Make read_tempfile() much faster, and make it close the file also on error.

[cubemap] / util.cpp

diff --git a/util.cpp b/util.cpp
index a5d6378fd6817ac5921f7009e7a1b9166794dd43..b79c6c3dccd5e0a58ca2f25a09b28c6d223bdd64 100644 (file)
--- a/util.cpp
+++ b/util.cpp
@@ -41,27 +41,41 @@ int make_tempfile(const std::string &contents)
 
 bool read_tempfile(int fd, std::string *contents)
 {
+       bool ok = true;
+       ssize_t ret, has_read;
+
+       off_t len = lseek(fd, 0, SEEK_END);
+       if (len == -1) {
+               perror("lseek");
+               ok = false;
+               goto done;
+       }
+
+       contents->resize(len);
+
        if (lseek(fd, 0, SEEK_SET) == -1) {
                perror("lseek");
-               return false;
+               ok = false;
+               goto done;
        }
 
-       char buf[4096];
-       for ( ;; ) {
-               ssize_t ret = read(fd, buf, sizeof(buf));
+       has_read = 0;
+       while (has_read < len) {
+               ret = read(fd, &((*contents)[has_read]), len - has_read);
                if (ret == -1) {
                        perror("read");
-                       return false;
+                       ok = false;
+                       goto done;
                }
                if (ret == 0) {
-                       // EOF.
-                       break;
+                       fprintf(stderr, "Unexpected EOF!\n");
+                       ok = false;
+                       goto done;
                }
-
-               contents->append(string(buf, buf + ret));
+               has_read += ret;
        }
 
-       int ret;
+done:
        do {
                ret = close(fd);  // Implicitly deletes the files.
        } while (ret == -1 && errno == EINTR);
@@ -71,5 +85,5 @@ bool read_tempfile(int fd, std::string *contents)
                // Can still continue.
        }
 
-       return true;
+       return ok;
 }