mirror of https://git.tukaani.org/xz.git
Docs: Add new example programs.
These have more comments than the old examples and human-readable error messages. More tutorial-like examples are needed but these are a start.
This commit is contained in:
Lasse Collin
parent
1bd2c2c553
commit
3a0c5378ab
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liblzma example programs
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========================
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Introduction
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The examples are written so that the same comments aren't
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repeated (much) in later files.
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On POSIX systems, the examples should build by just typing "make".
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The examples that use stdin or stdout don't set stdin and stdout
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to binary mode. On systems where it matters (e.g. Windows) it is
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possible that the examples won't work without modification.
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List of examples
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01_compress_easy.c Multi-call compression using
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a compression preset
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02_decompress.c Multi-call decompression
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03_compress_custom.c Like 01_compress_easy.c but using
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a custom filter chain
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(x86 BCJ + LZMA2)
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///////////////////////////////////////////////////////////////////////////////
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//
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/// \file 01_compress_easy.c
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/// \brief Compress from stdin to stdout in multi-call mode
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///
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/// Usage: ./01_compress_easy PRESET < INFILE > OUTFILE
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///
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/// Example: ./01_compress_easy 6 < foo > foo.xz
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//
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// Author: Lasse Collin
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//
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// This file has been put into the public domain.
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// You can do whatever you want with this file.
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//
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///////////////////////////////////////////////////////////////////////////////
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#include <stdbool.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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#include <lzma.h>
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static void
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show_usage_and_exit(const char *argv0)
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{
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fprintf(stderr, "Usage: %s PRESET < INFILE > OUTFILE\n"
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"PRESET is a number 0-9 and can optionally be "
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"by `e' to indicate extreme preset\n",
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argv0);
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exit(EXIT_FAILURE);
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}
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static uint32_t
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get_preset(int argc, char **argv)
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{
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// One argument whose first char must be 0-9.
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if (argc != 2 || argv[1][0] < '0' || argv[1][0] > '9')
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show_usage_and_exit(argv[0]);
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// Calculate the preste level 0-9.
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uint32_t preset = argv[1][0] - '0';
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// If there is a second char, it must be 'e'. It will set
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// the LZMA_PRESET_EXTREME flag.
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if (argv[1][1] != '\0') {
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if (argv[1][1] != 'e' || argv[1][2] != '\0')
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show_usage_and_exit(argv[0]);
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preset |= LZMA_PRESET_EXTREME;
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}
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return preset;
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}
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static bool
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init_encoder(lzma_stream *strm, uint32_t preset)
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{
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// Initialize the encoder using a preset. Set the integrity to check
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// to CRC64, which is the default in the xz command line tool. If
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// the .xz file needs to be decompressed with XZ Embedded, use
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// LZMA_CHECK_CRC32 instead.
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lzma_ret ret = lzma_easy_encoder(strm, preset, LZMA_CHECK_CRC64);
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// Return successfully if the initialization went fine.
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if (ret == LZMA_OK)
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return true;
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// Something went wrong. The possible errors are documented in
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// lzma/container.h (src/liblzma/api/lzma/container.h in the source
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// package or e.g. /usr/include/lzma/container.h depending on the
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// install prefix).
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const char *msg;
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switch (ret) {
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case LZMA_MEM_ERROR:
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msg = "Memory allocation failed";
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break;
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case LZMA_OPTIONS_ERROR:
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msg = "Specified preset is not supported";
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break;
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case LZMA_UNSUPPORTED_CHECK:
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msg = "Specified integrity check is not supported";
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break;
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default:
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// This is most likely LZMA_PROG_ERROR indicating a bug in
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// this program or in liblzma. It is inconvenient to have a
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// separate error message for errors that should be impossible
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// to occur, but knowing the error code is important for
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// debugging. That's why it is good to print the error code
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// at least when there is no good error message to show.
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msg = "Unknown error, possibly a bug";
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break;
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}
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fprintf(stderr, "Error initializing the encoder: %s (error code %u)\n",
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msg, ret);
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return false;
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}
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static bool
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compress(lzma_stream *strm, FILE *infile, FILE *outfile)
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{
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// This will be LZMA_RUN until the end of the input file is reached.
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// This tells lzma_code() when there will be no more input.
