# svn_string.h File Reference

Counted-length strings for Subversion, plus some C string goodies. More...

`#include <apr.h>`
`#include <apr_pools.h>`
`#include <apr_tables.h>`
`#include "svn_types.h"`

Go to the source code of this file.

## Data Structures
struct | svn_string_t
| A simple counted string. More...
struct | svn_stringbuf_t
| A buffered string, capable of appending without an allocation and copy for each append. More...
## Typedefs
typedef struct svn_string_t | svn_string_t
| A simple counted string.
typedef struct svn_stringbuf_t | svn_stringbuf_t
| A buffered string, capable of appending without an allocation and copy for each append.
## Functions
svn_string_t * | svn_string_create (const char *cstring, apr_pool_t *pool)
| Create a new bytestring containing a C string (NULL-terminated).
svn_string_t * | svn_string_ncreate (const char *bytes, apr_size_t size, apr_pool_t *pool)
| Create a new bytestring containing a generic string of bytes (NOT NULL-terminated).
svn_string_t * | svn_string_create_from_buf (const svn_stringbuf_t *strbuf, apr_pool_t *pool)
| Create a new string with the contents of the given stringbuf.
svn_string_t * | svn_string_createf (apr_pool_t *pool, const char *fmt,...)
| Create a new bytestring by formatting cstring (NULL-terminated) from varargs, which are as appropriate for apr_psprintf().
svn_string_t * | svn_string_createv (apr_pool_t *pool, const char *fmt, va_list ap)
| Create a new bytestring by formatting cstring (NULL-terminated) from a `va_list` (see svn_stringbuf_createf()).
svn_boolean_t | svn_string_isempty (const svn_string_t *str)
| Return TRUE if a bytestring is empty (has length zero).
svn_string_t * | svn_string_dup (const svn_string_t *original_string, apr_pool_t *pool)
| Return a duplicate of original_string.
svn_boolean_t | svn_string_compare (const svn_string_t *str1, const svn_string_t *str2)
| Return `TRUE` iff str1 and str2 have identical length and data.
apr_size_t | svn_string_first_non_whitespace (const svn_string_t *str)
| Return offset of first non-whitespace character in str, or return str->len if none.
apr_size_t | svn_string_find_char_backward (const svn_string_t *str, char ch)
| Return position of last occurrence of ch in str, or return str->len if no occurrence.
svn_stringbuf_t * | svn_stringbuf_create (const char *cstring, apr_pool_t *pool)
| Create a new bytestring containing a C string (NULL-terminated).
svn_stringbuf_t * | svn_stringbuf_ncreate (const char *bytes, apr_size_t size, apr_pool_t *pool)
| Create a new bytestring containing a generic string of bytes (NON-NULL-terminated).
svn_stringbuf_t * | svn_stringbuf_create_ensure (apr_size_t minimum_size, apr_pool_t *pool)
| Create a new empty bytestring with at least minimum_size bytes of space available in the memory block.
svn_stringbuf_t * | svn_stringbuf_create_from_string (const svn_string_t *str, apr_pool_t *pool)
| Create a new stringbuf with the contents of the given string.
svn_stringbuf_t * | svn_stringbuf_createf (apr_pool_t *pool, const char *fmt,...)
| Create a new bytestring by formatting cstring (NULL-terminated) from varargs, which are as appropriate for apr_psprintf().
svn_stringbuf_t * | svn_stringbuf_createv (apr_pool_t *pool, const char *fmt, va_list ap)
| Create a new bytestring by formatting cstring (NULL-terminated) from a `va_list` (see svn_stringbuf_createf()).
void | svn_stringbuf_ensure (svn_stringbuf_t *str, apr_size_t minimum_size)
| Make sure that the string str has at least minimum_size bytes of space available in the memory block.
void | svn_stringbuf_set (svn_stringbuf_t *str, const char *value)
| Set a bytestring str to value.
void | svn_stringbuf_setempty (svn_stringbuf_t *str)
| Set a bytestring str to empty (0 length).
svn_boolean_t | svn_stringbuf_isempty (const svn_stringbuf_t *str)
| Return `TRUE` if a bytestring is empty (has length zero).
void | svn_stringbuf_chop (svn_stringbuf_t *str, apr_size_t nbytes)
| Chop nbytes bytes off end of str, but not more than str->len.
void | svn_stringbuf_fillchar (svn_stringbuf_t *str, unsigned char c)
| Fill bytestring str with character c.
void | svn_stringbuf_appendbyte (svn_stringbuf_t *targetstr, char byte)
| Append a single character byte onto targetstr.
void | svn_stringbuf_appendbytes (svn_stringbuf_t *targetstr, const char *bytes, apr_size_t count)
| Append an array of bytes onto targetstr.
void | svn_stringbuf_appendstr (svn_stringbuf_t *targetstr, const svn_stringbuf_t *appendstr)
| Append an `svn_stringbuf_t` onto targetstr.
void | svn_stringbuf_appendcstr (svn_stringbuf_t *targetstr, const char *cstr)
| Append a C string onto targetstr.
svn_stringbuf_t * | svn_stringbuf_dup (const svn_stringbuf_t *original_string, apr_pool_t *pool)
| Return a duplicate of original_string.
svn_boolean_t | svn_stringbuf_compare (const svn_stringbuf_t *str1, const svn_stringbuf_t *str2)
| Return `TRUE` iff str1 and str2 have identical length and data.
apr_size_t | svn_stringbuf_first_non_whitespace (const svn_stringbuf_t *str)
| Return offset of first non-whitespace character in str, or return str->len if none.
void | svn_stringbuf_strip_whitespace (svn_stringbuf_t *str)
| Strip whitespace from both sides of str (modified in place).
apr_size_t | svn_stringbuf_find_char_backward (const svn_stringbuf_t *str, char ch)
| Return position of last occurrence of ch in str, or return str->len if no occurrence.
svn_boolean_t | svn_string_compare_stringbuf (const svn_string_t *str1, const svn_stringbuf_t *str2)
| Return `TRUE` iff str1 and str2 have identical length and data.
apr_array_header_t * | svn_cstring_split (const char *input, const char *sep_chars, svn_boolean_t chop_whitespace, apr_pool_t *pool)
| Divide input into substrings along sep_chars boundaries, return an array of copies of those substrings (plain const char*), allocating both the array and the copies in pool.
void | svn_cstring_split_append (apr_array_header_t *array, const char *input, const char *sep_chars, svn_boolean_t chop_whitespace, apr_pool_t *pool)
| Like svn_cstring_split(), but append to existing array instead of creating a new one.
svn_boolean_t | svn_cstring_match_glob_list (const char *str, const apr_array_header_t *list)
| Return `TRUE` iff str matches any of the elements of list, a list of zero or more glob patterns.
svn_boolean_t | svn_cstring_match_list (const char *str, const apr_array_header_t *list)
| Return `TRUE` iff str exactly matches any of the elements of list.
int | svn_cstring_count_newlines (const char *msg)
| Return the number of line breaks in msg, allowing any kind of newline termination (CR, LF, CRLF, or LFCR), even inconsistent.
char * | svn_cstring_join (const apr_array_header_t *strings, const char *separator, apr_pool_t *pool)
| Return a cstring which is the concatenation of strings (an array of char *) each followed by separator (that is, separator will also end the resulting string).
int | svn_cstring_casecmp (const char *str1, const char *str2)
| Compare two strings atr1 and atr2, treating case-equivalent unaccented Latin (ASCII subset) letters as equal.
svn_error_t * | svn_cstring_strtoi64 (apr_int64_t *n, const char *str, apr_int64_t minval, apr_int64_t maxval, int base)
| Parse the C string str into a 64 bit number, and return it in *n.
svn_error_t * | svn_cstring_atoi64 (apr_int64_t *n, const char *str)
| Parse the C string str into a 64 bit number, and return it in *n.
svn_error_t * | svn_cstring_atoi (int *n, const char *str)
| Parse the C string str into a 32 bit number, and return it in *n.
svn_error_t * | svn_cstring_strtoui64 (apr_uint64_t *n, const char *str, apr_uint64_t minval, apr_uint64_t maxval, int base)
| Parse the C string str into an unsigned 64 bit number, and return it in *n.
svn_error_t * | svn_cstring_atoui64 (apr_uint64_t *n, const char *str)
| Parse the C string str into an unsigned 64 bit number, and return it in *n.
svn_error_t * | svn_cstring_atoui (unsigned int *n, const char *str)
| Parse the C string str into an unsigned 32 bit number, and return it in *n.

