Compress _pages.ppm for faster execution (less disk traffic)

[ypp-sc-tools.web-live.git] / pctb / common.c

diff --git a/pctb/common.c b/pctb/common.c
index 2c2a085a30e9fdaa7ded64ffa7b10c82f31208ac..f95e585866657f8d8e29c19c7c31b5daeae9c977 100644 (file)
--- a/pctb/common.c
+++ b/pctb/common.c
@@ -49,31 +49,12 @@ int dbfile_gzopen(const char *basepath_spec) {
   assert(!dbfile);
 
   basepath= basepath_spec;
-  //uncomppath= masprintf("%s (uncompressed)", basepath);
 
   char *zpath= masprintf("%s.gz", basepath);
-  int zfd= open(zpath, O_RDONLY);
+  int e= gzopen(zpath, O_RDONLY, &dbfile, &dbzcat, 0);
   free(zpath);
-
-  if (zfd<0) { sysassert(errno==ENOENT); return 0; }
-
-  int pipefds[2];
-  sysassert(! pipe(pipefds) );
-
-  sysassert( (dbzcat=fork()) != -1 );
-  if (!dbzcat) {
-    sysassert( dup2(zfd,0)==0 );
-    sysassert( dup2(pipefds[1],1)==1 );
-    sysassert(! close(zfd) );
-    sysassert(! close(pipefds[0]) );
-    sysassert(! close(pipefds[1]) );
-    execlp("zcat","zcat",(char*)0);
-    sysassert(!"execlp zcat");
-  }
-  sysassert(! close(zfd) );
-  sysassert(! close(pipefds[1]) );
-  sysassert( dbfile= fdopen(pipefds[0], "r") );
-
+  if (e) { errno=e; sysassert(errno==ENOENT); return 0; }
+  
   return 1;
 }  
 
@@ -89,19 +70,7 @@ int dbfile_open(const char *tpath) {
 }  
 
 void dbfile_close(void) {
-  if (!dbfile) return;
-
-  sysassert(!ferror(dbfile));
-  sysassert(!fclose(dbfile));
-
-  if (dbzcat != -1) {
-    char *zcatstr= masprintf("zcat %s.gz", basepath);
-    waitpid_check_exitstatus(dbzcat,zcatstr,1);
-    free(zcatstr);
-    dbzcat= -1;
-  }
-
-  dbfile= 0;
+  gzclose(&dbfile, &dbzcat, basepath);
 }
 
 #define dbassertgl(x) ((x) ? (void)0 : dbfile_assertfail(file,line,#x))
@@ -148,3 +117,52 @@ void dbfile_assertfail(const char *file, int line, const char *m) {
          " %s",
          file,line, m);
 }
+
+int gzopen(const char *zpath, int oflags, FILE **f_r, pid_t *pid_r,
+          const char *gziplevel /* 0 for read; may be 0, or "-1" etc. */) {
+
+  int zfd= open(zpath, oflags, 0666);
+  if (!zfd) return errno;
+
+  int pipefds[2];
+  sysassert(! pipe(pipefds) );
+
+  int oi,io; const char *cmd; const char *stdiomode;
+  switch ((oflags & O_ACCMODE)) {
+  case O_RDONLY: oi=0; io=1; cmd="gunzip"; stdiomode="r"; break;
+  case O_WRONLY: oi=1; io=0; cmd="gzip";   stdiomode="w"; break;
+  default: abort();
+  }
+
+  sysassert( (*pid_r=fork()) != -1 );
+  if (!*pid_r) {
+    sysassert( dup2(zfd,oi)==oi );
+    sysassert( dup2(pipefds[io],io)==io );
+    sysassert(! close(zfd) );
+    sysassert(! close(pipefds[0]) );
+    sysassert(! close(pipefds[1]) );
+    execlp(cmd,cmd,gziplevel,(char*)0);
+    sysassert(!"execlp gzip/gunzip");
+  }
+  sysassert(! close(zfd) );
+  sysassert(! close(pipefds[io]) );
+  sysassert( *f_r= fdopen(pipefds[oi], stdiomode) );
+
+  return 0;
+}
+
+void gzclose(FILE **f, pid_t *p, const char *what) {
+  if (!*f) return;
+  
+  sysassert(!ferror(*f));
+  sysassert(!fclose(*f));
+
+  if (*p != -1) {
+    char *process= masprintf("%s (de)compressor",what);
+    waitpid_check_exitstatus(*p,process,1);
+    free(process);
+    *p= -1;
+  }
+
+  *f= 0;
+}