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- /** @file io.c
- * @brief Enchanced base IO functions.
- */
- #include <stdlib.h>
- #include <unistd.h>
- #include <assert.h>
- #include <errno.h>
- #include <stdio.h>
- /** @brief Writes data to file.
- *
- * The system write() can be interrupted by signal. This function will retry to
- * write in a case of interrupted call.
- *
- * @param [in] fd File descriptor.
- * @param [in] buf Buffer to write.
- * @param [in] n Number of bytes to write.
- * @return Number of bytes written or < 0 on error.
- */
- ssize_t faux_write(int fd, const void *buf, size_t n)
- {
- ssize_t bytes_written = 0;
- assert(fd != -1);
- assert(buf);
- if ((-1 == fd) || !buf)
- return -1;
- if (0 == n)
- return 0;
- do {
- bytes_written = write(fd, buf, n);
- } while ((bytes_written < 0) && (EINTR == errno));
- return bytes_written;
- }
- /** @brief Writes data block to file.
- *
- * The system write() can be interrupted by signal or can write less bytes
- * than specified. This function will continue to write data until all data
- * will be written or error occured.
- *
- * @param [in] fd File descriptor.
- * @param [in] buf Buffer to write.
- * @param [in] n Number of bytes to write.
- * @return Number of bytes written.
- * < n then insufficient space or error (but some data was already written).
- * < 0 - error.
- */
- ssize_t faux_write_block(int fd, const void *buf, size_t n)
- {
- ssize_t bytes_written = 0;
- size_t total_written = 0;
- size_t left = n;
- const void *data = buf;
- do {
- bytes_written = faux_write(fd, data, left);
- if (bytes_written < 0) { // Error
- if (total_written != 0)
- return total_written;
- return -1;
- }
- if (0 == bytes_written) // Insufficient space
- return total_written;
- data += bytes_written;
- left = left - bytes_written;
- total_written += bytes_written;
- } while (left > 0);
- return total_written;
- }
- /** @brief Reads data from file.
- *
- * The system read() can be interrupted by signal. This function will retry to
- * read if it was interrupted by signal.
- *
- * @param [in] fd File descriptor.
- * @param [in] buf Buffer to write.
- * @param [in] n Number of bytes to write.
- * @return Number of bytes readed or < 0 on error.
- * 0 bytes indicates EOF
- */
- ssize_t faux_read(int fd, void *buf, size_t n)
- {
- ssize_t bytes_readed = 0;
- assert(fd != -1);
- assert(buf);
- if ((-1 == fd) || !buf)
- return -1;
- if (0 == n)
- return 0;
- do {
- bytes_readed = read(fd, buf, n);
- } while ((bytes_readed < 0) && (EINTR == errno));
- return bytes_readed;
- }
- /** @brief Reads data block from file.
- *
- * The system read() can be interrupted by signal or can read less bytes
- * than specified. This function will continue to read data until all data
- * will be readed or error occured.
- *
- * @param [in] fd File descriptor.
- * @param [in] buf Buffer to write.
- * @param [in] n Number of bytes to write.
- * @return Number of bytes readed.
- * < n EOF or error (but some data was already readed).
- * < 0 Error.
- */
- size_t faux_read_block(int fd, void *buf, size_t n)
- {
- ssize_t bytes_readed = 0;
- size_t total_readed = 0;
- size_t left = n;
- void *data = buf;
- do {
- bytes_readed = read(fd, data, left);
- if (bytes_readed < 0) {
- if (total_readed != 0)
- return total_readed;
- return -1;
- }
- if (0 == bytes_readed) // EOF
- return total_readed;
- data += bytes_readed;
- left = left - bytes_readed;
- total_readed += bytes_readed;
- } while (left > 0);
- return total_readed;
- }
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