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-rw-r--r--libtecla-1.6.3/direader.c309
1 files changed, 309 insertions, 0 deletions
diff --git a/libtecla-1.6.3/direader.c b/libtecla-1.6.3/direader.c
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+++ b/libtecla-1.6.3/direader.c
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+/*
+ * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2012 by Martin C. Shepherd.
+ *
+ * All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, and/or sell copies of the Software, and to permit persons
+ * to whom the Software is furnished to do so, provided that the above
+ * copyright notice(s) and this permission notice appear in all copies of
+ * the Software and that both the above copyright notice(s) and this
+ * permission notice appear in supporting documentation.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+ * OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ * HOLDERS INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL
+ * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING
+ * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
+ * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Except as contained in this notice, the name of a copyright holder
+ * shall not be used in advertising or otherwise to promote the sale, use
+ * or other dealings in this Software without prior written authorization
+ * of the copyright holder.
+ */
+
+/*
+ * If file-system access is to be excluded, this module has no function,
+ * so all of its code should be excluded.
+ */
+#ifndef WITHOUT_FILE_SYSTEM
+
+/*
+ * Standard includes.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+/*
+ * Operating system includes.
+ */
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
+
+#include "direader.h"
+#include "errmsg.h"
+
+/*
+ * Use the reentrant POSIX threads version of readdir()?
+ */
+#if defined(PREFER_REENTRANT) && defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 199506L
+#define USE_READDIR_R 1
+#endif
+
+/*
+ * Objects of the following type are used to maintain the resources
+ * needed to read directories.
+ */
+struct DirReader {
+ ErrMsg *err; /* The error reporting buffer */
+ DIR *dir; /* The directory stream (if open, NULL otherwise) */
+ struct dirent *file; /* The latest directory entry */
+#ifdef USE_READDIR_R
+ struct dirent *buffer; /* A buffer used by the threaded version of */
+ /* readdir() */
+ int buffer_dim; /* The allocated size of buffer[] */
+#endif
+};
+
+static int _dr_path_is_dir(const char *pathname);
+
+/*.......................................................................
+ * Create a new DirReader object.
+ *
+ * Output:
+ * return DirReader * The new object, or NULL on error.
+ */
+DirReader *_new_DirReader(void)
+{
+ DirReader *dr; /* The object to be returned */
+/*
+ * Allocate the container.
+ */
+ dr = (DirReader *) malloc(sizeof(DirReader));
+ if(!dr) {
+ errno = ENOMEM;
+ return NULL;
+ };
+/*
+ * Before attempting any operation that might fail, initialize the
+ * container at least up to the point at which it can safely be passed
+ * to _del_DirReader().
+ */
+ dr->err = NULL;
+ dr->dir = NULL;
+ dr->file = NULL;
+#ifdef USE_READDIR_R
+ dr->buffer = NULL;
+ dr->buffer_dim = 0;
+#endif
+/*
+ * Allocate a place to record error messages.
+ */
+ dr->err = _new_ErrMsg();
+ if(!dr->err)
+ return _del_DirReader(dr);
+ return dr;
+}
+
+/*.......................................................................
+ * Delete a DirReader object.
+ *
+ * Input:
+ * dr DirReader * The object to be deleted.
+ * Output:
+ * return DirReader * The deleted object (always NULL).
+ */
+DirReader *_del_DirReader(DirReader *dr)
+{
+ if(dr) {
+ _dr_close_dir(dr);
+#ifdef USE_READDIR_R
+ free(dr->buffer);
+#endif
+ dr->err = _del_ErrMsg(dr->err);
+ free(dr);
+ };
+ return NULL;
+}
+
+/*.......................................................................
+ * Open a new directory.
+ *
+ * Input:
+ * dr DirReader * The directory reader resource object.
+ * path const char * The directory to be opened.
+ * Input/Output:
+ * errmsg char ** If an error occurs and errmsg isn't NULL, a
+ * pointer to an error description will be assigned
+ * to *errmsg.
+ * Output:
+ * return int 0 - OK.
+ * 1 - Error (see *errmsg for a description).
+ */
+int _dr_open_dir(DirReader *dr, const char *path, char **errmsg)
+{
+ DIR *dir = NULL; /* The directory stream */
+/*
+ * If a directory is already open, close it first.
