Implement reading over the file/writebuffer boundary

1 files changed, 17 insertions, 6 deletions

diff --git a/c_src/filebuffer.c b/c_src/filebuffer.c
index d35bfa7..fb06c64 100644
--- a/c_src/filebuffer.c
+++ b/c_src/filebuffer.c
@@ -163,12 +163,23 @@ bf_read(buffered_file *file, uint64_t offset, size_t length, char **error)
             memcpy(result, file->writebuffer + writebufferoffset, length);
     } else {
             if (offset + length > file->filesize) {
-                    free(result);
-                    set_error(error,
-                              "pread: trying to read over file/writebuffer "
-                              "boundary for offset %llu and length %zu\n",
-                              (long long unsigned int) offset, length);
-                    return NULL;
+                    uint64_t offset_1 = offset;
+                    size_t length_1 = file->filesize - offset;
+                    uint64_t offset_2 = offset_1 + length_1;
+                    size_t length_2 = length - length_1;
+                    unsigned char *result_1 = bf_read(file, offset_1, length_1, error);
+                    unsigned char *result_2 = bf_read(file, offset_2, length_2, error);
+                    if (result_1 == NULL || result_2 == NULL) {
+                            free(result_1);
+                            free(result_2);
+                            free(result);
+                            return NULL;
+                    }
+                    memcpy(result, result_1, length_1);
+                    memcpy(result + length_1, result_2, length_2);
+                    free(result_1);
+                    free(result_2);
+                    return result;
             }
 
 	    size_t bytes_read = 0;