Previously, we were only supporting line-continuation backslash characters
within lines of pre-processor directives, (as per the specification). With
OpenGL 4.3, line continuations are now supported anywhere within a shader.
While changing this, also fix a bug where the preprocessor was ignoring line
continuation characters when a line ended in multiple backslash characters.
The new code is also more efficient than the old. Previously, we would perform
a ralloc copy at each newline. We now perform copies only at each occurrence
of a line-continuation.
---
src/glsl/glcpp/pp.c | 108 ++++++++++++++++++++-------------------------------
1 file changed, 42 insertions(+), 66 deletions(-)
diff --git a/src/glsl/glcpp/pp.c b/src/glsl/glcpp/pp.c
index 11b2941..1135570 100644
--- a/src/glsl/glcpp/pp.c
+++ b/src/glsl/glcpp/pp.c
@@ -70,82 +70,58 @@ glcpp_warning (YYLTYPE *locp, glcpp_parser_t *parser, const
char *fmt, ...)
&parser->info_log_length, "\n");
}
-/* Searches backwards for '^ *#' from a given starting point. */
-static int
-in_directive(const char *shader, const char *ptr)
-{
- assert(ptr >= shader);
-
- /* Search backwards for '#'. If we find a \n first, it doesn't count */
- for (; ptr >= shader && *ptr != '#'; ptr--) {
- if (*ptr == '\n')
- return 0;
- }
- if (ptr >= shader) {
- /* Found '#'...look for spaces preceded by a newline */
- for (ptr--; ptr >= shader && isblank(*ptr); ptr--);
- // FIXME: I don't think the '\n' case can happen
- if (ptr < shader || *ptr == '\n')
- return 1;
- }
- return 0;
-}
-
-/* Remove any line continuation characters in preprocessing directives.
- * However, ignore any in GLSL code, as "There is no line continuation
- * character" (1.30 page 9) in GLSL.
+/* Remove any line continuation characters in the shader, (whether in
+ * preprocessing directives or in GLSL code).
*/
static char *
remove_line_continuations(glcpp_parser_t *ctx, const char *shader)
{
- int in_continued_line = 0;
- int extra_newlines = 0;
char *clean = ralloc_strdup(ctx, "");
- const char *search_start = shader;
- const char *newline;
- while ((newline = strchr(search_start, '\n')) != NULL) {
- const char *backslash = NULL;
-
- /* # of characters preceding the newline. */
- int n = newline - shader;
-
- /* Find the preceding '\', if it exists */
- if (n >= 1 && newline[-1] == '\\')
- backslash = newline - 1;
- else if (n >= 2 && newline[-1] == '\r' && newline[-2] == '\\')
- backslash = newline - 2;
-
- /* Double backslashes don't count (the backslash is escaped) */
- if (backslash != NULL && backslash[-1] == '\\') {
- backslash = NULL;
- }
-
- if (backslash != NULL) {
- /* We found a line continuation, but do we care? */
- if (!in_continued_line) {
- if (in_directive(shader, backslash)) {
- in_continued_line = 1;
- extra_newlines = 0;
- }
- }
- if (in_continued_line) {
- /* Copy everything before the \ */
- ralloc_strncat(&clean, shader, backslash -
shader);
+ const char *backslash, *newline;
+ int collapsed_newlines = 0;
+
+ while (1) {
+ backslash = strchr(shader, '\\');
+
+ /* If we have previously collapsed any
+ * line-continuations, then we want to insert
+ * additional newlines at the next occurrence of a
+ * newline character to avoid changing any line
+ * numbers. */
+ if (collapsed_newlines) {
+ newline = strchr(shader, '\n');
+ if (newline &&
+ (backslash == NULL || newline < backslash))
+ {
+ ralloc_strncat(&clean, shader,
+ newline - shader + 1);
+ while (collapsed_newlines--)
+ ralloc_strcat(&clean, "\n");
shader = newline + 1;
- extra_newlines++;
}
- } else if (in_continued_line) {
- /* Copy everything up to and including the \n */
- ralloc_strncat(&clean, shader, newline - shader + 1);
- shader = newline + 1;
- /* Output extra newlines to make line numbers match */
- for (; extra_newlines > 0; extra_newlines--)
- ralloc_strcat(&clean, "\n");
- in_continued_line = 0;
}
- search_start = newline + 1;
+
+ if (backslash == NULL)
+ break;
+
+ /* At each line continuation, (backslash followed by a
+ * newline), copy all preceding text to the output,
+ * then advance the shader pointer to the character
+ * after the newline. */
+ if (backslash[1] == '\n' ||
+ (backslash[1] == '\r' && backslash[2] == '\n'))
+ {
+ collapsed_newlines++;
+ ralloc_strncat(&clean, shader, backslash - shader);
+ if (backslash[1] == '\n')
+ shader = backslash + 2;
+ else
+ shader = backslash + 3;
+ }
}
+
ralloc_strcat(&clean, shader);
+
return clean;
}
--
1.7.10
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