Add lbx_mmap() to map archive members into memory.

Currently, the whole LBX archive is mapped into memory on the first call, then
offsets from that are returned.  If this proves to be problematic, it may have
to be changed.

diff --git a/src/lbx.c b/src/lbx.c
index 20c32e75ae7deb69b8389a7a041f924840585414..8ddcf1860ec51b6665767cb0d9bfc6738a900a2a 100644 (file)
--- a/src/lbx.c
+++ b/src/lbx.c
@@ -5,6 +5,9 @@
 #include <errno.h>
 #include <assert.h>
 
+#include <sys/stat.h>
+#include <sys/mman.h>
+
 #include "byteorder.h"
 #include "lbx.h"
 
@@ -265,12 +268,50 @@ size_t lbx_extract(struct lbx_state *lbx, size_t index, FILE *of)
        return _lbx_fextract(lbx, base, len, of);
 }
 
+void *lbx_mmap(struct lbx_state *lbx, size_t index, size_t *len)
+{
+       unsigned char *mapping;
+       struct stat statbuf;
+       size_t base;
+
+       if (index >= lbx->nfiles) {
+               lbx_errno = LBX_ERANGE;
+               return NULL;
+       }
+       
+       base = lbx->offsets[index];
+       *len = lbx->offsets[index+1] - lbx->offsets[index];
+
+       if (lbx->mem)
+               return lbx->mem + base;
+       
+       if (fstat(fileno(lbx->f), &statbuf) == -1) {
+               lbx_errno = -errno;
+               return NULL;
+       }
+
+       mapping = mmap(NULL, statbuf.st_size, PROT_READ, 0, fileno(lbx->f), 0);
+       if (mapping == MAP_FAILED) {
+               lbx_errno = -errno;
+               return NULL;
+       }
+
+       lbx->mem     = mapping;
+       lbx->memsize = statbuf.st_size;
+       return mapping + base;
+}
+
 void lbx_close(struct lbx_state *lbx)
 {
        if (!lbx) return;
 
-       if (lbx->f)
+       if (lbx->f) {
                fclose(lbx->f);
+               if (lbx->mem) {
+                       munmap(lbx->mem, lbx->memsize);
+               }
+       }
+
        free(lbx);
 }
 

diff --git a/src/lbx.h b/src/lbx.h
index 92c533b39c3aa47956f58cabab0ed21f820671c5..78e4502bec5f0f60167be60c63d35b765323507d 100644 (file)
--- a/src/lbx.h
+++ b/src/lbx.h
@@ -30,6 +30,7 @@ size_t lbx_numfiles(LBX *);
 /* File operations */
 int    lbx_stat(LBX *, size_t, struct lbx_statbuf *);
 size_t lbx_extract(LBX *, size_t, FILE *);
+void  *lbx_mmap(LBX *, size_t, size_t *);
 
 /* Misc operations */
 const char *lbx_strerror(void);