ref: fc4bfd57d261e5c99c5d4367adf5c72e8c7e6496
dir: /sys/src/cmd/gzip/gzip.c/
#include <u.h> #include <libc.h> #include <bio.h> #include <flate.h> #include "gzip.h" static int gzipf(char*, int); static int gzip(char*, long, int, Biobuf*); static int crcread(void *fd, void *buf, int n); static int gzwrite(void *bout, void *buf, int n); static Biobuf bout; static ulong crc; static ulong *crctab; static int debug; static int eof; static int level; static ulong totr; static int verbose; void usage(void) { fprint(2, "usage: gzip [-vcD] [-1-9] [file ...]\n"); exits("usage"); } void main(int argc, char *argv[]) { int i, ok, stdout; level = 6; stdout = 0; ARGBEGIN{ case 'D': debug++; break; case 'v': verbose++; break; case 'c': stdout = 1; break; case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': level = ARGC() - '0'; break; default: usage(); break; }ARGEND crctab = mkcrctab(GZCRCPOLY); ok = deflateinit(); if(ok != FlateOk) sysfatal("deflateinit failed: %s", flateerr(ok)); if(argc == 0){ Binit(&bout, 1, OWRITE); ok = gzip(nil, time(0), 0, &bout); Bterm(&bout); }else{ ok = 1; for(i = 0; i < argc; i++) ok &= gzipf(argv[i], stdout); } exits(ok ? nil: "errors"); } static int gzipf(char *file, int stdout) { Dir *dir; char ofile[256], *f, *s; int ifd, ofd, ok; ifd = open(file, OREAD); if(ifd < 0){ fprint(2, "gzip: can't open %s: %r\n", file); return 0; } dir = dirfstat(ifd); if(dir == nil){ fprint(2, "gzip: can't stat %s: %r\n", file); close(ifd); return 0; } if(dir->mode & DMDIR){ fprint(2, "gzip: can't compress a directory\n"); close(ifd); free(dir); return 0; } if(stdout){ ofd = 1; strcpy(ofile, "<stdout>"); }else{ f = strrchr(file, '/'); if(f != nil) f++; else f = file; s = strrchr(f, '.'); if(s != nil && s != ofile && strcmp(s, ".tar") == 0){ *s = '\0'; snprint(ofile, sizeof(ofile), "%s.tgz", f); }else snprint(ofile, sizeof(ofile), "%s.gz", f); ofd = create(ofile, OWRITE, 0666); if(ofd < 0){ fprint(2, "gzip: can't open %s: %r\n", ofile); close(ifd); return 0; } } if(verbose) fprint(2, "compressing %s to %s\n", file, ofile); Binit(&bout, ofd, OWRITE); ok = gzip(file, dir->mtime, ifd, &bout); if(!ok || Bflush(&bout) < 0){ fprint(2, "gzip: error writing %s: %r\n", ofile); if(!stdout) remove(ofile); } Bterm(&bout); free(dir); close(ifd); close(ofd); return ok; } static int gzip(char *file, long mtime, int ifd, Biobuf *bout) { int flags, err; flags = 0; Bputc(bout, GZMAGIC1); Bputc(bout, GZMAGIC2); Bputc(bout, GZDEFLATE); if(file != nil) flags |= GZFNAME; Bputc(bout, flags); Bputc(bout, mtime); Bputc(bout, mtime>>8); Bputc(bout, mtime>>16); Bputc(bout, mtime>>24); Bputc(bout, 0); Bputc(bout, GZOSINFERNO); if(flags & GZFNAME) Bwrite(bout, file, strlen(file)+1); crc = 0; eof = 0; totr = 0; err = deflate(bout, gzwrite, (void*)ifd, crcread, level, debug); if(err != FlateOk){ fprint(2, "gzip: deflate failed: %s\n", flateerr(err)); return 0; } Bputc(bout, crc); Bputc(bout, crc>>8); Bputc(bout, crc>>16); Bputc(bout, crc>>24); Bputc(bout, totr); Bputc(bout, totr>>8); Bputc(bout, totr>>16); Bputc(bout, totr>>24); return 1; } static int crcread(void *fd, void *buf, int n) { int nr, m; nr = 0; for(; !eof && n > 0; n -= m){ m = read((int)(uintptr)fd, (char*)buf+nr, n); if(m <= 0){ eof = 1; if(m < 0) return -1; break; } nr += m; } crc = blockcrc(crctab, crc, buf, nr); totr += nr; return nr; } static int gzwrite(void *bout, void *buf, int n) { if(n != Bwrite(bout, buf, n)){ eof = 1; return -1; } return n; }