#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;
}