## Detailed Description

Counted-length strings for Subversion, plus some C string goodies.

There are two string datatypes: `svn_string_t` and `svn_stringbuf_t`. The former is a simple pointer/length pair useful for passing around strings (or arbitrary bytes) with a counted length. `svn_stringbuf_t` is buffered to enable efficient appending of strings without an allocation and copy for each append operation.

`svn_string_t` contains a `const char *` for its data, so it is most appropriate for constant data and for functions which expect constant, counted data. Functions should generally use `const `svn_string_t` *` as their parameter to indicate they are expecting a constant, counted string.

`svn_stringbuf_t` uses a plain `char *` for its data, so it is most appropriate for modifiable data.

### Invariants

1. Null termination:

Both structures maintain a significant invariant:

`s->data[s->len] == '\0'`

The functions defined within this header file will maintain the invariant (which does imply that memory is allocated/defined as `len+1` bytes). If code outside of the `svn_string.h` functions manually builds these structures, then they must enforce this invariant.

Note that an `svn_string(buf)_t` may contain binary data, which means that strlen(s->data) does not have to equal `s->len`. The NULL terminator is provided to make it easier to pass `s->data` to C string interfaces.

2. Non-NULL input:

All the functions assume their input data is non-NULL, unless otherwise documented, and may seg fault if passed NULL. The input data may *contain* null bytes, of course, just the data pointer itself must not be NULL.

### Memory allocation

All the functions make a deep copy of all input data, and never store a pointer to the original input data.

Definition in file svn_string.h.

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