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106 lines
2.8 KiB
C
106 lines
2.8 KiB
C
#include "pixz.h"
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#pragma mark FUNCTION DECLARATIONS
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static void extract_file(const char *target);
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static void extract_block(off_t block_seek, off_t skip, off_t size);
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#pragma mark FUNCTION DEFINITIONS
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int main(int argc, char **argv) {
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if (argc != 3)
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die("Need two arguments");
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if (!(gInFile = fopen(argv[1], "r")))
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die("Can't open input file");
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char *target = argv[2];
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decode_index();
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read_file_index();
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extract_file(target);
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free_file_index();
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lzma_index_end(gIndex, NULL);
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return 0;
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}
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static void extract_file(const char *target) {
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// find it in the index
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file_index_t *f;
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for (f = gFileIndex; f != NULL; f = f->next) {
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if (f->name && strcmp(f->name, target) == 0)
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break;
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}
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if (!f)
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die("Can't find target file");
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off_t fstart = f->offset, fsize = f->next->offset - fstart;
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// extract the data
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lzma_index_record rec;
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lzma_index_rewind(gIndex);
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while (fsize && !lzma_index_read(gIndex, &rec)) {
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off_t bstart = rec.uncompressed_offset,
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bsize = rec.uncompressed_size;
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if (fstart > bstart + bsize)
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continue;
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off_t dstart = fstart > bstart ? fstart - bstart : 0;
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bsize -= dstart;
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off_t dsize = fsize > bsize ? bsize : fsize;
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fsize -= dsize;
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extract_block(rec.stream_offset, dstart, dsize);
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}
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if (fsize)
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die("Block with file contents missing");
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}
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static void extract_block(off_t block_seek, off_t skip, off_t size) {
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void *bdata = decode_block_start(block_seek);
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uint8_t ibuf[CHUNKSIZE], obuf[CHUNKSIZE];
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gStream.avail_in = 0;
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lzma_ret err = LZMA_OK;
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while (size && err != LZMA_STREAM_END) {
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gStream.next_out = obuf;
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gStream.avail_out = CHUNKSIZE;
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if (gStream.avail_in == 0) {
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gStream.avail_in = fread(ibuf, 1, CHUNKSIZE, gInFile);
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if (ferror(gInFile))
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die("Error reading block data");
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gStream.next_in = ibuf;
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}
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err = lzma_code(&gStream, LZMA_RUN);
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if (err != LZMA_OK && err != LZMA_STREAM_END)
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die("Error decoding block");
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// do we want to write?
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uint8_t *start = obuf;
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size_t out = gStream.next_out - obuf;
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if (out <= skip) {
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skip -= out;
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continue;
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}
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// what do we want to write?
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start += skip;
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out -= skip;
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skip = 0;
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if (out > size)
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out = size;
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if (fwrite(start, out, 1, stdout) != 1)
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die("Error writing output");
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size -= out;
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}
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if (size)
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die("Block data missing");
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lzma_end(&gStream);
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free(bdata);
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}
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