src/glsl/s_expression.cpp

   1 /* -*- c++ -*- */
   2 /*
   3  * Copyright © 2010 Intel Corporation
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a
   6  * copy of this software and associated documentation files (the "Software"),
   7  * to deal in the Software without restriction, including without limitation
   8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9  * and/or sell copies of the Software, and to permit persons to whom the
  10  * Software is furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice (including the next
  13  * paragraph) shall be included in all copies or substantial portions of the
  14  * Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  22  * DEALINGS IN THE SOFTWARE.
  23  */
  24
  25 #include <assert.h>
  26 #include "s_expression.h"
  27
  28 s_symbol::s_symbol(const char *tmp, size_t n)
  29 {
  30    this->str = ralloc_strndup (this, tmp, n);
  31    assert(this->str != NULL);
  32 }
  33
  34 s_list::s_list()
  35 {
  36 }
  37
  38 static void
  39 skip_whitespace(const char *& src)
  40 {
  41    src += strspn(src, " \v\t\r\n");
  42    /* Also skip Scheme-style comments: semi-colon 'til end of line */
  43    if (src[0] == ';') {
  44       src += strcspn(src, "\n");
  45       skip_whitespace(src);
  46    }
  47 }
  48
  49 static s_expression *
  50 read_atom(void *ctx, const char *& src)
  51 {
  52    s_expression *expr = NULL;
  53
  54    skip_whitespace(src);
  55
  56    size_t n = strcspn(src, "( \v\t\r\n);");
  57    if (n == 0)
  58       return NULL; // no atom
  59
  60    // Check if the atom is a number.
  61    char *float_end = NULL;
  62    double f = glsl_strtod(src, &float_end);
  63    if (float_end != src) {
  64       char *int_end = NULL;
  65       int i = strtol(src, &int_end, 10);
  66       // If strtod matched more characters, it must have a decimal part
  67       if (float_end > int_end)
  68          expr = new(ctx) s_float(f);
  69       else
  70          expr = new(ctx) s_int(i);
  71    } else {
  72       // Not a number; return a symbol.
  73       expr = new(ctx) s_symbol(src, n);
  74    }
  75
  76    src += n;
  77
  78    return expr;
  79 }
  80
  81 s_expression *
  82 s_expression::read_expression(void *ctx, const char *&src)
  83 {
  84    assert(src != NULL);
  85
  86    s_expression *atom = read_atom(ctx, src);
  87    if (atom != NULL)
  88       return atom;
  89
  90    skip_whitespace(src);
  91    if (src[0] == '(') {
  92       ++src;
  93
  94       s_list *list = new(ctx) s_list;
  95       s_expression *expr;
  96
  97       while ((expr = read_expression(ctx, src)) != NULL) {
  98          list->subexpressions.push_tail(expr);
  99       }
 100       skip_whitespace(src);
 101       if (src[0] != ')') {
 102          printf("Unclosed expression (check your parenthesis).\n");
 103          return NULL;
 104       }
 105       ++src;
 106       return list;
 107    }
 108    return NULL;
 109 }
 110
 111 void s_int::print()
 112 {
 113    printf("%d", this->val);
 114 }
 115
 116 void s_float::print()
 117 {
 118    printf("%f", this->val);
 119 }
 120
 121 void s_symbol::print()
 122 {
 123    printf("%s", this->str);
 124 }
 125
 126 void s_list::print()
 127 {
 128    printf("(");
 129    foreach_iter(exec_list_iterator, it, this->subexpressions) {
 130       s_expression *expr = (s_expression*) it.get();
 131       expr->print();
 132       if (!expr->next->is_tail_sentinel())
 133          printf(" ");
 134    }
 135    printf(")");
 136 }
 137
 138 // --------------------------------------------------
 139
 140 bool
 141 s_pattern::match(s_expression *expr)
 142 {
 143    switch (type)
 144    {
 145    case EXPR:   *p_expr = expr; break;
 146    case LIST:   if (expr->is_list())   *p_list   = (s_list *)   expr; break;
 147    case SYMBOL: if (expr->is_symbol()) *p_symbol = (s_symbol *) expr; break;
 148    case NUMBER: if (expr->is_number()) *p_number = (s_number *) expr; break;
 149    case INT:    if (expr->is_int())    *p_int    = (s_int *)    expr; break;
 150    case STRING:
 151       s_symbol *sym = SX_AS_SYMBOL(expr);
 152       if (sym != NULL && strcmp(sym->value(), literal) == 0)
 153          return true;
 154       return false;
 155    };
 156
 157    return *p_expr == expr;
 158 }
 159
 160 bool
 161 s_match(s_expression *top, unsigned n, s_pattern *pattern, bool partial)
 162 {
 163    s_list *list = SX_AS_LIST(top);
 164    if (list == NULL)
 165       return false;
 166
 167    unsigned i = 0;
 168    foreach_iter(exec_list_iterator, it, list->subexpressions) {
 169       if (i >= n)
 170          return partial; /* More actual items than the pattern expected */
 171
 172       s_expression *expr = (s_expression *) it.get();
 173       if (expr == NULL || !pattern[i].match(expr))
 174          return false;
 175
 176       i++;
 177    }
 178
 179    if (i < n)
 180       return false; /* Less actual items than the pattern expected */
 181
 182    return true;
 183 }