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glsl: Fix isinf() for non-C99-compliant compilers.

Commit ede60bc (glsl: Add isinf() and
isnan() builtins) uses "+INF" in the .ir file to represent infinity.
This worked on C99-compliant compilers, since the s-expression reader
uses strtod() to read numbers, and C99 requires strtod() to understand
"+INF".  However, it didn't work on non-C99-compliant compilers such
as MSVC.

This patch modifies the s-expression reader to explicitly check for
"+INF" rather than relying on strtod() to support it.

This is a candidate for the 8.0 branch.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=44767
Tested-by: Morgan Armand <morgan.devel@gmail.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
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1 parent 5e576ef commit 4f82fed49359676fc19598f8c65ca51958dd2d79 @stereotype441 stereotype441 committed Jan 17, 2012
Showing with 22 additions and 14 deletions.
  1. +22 −14 src/glsl/s_expression.cpp
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@@ -23,6 +23,7 @@
*/
#include <assert.h>
+#include <limits>
#include "s_expression.h"
s_symbol::s_symbol(const char *str, size_t n)
@@ -64,21 +65,28 @@ read_atom(void *ctx, const char *&src, char *&symbol_buffer)
if (n == 0)
return NULL; // no atom
- // Check if the atom is a number.
- char *float_end = NULL;
- double f = glsl_strtod(src, &float_end);
- if (float_end != src) {
- char *int_end = NULL;
- int i = strtol(src, &int_end, 10);
- // If strtod matched more characters, it must have a decimal part
- if (float_end > int_end)
- expr = new(ctx) s_float(f);
- else
- expr = new(ctx) s_int(i);
+ // Check for the special symbol '+INF', which means +Infinity. Note: C99
+ // requires strtod to parse '+INF' as +Infinity, but we still support some
+ // non-C99-compliant compilers (e.g. MSVC).
+ if (n == 4 && strncmp(src, "+INF", 4) == 0) {
+ expr = new(ctx) s_float(std::numeric_limits<float>::infinity());
} else {
- // Not a number; return a symbol.
- symbol_buffer[n] = '\0';
- expr = new(ctx) s_symbol(symbol_buffer, n);
+ // Check if the atom is a number.
+ char *float_end = NULL;
+ double f = glsl_strtod(src, &float_end);
+ if (float_end != src) {
+ char *int_end = NULL;
+ int i = strtol(src, &int_end, 10);
+ // If strtod matched more characters, it must have a decimal part
+ if (float_end > int_end)
+ expr = new(ctx) s_float(f);
+ else
+ expr = new(ctx) s_int(i);
+ } else {
+ // Not a number; return a symbol.
+ symbol_buffer[n] = '\0';
+ expr = new(ctx) s_symbol(symbol_buffer, n);
+ }
}
src += n;

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