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Added ability for dynamic functions.

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This commit is contained in:
Lewis Van Winkle
2016-02-23 17:13:11 -06:00
parent 52a4995d6c
commit d9138d4bff
3 changed files with 263 additions and 197 deletions
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155
tinyexpr.c
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@@ -29,15 +29,16 @@
#include <stdio.h>
enum {TOK_NULL, TOK_END, TOK_OPEN, TOK_CLOSE, TOK_NUMBER, TOK_INFIX, TOK_FUNCTION1, TOK_FUNCTION2, TOK_VARIABLE, TOK_SEP, TOK_ERROR};
enum {TOK_NULL, TOK_END, TOK_OPEN, TOK_CLOSE, TOK_NUMBER, TOK_INFIX, TOK_FUNCTION0, TOK_FUNCTION1, TOK_FUNCTION2, TOK_VARIABLE, TOK_SEP, TOK_ERROR};
enum {TE_CONSTANT = -2};
typedef struct {
typedef struct state {
const char *start;
const char *next;
int type;
union {double value; te_fun1 f1; te_fun2 f2; const double *var;};
union {double value; te_fun0 f0; te_fun1 f1; te_fun2 f2; const double *bound;};
const te_variable *lookup;
int lookup_len;
@@ -46,8 +47,9 @@ typedef struct {
static te_expr *new_expr(te_expr *l, te_expr *r) {
static te_expr *new_expr(int type, te_expr *l, te_expr *r) {
te_expr *ret = malloc(sizeof(te_expr));
ret->type = type;
ret->left = l;
ret->right = r;
ret->bound = 0;
@@ -63,45 +65,38 @@ void te_free(te_expr *n) {
}
typedef struct {
const char *name;
union {const void *v; double *value; te_fun1 f1; te_fun2 f2;};
int arity;
} builtin;
static const double pi = 3.14159265358979323846;
static const double e = 2.71828182845904523536;
static const builtin functions[] = {
static const te_variable functions[] = {
/* must be in alphabetical order */
{"abs", {fabs}, 1},
{"acos", {acos}, 1},
{"asin", {asin}, 1},
{"atan", {atan}, 1},
{"atan2", {atan2}, 2},
{"ceil", {ceil}, 1},
{"cos", {cos}, 1},
{"cosh", {cosh}, 1},
{"e", {&e}, 0},
{"exp", {exp}, 1},
{"floor", {floor}, 1},
{"ln", {log}, 1},
{"log", {log10}, 1},
{"pi", {&pi}, 0},
{"pow", {pow}, 2},
{"sin", {sin}, 1},
{"sinh", {sinh}, 1},
{"sqrt", {sqrt}, 1},
{"tan", {tan}, 1},
{"tanh", {tanh}, 1},
{"abs", fabs, TE_FUNCTION1},
{"acos", acos, TE_FUNCTION1},
{"asin", asin, TE_FUNCTION1},
{"atan", atan, TE_FUNCTION1},
{"atan2", atan2, TE_FUNCTION2},
{"ceil", ceil, TE_FUNCTION1},
{"cos", cos, TE_FUNCTION1},
{"cosh", cosh, TE_FUNCTION1},
{"e", &e, TE_VARIABLE},
{"exp", exp, TE_FUNCTION1},
{"floor", floor, TE_FUNCTION1},
{"ln", log, TE_FUNCTION1},
{"log", log10, TE_FUNCTION1},
{"pi", &pi, TE_VARIABLE},
{"pow", pow, TE_FUNCTION2},
{"sin", sin, TE_FUNCTION1},
{"sinh", sinh, TE_FUNCTION1},
{"sqrt", sqrt, TE_FUNCTION1},
{"tan", tan, TE_FUNCTION1},
{"tanh", tanh, TE_FUNCTION1},
{0}
};
static const builtin *find_function(const char *name, int len) {
static const te_variable *find_function(const char *name, int len) {
int imin = 0;
int imax = sizeof(functions) / sizeof(builtin) - 2;
int imax = sizeof(functions) / sizeof(te_variable) - 2;
/*Binary search.*/
while (imax >= imin) {
@@ -121,12 +116,12 @@ static const builtin *find_function(const char *name, int len) {
}
static const double *find_var(const state *s, const char *name, int len) {
static const te_variable *find_var(const state *s, const char *name, int len) {
int i;
if (!s->lookup) return 0;
for (i = 0; i < s->lookup_len; ++i) {
if (strncmp(name, s->lookup[i].name, len) == 0 && s->lookup[i].name[len] == '\0') {
return s->lookup[i].value;
return s->lookup + i;
}
}
return 0;
@@ -163,29 +158,24 @@ void next_token(state *s) {
start = s->next;
while ((s->next[0] >= 'a' && s->next[0] <= 'z') || (s->next[0] >= '0' && s->next[0] <= '9')) s->next++;
const double *var = find_var(s, start, s->next - start);
if (var) {