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lzma_action action = LZMA_RUN;
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// Buffers to temporarily hold uncompressed input
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// and compressed output.
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uint8_t inbuf[BUFSIZ];
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uint8_t outbuf[BUFSIZ];
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// Initialize the input and output pointers. Initializing next_in
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// and avail_in isn't really necessary when we are going to encode
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// just one file since LZMA_STREAM_INIT takes care of initializing
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// those already. But it doesn't hurt much and it will be needed
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// if encoding more than one file like we will in 02_decompress.c.
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//
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// While we don't care about strm->total_in or strm->total_out in this
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// example, it is worth noting that initializing the encoder will
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// always reset total_in and total_out to zero. But the encoder
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// initialization doesn't touch next_in, avail_in, next_out, or
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// avail_out.
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strm->next_in = NULL;
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strm->avail_in = 0;
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strm->next_out = outbuf;
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strm->avail_out = sizeof(outbuf);
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// Loop until the file has been successfully compressed or until
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// an error occurs.
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while (true) {
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// Fill the input buffer if it is empty.
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if (strm->avail_in == 0 && !feof(infile)) {
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strm->next_in = inbuf;
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strm->avail_in = fread(inbuf, 1, sizeof(inbuf),
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infile);
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if (ferror(infile)) {
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fprintf(stderr, "Read error: %s\n",
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strerror(errno));
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return false;
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}
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// Once the end of the input file has been reached,
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// we need to tell lzma_code() that no more input
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// will be coming and that it should finish the
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// encoding.
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if (feof(infile))
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action = LZMA_FINISH;
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}
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// Tell liblzma do the actual encoding.
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//
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// This reads up to strm->avail_in bytes of input starting
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// from strm->next_in. avail_in will be decremented and
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// next_in incremented by an equal amount to match the
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// number of input bytes consumed.
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//
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// Up to strm->avail_out bytes of compressed output will be
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// written starting from strm->next_out. avail_out and next_out
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// will be incremented by an equal amount to match the number
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// of output bytes written.
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//
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// The encoder has to do internal buffering, which means that
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// it may take quite a bit of input before the same data is
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// available in compressed form in the output buffer.
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lzma_ret ret = lzma_code(strm, action);
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// If the output buffer is full or if the compression finished
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// successfully, write the data from the output bufffer to
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// the output file.
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if (strm->avail_out == 0 || ret == LZMA_STREAM_END) {
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// When lzma_code() has returned LZMA_STREAM_END,
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// the output buffer is likely to be only partially
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// full. Calculate how much new data there is to
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// be written to the output file.
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size_t write_size = sizeof(outbuf) - strm->avail_out;
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if (fwrite(outbuf, 1, write_size, outfile)
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!= write_size) {
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fprintf(stderr, "Write error: %s\n",
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strerror(errno));
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return false;
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}
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// Reset next_out and 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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// Normally the return value of lzma_code() will be LZMA_OK
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// until everything has been encoded.
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if (ret != LZMA_OK) {
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// Once everything has been encoded successfully, the
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// return value of lzma_code() will be LZMA_STREAM_END.
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//
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// It is important to check for LZMA_STREAM_END. Do not
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// assume that getting ret != LZMA_OK would mean that
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// everything has gone well.
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if (ret == LZMA_STREAM_END)
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return true;
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// It's not LZMA_OK nor LZMA_STREAM_END,
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// so it must be an error code. See lzma/base.h
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// (src/liblzma/api/lzma/base.h in the source package
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// or e.g. /usr/include/lzma/base.h depending on the
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// install prefix) for the list and documentation of
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// possible values. Most values listen in lzma_ret
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// enumeration aren't possible in this example.
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const char *msg;
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switch (ret) {
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case LZMA_MEM_ERROR:
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msg = "Memory allocation failed";
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break;
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case LZMA_DATA_ERROR:
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// This error is returned if the compressed
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// or uncompressed size get near 8 EiB
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// (2^63 bytes) because that's where the .xz
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// file format size limits currently are.
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// That is, the possibility of this error
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// is mostly theoretical unless you are doing
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// something very unusual.
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//
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// Note that strm->total_in and strm->total_out
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// have nothing to do with this error. Changing
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// those variables won't increase or decrease
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// the chance of getting this error.
