/**
* @copyright
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
* ====================================================================
* @endcopyright
*
* @file svn_string_private.h
* @brief Non-public string utility functions.
*/
#ifndef SVN_STRING_PRIVATE_H
#define SVN_STRING_PRIVATE_H
#include "svn_string.h" /* for svn_boolean_t, svn_error_t */
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
/**
* @defgroup svn_string String handling
* @{
*/
/** Private functions.
*
* @defgroup svn_string_private Private functions
* @{
*/
/** A self-contained memory buffer of known size.
*
* Intended to be used where a single variable-sized buffer is needed
* within an iteration, a scratch pool is available and we want to
* avoid the cost of creating another pool just for the iteration.
*/
typedef struct svn_membuf_t
{
/** The a pool from which this buffer was originally allocated, and is not
* necessarily specific to this buffer. This is used only for allocating
* more memory from when the buffer needs to grow.
*/
apr_pool_t *pool;
/** pointer to the memory */
void *data;
/** total size of buffer allocated */
apr_size_t size;
} svn_membuf_t;
/* Initialize a memory buffer of the given size */
void
svn_membuf__create(svn_membuf_t *membuf, apr_size_t size, apr_pool_t *pool);
/* Ensure that the given memory buffer has at least the given size */
void
svn_membuf__ensure(svn_membuf_t *membuf, apr_size_t size);
/* Resize the given memory buffer, preserving its contents. */
void
svn_membuf__resize(svn_membuf_t *membuf, apr_size_t size);
/* Zero-fill the given memory */
void
svn_membuf__zero(svn_membuf_t *membuf);
/* Zero-fill the given memory buffer up to the smaller of SIZE and the
current buffer size. */
void
svn_membuf__nzero(svn_membuf_t *membuf, apr_size_t size);
/* Inline implementation of svn_membuf__zero.
* Note that PMEMBUF is evaluated only once.
*/
#define SVN_MEMBUF__ZERO(pmembuf) \
do \
{ \
svn_membuf_t *const _m_b_f_ = (pmembuf); \
memset(_m_b_f_->data, 0, _m_b_f_->size); \
} \
while(0)
/* Inline implementation of svn_membuf__nzero
* Note that PMEMBUF and PSIZE are evaluated only once.
*/
#define SVN_MEMBUF__NZERO(pmembuf, psize) \
do \
{ \
svn_membuf_t *const _m_b_f_ = (pmembuf); \
const apr_size_t _s_z_ = (psize); \
if (_s_z_ > _m_b_f_->size) \
memset(_m_b_f_->data, 0, _m_b_f_->size); \
else \
memset(_m_b_f_->data, 0, _s_z_); \
} \
while(0)
#ifndef SVN_DEBUG
/* In non-debug mode, just use these inlie replacements */
#define svn_membuf__zero(B) SVN_MEMBUF__ZERO((B))
#define svn_membuf__nzero(B, S) SVN_MEMBUF__NZERO((B), (S))
#endif
/** Returns the #svn_string_t information contained in the data and
* len members of @a strbuf. This is effectively a typecast, converting
* @a strbuf into an #svn_string_t. This first will become invalid and must
* not be accessed after this function returned.
*/
svn_string_t *
svn_stringbuf__morph_into_string(svn_stringbuf_t *strbuf);
/** Utility macro to define static svn_string_t objects. @a value must
* be a static string; the "" in the macro declaration tries to ensure this.
*
* Usage:
* static const svn_string_t my_string = SVN__STATIC_STRING("my text");
*/
#define SVN__STATIC_STRING(value) { value "", sizeof(value "") - 1 }
/** Like strtoul but with a fixed base of 10 and without overflow checks.
* This allows the compiler to generate massively faster (4x on 64bit LINUX)
* code. Overflow checks may be added on the caller side where you might
* want to test for a more specific value range anyway.
*/
unsigned long
svn__strtoul(const char *buffer, const char **end);
/** Number of chars needed to represent signed (19 places + sign + NUL) or
* unsigned (20 places + NUL) integers as strings.
*/
#define SVN_INT64_BUFFER_SIZE 21
/** Writes the @a number as string into @a dest. The latter must provide
* space for at least #SVN_INT64_BUFFER_SIZE characters. Returns the number
* chars written excluding the terminating NUL.
*/
apr_size_t
svn__ui64toa(char * dest, apr_uint64_t number);
/** Writes the @a number as string into @a dest. The latter must provide
* space for at least #SVN_INT64_BUFFER_SIZE characters. Returns the number
* chars written excluding the terminating NUL.
*/
apr_size_t
svn__i64toa(char * dest, apr_int64_t number);
/** Returns a decimal string for @a number allocated in @a pool. Put in
* the @a separator at each third place.
*/
char *
svn__ui64toa_sep(apr_uint64_t number, char separator, apr_pool_t *pool);
/** Returns a decimal string for @a number allocated in @a pool. Put in
* the @a separator at each third place.
