forked from KolibriOS/kolibrios
255 lines
7.7 KiB
C
255 lines
7.7 KiB
C
/* libwapcaplet.h
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*
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* String internment and management tools.
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*
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* Copyright 2009 The NetSurf Browser Project.
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* Daniel Silverstone <dsilvers@netsurf-browser.org>
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*/
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#ifndef libwapcaplet_h_
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#define libwapcaplet_h_
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#ifdef __cplusplus
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extern "C"
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{
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#endif
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#include <sys/types.h>
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#include <stdbool.h>
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#include <stdint.h>
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/**
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* The type of a reference counter used in libwapcaplet.
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*/
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typedef uint32_t lwc_refcounter;
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/**
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* The type of a hash value used in libwapcaplet.
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*/
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typedef uint32_t lwc_hash;
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/**
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* An interned string.
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*
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* NOTE: The contents of this struct are considered *PRIVATE* and may
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* change in future revisions. Do not rely on them whatsoever.
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* They're only here at all so that the ref, unref and matches etc can
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* use them.
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*/
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typedef struct lwc_string_s {
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struct lwc_string_s ** prevptr;
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struct lwc_string_s * next;
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size_t len;
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lwc_hash hash;
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lwc_refcounter refcnt;
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struct lwc_string_s * insensitive;
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} lwc_string;
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/**
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* String iteration function
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*
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* @param str A string which has been interned.
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* @param pw The private pointer for the allocator.
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*/
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typedef void (*lwc_iteration_callback_fn)(lwc_string *str, void *pw);
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/**
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* Result codes which libwapcaplet might return.
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*/
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typedef enum lwc_error_e {
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lwc_error_ok = 0, /**< No error. */
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lwc_error_oom = 1, /**< Out of memory. */
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lwc_error_range = 2 /**< Substring internment out of range. */
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} lwc_error;
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/**
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* Intern a string.
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*
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* Take a copy of the string data referred to by \a s and \a slen and
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* intern it. The resulting ::lwc_string can be used for simple and
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* caseless comparisons by ::lwc_string_isequal and
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* ::lwc_string_caseless_isequal respectively.
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*
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* @param s Pointer to the start of the string to intern.
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* @param slen Length of the string in characters. (Not including any
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* terminators)
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* @param ret Pointer to ::lwc_string pointer to fill out.
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* @return Result of operation, if not OK then the value pointed
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* to by \a ret will not be valid.
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*
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* @note The memory pointed to by \a s is not referenced by the result.
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* @note If the string was already present, its reference count is
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* incremented rather than allocating more memory.
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*
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* @note The returned string is currently NULL-terminated but this
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* will not necessarily be the case in future. Try not to rely
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* on it.
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*/
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extern lwc_error lwc_intern_string(const char *s, size_t slen,
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lwc_string **ret);
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/**
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* Intern a substring.
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*
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* Intern a subsequence of the provided ::lwc_string.
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*
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* @param str String to acquire substring from.
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* @param ssoffset Substring offset into \a str.
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* @param sslen Substring length.
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* @param ret Pointer to pointer to ::lwc_string to fill out.
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* @return Result of operation, if not OK then the value
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* pointed to by \a ret will not be valid.
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*/
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extern lwc_error lwc_intern_substring(lwc_string *str,
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size_t ssoffset, size_t sslen,
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lwc_string **ret);
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/**
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* Increment the reference count on an lwc_string.
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*
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* This increases the reference count on the given string. You should
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* use this when copying a string pointer into a persistent data
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* structure.
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*
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* @verb
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* myobject->str = lwc_string_ref(myparent->str);
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* @endverb
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*
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* @param str The string to create another reference to.
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* @return The string pointer to use in your new data structure.
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*
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* @note Use this if copying the string and intending both sides to retain
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* ownership.
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*/
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#define lwc_string_ref(str) ({lwc_string *__lwc_s = (str); __lwc_s->refcnt++; __lwc_s;})
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/**
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* Release a reference on an lwc_string.
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*
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* This decreases the reference count on the given ::lwc_string.
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*
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* @param str The string to unref.
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*
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* @note If the reference count reaches zero then the string will be
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* freed. (Ref count of 1 where string is its own insensitve match
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* will also result in the string being freed.)