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msg = "File size limits exceeded";
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break;
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default:
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// This is most likely LZMA_PROG_ERROR, but
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// if this program is buggy (or liblzma has
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// a bug), it may be e.g. LZMA_BUF_ERROR or
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// LZMA_OPTIONS_ERROR too.
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//
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// It is inconvenient to have a separate
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// error message for errors that should be
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// impossible to occur, but knowing the error
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// code is important for debugging. That's why
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// it is good to print the error code at least
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// when there is no good error message to show.
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msg = "Unknown error, possibly a bug";
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break;
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}
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fprintf(stderr, "Encoder error: %s (error code %u)\n",
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msg, ret);
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return false;
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}
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}
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}
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extern int
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main(int argc, char **argv)
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{
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// Get the preset number from the command line.
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uint32_t preset = get_preset(argc, argv);
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// Initialize a lzma_stream structure. When it is allocated on stack,
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// it is simplest to use LZMA_STREAM_INIT macro like below. When it
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// is allocated on heap, using memset(strmptr, 0, sizeof(*strmptr))
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// works (as long as NULL pointers are represented with zero bits
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// as they are on practically all computers today).
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lzma_stream strm = LZMA_STREAM_INIT;
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// Initialize the encoder. If it succeeds, compress from
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// stdin to stdout.
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bool success = init_encoder(&strm, preset);
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if (success)
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success = compress(&strm, stdin, stdout);
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// Free the memory allocated for the encoder. If we were encoding
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// multiple files, this would only need to be done after the last
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// file. See 02_decompress.c for handling of multiple files.
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//
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// It is OK to call lzma_end() multiple times or when it hasn't been
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// actually used except initialized with LZMA_STREAM_INIT.
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lzma_end(&strm);
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// Close stdout to catch possible write errors that can occur
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// when pending data is flushed from the stdio buffers.
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if (fclose(stdout)) {
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fprintf(stderr, "Write error: %s\n", strerror(errno));
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success = false;
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}
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return success ? EXIT_SUCCESS : EXIT_FAILURE;
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}
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///////////////////////////////////////////////////////////////////////////////
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//
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/// \file 02_decompress.c
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/// \brief Decompress .xz files to stdout
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///
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/// Usage: ./02_decompress INPUT_FILES... > OUTFILE
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///
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/// Example: ./02_decompress foo.xz bar.xz > foobar
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//
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// Author: Lasse Collin
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//
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// This file has been put into the public domain.
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// You can do whatever you want with this file.
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//
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///////////////////////////////////////////////////////////////////////////////
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#include <stdbool.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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#include <lzma.h>
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static bool
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init_decoder(lzma_stream *strm)
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{
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// Initialize a .xz decoder. The decoder supports a memory usage limit
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// and a set of flags.
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//
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// The memory usage of the decompressor depends on the settings used
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// to compress a .xz file. It can vary from less than a megabyte to
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// a few gigabytes, but in practice (at least for now) it rarely
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// exceeds 65 MiB because that's how much memory is required to
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// decompress files created with "xz -9". Settings requiring more
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// memory take extra effort to use and don't (at least for now)
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// provide significantly better compression in most cases.
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//
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// Memory usage limit is useful if it is important that the
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// decompressor won't consume gigabytes of memory. The need
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// for limiting depends on the application. In this example,
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// no memory usage limiting is used. This is done by setting
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// the limit to UINT64_MAX.
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//
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// The .xz format allows concatenating compressed files as is:
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//
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// echo foo | xz > foobar.xz
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// echo bar | xz >> foobar.xz
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//
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// When decompressing normal standalone .xz files, LZMA_CONCATENATED
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// should always be used to support decompression of concatenated
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// .xz files. If LZMA_CONCATENATED isn't used, the decoder will stop
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// after the first .xz stream. This can be useful when .xz data has
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// been embedded inside another file format.
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//
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// Flags other than LZMA_CONCATENATED are supported too, and can
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// be combined with bitwise-or. See lzma/container.h
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// (src/liblzma/api/lzma/container.h in the source package or e.g.
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// /usr/include/lzma/container.h depending on the install prefix)
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// for details.
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lzma_ret ret = lzma_stream_decoder(
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strm, UINT64_MAX, LZMA_CONCATENATED);
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// Return successfully if the initialization went fine.