*/
char *
svn__i64toa_sep(apr_int64_t number, char separator, apr_pool_t *pool);
/** Writes the @a number as base36-encoded string into @a dest. The latter
* must provide space for at least #SVN_INT64_BUFFER_SIZE characters.
* Returns the number chars written excluding the terminating NUL.
*
* @note The actual maximum buffer requirement is much shorter than
* #SVN_INT64_BUFFER_SIZE but introducing yet another constant is only
* marginally useful and may open the door to security issues when e.g.
* switching between base10 and base36 encoding.
*/
apr_size_t
svn__ui64tobase36(char *dest, apr_uint64_t number);
/** Returns the value of the base36 encoded unsigned integer starting at
* @a source. If @a next is not NULL, @a *next will be set to the first
* position after the integer.
*
* The data in @a source will be considered part of the number to parse
* as long as the characters are within the base36 range. If there are
* no such characters to begin with, 0 is returned. Inputs with more than
* #SVN_INT64_BUFFER_SIZE digits will not be fully parsed, i.e. the value
* of @a *next as well as the return value are undefined.
*/
apr_uint64_t
svn__base36toui64(const char **next, const char *source);
/**
* The upper limit of the similarity range returned by
* svn_cstring__similarity() and svn_string__similarity().
*/
#define SVN_STRING__SIM_RANGE_MAX 1000000
/**
* Computes the similarity score of STRA and STRB. Returns the ratio
* of the length of their longest common subsequence and the average
* length of the strings, normalized to the range
* [0..SVN_STRING__SIM_RANGE_MAX]. The result is equivalent to
* Python's
*
* difflib.SequenceMatcher.ratio
*
* Optionally sets *RLCS to the length of the longest common
* subsequence of STRA and STRB. Using BUFFER for temporary storage,
* requires memory proportional to the length of the shorter string.
*
* The LCS algorithm used is described in, e.g.,
*
* http://en.wikipedia.org/wiki/Longest_common_subsequence_problem
*
* Q: Why another LCS when we already have one in libsvn_diff?
* A: svn_diff__lcs is too heavyweight and too generic for the
* purposes of similarity testing. Whilst it would be possible
* to use a character-based tokenizer with it, we really only need
* the *length* of the LCS for the similarity score, not all the
* other information that svn_diff__lcs produces in order to
* make printing diffs possible.
*
* Q: Is there a limit on the length of the string parameters?
* A: Only available memory. But note that the LCS algorithm used
* has O(strlen(STRA) * strlen(STRB)) worst-case performance,
* so do keep a rein on your enthusiasm.
*/
apr_size_t
svn_cstring__similarity(const char *stra, const char *strb,
svn_membuf_t *buffer, apr_size_t *rlcs);
/**
* Like svn_cstring__similarity, but accepts svn_string_t's instead
* of NUL-terminated character strings.
*/
apr_size_t
svn_string__similarity(const svn_string_t *stringa,
const svn_string_t *stringb,
svn_membuf_t *buffer, apr_size_t *rlcs);
/* Return the lowest position at which A and B differ. If no difference
* can be found in the first MAX_LEN characters, MAX_LEN will be returned.
*/
apr_size_t
svn_cstring__match_length(const char *a,
const char *b,
apr_size_t max_len);
/* Return the number of bytes before A and B that don't differ. If no
* difference can be found in the first MAX_LEN characters, MAX_LEN will
* be returned. Please note that A-MAX_LEN and B-MAX_LEN must both be
* valid addresses.
*/
apr_size_t
svn_cstring__reverse_match_length(const char *a,
const char *b,
apr_size_t max_len);
/** @} */
/** Prefix trees.
*
* Prefix trees allow for a space-efficient representation of a set of path-
* like strings, i.e. those that share common prefixes. Any given string
* value will be stored only once, i.e. two strings stored in the same tree
* are equal if and only if the point to the same #svn_prefix_string__t.
*
* @defgroup svn_prefix_string Strings in prefix trees.
* @{
*/
/**
* Opaque data type for prefix-tree-based strings.
*/
typedef struct svn_prefix_string__t svn_prefix_string__t;
/**
* Opaque data type representing a prefix tree
*/
typedef struct svn_prefix_tree__t svn_prefix_tree__t;
/**
* Return a new prefix tree allocated in @a pool.
*/
svn_prefix_tree__t *
svn_prefix_tree__create(apr_pool_t *pool);
/**
* Return a string with the value @a s stored in @a tree. If no such string
* exists yet, add it automatically.
*/
svn_prefix_string__t *
svn_prefix_string__create(svn_prefix_tree__t *tree,
const char *s);
/**
* Return the contents of @a s as a new string object allocated in @a pool.
*/
svn_string_t *
svn_prefix_string__expand(const svn_prefix_string__t *s,
apr_pool_t *pool);
/**
* Compare the two strings @a lhs and @a rhs that must be part of the same
* tree.
*/
int
svn_prefix_string__compare(const svn_prefix_string__t *lhs,
const svn_prefix_string__t *rhs);
/** @} */
/** @} */
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* SVN_STRING_PRIVATE_H */