X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fdata%2Fvalue.h;h=6955eea0bd358e144fc1bd4ff8ed9e615aa7b68f;hb=a34c42168e0cd3373860a6cc3f518cb0e329db47;hp=97c24050ef6264712e05c2dd8b98ea069a0ccd89;hpb=14aac9fe7a7efbb6c9bded2ed5969a643cb76645;p=pspp-builds.git diff --git a/src/data/value.h b/src/data/value.h index 97c24050..6955eea0 100644 --- a/src/data/value.h +++ b/src/data/value.h @@ -1,5 +1,5 @@ /* PSPP - a program for statistical analysis. - Copyright (C) 1997-9, 2000, 2007 Free Software Foundation, Inc. + Copyright (C) 1997-9, 2000, 2007, 2009 Free Software Foundation, Inc. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -17,47 +17,175 @@ #ifndef DATA_VALUE_H #define DATA_VALUE_H 1 -#include +#include #include -#include -#include "minmax.h" +#include +#include +#include "xalloc.h" + +/* Maximum length of a "short" string, that is represented in + "union value" without a separate pointer. -/* "Short" strings, which are generally those no more than 8 - characters wide, can participate in more operations than - longer strings. */ -#define MAX_SHORT_STRING (MAX (ROUND_UP (SIZEOF_DOUBLE, 2), 8)) -#define MIN_LONG_STRING (MAX_SHORT_STRING + 1) + This is an implementation detail of the "union value" code. + There is little reason for client code to use it. */ +#define MAX_SHORT_STRING 8 -/* A numeric or short string value. - Multiple consecutive values represent a long string. */ +/* A numeric or string value. + + The client is responsible for keeping track of the value's + width. + + This structure is semi-opaque: + + - If the value is a number, clients may access the 'f' + member directly. + + - Clients should not access other members directly. +*/ union value { double f; - char s[MAX_SHORT_STRING]; + char short_string[MAX_SHORT_STRING]; + char *long_string; }; -union value *value_dup (const union value *, int width); -union value *value_create (int width); - -int compare_values (const void *, const void *, const void *var); -unsigned hash_value (const void *, const void *var); +static inline void value_init (union value *, int width); +static inline bool value_needs_init (int width); +static inline bool value_try_init (union value *, int width); +static inline void value_destroy (union value *, int width); -int compare_values_short (const void *, const void *, const void *var); -unsigned hash_value_short (const void *, const void *var); +static inline double value_num (const union value *); +static inline const char *value_str (const union value *, int width); +static inline char *value_str_rw (union value *, int width); -static inline size_t value_cnt_from_width (int width); -void value_copy (union value *, const union value *, int width); +static inline void value_copy (union value *, const union value *, int width); +void value_copy_rpad (union value *, int dst_width, + const union value *, int src_width, + char pad); +void value_copy_str_rpad (union value *, int dst_width, const char *, + char pad); +void value_copy_buf_rpad (union value *dst, int dst_width, + const char *src, size_t src_len, char pad); void value_set_missing (union value *, int width); +int value_compare_3way (const union value *, const union value *, int width); +bool value_equal (const union value *, const union value *, int width); +unsigned int value_hash (const union value *, int width, unsigned int basis); + bool value_is_resizable (const union value *, int old_width, int new_width); +bool value_needs_resize (int old_width, int new_width); void value_resize (union value *, int old_width, int new_width); -int value_compare_3way (const union value *, const union value *, int width); -/* Number of "union value"s required for a variable of the given - WIDTH. */ -static inline size_t -value_cnt_from_width (int width) +static inline void value_swap (union value *, union value *); + +struct pool; +void value_init_pool (struct pool *, union value *, int width); +void value_resize_pool (struct pool *, union value *, + int old_width, int new_width); + +/* Initializes V as a value of the given WIDTH, where 0 + represents a numeric value and a positive integer represents a + string value WIDTH bytes long. + + A WIDTH of -1 is ignored. + + The contents of value V are indeterminate after + initialization. */ +static inline void +value_init (union value *v, int width) +{ + if (width > MAX_SHORT_STRING) + v->long_string = xmalloc (width); +} + +/* Returns true if a value of the given WIDTH actually needs to + have the value_init and value_destroy functions called, false + if those functions are no-ops for values of the given WIDTH. + + Using this function is only a valuable optimization if a large + number of values of the given WIDTH are to be initialized*/ +static inline bool +value_needs_init (int width) +{ + return width > MAX_SHORT_STRING; +} + +/* Same as value_init, except that failure to allocate memory + causes it to return false instead of terminating the + program. On success, returns true. */ +static inline bool +value_try_init (union value *v, int width) +{ + if (width > MAX_SHORT_STRING) + { + v->long_string = malloc (width); + return v->long_string != NULL; + } + else + return true; +} + +/* Frees any memory allocated by value_init for V, which must + have the given WIDTH. */ +static inline void +value_destroy (union value *v, int width) +{ + if (width > MAX_SHORT_STRING) + free (v->long_string); +} + +/* Returns the numeric value in V, which must have width 0. */ +static inline double +value_num (const union value *v) +{ + return v->f; +} + +/* Returns the string value in V, which must have width WIDTH. + + The returned value is not null-terminated. + + It is important that WIDTH be the actual value that was passed + to value_init. Passing, e.g., a smaller value because only + that number of bytes will be accessed will not always work. */ +static inline const char * +value_str (const union value *v, int width) +{ + assert (width > 0); + return (width > MAX_SHORT_STRING ? v->long_string : v->short_string); +} + +/* Returns the string value in V, which must have width WIDTH. + + The returned value is not null-terminated. + + It is important that WIDTH be the actual value that was passed + to value_init. Passing, e.g., a smaller value because only + that number of bytes will be accessed will not always work. */ +static inline char * +value_str_rw (union value *v, int width) +{ + assert (width > 0); + return (width > MAX_SHORT_STRING ? v->long_string : v->short_string); +} + +/* Copies SRC to DST, given that they both contain data of the + given WIDTH. */ +static inline void +value_copy (union value *dst, const union value *src, int width) +{ + if (width <= MAX_SHORT_STRING) + *dst = *src; + else if (dst != src) + memcpy (dst->long_string, src->long_string, width); +} + +/* Exchanges the contents of A and B. */ +static inline void +value_swap (union value *a, union value *b) { - return width == 0 ? 1 : DIV_RND_UP (width, MAX_SHORT_STRING); + union value tmp = *a; + *a = *b; + *b = tmp; } #endif /* data/value.h */