/**
* Checks if array subscript is valid and if so sets array_index.
*/
static bool
valid_array_index(const GLchar *name, unsigned *array_index)
{
long idx = 0;
const GLchar *out_base_name_end;
idx = parse_program_resource_name(name, &out_base_name_end);
if (idx < 0)
return false;
if (array_index)
*array_index = idx;
return true;
}
/**
* Called via glGetUniformLocation().
*
* Returns the uniform index into UniformStorage (also the
* glGetActiveUniformsiv uniform index), and stores the referenced
* array offset in *offset, or GL_INVALID_INDEX (-1).
*/
extern "C" unsigned
_mesa_get_uniform_location(struct gl_shader_program *shProg,
const GLchar *name,
unsigned *out_offset)
{
/* Page 80 (page 94 of the PDF) of the OpenGL 2.1 spec says:
*
* "The first element of a uniform array is identified using the
* name of the uniform array appended with "[0]". Except if the last
* part of the string name indicates a uniform array, then the
* location of the first element of that array can be retrieved by
* either using the name of the uniform array, or the name of the
* uniform array appended with "[0]"."
*
* Note: since uniform names are not allowed to use whitespace, and array
* indices within uniform names are not allowed to use "+", "-", or leading
* zeros, it follows that each uniform has a unique name up to the possible
* ambiguity with "[0]" noted above. Therefore we don't need to worry
* about mal-formed inputs--they will properly fail when we try to look up
* the uniform name in shProg->UniformHash.
*/
const GLchar *base_name_end;
long offset = parse_program_resource_name(name, &base_name_end);
bool array_lookup = offset >= 0;
char *name_copy;
if (array_lookup) {
name_copy = (char *) malloc(base_name_end - name + 1);
memcpy(name_copy, name, base_name_end - name);
name_copy[base_name_end - name] = '\0';
} else {
name_copy = (char *) name;
offset = 0;
}
unsigned location = 0;
const bool found = shProg->UniformHash->get(location, name_copy);
assert(!found
|| strcmp(name_copy, shProg->UniformStorage[location].name) == 0);
/* Free the temporary buffer *before* possibly returning an error.
*/
if (name_copy != name)
free(name_copy);
if (!found)
return GL_INVALID_INDEX;
/* If the uniform is an array, fail if the index is out of bounds.
* (A negative index is caught above.) This also fails if the uniform
* is not an array, but the user is trying to index it, because
* array_elements is zero and offset >= 0.
*/
if (array_lookup
&& offset >= (long) shProg->UniformStorage[location].array_elements) {
return GL_INVALID_INDEX;
}
*out_offset = offset;
return location;
}
