mirror of
https://git.tukaani.org/xz.git
synced 2024-04-04 12:36:23 +02:00
Docs: Add doc/examples/11_file_info.c.
This commit is contained in:
parent
1520f6ec80
commit
c2e29f06a7
2 changed files with 208 additions and 1 deletions
206
doc/examples/11_file_info.c
Normal file
206
doc/examples/11_file_info.c
Normal file
|
@ -0,0 +1,206 @@
|
|||
///////////////////////////////////////////////////////////////////////////////
|
||||
//
|
||||
/// \file 11_file_info.c
|
||||
/// \brief Get uncmopressed size of .xz file(s)
|
||||
///
|
||||
/// Usage: ./11_file_info INFILE1.xz [INFILEn.xz]...
|
||||
///
|
||||
/// Example: ./11_file_info 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 <inttypes.h>
|
||||
#include <stdlib.h>
|
||||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
#include <errno.h>
|
||||
#include <lzma.h>
|
||||
|
||||
|
||||
static bool
|
||||
print_file_size(lzma_stream *strm, FILE *infile, const char *filename)
|
||||
{
|
||||
// Get the file size. In standard C it can be done by seeking to
|
||||
// the end of the file and then getting the file position.
|
||||
// In POSIX one can use fstat() and then st_size from struct stat.
|
||||
// Also note that fseek() and ftell() use long and thus don't support
|
||||
// large files on 32-bit systems (POSIX versions fseeko() and
|
||||
// ftello() can support large files).
|
||||
if (fseek(infile, 0, SEEK_END)) {
|
||||
fprintf(stderr, "Error seeking the file `%s': %s\n",
|
||||
filename, strerror(errno));
|
||||
return false;
|
||||
}
|
||||
|
||||
const long file_size = ftell(infile);
|
||||
|
||||
// The decoder wants to start from the beginning of the .xz file.
|
||||
rewind(infile);
|
||||
|
||||
// Initialize the decoder.
|
||||
lzma_index *i;
|
||||
lzma_ret ret = lzma_file_info_decoder(strm, &i, UINT64_MAX,
|
||||
(uint64_t)file_size);
|
||||
switch (ret) {
|
||||
case LZMA_OK:
|
||||
// Initialization succeeded.
|
||||
break;
|
||||
|
||||
case LZMA_MEM_ERROR:
|
||||
fprintf(stderr, "Out of memory when initializing "
|
||||
"the .xz file info decoder\n");
|
||||
return false;
|
||||
|
||||
case LZMA_PROG_ERROR:
|
||||
default:
|
||||
fprintf(stderr, "Unknown error, possibly a bug\n");
|
||||
return false;
|
||||
}
|
||||
|
||||
// This example program reuses the same lzma_stream structure
|
||||
// for multiple files, so we need to reset this when starting
|
||||
// a new file.
|
||||
strm->avail_in = 0;
|
||||
|
||||
// Buffer for input data.
|
||||
uint8_t inbuf[BUFSIZ];
|
||||
|
||||
// Pass data to the decoder and seek when needed.
|
||||
while (true) {
|
||||
if (strm->avail_in == 0) {
|
||||
strm->next_in = inbuf;
|
||||
strm->avail_in = fread(inbuf, 1, sizeof(inbuf),
|
||||
infile);
|
||||
|
||||
if (ferror(infile)) {
|
||||
fprintf(stderr,
|
||||
"Error reading from `%s': %s\n",
|
||||
filename, strerror(errno));
|
||||
return false;
|
||||
}
|
||||
|
||||
// We don't need to care about hitting the end of
|
||||
// the file so no need to check for feof().
|
||||
}
|
||||
|
||||
ret = lzma_code(strm, LZMA_RUN);
|
||||
|
||||
switch (ret) {
|
||||
case LZMA_OK:
|
||||
break;
|
||||
|
||||
case LZMA_SEEK_NEEDED:
|
||||
// The cast is safe because liblzma won't ask us to
|
||||
// seek past the known size of the input file which
|
||||
// did fit into a long.
|
||||
//
|
||||
// NOTE: Remember to change these to off_t if you
|
||||
// switch fseeko() or lseek().
