source: trunk/lib/libtraceio-zlib.c @ 1155

#include "libtraceio.h"
#include <zlib.h>
#include <stdlib.h>
#include <errno.h>

struct libtrace_io_t {
        gzFile file;
};

ssize_t libtrace_io_read(libtrace_io_t *io, void *buf, size_t len)
{
        int err=gzread(io->file,buf,(unsigned) len);
        int err2=errno;
        if (err>=0) {
                /* successfully read <x> bytes */
                return (ssize_t)err;
        }
        switch(err) {
                case Z_STREAM_END:
                        return 0;
                case Z_ERRNO: 
                        if (err2==0)
                                return 0; /* EOF */
                        return -1;
                case Z_MEM_ERROR:
                        errno=ENOMEM;
                        return -1;
                default:
                      /* Some decompression error or something */
                      errno=EINVAL;
                      return -1;
        }
}

libtrace_io_t *libtrace_io_fdopen(int fd, const char *mode)
{
        libtrace_io_t *io = (libtrace_io_t*)malloc(sizeof(libtrace_io_t));
        if (io == NULL)
                return NULL;
        io->file = gzdopen(fd,mode);
        if (!io->file) {
                free(io);
                return NULL;
        }
        return io;
}

libtrace_io_t *libtrace_io_open(const char *path, const char *mode)
{
        libtrace_io_t *io = (libtrace_io_t*)malloc(sizeof(libtrace_io_t));
        if (io == NULL)
                return NULL;
        io->file = gzopen(path,mode);
        return io;
}

/* Technically close returns -1 on failure, but if the close fails, really
 * what are you going to do about it?
 */
void libtrace_io_close(libtrace_io_t *io)
{
        (void)gzclose(io->file);
        io->file=NULL;
        free(io);
}

ssize_t libtrace_io_write(libtrace_io_t *io, const void *buf, size_t len)
{
        /* gzip doesn't like writing 0 bytes - tends to break the
         * crc calculations */
        if (len == 0)
                return 0;
        return (ssize_t)gzwrite(io->file,buf,(unsigned)len);
}

off_t libtrace_io_seek(libtrace_io_t *io, off_t offset, int whence)
{
        return gzseek(io->file,offset,whence);
}

ssize_t libtrace_io_tell(libtrace_io_t *io)
{
        return (ssize_t)gztell(io->file);
}