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if (ret == LZMA_OK)
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return true;
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// Something went wrong. The possible errors are documented in
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// lzma/container.h (src/liblzma/api/lzma/container.h in the source
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// package or e.g. /usr/include/lzma/container.h depending on the
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// install prefix).
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//
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// Note that LZMA_MEMLIMIT_ERROR is never possible here. If you
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// specify a very tiny limit, the error will be delayed until
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// the first headers have been parsed by a call to lzma_code().
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const char *msg;
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switch (ret) {
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case LZMA_MEM_ERROR:
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msg = "Memory allocation failed";
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break;
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case LZMA_OPTIONS_ERROR:
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msg = "Unsupported decompressor flags";
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break;
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default:
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// This is most likely LZMA_PROG_ERROR indicating a bug in
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// this program or in liblzma. It is inconvenient to have a
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// separate error message for errors that should be impossible
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// to occur, but knowing the error code is important for
|
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// debugging. That's why it is good to print the error code
|
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// at least when there is no good error message to show.
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msg = "Unknown error, possibly a bug";
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break;
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}
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fprintf(stderr, "Error initializing the decoder: %s (error code %u)\n",
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msg, ret);
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return false;
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}
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static bool
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decompress(lzma_stream *strm, const char *inname, FILE *infile, FILE *outfile)
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{
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// When LZMA_CONCATENATED flag was used when initializing the decoder,
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// we need to tell lzma_code() when there will be no more input.
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// This is done by setting action to LZMA_FINISH instead of LZMA_RUN
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// in the same way as it is done when encoding.
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//
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// When LZMA_CONCATENATED isn't used, there is no need to use
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// LZMA_FINISH to tell when all the input has been read, but it
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// is still OK to use it if you want. When LZMA_CONCATENATED isn't
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// used, the decoder will stop after the first .xz stream. In that
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// case some unused data may be left in strm->next_in.
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lzma_action action = LZMA_RUN;
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uint8_t inbuf[BUFSIZ];
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uint8_t outbuf[BUFSIZ];
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strm->next_in = NULL;
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strm->avail_in = 0;
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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 && !feof(infile)) {
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strm->next_in = inbuf;
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strm->avail_in = fread(inbuf, 1, sizeof(inbuf),
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infile);
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if (ferror(infile)) {
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fprintf(stderr, "%s: Read error: %s\n",
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inname, strerror(errno));
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return false;
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}
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// Once the end of the input file has been reached,
|
||||
// we need to tell lzma_code() that no more input
|
||||
// will be coming. As said before, this isn't required
|
||||
// if the LZMA_CONATENATED flag isn't used when
|
||||
// initializing the decoder.
|
||||
if (feof(infile))
|
||||
action = LZMA_FINISH;
|
||||
}
|
||||
|
||||
lzma_ret ret = lzma_code(strm, action);
|
||||
|
||||
if (strm->avail_out == 0 || ret == LZMA_STREAM_END) {
|
||||
size_t write_size = sizeof(outbuf) - strm->avail_out;
|
||||
|
||||
if (fwrite(outbuf, 1, write_size, outfile)
|
||||
!= write_size) {
|
||||
fprintf(stderr, "Write error: %s\n",
|
||||
strerror(errno));
|
||||
return false;
|
||||
}
|
||||
|
||||
strm->next_out = outbuf;
|
||||
strm->avail_out = sizeof(outbuf);
|
||||
}
|
||||
|
||||
if (ret != LZMA_OK) {
|
||||
// Once everything has been decoded successfully, the
|
||||
// return value of lzma_code() will be LZMA_STREAM_END.
|
||||
//
|
||||
// It is important to check for LZMA_STREAM_END. Do not
|
||||
// assume that getting ret != LZMA_OK would mean that
|
||||
// everything has gone well or that when you aren't
|
||||
// getting more output it must have successfully
|
||||
// decoded everything.
