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      1 /*
      2  * Copyright  2010 Intel Corporation
      3  *
      4  * Permission is hereby granted, free of charge, to any person obtaining a
      5  * copy of this software and associated documentation files (the "Software"),
      6  * to deal in the Software without restriction, including without limitation
      7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      8  * and/or sell copies of the Software, and to permit persons to whom the
      9  * Software is furnished to do so, subject to the following conditions:
     10  *
     11  * The above copyright notice and this permission notice (including the next
     12  * paragraph) shall be included in all copies or substantial portions of the
     13  * Software.
     14  *
     15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
     21  * DEALINGS IN THE SOFTWARE.
     22  */
     23 
     24 #include <assert.h>
     25 #include <string.h>
     26 #include <ctype.h>
     27 #include "glcpp.h"
     28 #include "main/core.h" /* for isblank() on MSVC */
     29 
     30 void
     31 glcpp_error (YYLTYPE *locp, glcpp_parser_t *parser, const char *fmt, ...)
     32 {
     33 	va_list ap;
     34 
     35 	parser->error = 1;
     36 	ralloc_asprintf_rewrite_tail(&parser->info_log,
     37 				     &parser->info_log_length,
     38 				     "%u:%u(%u): "
     39 				     "preprocessor error: ",
     40 				     locp->source,
     41 				     locp->first_line,
     42 				     locp->first_column);
     43 	va_start(ap, fmt);
     44 	ralloc_vasprintf_rewrite_tail(&parser->info_log,
     45 				      &parser->info_log_length,
     46 				      fmt, ap);
     47 	va_end(ap);
     48 	ralloc_asprintf_rewrite_tail(&parser->info_log,
     49 				     &parser->info_log_length, "\n");
     50 }
     51 
     52 void
     53 glcpp_warning (YYLTYPE *locp, glcpp_parser_t *parser, const char *fmt, ...)
     54 {
     55 	va_list ap;
     56 
     57 	ralloc_asprintf_rewrite_tail(&parser->info_log,
     58 				     &parser->info_log_length,
     59 				     "%u:%u(%u): "
     60 				     "preprocessor warning: ",
     61 				     locp->source,
     62 				     locp->first_line,
     63 				     locp->first_column);
     64 	va_start(ap, fmt);
     65 	ralloc_vasprintf_rewrite_tail(&parser->info_log,
     66 				      &parser->info_log_length,
     67 				      fmt, ap);
     68 	va_end(ap);
     69 	ralloc_asprintf_rewrite_tail(&parser->info_log,
     70 				     &parser->info_log_length, "\n");
     71 }
     72 
     73 /* Searches backwards for '^ *#' from a given starting point. */
     74 static int
     75 in_directive(const char *shader, const char *ptr)
     76 {
     77 	assert(ptr >= shader);
     78 
     79 	/* Search backwards for '#'. If we find a \n first, it doesn't count */
     80 	for (; ptr >= shader && *ptr != '#'; ptr--) {
     81 		if (*ptr == '\n')
     82 			return 0;
     83 	}
     84 	if (ptr >= shader) {
     85 		/* Found '#'...look for spaces preceded by a newline */
     86 		for (ptr--; ptr >= shader && isblank(*ptr); ptr--);
     87 		// FIXME: I don't think the '\n' case can happen
     88 		if (ptr < shader || *ptr == '\n')
     89 			return 1;
     90 	}
     91 	return 0;
     92 }
     93 
     94 /* Remove any line continuation characters in preprocessing directives.
     95  * However, ignore any in GLSL code, as "There is no line continuation
     96  * character" (1.30 page 9) in GLSL.
     97  */
     98 static char *
     99 remove_line_continuations(glcpp_parser_t *ctx, const char *shader)
    100 {
    101 	int in_continued_line = 0;
    102 	int extra_newlines = 0;
    103 	char *clean = ralloc_strdup(ctx, "");
    104 	const char *search_start = shader;
    105 	const char *newline;
    106 	while ((newline = strchr(search_start, '\n')) != NULL) {
    107 		const char *backslash = NULL;
    108 
    109 		/* # of characters preceding the newline. */
    110 		int n = newline - shader;
    111 
    112 		/* Find the preceding '\', if it exists */
    113 		if (n >= 1 && newline[-1] == '\\')
    114 			backslash = newline - 1;
    115 		else if (n >= 2 && newline[-1] == '\r' && newline[-2] == '\\')
    116 			backslash = newline - 2;
    117 
    118 		/* Double backslashes don't count (the backslash is escaped) */
    119 		if (backslash != NULL && backslash[-1] == '\\') {
    120 			backslash = NULL;
    121 		}
    122 
    123 		if (backslash != NULL) {
    124 			/* We found a line continuation, but do we care? */
    125 			if (!in_continued_line) {
    126 				if (in_directive(shader, backslash)) {
    127 					in_continued_line = 1;
    128 					extra_newlines = 0;
    129 				}
    130 			}
    131 			if (in_continued_line) {
    132 				/* Copy everything before the \ */
    133 				ralloc_strncat(&clean, shader, backslash - shader);
    134 				shader = newline + 1;
    135 				extra_newlines++;
    136 			}
    137 		} else if (in_continued_line) {
    138 			/* Copy everything up to and including the \n */
    139 			ralloc_strncat(&clean, shader, newline - shader + 1);
    140 			shader = newline + 1;
    141 			/* Output extra newlines to make line numbers match */
    142 			for (; extra_newlines > 0; extra_newlines--)
    143 				ralloc_strcat(&clean, "\n");
    144 			in_continued_line = 0;
    145 		}
    146 		search_start = newline + 1;
    147 	}
    148 	ralloc_strcat(&clean, shader);
    149 	return clean;
    150 }
    151 
    152 int
    153 glcpp_preprocess(void *ralloc_ctx, const char **shader, char **info_log,
    154 	   const struct gl_extensions *extensions, int api)
    155 {
    156 	int errors;
    157 	glcpp_parser_t *parser = glcpp_parser_create (extensions, api);
    158 	*shader = remove_line_continuations(parser, *shader);
    159 
    160 	glcpp_lex_set_source_string (parser, *shader);
    161 
    162 	glcpp_parser_parse (parser);
    163 
    164 	if (parser->skip_stack)
    165 		glcpp_error (&parser->skip_stack->loc, parser, "Unterminated #if\n");
    166 
    167 	ralloc_strcat(info_log, parser->info_log);
    168 
    169 	ralloc_steal(ralloc_ctx, parser->output);
    170 	*shader = parser->output;
    171 
    172 	errors = parser->error;
    173 	glcpp_parser_destroy (parser);
    174 	return errors;
    175 }
    176