|
||||
if (fseek(infile, (long)(strm->seek_pos), SEEK_SET)) {
|
||||
fprintf(stderr, "Error seeking the "
|
||||
"file `%s': %s\n",
|
||||
filename, strerror(errno));
|
||||
return false;
|
||||
}
|
||||
|
||||
// The old data in the inbuf is useless now. Set
|
||||
// avail_in to zero so that we will read new input
|
||||
// from the new file position on the next iteration
|
||||
// of this loop.
|
||||
strm->avail_in = 0;
|
||||
break;
|
||||
|
||||
case LZMA_STREAM_END:
|
||||
// File information was successfully decoded.
|
||||
// See <lzma/index.h> for functions that can be
|
||||
// used on it. In this example we just print
|
||||
// the uncompressed size (in bytes) of
|
||||
// the .xz file followed by its file name.
|
||||
printf("%10" PRIu64 " %s\n",
|
||||
lzma_index_uncompressed_size(i),
|
||||
filename);
|
||||
|
||||
// Free the memory of the lzma_index structure.
|
||||
lzma_index_end(i, NULL);
|
||||
|
||||
return true;
|
||||
|
||||
case LZMA_FORMAT_ERROR:
|
||||
// .xz magic bytes weren't found.
|
||||
fprintf(stderr, "The file `%s' is not "
|
||||
"in the .xz format\n", filename);
|
||||
return false;
|
||||
|
||||
case LZMA_OPTIONS_ERROR:
|
||||
fprintf(stderr, "The file `%s' has .xz headers that "
|
||||
"are not supported by this liblzma "
|
||||
"version\n", filename);
|
||||
return false;
|
||||
|
||||
case LZMA_DATA_ERROR:
|
||||
fprintf(stderr, "The file `%s' is corrupt\n",
|
||||
filename);
|
||||
return false;
|
||||
|
||||
case LZMA_MEM_ERROR:
|
||||
fprintf(stderr, "Memory allocation failed when "
|
||||
"decoding the file `%s'\n", filename);
|
||||
return false;
|
||||
|
||||
// LZMA_MEMLIMIT_ERROR shouldn't happen because we used
|
||||
// UINT64_MAX as the limit.
|
||||
//
|
||||
// LZMA_BUF_ERROR shouldn't happen because we always provide
|
||||
// new input when the input buffer is empty. The decoder
|
||||
// knows the input file size and thus won't try to read past
|
||||
// the end of the file.
|
||||
case LZMA_MEMLIMIT_ERROR:
|
||||
case LZMA_BUF_ERROR:
|
||||
case LZMA_PROG_ERROR:
|
||||
default:
|
||||
fprintf(stderr, "Unknown error, possibly a bug\n");
|
||||
return false;
|
||||
}
|
||||
}
|
||||
|
||||
// This line is never reached.
|
||||
}
|
||||
|
||||
|
||||
extern int
|
||||
main(int argc, char **argv)
|
||||
{
|
||||
bool success = true;
|
||||
lzma_stream strm = LZMA_STREAM_INIT;
|
||||
|
||||
for (int i = 1; i < argc; ++i) {
|
||||
FILE *infile = fopen(argv[i], "rb");
|
||||
|
||||
if (infile == NULL) {
|
||||
fprintf(stderr, "Cannot open the file `%s': %s\n",
|
||||
argv[i], strerror(errno));
|
||||
success = false;
|
||||
}
|
||||
|
||||
success &= print_file_size(&strm, infile, argv[i]);
|
||||
|
||||
(void)fclose(infile);
|
||||
}
|
||||
|
||||
lzma_end(&strm);
|
||||
|
||||
// Close stdout to catch possible write errors that can occur
|
||||
// when pending data is flushed from the stdio buffers.
|
||||
if (fclose(stdout)) {
|
||||
fprintf(stderr, "Write error: %s\n", strerror(errno));
|
||||
success = false;
|
||||
}
|
||||
|
||||
return success ? EXIT_SUCCESS : EXIT_FAILURE;
|
||||
}
|
|
@ -13,7 +13,8 @@ PROGS = \
|
|||
01_compress_easy \
|
||||
02_decompress \
|
||||
03_compress_custom \
|
||||
04_compress_easy_mt
|
||||
04_compress_easy_mt \
|
||||
11_file_info
|
||||
|
||||
all: $(PROGS)
|
||||
|
||||
|
|
Loading…
Reference in a new issue