X-Git-Url: http://git.scottworley.com/overonion/blobdiff_plain/b398ee5ae7abfa019f84628204f3c1cd146ed39e..3adfbe9d667f73d8049153e924fb65886ebb67b6:/reverse_lib.c diff --git a/reverse_lib.c b/reverse_lib.c index a800db8..dad7e0d 100644 --- a/reverse_lib.c +++ b/reverse_lib.c @@ -2,62 +2,50 @@ #define BUFFER_SIZE 4096 -#include -#include -#include -#include -#include #include +#include +#include +#include +#include #include +#include static void write_all(int fd, const void *buf, size_t count) { const char* cbuf = buf; size_t written = 0; while (written < count) { int ret = write(fd, &cbuf[written], count - written); - if (ret == -1) { - err(EX_IOERR, "Could not write"); - } + if (ret == -1) err(EX_IOERR, "Could not write"); written += ret; } } -void reverse_file(const char* input_filename) { +void reverse_file(const char* input_filename, int output_fd) { int fd = open(input_filename, O_RDONLY); - if (fd == -1) { - err(EX_NOINPUT, "Could not open specified file"); - } + if (fd == -1) err(EX_NOINPUT, "Could not open specified file"); struct stat stats; - if (fstat(fd, &stats) == -1) { - err(EX_NOINPUT, "Could not stat input"); - } + if (fstat(fd, &stats) == -1) err(EX_NOINPUT, "Could not stat input"); long page_size = sysconf(_SC_PAGE_SIZE); off_t pages = (stats.st_size - 1) / page_size + 1; long map_size = pages * page_size; char *m = mmap(NULL, map_size, PROT_READ, MAP_SHARED, fd, 0); - if (m == MAP_FAILED) { - err(EX_NOINPUT, "Could not mmap input"); - } + if (m == MAP_FAILED) err(EX_NOINPUT, "Could not mmap input"); char buf[BUFFER_SIZE]; off_t buf_offset = 0; for (off_t p = stats.st_size - 1; p >= 0; p--) { buf[buf_offset++] = m[p]; if (buf_offset >= BUFFER_SIZE) { - write_all(1, buf, buf_offset); + write_all(output_fd, buf, buf_offset); buf_offset = 0; } } if (buf_offset) { - write_all(1, buf, buf_offset); + write_all(output_fd, buf, buf_offset); } - if (munmap(m, map_size) == -1) { - err(EX_IOERR, "Could not unmap input"); - } - if (close(fd) == -1) { - err(EX_IOERR, "Could not close input"); - } + if (munmap(m, map_size) == -1) err(EX_IOERR, "Could not unmap input"); + if (close(fd) == -1) err(EX_IOERR, "Could not close input"); }