|
||||
if (ret == LZMA_STREAM_END)
|
||||
return true;
|
||||
|
||||
// It's not LZMA_OK nor LZMA_STREAM_END,
|
||||
// so it must be an error code. See lzma/base.h
|
||||
// (src/liblzma/api/lzma/base.h in the source package
|
||||
// or e.g. /usr/include/lzma/base.h depending on the
|
||||
// install prefix) for the list and documentation of
|
||||
// possible values. Many values listen in lzma_ret
|
||||
// enumeration aren't possible in this example, but
|
||||
// can be made possible by enabling memory usage limit
|
||||
// or adding flags to the decoder initialization.
|
||||
const char *msg;
|
||||
switch (ret) {
|
||||
case LZMA_MEM_ERROR:
|
||||
msg = "Memory allocation failed";
|
||||
break;
|
||||
|
||||
case LZMA_FORMAT_ERROR:
|
||||
// .xz magic bytes weren't found.
|
||||
msg = "The input is not in the .xz format";
|
||||
break;
|
||||
|
||||
case LZMA_OPTIONS_ERROR:
|
||||
// For example, the headers specify a filter
|
||||
// that isn't supported by this liblzma
|
||||
// version (or it hasn't been enabled when
|
||||
// building liblzma, but no-one sane does
|
||||
// that unless building liblzma for an
|
||||
// embedded system). Upgrading to a newer
|
||||
// liblzma might help.
|
||||
//
|
||||
// Note that it is unlikely that the file has
|
||||
// accidentally became corrupt if you get this
|
||||
// error. The integrity of the .xz headers is
|
||||
// always verified with a CRC32, so
|
||||
// unintentionally corrupt files can be
|
||||
// distinguished from unsupported files.
|
||||
msg = "Unsupported compression options";
|
||||
break;
|
||||
|
||||
case LZMA_DATA_ERROR:
|
||||
msg = "Compressed file is corrupt";
|
||||
break;
|
||||
|
||||
case LZMA_BUF_ERROR:
|
||||
// Typically this error means that a valid
|
||||
// file has got truncated, but it might also
|
||||
// be a damaged part in the file that makes
|
||||
// the decoder think the file is truncated.
|
||||
// If you prefer, you can use the same error
|
||||
// message for this as for LZMA_DATA_ERROR.
|
||||
msg = "Compressed file is truncated or "
|
||||
"otherwise corrupt";
|
||||
break;
|
||||
|
||||
default:
|
||||
// This is most likely LZMA_PROG_ERROR.
|
||||
msg = "Unknown error, possibly a bug";
|
||||
break;
|
||||
}
|
||||
|
||||
fprintf(stderr, "%s: Decoder error: "
|
||||
"%s (error code %u)\n",
|
||||
inname, msg, ret);
|
||||
return false;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
extern int
|
||||
main(int argc, char **argv)
|
||||
{
|
||||
if (argc <= 1) {
|
||||
fprintf(stderr, "Usage: %s FILES...\n", argv[0]);
|
||||
return EXIT_FAILURE;
|
||||
}
|
||||
|
||||
lzma_stream strm = LZMA_STREAM_INIT;
|
||||
|
||||
bool success = true;
|
||||
|
||||
// Try to decompress all files.
|
||||
for (int i = 1; i < argc; ++i) {
|
||||
if (!init_decoder(&strm)) {
|
||||
// Decoder initialization failed. There's no point
|
||||
// to retry it so we need to exit.
|
||||
success = false;
|
||||
break;
|
||||
}
|
||||
|
||||
FILE *infile = fopen(argv[i], "rb");
|
||||
|
||||
if (infile == NULL) {
|
||||
fprintf(stderr, "%s: Error opening the "
|
||||
"input file: %s\n",
|
||||
argv[i], strerror(errno));
|
||||
success = false;
|
||||
} else {
|
||||
success &= decompress(&strm, argv[i], infile, stdout);
|
||||
fclose(infile);
|
||||
}
|
||||
}
|
||||
|
||||
// Free the memory allocated for the decoder. This only needs to be
|
||||
// done after the last file.
