add FileReader class

src/FileReader.cc

@@ -0,0 +1,74 @@
+#include "FileReader.h"
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#ifdef _WIN32
+#define JES_O_BINARY O_BINARY
+#else
+#define JES_O_BINARY 0
+#endif
+
+/**
+ * Load a file into memory.
+ *
+ * @param[in] fname File name.
+ * @param[out] buf Pointer to memory buffer containing file. Must be freed by
+ *   caller with delete[].
+ * @param[out] size Set to length of the file. If the return value is true
+ *   and *size is 0, then no buffer was allocated and *buf should not be used.
+ *
+ * @retval false The file failed to load. In this case the output parameter
+ *   values *buf and *size should not be used.
+ * @retval true The file was loaded successfully.
+ */
+bool FileReader::load(const char * fname, uint8_t ** buf, size_t * size)
+{
+    struct stat st;
+    if (stat(fname, &st) != 0)
+    {
+        return false;
+    }
+
+    if (st.st_size < 0)
+    {
+        return false;
+    }
+
+    *size = st.st_size;
+    if (st.st_size == 0)
+    {
+        return true;
+    }
+
+    int fd = open(fname, O_RDONLY | JES_O_BINARY);
+    if (fd < 0)
+    {
+        return false;
+    }
+
+    *buf = new uint8_t[st.st_size];
+
+    off_t n_bytes_read = 0u;
+    for (;;)
+    {
+        off_t rd_size = read(fd, &(*buf)[n_bytes_read], st.st_size - n_bytes_read);
+        if (rd_size <= 0)
+            break;
+        n_bytes_read += rd_size;
+        if (n_bytes_read >= st.st_size)
+            break;
+    }
+    if (n_bytes_read != st.st_size)
+    {
+        delete[] *buf;
+        *buf = NULL;
+        close(fd);
+        return false;
+    }
+
+    close(fd);
+
+    return true;
+}

src/FileReader.h

@@ -0,0 +1,13 @@
+#ifndef JES_FILEREADER_H
+#define JES_FILEREADER_H
+
+#include <stdint.h>
+#include <stdlib.h>
+
+class FileReader
+{
+public:
+    static bool load(const char * fname, uint8_t ** buf, size_t * size);
+};
+
+#endif