s->type = TOK_VARIABLE;
s->var = var;
const te_variable *var = find_var(s, start, s->next - start);
if (!var) var = find_function(start, s->next - start);
if (!var) {
s->type = TOK_ERROR;
} else {
if (s->next - start > 15) {
s->type = TOK_ERROR;
} else {
const builtin *f = find_function(start, s->next - start);
if (!f) {
s->type = TOK_ERROR;
} else {
if (f->arity == 0) {
s->type = TOK_NUMBER;
s->value = *f->value;
} else if (f->arity == 1) {
s->type = TOK_FUNCTION1;
s->f1 = f->f1;
} else if (f->arity == 2) {
s->type = TOK_FUNCTION2;
s->f2 = f->f2;
}
}
if (var->type == TE_VARIABLE) {
s->type = TOK_VARIABLE;
s->bound = var->value;
} else if (var->type == TE_FUNCTION0) {
s->type = TOK_FUNCTION0;
s->f0 = var->value;
} else if (var->type == TE_FUNCTION1) {
s->type = TOK_FUNCTION1;
s->f1 = var->value;
} else if (var->type == TE_FUNCTION2) {
s->type = TOK_FUNCTION2;
s->f2 = var->value;
}
}
@@ -220,26 +210,32 @@ static te_expr *base(state *s) {
switch (s->type) {
case TOK_NUMBER:
ret = new_expr(0, 0);
ret = new_expr(TE_CONSTANT, 0, 0);
ret->value = s->value;
next_token(s);
break;
case TOK_VARIABLE:
ret = new_expr(0, 0);
ret->bound = s->var;
ret = new_expr(TE_VARIABLE, 0, 0);
ret->bound = s->bound;
next_token(s);
break;
case TOK_FUNCTION0:
ret = new_expr(TE_FUNCTION0, 0, 0);
ret->f0 = s->f0;
next_token(s);
break;
case TOK_FUNCTION1:
ret = new_expr(0, 0);
ret = new_expr(TE_FUNCTION1, 0, 0);
ret->f1 = s->f1;
next_token(s);
ret->left = power(s);
break;
case TOK_FUNCTION2:
ret = new_expr(0, 0);
ret = new_expr(TE_FUNCTION2, 0, 0);
ret->f2 = s->f2;
next_token(s);
@@ -275,7 +271,7 @@ static te_expr *base(state *s) {
break;
default:
ret = new_expr(0, 0);
ret = new_expr(0, 0, 0);
s->type = TOK_ERROR;
ret->value = 0.0/0.0;
break;
@@ -298,7 +294,7 @@ static te_expr *power(state *s) {
if (sign == 1) {
ret = base(s);
} else {
ret = new_expr(base(s), 0);
ret = new_expr(TE_FUNCTION1, base(s), 0);
ret->f1 = negate;
}
@@ -313,7 +309,7 @@ static te_expr *factor(state *s) {
while (s->type == TOK_INFIX && (s->f2 == pow)) {
te_fun2 t = s->f2;
next_token(s);
ret = new_expr(ret, power(s));
ret = new_expr(TE_FUNCTION2, ret, power(s));
ret->f2 = t;
}
@@ -328,7 +324,7 @@ static te_expr *term(state *s) {
while (s->type == TOK_INFIX && (s->f2 == mul || s->f2 == divide || s->f2 == fmod)) {
te_fun2 t = s->f2;
next_token(s);
ret = new_expr(ret, factor(s));
ret = new_expr(TE_FUNCTION2, ret, factor(s));
ret->f2 = t;
}
@@ -343,7 +339,7 @@ static te_expr *expr(state *s) {
while (s->type == TOK_INFIX && (s->f2 == add || s->f2 == sub)) {
te_fun2 t = s->f2;
next_token(s);
ret = new_expr(ret, term(s));
ret = new_expr(TE_FUNCTION2, ret, term(s));
ret->f2 = t;
}
@@ -357,7 +353,7 @@ static te_expr *list(state *s) {
while (s->type == TOK_SEP) {
next_token(s);
ret = new_expr(ret, term(s));
ret = new_expr(TE_FUNCTION2, ret, term(s));
ret->f2 = comma;
}
@@ -366,23 +362,21 @@ static te_expr *list(state *s) {
double te_eval(const te_expr *n) {
double ret;
if (n->bound) {
ret = *n->bound;
} else if (n->left == 0 && n->right == 0) {
ret = n->value;
} else if (n->left && n->right == 0) {
ret = n->f1(te_eval(n->left));
} else {
ret = n->f2(te_eval(n->left), te_eval(n->right));
switch (n->type) {
case TE_CONSTANT: return n->value;
case TE_VARIABLE: return *n->bound;
case TE_FUNCTION0: return n->f0();
case TE_FUNCTION1: return n->f1(te_eval(n->left));
case TE_FUNCTION2: return n->f2(te_eval(n->left), te_eval(n->right));
default: return 0.0/0.0;
}
return ret;
}
static void optimize(te_expr *n) {
/* Evaluates as much as possible. */
/*
if (n->bound) return;
if (n->left) optimize(n->left);
@@ -405,6 +399,7 @@ static void optimize(te_expr *n) {
n->value = r;
}
}
*/
}