/* -*- mode: c; indent-tabs-mode: nil -*- */ /* * include/k5-buf.h * * Copyright 2008 Massachusetts Institute of Technology. * All Rights Reserved. * * Export of this software from the United States of America may * require a specific license from the United States Government. * It is the responsibility of any person or organization contemplating * export to obtain such a license before exporting. * * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and * distribute this software and its documentation for any purpose and * without fee is hereby granted, provided that the above copyright * notice appear in all copies and that both that copyright notice and * this permission notice appear in supporting documentation, and that * the name of M.I.T. not be used in advertising or publicity pertaining * to distribution of the software without specific, written prior * permission. Furthermore if you modify this software you must label * your software as modified software and not distribute it in such a * fashion that it might be confused with the original M.I.T. software. * M.I.T. makes no representations about the suitability of * this software for any purpose. It is provided "as is" without express * or implied warranty. * * * k5buf string buffer module interface */ #ifndef K5_BUF_H #define K5_BUF_H #if defined(_MSDOS) || defined(_WIN32) #include <win-mac.h> #endif #ifndef KRB5_CALLCONV #define KRB5_CALLCONV #define KRB5_CALLCONV_C #endif #include <stdarg.h> #include <string.h> #include <unistd.h> /* The k5buf module is intended to allow multi-step string construction in a fixed or dynamic buffer without the need to check for a failure at each step (and without aborting on malloc failure). If an allocation failure occurs or if the fixed buffer runs out of room, the error will be discovered when the caller retrieves the C string value or checks the length of the resulting buffer. k5buf structures are stack-allocated, but are intended to be opaque, so do not access the fields directly. This is a tool, not a way of life, so do not put k5buf structure pointers into the public API or into significant internal APIs. */ /* We must define the k5buf structure here to allow stack allocation. The structure is intended to be opaque, so the fields have funny names. */ struct k5buf { int xx_buftype; char *xx_data; size_t xx_space; size_t xx_len; }; /* Initialize a k5buf using a fixed-sized, existing buffer. SPACE must be more than zero, or an assertion failure will result. */ void krb5int_buf_init_fixed(struct k5buf *buf, char *data, size_t space); /* Initialize a k5buf using an internally allocated dynamic buffer. The buffer contents must be freed with krb5int_free_buf. */ void krb5int_buf_init_dynamic(struct k5buf *buf); /* Add a C string to BUF. */ void krb5int_buf_add(struct k5buf *buf, const char *data); /* Add a counted set of bytes to BUF. If is okay for DATA[0..LEN-1] to contain null bytes if you are prepared to deal with that in the output (use krb5int_buf_len to retrieve the length of the output). */ void krb5int_buf_add_len(struct k5buf *buf, const char *data, size_t len); /* Add sprintf-style formatted data to BUF. */ void krb5int_buf_add_fmt(struct k5buf *buf, const char *fmt, ...) #if !defined(__cplusplus) && (__GNUC__ > 2) __attribute__((__format__(__printf__, 2, 3))) #endif ; /* Truncate BUF. LEN must be between 0 and the existing buffer length, or an assertion failure will result. */ void krb5int_buf_truncate(struct k5buf *buf, size_t len); /* Retrieve the byte array value of BUF, or NULL if there has been an allocation failure or the fixed buffer ran out of room. The byte array will be a C string unless binary data was added with krb5int_buf_add_len; it will be null-terminated regardless. Modifying the byte array does not invalidate the buffer, as long as its length is not changed. For a fixed buffer, the return value will always be equal to the passed-in value of DATA at initialization time if it is not NULL. For a dynamic buffer, any buffer modification operation except krb5int_buf_truncate may invalidate the byte array address. */ char *krb5int_buf_data(struct k5buf *buf); /* Retrieve the length of BUF, or -1 if there has been an allocation failure or the fixed buffer ran out of room. The length is equal to strlen(krb5int_buf_data(buf)) unless binary data was added with krb5int_buf_add_len. */ ssize_t krb5int_buf_len(struct k5buf *buf); /* Free the storage used in the dynamic buffer BUF. The caller may choose to take responsibility for freeing the return value of krb5int_buf_data instead of using this function. If BUF is a fixed buffer, an assertion failure will result. It is unnecessary (though harmless) to free a buffer after an error is detected; the storage will already have been freed in that case. */ void krb5int_free_buf(struct k5buf *buf); #endif /* K5_BUF_H */