+ */
+ (void) _dr_close_dir(dr);
+/*
+ * Is the path a directory?
+ */
+ if(!_dr_path_is_dir(path)) {
+ if(errmsg) {
+ _err_record_msg(dr->err, "Can't open directory: ", path, END_ERR_MSG);
+ *errmsg = _err_get_msg(dr->err);
+ };
+ return 1;
+ };
+/*
+ * Attempt to open the directory.
+ */
+ dir = opendir(path);
+ if(!dir) {
+ if(errmsg) {
+ _err_record_msg(dr->err, "Can't open directory: ", path, END_ERR_MSG);
+ *errmsg = _err_get_msg(dr->err);
+ };
+ return 1;
+ };
+/*
+ * If using POSIX threads, allocate a buffer for readdir_r().
+ */
+#ifdef USE_READDIR_R
+ {
+ size_t size;
+ int name_max = pathconf(path, _PC_NAME_MAX);
+#ifdef NAME_MAX
+ if(name_max < 0)
+ name_max = NAME_MAX;
+#endif
+ if(name_max < 0) {
+ if(errmsg) {
+ _err_record_msg(dr->err, "Unable to deduce readdir() buffer size.",
+ END_ERR_MSG);
+ *errmsg = _err_get_msg(dr->err);
+ };
+ closedir(dir);
+ return 1;
+ };
+/*
+ * How big a buffer do we need to allocate?
+ */
+ size = sizeof(struct dirent) + name_max;
+/*
+ * Extend the buffer?
+ */
+ if(size > dr->buffer_dim || !dr->buffer) {
+ struct dirent *buffer = (struct dirent *) (dr->buffer ?
+ realloc(dr->buffer, size) :
+ malloc(size));
+ if(!buffer) {
+ if(errmsg) {
+ _err_record_msg(dr->err, "Insufficient memory for readdir() buffer.",
+ END_ERR_MSG);
+ *errmsg = _err_get_msg(dr->err);
+ };
+ closedir(dir);
+ errno = ENOMEM;
+ return 1;
+ };
+ dr->buffer = buffer;
+ dr->buffer_dim = size;
+ };
+ };
+#endif
+/*
+ * Record the successfully opened directory.
+ */
+ dr->dir = dir;
+ return 0;
+}
+
+/*.......................................................................
+ * If the DirReader object is currently contains an open directory,
+ * close it.
+ *
+ * Input:
+ * dr DirReader * The directory reader resource object.
+ */
+void _dr_close_dir(DirReader *dr)
+{
+ if(dr && dr->dir) {
+ closedir(dr->dir);
+ dr->dir = NULL;
+ dr->file = NULL;
+ _err_clear_msg(dr->err);
+ };
+}
+
+/*.......................................................................
+ * Read the next file from the directory opened with _dr_open_dir().
+ *
+ * Input:
+ * dr DirReader * The directory reader resource object.
+ * Output:
+ * return char * The name of the new file, or NULL if we reached
+ * the end of the directory.
+ */
+char *_dr_next_file(DirReader *dr)
+{
+/*
+ * Are we currently reading a directory?
+ */
+ if(dr->dir) {
+/*
+ * Read the next directory entry.
+ */
+#ifdef USE_READDIR_R
+ if(readdir_r(dr->dir, dr->buffer, &dr->file) == 0 && dr->file)
+ return dr->file->d_name;
+#else
+ dr->file = readdir(dr->dir);
+ if(dr->file)
+ return dr->file->d_name;
+#endif
+ };
+/*
+ * When the end of a directory is reached, close it.
+ */
+ _dr_close_dir(dr);
+ return NULL;
+}
+
+/*.......................................................................
+ * Return 1 if the specified pathname refers to a directory.
+ *
+ * Input:
+ * pathname const char * The path to test.
+ * Output:
+ * return int 0 - Not a directory.
+ * 1 - pathname[] refers to a directory.
+ */
+static int _dr_path_is_dir(const char *pathname)
+{
+ struct stat statbuf; /* The file-statistics return buffer */
+/*
+ * Look up the file attributes.
+ */
+ if(stat(pathname, &statbuf) < 0)
+ return 0;
+/*
+ * Is the file a directory?
+ */
+ return S_ISDIR(statbuf.st_mode) != 0;
+}
+
+#endif /* ifndef WITHOUT_FILE_SYSTEM */
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