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/* -*- c++ -*- */
/*
* Copyright © 2010 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include <assert.h>
#include <stdio.h>
#include <math.h>
#include "s_expression.h"
s_symbol::s_symbol(const char *str, size_t n)
{
/* Assume the given string is already nul-terminated and in memory that
* will live as long as this node.
*/
assert(str[n] == '\0');
this->str = str;
}
s_list::s_list()
{
}
static void
skip_whitespace(const char *&src, char *&symbol_buffer)
{
size_t n = strspn(src, " \v\t\r\n");
src += n;
symbol_buffer += n;
/* Also skip Scheme-style comments: semi-colon 'til end of line */
if (src[0] == ';') {
n = strcspn(src, "\n");
src += n;
symbol_buffer += n;
skip_whitespace(src, symbol_buffer);
}
}
static s_expression *
read_atom(void *ctx, const char *&src, char *&symbol_buffer)
{
s_expression *expr = NULL;
skip_whitespace(src, symbol_buffer);
size_t n = strcspn(src, "( \v\t\r\n);");
if (n == 0)
return NULL; // no atom
// Check for the special symbol '+INF', which means +Infinity. Note: C99
// requires strtof to parse '+INF' as +Infinity, but we still support some
// non-C99-compliant compilers (e.g. MSVC).
if (n == 4 && strncmp(src, "+INF", 4) == 0) {
expr = new(ctx) s_float(INFINITY);
} else {
// Check if the atom is a number.
char *float_end = NULL;
float f = _mesa_strtof(src, &float_end);
if (float_end != src) {
char *int_end = NULL;
int i = strtol(src, &int_end, 10);
// If strtof matched more characters, it must have a decimal part
if (float_end > int_end)
expr = new(ctx) s_float(f);
else
expr = new(ctx) s_int(i);
} else {
// Not a number; return a symbol.
symbol_buffer[n] = '\0';
expr = new(ctx) s_symbol(symbol_buffer, n);
}
}
src += n;
symbol_buffer += n;
return expr;
}
static s_expression *
__read_expression(void *ctx, const char *&src, char *&symbol_buffer)
{
s_expression *atom = read_atom(ctx, src, symbol_buffer);
if (atom != NULL)
return atom;
skip_whitespace(src, symbol_buffer);
if (src[0] == '(') {
++src;
++symbol_buffer;
s_list *list = new(ctx) s_list;
s_expression *expr;
while ((expr = __read_expression(ctx, src, symbol_buffer)) != NULL) {
list->subexpressions.push_tail(expr);
}
skip_whitespace(src, symbol_buffer);
if (src[0] != ')') {
printf("Unclosed expression (check your parenthesis).\n");
return NULL;
}
++src;
++symbol_buffer;
return list;
}
return NULL;
}
s_expression *
s_expression::read_expression(void *ctx, const char *&src)
{
assert(src != NULL);
/* When we encounter a Symbol, we need to save a nul-terminated copy of
* the string. However, ralloc_strndup'ing every individual Symbol is
* extremely expensive. We could avoid this by simply overwriting the
* next character (guaranteed to be whitespace, parens, or semicolon) with
* a nul-byte. But overwriting non-whitespace would mess up parsing.
*
* So, just copy the whole buffer ahead of time. Walk both, leaving the
* original source string unmodified, and altering the copy to contain the
* necessary nul-bytes whenever we encounter a symbol.
*/
char *symbol_buffer = ralloc_strdup(ctx, src);
return __read_expression(ctx, src, symbol_buffer);
}
void s_int::print()
{
printf("%d", this->val);
}
void s_float::print()
{
printf("%f", this->val);
}
void s_symbol::print()
{
printf("%s", this->str);
}
void s_list::print()
{
printf("(");
foreach_in_list(s_expression, expr, &this->subexpressions) {
expr->print();
if (!expr->next->is_tail_sentinel())
printf(" ");
}
printf(")");
}
// --------------------------------------------------
bool
s_pattern::match(s_expression *expr)
{
switch (type)
{
case EXPR: *p_expr = expr; break;
case LIST: if (expr->is_list()) *p_list = (s_list *) expr; break;
case SYMBOL: if (expr->is_symbol()) *p_symbol = (s_symbol *) expr; break;
case NUMBER: if (expr->is_number()) *p_number = (s_number *) expr; break;
case INT: if (expr->is_int()) *p_int = (s_int *) expr; break;
case STRING:
s_symbol *sym = SX_AS_SYMBOL(expr);
if (sym != NULL && strcmp(sym->value(), literal) == 0)
return true;
return false;
};
return *p_expr == expr;
}
bool
s_match(s_expression *top, unsigned n, s_pattern *pattern, bool partial)
{
s_list *list = SX_AS_LIST(top);
if (list == NULL)
return false;
unsigned i = 0;
foreach_in_list(s_expression, expr, &list->subexpressions) {
if (i >= n)
return partial; /* More actual items than the pattern expected */
if (expr == NULL || !pattern[i].match(expr))
return false;
i++;
}
if (i < n)
return false; /* Less actual items than the pattern expected */
return true;
}
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