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*/
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#define lwc_string_unref(str) { \
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lwc_string *__lwc_s = (str); \
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__lwc_s->refcnt--; \
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if ((__lwc_s->refcnt == 0) || \
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((__lwc_s->refcnt == 1) && (__lwc_s->insensitive == __lwc_s))) \
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lwc_string_destroy(__lwc_s); \
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}
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/**
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* Destroy an unreffed lwc_string.
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*
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* This destroys an lwc_string whose reference count indicates that it should be.
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*
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* @param str The string to unref.
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*/
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extern void lwc_string_destroy(lwc_string *str);
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/**
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* Check if two interned strings are equal.
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*
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* @param str1 The first string in the comparison.
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* @param str2 The second string in the comparison.
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* @param ret A pointer to a boolean to be filled out with the result.
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* @return Result of operation, if not ok then value pointed to
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* by \a ret will not be valid.
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*/
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#define lwc_string_isequal(str1, str2, ret) \
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((*(ret) = ((str1) == (str2))), lwc_error_ok)
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/**
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* Check if two interned strings are case-insensitively equal.
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*
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* @param str1 The first string in the comparison.
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* @param str2 The second string in the comparison.
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* @param ret A pointer to a boolean to be filled out with the result.
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* @return Result of operation, if not ok then value pointed to
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* by \a ret will not be valid.
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*/
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#define lwc_string_caseless_isequal(_str1,_str2,_ret) ({ \
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lwc_error __lwc_err = lwc_error_ok; \
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lwc_string *__lwc_str1 = (_str1); \
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lwc_string *__lwc_str2 = (_str2); \
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bool *__lwc_ret = (_ret); \
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\
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if (__lwc_str1->insensitive == NULL) { \
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__lwc_err = lwc__intern_caseless_string(__lwc_str1); \
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} \
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if (__lwc_err == lwc_error_ok && __lwc_str2->insensitive == NULL) { \
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__lwc_err = lwc__intern_caseless_string(__lwc_str2); \
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} \
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if (__lwc_err == lwc_error_ok) \
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*__lwc_ret = (__lwc_str1->insensitive == __lwc_str2->insensitive); \
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__lwc_err; \
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})
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/**
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* Intern a caseless copy of the passed string.
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*
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* @param str The string to intern the caseless copy of.
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*
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* @return lwc_error_ok if successful, otherwise the
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* error code describing the issue.,
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*
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* @note This is for "internal" use by the caseless comparison
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* macro and not for users.
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*/
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extern lwc_error
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lwc__intern_caseless_string(lwc_string *str);
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/**
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* Retrieve the data pointer for an interned string.
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*
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* @param str The string to retrieve the data pointer for.
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* @return The C string data pointer for \a str.
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*
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* @note The data we point at belongs to the string and will
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* die with the string. Keep a ref if you need it.
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* @note You may not rely on the NULL termination of the strings
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* in future. Any code relying on it currently should be
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* modified to use ::lwc_string_length if possible.
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*/
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#define lwc_string_data(str) ((const char *)((str)+1))
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/**
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* Retrieve the data length for an interned string.
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*
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* @param str The string to retrieve the length of.
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* @return The length of \a str.
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*/
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#define lwc_string_length(str) ((str)->len)
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/**
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* Retrieve (or compute if unavailable) a hash value for the content of the string.
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*
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* @param str The string to get the hash for.
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* @return The 32 bit hash of \a str.
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*
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* @note This API should only be used as a convenient way to retrieve a hash
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* value for the string. This hash value should not be relied on to be
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* unique within an invocation of the program, nor should it be relied upon
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* to be stable between invocations of the program. Never use the hash
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* value as a way to directly identify the value of the string.
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*/
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#define lwc_string_hash_value(str) ((str)->hash)
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/**
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* Iterate the context and return every string in it.
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*
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* @param cb The callback to give the string to.
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* @param pw The private word for the callback.
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*/
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extern void lwc_iterate_strings(lwc_iteration_callback_fn cb, void *pw);
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#ifdef __cplusplus
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}
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#endif
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#endif /* libwapcaplet_h_ */
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