diff options
author | wmeier <wmeier@f5534014-38df-0310-8fa8-9805f1628bb7> | 2010-10-14 17:50:35 +0000 |
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committer | wmeier <wmeier@f5534014-38df-0310-8fa8-9805f1628bb7> | 2010-10-14 17:50:35 +0000 |
commit | 29291ca8942e87eb7dc477a1cb9362f6ce099294 (patch) | |
tree | fc74c7baa8f4784253d68f6ff638e9850da12ab3 /epan/value_string.c | |
parent | e3cdbc3b5c76791e5d3294f5284aae493ab39f52 (diff) |
Rework "extended value strings":
- Allow direct access when a range of values begins with a value other than 0;
- Provide value_string_ext_new() for creating extended value strings at runtime;
- Do access to value_string_ext members via a macro (all but value_string.c);
- Update documentation.
git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@34514 f5534014-38df-0310-8fa8-9805f1628bb7
Diffstat (limited to 'epan/value_string.c')
-rw-r--r-- | epan/value_string.c | 209 |
1 files changed, 151 insertions, 58 deletions
diff --git a/epan/value_string.c b/epan/value_string.c index 91c22bbda7..53bdb10436 100644 --- a/epan/value_string.c +++ b/epan/value_string.c @@ -33,6 +33,7 @@ #include "value_string.h" #include <string.h> +/* --------------------------------------------------------------------*/ /* Tries to match val against each element in the value_string array vs. Returns the associated string ptr on a match. Formats val with fmt, and returns the resulting string, on failure. */ @@ -49,19 +50,7 @@ val_to_str(const guint32 val, const value_string *vs, const char *fmt) { return ep_strdup_printf(fmt, val); } -const gchar* -val_to_str_ext(const guint32 val, const value_string_ext *vs, const char *fmt) { - const gchar *ret; - - g_assert(fmt != NULL); - - ret = match_strval_ext(val, vs); - if (ret != NULL) - return ret; - - return ep_strdup_printf(fmt, val); -} - +/* --------------------------------------------------------------------*/ /* Tries to match val against each element in the value_string array vs. Returns the associated string ptr on a match. Returns 'unknown_str', on failure. */ @@ -78,19 +67,7 @@ val_to_str_const(const guint32 val, const value_string *vs, const char *unknown_ return unknown_str; } -const gchar* -val_to_str_ext_const(const guint32 val, const value_string_ext *vs, const char *unknown_str) { - const gchar *ret; - - g_assert(unknown_str != NULL); - - ret = match_strval_ext(val, vs); - if (ret != NULL) - return ret; - - return unknown_str; -} - +/* --------------------------------------------------------------------*/ /* Tries to match val against each element in the value_string array vs. Returns the associated string ptr, and sets "*idx" to the index in that table, on a match, and returns NULL, and sets "*idx" to -1, @@ -120,89 +97,205 @@ match_strval(const guint32 val, const value_string *vs) { return match_strval_idx(val, vs, &ignore_me); } +/* --------------------------------------------------------------------*/ +/* value_string_ext functions + * + * Extended value strings allow fast(er) value_string array lookups by + * using (if possible) direct access or a binary search of the array. + * + * If the values in the value_string array are a contiguous range of values + * from min to max, the value will be used as as a direct index into the array. + * + * If the values in the array are not contiguous (ie: there are "gaps"), + * but are in assending order a binary search will be used. + * + * If direct access or binary search cannot be used, then a linear search + * is used. + * + * Note that the value_string array used with VALUE_STRING_EXT_INIT + * *must* be terminated with {0, NULL}). + * + * Extended value strings are defined at compile time as follows: + * static const value_string vs[] = { {value1, "string1"}, {value2, "string2"}, ..., {0, NULL}}; + * static value_string_ext vse = VALUE_STRING_EXT_INIT(vs); + * + * Extended value strings can be created at runtime by calling + * value_string_ext_new(<ptr to value_string array>, + * <total number of entries in the value_string_array>, + * <value_string_name>); + * Note: <total number of entries in the value_string_array> should include the {0, NULL} entry + * + */ + +/* --------------------------------------------------------------------*/ + +/* Create a value_string_ext given a ptr to a value_string array and the total number of entries. */ +/* Note: The total number of entries should include the required {0, NULL} terminating entry of the array. */ +/* Return: a pointer to a gmalloc'd and initialized value_string_ext struct. */ +value_string_ext * +value_string_ext_new(value_string *vs, guint vs_tot_num_entries, gchar *vs_name) { + value_string_ext *vse; + g_assert (vs_name != NULL); + g_assert (vs_tot_num_entries > 0); + g_assert (vs[vs_tot_num_entries-1].strptr == NULL); /* Null-terminated value-string ? */ + vse = g_malloc(sizeof (value_string_ext)); + vse->_vs_p = vs; + vse->_vs_num_entries = vs_tot_num_entries - 1; /* remember the actual number of entries */ + vse->_vs_first_value = 0; /* initialized in _match_strval_ext_init */ + vse->_vs_match = (_value_string_match_t) _match_strval_ext_init; + vse->_vs_name = vs_name; + return vse; +} + +/* Looks up val in a value_string array using access method (direct, binary search + * or linear) determined at rutime during the initial access); (see _match_strval_ext_init) + * Returns the associated string ptr on a match, and returns NULL on failure. + */ +const gchar* +match_strval_ext(const guint32 val, const value_string_ext *vse) { + if (vse) + return vse->_vs_match(val, vse); + return NULL; +} + +/* Similar to match_strval_ext except that on failure + * Formats val with fmt, and returns the resulting string + */ +const gchar* +val_to_str_ext(const guint32 val, const value_string_ext *vse, const char *fmt) { + const gchar *ret; + + g_assert(fmt != NULL); + + ret = match_strval_ext(val, vse); + if (ret != NULL) + return ret; + + return ep_strdup_printf(fmt, val); +} + +/* Similar to match_strval_ext except that on failure + * Returns 'unknown_str' + */ +const gchar* +val_to_str_ext_const(const guint32 val, const value_string_ext *vse, const char *unknown_str) { + const gchar *ret; + + g_assert(unknown_str != NULL); + + ret = match_strval_ext(val, vse); + if (ret != NULL) + return ret; + + return unknown_str; +} + static const gchar * -_match_strval_linear(const guint32 val, const value_string_ext *vs) +_match_strval_linear(const guint32 val, const value_string_ext *vse) { - return match_strval(val, vs->vals); + const value_string *vs_p = vse->_vs_p; + guint i; + for (i=0; i<vse->_vs_num_entries; i++) { + if (vs_p[i].value == val) { + return vs_p[i].strptr; + } + } + return NULL; } static const gchar * -_match_strval_index(const guint32 val, const value_string_ext *vs) +_match_strval_index(const guint32 val, const value_string_ext *vse) { - return (val < vs->length) ? vs->vals[val].strptr : NULL; + if ((val - vse->_vs_first_value) < vse->_vs_num_entries) { + g_assert (val == vse->_vs_p[val - vse->_vs_first_value].value); + return vse->_vs_p[val - vse->_vs_first_value].strptr; + } + return NULL; } static const gchar * -_match_strval_bsearch(const guint32 val, const value_string_ext *vs) +_match_strval_bsearch(const guint32 val, const value_string_ext *vse) { guint low, idx, max; guint32 item; - for (low = 0, max = vs->length; low < max; ) { + for (low = 0, max = vse->_vs_num_entries; low < max; ) { idx = (low + max) / 2; - item = vs->vals[idx].value; + item = vse->_vs_p[idx].value; if (val < item) max = idx; else if (val > item) low = idx + 1; else - return vs->vals[idx].strptr; + return vse->_vs_p[idx].strptr; } return NULL; } +/* Init value_string_ext struct + - Go thru the value_string array to determine whether indexed access + or binary search access is possible; + - Verify that the value_string array does not contain any + NULL string pointers; + - Verify that the value_string array is terminated + by {0, NULL}; +*/ const gchar * -match_strval_ext_init(const guint32 val, value_string_ext *vse) +_match_strval_ext_init(const guint32 val, value_string_ext *vse) { - const value_string *vals = vse->vals; + const value_string *vs_p = vse->_vs_p; + const guint vs_num_entries = vse->_vs_num_entries; /* The way matching of value is done in a value_string: * 0 Sequential search (as in a normal value string) * 1 Binary search, the values MUST be in numerical order. - * 2 The value used as an index(the value string MUST have all values 0-max defined) + * 2 The value used as an index(the value string MUST have all values between first and last defined in numerical order) */ enum { VS_SEARCH = 0, VS_BIN_TREE, VS_INDEX } type = VS_INDEX; - guint32 prev = 0; - guint i; + guint32 prev_value; + guint first_value; + guint i; - for (i = 0; i < vse->length; i++) { - if (type == VS_INDEX && vals[i].value != i) - type = VS_BIN_TREE; + g_assert((vs_p[vs_num_entries].value==0) && (vs_p[vs_num_entries].strptr==NULL)); - if (type == VS_BIN_TREE && prev > vals[i].value) { + vse->_vs_first_value = vs_p[0].value; + first_value = vs_p[0].value; + prev_value = first_value; + + for (i = 0; i < vs_num_entries; i++) { + g_assert(vs_p[i].strptr != NULL); + if ((type == VS_INDEX) && (vs_p[i].value != (i + first_value))) { + type = VS_BIN_TREE; + } + if ((type == VS_BIN_TREE) && (prev_value > vs_p[i].value)) { type = VS_SEARCH; break; } - prev = vals[i].value; + prev_value = vs_p[i].value; } - + switch (type) { case VS_SEARCH: - vse->match = _match_strval_linear; - break; - case VS_INDEX: - vse->match = _match_strval_index; + vse->_vs_match = _match_strval_linear; + g_warning("Extended value string: %s not sorted; accessing linearly", vse->_vs_name); break; case VS_BIN_TREE: - vse->match = _match_strval_bsearch; + vse->_vs_match = _match_strval_bsearch; + break; + case VS_INDEX: + vse->_vs_match = _match_strval_index; break; default: g_assert_not_reached(); break; } - return vse->match(val, vse); -} - -const gchar* -match_strval_ext(const guint32 val, const value_string_ext *vs) { - if (vs) - return vs->match(val, vs); - return NULL; + return vse->_vs_match(val, vse); } +/* ----------- */ /* Tries to match val against each element in the value_string array vs. Returns the associated string ptr on a match. |