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 *str, size_t n)
  29 {
  30    /* Assume the given string is already nul-terminated and in memory that
  31     * will live as long as this node.
  32     */
  33    assert(str[n] == '\0');
  34    this->str = str;
  35 }
  36
  37 s_list::s_list()
  38 {
  39 }
  40
  41 static void
  42 skip_whitespace(const char *&src, char *&symbol_buffer)
  43 {
  44    size_t n = strspn(src, " \v\t\r\n");
  45    src += n;
  46    symbol_buffer += n;
  47    /* Also skip Scheme-style comments: semi-colon 'til end of line */
  48    if (src[0] == ';') {
  49       n = strcspn(src, "\n");
  50       src += n;
  51       symbol_buffer += n;
  52       skip_whitespace(src, symbol_buffer);
  53    }
  54 }
  55
  56 static s_expression *
  57 read_atom(void *ctx, const char *&src, char *&symbol_buffer)
  58 {
  59    s_expression *expr = NULL;
  60
  61    skip_whitespace(src, symbol_buffer);
  62
  63    size_t n = strcspn(src, "( \v\t\r\n);");
  64    if (n == 0)
  65       return NULL; // no atom
  66
  67    // Check if the atom is a number.
  68    char *float_end = NULL;
  69    double f = glsl_strtod(src, &float_end);
  70    if (float_end != src) {
  71       char *int_end = NULL;
  72       int i = strtol(src, &int_end, 10);
  73       // If strtod matched more characters, it must have a decimal part
  74       if (float_end > int_end)
  75          expr = new(ctx) s_float(f);
  76       else
  77          expr = new(ctx) s_int(i);
  78    } else {
  79       // Not a number; return a symbol.
  80       symbol_buffer[n] = '\0';
  81       expr = new(ctx) s_symbol(symbol_buffer, n);
  82    }
  83
  84    src += n;
  85    symbol_buffer += n;
  86
  87    return expr;
  88 }
  89
  90 static s_expression *
  91 __read_expression(void *ctx, const char *&src, char *&symbol_buffer)
  92 {
  93    s_expression *atom = read_atom(ctx, src, symbol_buffer);
  94    if (atom != NULL)
  95       return atom;
  96
  97    skip_whitespace(src, symbol_buffer);
  98    if (src[0] == '(') {
  99       ++src;
 100       ++symbol_buffer;
 101
 102       s_list *list = new(ctx) s_list;
 103       s_expression *expr;
 104
 105       while ((expr = __read_expression(ctx, src, symbol_buffer)) != NULL) {
 106          list->subexpressions.push_tail(expr);
 107       }
 108       skip_whitespace(src, symbol_buffer);
 109       if (src[0] != ')') {
 110          printf("Unclosed expression (check your parenthesis).\n");
 111          return NULL;
 112       }
 113       ++src;
 114       ++symbol_buffer;
 115       return list;
 116    }
 117    return NULL;
 118 }
 119
 120 s_expression *
 121 s_expression::read_expression(void *ctx, const char *&src)
 122 {
 123    assert(src != NULL);
 124
 125    /* When we encounter a Symbol, we need to save a nul-terminated copy of
 126     * the string.  However, ralloc_strndup'ing every individual Symbol is
 127     * extremely expensive.  We could avoid this by simply overwriting the
 128     * next character (guaranteed to be whitespace, parens, or semicolon) with
 129     * a nul-byte.  But overwriting non-whitespace would mess up parsing.
 130     *
 131     * So, just copy the whole buffer ahead of time.  Walk both, leaving the
 132     * original source string unmodified, and altering the copy to contain the
 133     * necessary nul-bytes whenever we encounter a symbol.
 134     */
 135    char *symbol_buffer = ralloc_strdup(ctx, src);
 136    return __read_expression(ctx, src, symbol_buffer);
 137 }
 138
 139 void s_int::print()
 140 {
 141    printf("%d", this->val);
 142 }
 143
 144 void s_float::print()
 145 {
 146    printf("%f", this->val);
 147 }
 148
 149 void s_symbol::print()
 150 {
 151    printf("%s", this->str);
 152 }
 153
 154 void s_list::print()
 155 {
 156    printf("(");
 157    foreach_iter(exec_list_iterator, it, this->subexpressions) {
 158       s_expression *expr = (s_expression*) it.get();
 159       expr->print();
 160       if (!expr->next->is_tail_sentinel())
 161          printf(" ");
 162    }
 163    printf(")");
 164 }
 165
 166 // --------------------------------------------------
 167
 168 bool
 169 s_pattern::match(s_expression *expr)
 170 {
 171    switch (type)
 172    {
 173    case EXPR:   *p_expr = expr; break;
 174    case LIST:   if (expr->is_list())   *p_list   = (s_list *)   expr; break;
 175    case SYMBOL: if (expr->is_symbol()) *p_symbol = (s_symbol *) expr; break;
 176    case NUMBER: if (expr->is_number()) *p_number = (s_number *) expr; break;
 177    case INT:    if (expr->is_int())    *p_int    = (s_int *)    expr; break;
 178    case STRING:
 179       s_symbol *sym = SX_AS_SYMBOL(expr);
 180       if (sym != NULL && strcmp(sym->value(), literal) == 0)
 181          return true;
 182       return false;
 183    };
 184
 185    return *p_expr == expr;
 186 }
 187
 188 bool
 189 s_match(s_expression *top, unsigned n, s_pattern *pattern, bool partial)
 190 {
 191    s_list *list = SX_AS_LIST(top);
 192    if (list == NULL)
 193       return false;
 194
 195    unsigned i = 0;
 196    foreach_iter(exec_list_iterator, it, list->subexpressions) {
 197       if (i >= n)
 198          return partial; /* More actual items than the pattern expected */
 199
 200       s_expression *expr = (s_expression *) it.get();
 201       if (expr == NULL || !pattern[i].match(expr))
 202          return false;
 203
 204       i++;
 205    }
 206
 207    if (i < n)
 208       return false; /* Less actual items than the pattern expected */
 209
 210    return true;
 211 }