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 <cstdio>
  26 #include <cstdlib>
  27 #include <cstring>
  28 #include <assert.h>
  29 #include "s_expression.h"
  30
  31 s_symbol::s_symbol(const char *tmp, size_t n)
  32 {
  33    this->str = ralloc_strndup (this, tmp, n);
  34    assert(this->str != NULL);
  35 }
  36
  37 s_list::s_list()
  38 {
  39 }
  40
  41 static void
  42 skip_whitespace(const char *& src)
  43 {
  44    src += strspn(src, " \v\t\r\n");
  45    /* Also skip Scheme-style comments: semi-colon 'til end of line */
  46    if (src[0] == ';') {
  47       src += strcspn(src, "\n");
  48       skip_whitespace(src);
  49    }
  50 }
  51
  52 static s_expression *
  53 read_atom(void *ctx, const char *& src)
  54 {
  55    s_expression *expr = NULL;
  56
  57    skip_whitespace(src);
  58
  59    size_t n = strcspn(src, "( \v\t\r\n);");
  60    if (n == 0)
  61       return NULL; // no atom
  62
  63    // Check if the atom is a number.
  64    char *float_end = NULL;
  65    double f = glsl_strtod(src, &float_end);
  66    if (float_end != src) {
  67       char *int_end = NULL;
  68       int i = strtol(src, &int_end, 10);
  69       // If strtod matched more characters, it must have a decimal part
  70       if (float_end > int_end)
  71          expr = new(ctx) s_float(f);
  72       else
  73          expr = new(ctx) s_int(i);
  74    } else {
  75       // Not a number; return a symbol.
  76       expr = new(ctx) s_symbol(src, n);
  77    }
  78
  79    src += n;
  80
  81    return expr;
  82 }
  83
  84 s_expression *
  85 s_expression::read_expression(void *ctx, const char *&src)
  86 {
  87    assert(src != NULL);
  88
  89    s_expression *atom = read_atom(ctx, src);
  90    if (atom != NULL)
  91       return atom;
  92
  93    skip_whitespace(src);
  94    if (src[0] == '(') {
  95       ++src;
  96
  97       s_list *list = new(ctx) s_list;
  98       s_expression *expr;
  99
 100       while ((expr = read_expression(ctx, src)) != NULL) {
 101          list->subexpressions.push_tail(expr);
 102       }
 103       skip_whitespace(src);
 104       if (src[0] != ')') {
 105          printf("Unclosed expression (check your parenthesis).\n");
 106          return NULL;
 107       }
 108       ++src;
 109       return list;
 110    }
 111    return NULL;
 112 }
 113
 114 void s_int::print()
 115 {
 116    printf("%d", this->val);
 117 }
 118
 119 void s_float::print()
 120 {
 121    printf("%f", this->val);
 122 }
 123
 124 void s_symbol::print()
 125 {
 126    printf("%s", this->str);
 127 }
 128
 129 void s_list::print()
 130 {
 131    printf("(");
 132    foreach_iter(exec_list_iterator, it, this->subexpressions) {
 133       s_expression *expr = (s_expression*) it.get();
 134       expr->print();
 135       if (!expr->next->is_tail_sentinel())
 136          printf(" ");
 137    }
 138    printf(")");
 139 }
 140
 141 // --------------------------------------------------
 142
 143 bool
 144 s_pattern::match(s_expression *expr)
 145 {
 146    switch (type)
 147    {
 148    case EXPR:   *p_expr = expr; break;
 149    case LIST:   if (expr->is_list())   *p_list   = (s_list *)   expr; break;
 150    case SYMBOL: if (expr->is_symbol()) *p_symbol = (s_symbol *) expr; break;
 151    case NUMBER: if (expr->is_number()) *p_number = (s_number *) expr; break;
 152    case INT:    if (expr->is_int())    *p_int    = (s_int *)    expr; break;
 153    case STRING:
 154       s_symbol *sym = SX_AS_SYMBOL(expr);
 155       if (sym != NULL && strcmp(sym->value(), literal) == 0)
 156          return true;
 157       return false;
 158    };
 159
 160    return *p_expr == expr;
 161 }
 162
 163 bool
 164 s_match(s_expression *top, unsigned n, s_pattern *pattern, bool partial)
 165 {
 166    s_list *list = SX_AS_LIST(top);
 167    if (list == NULL)
 168       return false;
 169
 170    unsigned i = 0;
 171    foreach_iter(exec_list_iterator, it, list->subexpressions) {
 172       if (i >= n)
 173          return partial; /* More actual items than the pattern expected */
 174
 175       s_expression *expr = (s_expression *) it.get();
 176       if (expr == NULL || !pattern[i].match(expr))
 177          return false;
 178
 179       i++;
 180    }
 181
 182    if (i < n)
 183       return false; /* Less actual items than the pattern expected */
 184
 185    return true;
 186 }