|
||||
lzma_end(&strm);
|
||||
|
||||
if (fclose(stdout)) {
|
||||
fprintf(stderr, "Write error: %s\n", strerror(errno));
|
||||
success = false;
|
||||
}
|
||||
|
||||
return success ? EXIT_SUCCESS : EXIT_FAILURE;
|
||||
}
|
||||
|
|
@ -0,0 +1,193 @@
|
|||
///////////////////////////////////////////////////////////////////////////////
|
||||
//
|
||||
/// \file 03_compress_custom.c
|
||||
/// \brief Compress in multi-call mode using x86 BCJ and LZMA2
|
||||
///
|
||||
/// Usage: ./03_compress_custom < INFILE > OUTFILE
|
||||
///
|
||||
/// Example: ./03_compress_custom < foo > foo.xz
|
||||
//
|
||||
// Author: Lasse Collin
|
||||
//
|
||||
// This file has been put into the public domain.
|
||||
// You can do whatever you want with this file.
|
||||
//
|
||||
///////////////////////////////////////////////////////////////////////////////
|
||||
|
||||
#include <stdbool.h>
|
||||
#include <stdlib.h>
|
||||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
#include <errno.h>
|
||||
#include <lzma.h>
|
||||
|
||||
|
||||
static bool
|
||||
init_encoder(lzma_stream *strm)
|
||||
{
|
||||
// Use the default preset (6) for LZMA2.
|
||||
//
|
||||
// The lzma_options_lzma structure and the lzma_lzma_preset() function
|
||||
// are declared in lzma/lzma.h (src/liblzma/api/lzma/lzma.h in the
|
||||
// source package or e.g. /usr/include/lzma/lzma.h depending on
|
||||
// the install prefix).
|
||||
lzma_options_lzma opt_lzma2;
|
||||
if (lzma_lzma_preset(&opt_lzma2, LZMA_PRESET_DEFAULT)) {
|
||||
// It should never fail because the default preset
|
||||
// (and presets 0-9 optionally with LZMA_PRESET_EXTREME)
|
||||
// are supported by all stable liblzma versions.
|
||||
//
|
||||
// (The encoder initialization later in this function may
|
||||
// still fail due to unsupported preset *if* the features
|
||||
// required by the preset have been disabled at build time,
|
||||
// but no-one does such things except on embedded systems.)
|
||||
fprintf(stderr, "Unsupported preset, possibly a bug\n");
|
||||
return false;
|
||||
}
|
||||
|
||||
// Now we could customize the LZMA2 options if we wanted. For example,
|
||||
// we could set the the dictionary size (opt_lzma2.dict_size) to
|
||||
// something else than the default (8 MiB) of the default preset.
|
||||
// See lzma/lzma.h for details of all LZMA2 options.
|
||||
//
|
||||
// The x86 BCJ filter will try to modify the x86 instruction stream so
|
||||
// that LZMA2 can compress it better. The x86 BCJ filter doesn't need
|
||||
// any options so it will be set to NULL below.
|
||||
//
|
||||
// Construct the filter chain. The uncompressed data goes first to
|
||||
// the first filter in the array, in this case the x86 BCJ filter.
|
||||
// The array is always terminated by setting .id = LZMA_VLI_UNKNOWN.
|
||||
//
|
||||
// See lzma/filter.h for more information about the lzma_filter
|
||||
// structure.
|
||||
lzma_filter filters[] = {
|
||||
{ .id = LZMA_FILTER_X86, .options = NULL },
|
||||
{ .id = LZMA_FILTER_LZMA2, .options = &opt_lzma2 },
|
||||
{ .id = LZMA_VLI_UNKNOWN, .options = NULL },
|
||||
};
|
||||
|
||||
// Initialize the encoder using the custom filter chain.
|
||||
lzma_ret ret = lzma_stream_encoder(strm, filters, LZMA_CHECK_CRC64);
|
||||
|
||||
if (ret == LZMA_OK)
|
||||
return true;
|
||||
|
||||
const char *msg;
|
||||
switch (ret) {
|
||||
case LZMA_MEM_ERROR:
|
||||
msg = "Memory allocation failed";
|
||||
break;
|
||||
|
||||
case LZMA_OPTIONS_ERROR:
|
||||
// We are no longer using a plain preset so this error
|
||||
// message has been edited accordingly compared to
|
||||
// 01_compress_easy.c.
|
||||
msg = "Specified filter chain is not supported";
|
||||
break;
|
||||
|
||||
case LZMA_UNSUPPORTED_CHECK:
|
||||
msg = "Specified integrity check is not supported";
|
||||
break;
|
||||
|
||||
default:
|
||||
msg = "Unknown error, possibly a bug";
|
||||
break;
|
||||
}
|
||||
|
||||
fprintf(stderr, "Error initializing the encoder: %s (error code %u)\n",
|
||||
msg, ret);
|
||||
return false;
|
||||
}
|
||||
|
||||
|
||||
// This function is identical to the one in 01_compress_easy.c.
