Move the “read the whole file” logic into a new file.

[cubemap] / util.cpp

diff --git a/util.cpp b/util.cpp
new file mode 100644 (file)
index 0000000..c8e26d2
--- /dev/null
+++ b/util.cpp
@@ -0,0 +1,74 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "util.h"
+
+using namespace std;
+
+int make_tempfile(const std::string &contents)
+{
+       char filename[] = "/tmp/cubemap.XXXXXX";
+       int fd = mkstemp(filename);
+       if (fd == -1) {
+               perror("mkstemp");
+               return -1;
+       }
+
+       if (unlink(filename) == -1) {
+               perror("unlink");
+               // Can still continue;
+       }
+
+       const char *ptr = contents.data();
+       size_t to_write = contents.size();
+       while (to_write > 0) {
+               ssize_t ret = write(fd, ptr, to_write);
+               if (ret == -1) {
+                       perror("write");
+                       close(fd);
+                       return -1;
+               }
+
+               ptr += ret;
+               to_write -= ret;
+       }
+
+       return fd;
+}
+
+bool read_tempfile(int fd, std::string *contents)
+{
+       if (lseek(fd, 0, SEEK_SET) == -1) {
+               perror("lseek");
+               return false;
+       }
+
+       char buf[4096];
+       for ( ;; ) {
+               ssize_t ret = read(fd, buf, sizeof(buf));
+               if (ret == -1) {
+                       perror("read");
+                       return false;
+               }
+               if (ret == 0) {
+                       // EOF.
+                       break;
+               }
+
+               contents->append(string(buf, buf + ret));
+       }
+
+       int ret;
+       do {
+               ret = close(fd);  // Implicitly deletes the files.
+       } while (ret == -1 && errno == EINTR);
+       
+       if (ret == -1) {
+               perror("close");
+               // Can still continue.
+       }
+
+       return true;
+}