1 files changed, 78 insertions, 0 deletions
diff --git a/reference/C/CONTRIB/SNIP/pfopen.c b/reference/C/CONTRIB/SNIP/pfopen.c
new file mode 100755
index 0000000..38c7e0c
--- /dev/null
+++ b/reference/C/CONTRIB/SNIP/pfopen.c
@@ -0,0 +1,78 @@
+/*
+ *  Written and released to the public domain by David Engel.
+ *
+ *  This function attempts to open a file which may be in any of
+ *  several directories.  It is particularly useful for opening
+ *  configuration files.  For example, PROG.EXE can easily open
+ *  PROG.CFG (which is kept in the same directory) by executing:
+ *
+ *      cfg_file = pfopen("PROG.CFG", "r", getenv("PATH"));
+ *
+ *  NULL is returned if the file can't be opened.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef unix
+ #define SEP_CHARS ":"
+#else
+ #define SEP_CHARS ";"
+#endif
+
+FILE *pfopen(const char *name, const char *mode, const char *dirs)
+{
+    char *ptr;
+    char *tdirs;
+    FILE *file = NULL;
+
+    if (dirs == NULL || dirs[0] == '\0')
+        return NULL;
+
+    if ((tdirs = malloc(strlen(dirs)+1)) == NULL)
+        return NULL;
+
+    strcpy(tdirs, dirs);
+
+    for (ptr = strtok(tdirs, SEP_CHARS); file == NULL && ptr != NULL;
+        ptr = strtok(NULL, SEP_CHARS))
+    {
+        size_t len;
+        char work[FILENAME_MAX];
+
+        strcpy(work, ptr);
+        len = strlen(work);
+        if (len && work[len-1] != '/' && work[len-1] != '\\')
+            strcat(work, "/");
+        strcat(work, name);
+
+        file = fopen(work, mode);
+    }
+
+    free(tdirs);
+
+    return file;
+}
+
+#ifdef TEST
+
+int main(int argc, char **argv)
+{
+    FILE *file;
+
+    if (argc != 4)
+    {
+        fprintf(stderr, "usage: pfopen name mode dirs\n");
+        exit(1);
+    }
+
+    file = pfopen(argv[1], argv[2], argv[3]);
+
+    printf("%s \"%s\" with mode \"%s\"\n", (file == NULL) ?
+        "Could not open" : "Opened", argv[1], argv[2]);
+
+    return 0;
+}
+
+#endif