|
||||
static bool
|
||||
compress(lzma_stream *strm, FILE *infile, FILE *outfile)
|
||||
{
|
||||
lzma_action action = LZMA_RUN;
|
||||
|
||||
uint8_t inbuf[BUFSIZ];
|
||||
uint8_t outbuf[BUFSIZ];
|
||||
|
||||
strm->next_in = NULL;
|
||||
strm->avail_in = 0;
|
||||
strm->next_out = outbuf;
|
||||
strm->avail_out = sizeof(outbuf);
|
||||
|
||||
while (true) {
|
||||
if (strm->avail_in == 0 && !feof(infile)) {
|
||||
strm->next_in = inbuf;
|
||||
strm->avail_in = fread(inbuf, 1, sizeof(inbuf),
|
||||
infile);
|
||||
|
||||
if (ferror(infile)) {
|
||||
fprintf(stderr, "Read error: %s\n",
|
||||
strerror(errno));
|
||||
return false;
|
||||
}
|
||||
|
||||
if (feof(infile))
|
||||
action = LZMA_FINISH;
|
||||
}
|
||||
|
||||
lzma_ret ret = lzma_code(strm, action);
|
||||
|
||||
if (strm->avail_out == 0 || ret == LZMA_STREAM_END) {
|
||||
size_t write_size = sizeof(outbuf) - strm->avail_out;
|
||||
|
||||
if (fwrite(outbuf, 1, write_size, outfile)
|
||||
!= write_size) {
|
||||
fprintf(stderr, "Write error: %s\n",
|
||||
strerror(errno));
|
||||
return false;
|
||||
}
|
||||
|
||||
strm->next_out = outbuf;
|
||||
strm->avail_out = sizeof(outbuf);
|
||||
}
|
||||
|
||||
if (ret != LZMA_OK) {
|
||||
if (ret == LZMA_STREAM_END)
|
||||
return true;
|
||||
|
||||
const char *msg;
|
||||
switch (ret) {
|
||||
case LZMA_MEM_ERROR:
|
||||
msg = "Memory allocation failed";
|
||||
break;
|
||||
|
||||
case LZMA_DATA_ERROR:
|
||||
msg = "File size limits exceeded";
|
||||
break;
|
||||
|
||||
default:
|
||||
msg = "Unknown error, possibly a bug";
|
||||
break;
|
||||
}
|
||||
|
||||
fprintf(stderr, "Encoder error: %s (error code %u)\n",
|
||||
msg, ret);
|
||||
return false;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
extern int
|
||||
main(void)
|
||||
{
|
||||
lzma_stream strm = LZMA_STREAM_INIT;
|
||||
|
||||
bool success = init_encoder(&strm);
|
||||
if (success)
|
||||
success = compress(&strm, stdin, stdout);
|
||||
|
||||
lzma_end(&strm);
|
||||
|
||||
if (fclose(stdout)) {
|
||||
fprintf(stderr, "Write error: %s\n", strerror(errno));
|
||||
success = false;
|
||||
}
|
||||
|
||||
return success ? EXIT_SUCCESS : EXIT_FAILURE;
|
||||
}
|
||||
|
|
@ -0,0 +1,23 @@
|
|||
#
|
||||
# Author: Lasse Collin
|
||||
#
|
||||
# This file has been put into the public domain.
|
||||
# You can do whatever you want with this file.
|
||||
#
|
||||
|
||||
CC = c99
|
||||
CFLAGS = -g
|
||||
LDFLAGS = -llzma
|
||||
|
||||
PROGS = \
|
||||
01_compress_easy \
|
||||
02_decompress \
|
||||
03_compress_custom
|
||||
|
||||
all: $(PROGS)
|
||||
|
||||
.c:
|
||||
$(CC) $(CFLAGS) -o $@ $< $(LDFLAGS)
|
||||
|
||||
clean:
|
||||
-rm -f $(PROGS)
|
||||
Loading…
Reference in New Issue