) {
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res.append((char *) outbuf, sizeof(outbuf) - strm().avail_out);
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strm().next_out = outbuf;
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strm().avail_out = sizeof(outbuf);
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}
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if (ret == LZMA_STREAM_END)
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return res;
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if (ret != LZMA_OK)
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throw Error("error while decompressing xz file");
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}
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}
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ref<std::string> decompressXZ(const std::string & in)
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{
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LzmaStream strm;
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lzma_ret ret = lzma_stream_decoder(
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&strm(), UINT64_MAX, LZMA_CONCATENATED);
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if (ret != LZMA_OK)
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throw Error("unable to initialise lzma decoder");
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lzma_action action = LZMA_RUN;
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uint8_t outbuf[BUFSIZ];
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ref<std::string> res = make_ref<std::string>();
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strm().next_in = (uint8_t *) in.c_str();
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strm().avail_in = in.size();
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strm().next_out = outbuf;
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strm().avail_out = sizeof(outbuf);
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while (true) {
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if (strm().avail_in == 0)
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action = LZMA_FINISH;
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lzma_ret ret = lzma_code(&strm(), action);
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if (strm().avail_out == 0 || ret == LZMA_STREAM_END) {
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res->append((char *) outbuf, sizeof(outbuf) - strm().avail_out);
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strm().next_out = outbuf;
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strm().avail_out = sizeof(outbuf);
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}
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if (ret == LZMA_STREAM_END)
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return res;
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if (ret != LZMA_OK)
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throw Error("error while decompressing xz file");
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}
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}
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}
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