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- /** @file file.c
- * @brief Functions for working with files.
- *
- * This library was created to exclude glibc's file stream operations like
- * fopen(), fgets() etc. These functions use glibc internal buffer. To work
- * with buffer glibc has its own fflush() function and special behaviour while
- * fclose(). It brings a problems with stream file objects and system file
- * descriptors while fork(). The file streams and system file descriptors can't
- * be used interchangeably. So faux file library uses standard system file
- * operations like open(), read() and emulate some usefull stream function like
- * getline(). The faux file object has own buffer and doesn't use glibc's one.
- * The faux_file_close() doesn't lseek() file descriptor as fclose() can do.
- * You can use faux file object and standard file operation in the same time.
- * The only thing to remember is internal buffer that can contain already
- * readed bytes.
- */
- #include <stdlib.h>
- #include <sys/types.h>
- #include <sys/stat.h>
- #include <fcntl.h>
- #include <unistd.h>
- #include <string.h>
- #include <assert.h>
- #include <errno.h>
- #include "private.h"
- #include "faux/faux.h"
- #include "faux/file.h"
- #include "faux/str.h"
- /** @brief Create file object using existent fd.
- *
- * Create file object an link it to existent file descriptor.
- *
- * @return Allocated and initialized file object or NULL on error.
- */
- faux_file_t *faux_file_fdopen(int fd) {
- struct stat stat_struct = {};
- faux_file_t *f = NULL;
- // Before object creation check is fd valid.
- // Try to get stat().
- if (fstat(fd, &stat_struct) < 0)
- return NULL; // Illegal fd
- f = faux_zmalloc(sizeof(*f));
- assert(f);
- if (!f)
- return NULL;
- // Init
- f->fd = fd;
- f->buf_size = FAUX_FILE_CHUNK_SIZE;
- f->buf = faux_zmalloc(f->buf_size);
- assert(f->buf);
- if (!f->buf) {
- faux_free(f);
- return NULL;
- }
- f->len = 0;
- f->eof = BOOL_FALSE;
- return f;
- }
- faux_file_t *faux_file_open(const char *pathname, int flags, mode_t mode) {
- int fd = -1;
- assert(pathname);
- if (!pathname)
- return NULL;
- fd = open(pathname, flags, mode);
- if (fd < 0)
- return NULL;
- return faux_file_fdopen(fd);
- }
- int faux_file_close(faux_file_t *f) {
- int fd = -1;
- assert(f);
- if (!f)
- return -1;
- fd = f->fd;
- faux_free(f->buf);
- faux_free(f);
- return close(fd);
- }
- int faux_file_fileno(faux_file_t *f) {
- assert(f);
- if (!f)
- return -1;
- return f->fd;
- }
- bool_t faux_file_eof(const faux_file_t *f) {
- assert(f);
- if (!f)
- return BOOL_FALSE;
- return f->eof;
- }
- static char *faux_file_takeaway(faux_file_t *f,
- size_t bytes_get, size_t bytes_drop) {
- size_t remove_len = 0;
- char *line = NULL;
- assert(f);
- if (!f)
- return NULL;
- remove_len = bytes_get + bytes_drop;
- // Try to take away more bytes than buffer contain
- if ((remove_len > f->len) || (0 == remove_len))
- return NULL;
- line = faux_zmalloc(bytes_get + 1); // One extra byte for '\0'
- assert(line);
- if (!line)
- return NULL; // Memory problems
- memcpy(line, f->buf, bytes_get);
- // Remove block from the internal buffer
- f->len = f->len - remove_len;
- memmove(f->buf, f->buf + remove_len, f->len);
- return line;
- }
- static char *faux_file_takeaway_rest(faux_file_t *f) {
- assert(f);
- if (!f)
- return NULL;
- return faux_file_takeaway(f, f->len, 0);
- }
- static char *faux_file_takeaway_line(faux_file_t *f) {
- char *find = NULL;
- const char *eol = "\n\r";
- size_t line_len = 0;
- assert(f);
- if (!f)
- return NULL;
- // Search buffer for EOL
- find = faux_str_charsn(f->buf, eol, f->len);
- if (!find)
- return NULL; // End of line is not found
- line_len = find - f->buf;
- // Takeaway line without trailing EOL. So drop one last byte
- return faux_file_takeaway(f, line_len, 1);
- }
- static int faux_file_enlarge_buffer(faux_file_t *f) {
- size_t new_size = 0;
- char *new_buf = NULL;
- assert(f);
- if (!f)
- return -1;
- new_size = f->buf_size + FAUX_FILE_CHUNK_SIZE;
- new_buf = realloc(f->buf, new_size);
- assert(new_buf);
- if (!new_buf)
- return -1;
- // NULLify newly allocated memory
- faux_bzero(new_buf + f->buf_size, new_size - f->buf_size);
- f->buf = new_buf;
- f->buf_size = new_size;
- return 0;
- }
- char *faux_file_getline(faux_file_t *f) {
- ssize_t bytes_readed = 0;
- assert(f);
- if (!f)
- return NULL;
- do {
- char *find = NULL;
- // May be buffer already contain line
- find = faux_file_takeaway_line(f);
- if (find)
- return find;
- if (f->buf_size == f->len) { // Buffer is full but doesn't contain line
- if (faux_file_enlarge_buffer(f) < 0) // Make buffer larger
- return NULL; // Memory problem
- }
- // Read new data from file
- do {
- bytes_readed = read(f->fd, f->buf + f->len, f->buf_size - f->len);
- if ((bytes_readed < 0) && (errno != EINTR))
- return NULL; // Some file error
- } while (bytes_readed < 0); // i.e. EINTR
- f->len += bytes_readed;
- } while (bytes_readed > 0);
- // EOF (here bytes_readed == 0)
- f->eof = BOOL_TRUE;
- // The last line can be without eol. Consider it as a line too
- return faux_file_takeaway_rest(f);
- }
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