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