/* Get name length of a program resource. This consists of * base name + 3 for '[0]' if resource is an array. */ extern unsigned _mesa_program_resource_name_len(struct gl_program_resource *res) { unsigned length = strlen(_mesa_program_resource_name(res)); if (_mesa_program_resource_array_size(res) && add_index_to_name(res)) length += 3; return length; }
/* Get full name of a program resource. */ bool _mesa_get_program_resource_name(struct gl_shader_program *shProg, GLenum programInterface, GLuint index, GLsizei bufSize, GLsizei *length, GLchar *name, const char *caller) { GET_CURRENT_CONTEXT(ctx); /* Find resource with given interface and index. */ struct gl_program_resource *res = _mesa_program_resource_find_index(shProg, programInterface, index); /* The error INVALID_VALUE is generated if <index> is greater than * or equal to the number of entries in the active resource list for * <programInterface>. */ if (!res) { _mesa_error(ctx, GL_INVALID_VALUE, "%s(index %u)", caller, index); return false; } if (bufSize < 0) { _mesa_error(ctx, GL_INVALID_VALUE, "%s(bufSize %d)", caller, bufSize); return false; } GLsizei localLength; if (length == NULL) length = &localLength; _mesa_copy_string(name, bufSize, length, _mesa_program_resource_name(res)); if (_mesa_program_resource_array_size(res) && add_index_to_name(res)) { int i; /* The comparison is strange because *length does *NOT* include the * terminating NUL, but maxLength does. */ for (i = 0; i < 3 && (*length + i + 1) < bufSize; i++) name[*length + i] = "[0]"[i]; name[*length + i] = '\0'; *length += i; } return true; }
/** * Get info about the transform feedback outputs which are to be written * to the feedback buffer(s). */ void GLAPIENTRY _mesa_GetTransformFeedbackVarying(GLuint program, GLuint index, GLsizei bufSize, GLsizei *length, GLsizei *size, GLenum *type, GLchar *name) { const struct gl_shader_program *shProg; struct gl_program_resource *res; GET_CURRENT_CONTEXT(ctx); shProg = _mesa_lookup_shader_program(ctx, program); if (!shProg) { _mesa_error(ctx, GL_INVALID_VALUE, "glGetTransformFeedbackVarying(program=%u)", program); return; } res = _mesa_program_resource_find_index((struct gl_shader_program *) shProg, GL_TRANSFORM_FEEDBACK_VARYING, index); if (!res) { _mesa_error(ctx, GL_INVALID_VALUE, "glGetTransformFeedbackVarying(index=%u)", index); return; } /* return the varying's name and length */ _mesa_copy_string(name, bufSize, length, _mesa_program_resource_name(res)); /* return the datatype and value's size (in datatype units) */ if (type) _mesa_program_resource_prop((struct gl_shader_program *) shProg, res, index, GL_TYPE, (GLint*) type, "glGetTransformFeedbackVarying"); if (size) _mesa_program_resource_prop((struct gl_shader_program *) shProg, res, index, GL_ARRAY_SIZE, (GLint*) size, "glGetTransformFeedbackVarying"); }
/* Find a program resource with specific name in given interface. */ struct gl_program_resource * _mesa_program_resource_find_name(struct gl_shader_program *shProg, GLenum programInterface, const char *name) { struct gl_program_resource *res = shProg->ProgramResourceList; for (unsigned i = 0; i < shProg->NumProgramResourceList; i++, res++) { if (res->Type != programInterface) continue; /* Resource basename. */ const char *rname = _mesa_program_resource_name(res); unsigned baselen = strlen(rname); switch (programInterface) { case GL_TRANSFORM_FEEDBACK_VARYING: case GL_UNIFORM_BLOCK: case GL_UNIFORM: if (strncmp(rname, name, baselen) == 0) { /* Basename match, check if array or struct. */ if (name[baselen] == '\0' || name[baselen] == '[' || name[baselen] == '.') { return res; } } break; case GL_PROGRAM_INPUT: case GL_PROGRAM_OUTPUT: if (array_index_of_resource(res, name) >= 0) return res; break; default: assert(!"not implemented for given interface"); } } return NULL; }
/* Find a program resource with specific name in given interface. */ struct gl_program_resource * _mesa_program_resource_find_name(struct gl_shader_program *shProg, GLenum programInterface, const char *name, unsigned *array_index) { struct gl_program_resource *res = shProg->ProgramResourceList; for (unsigned i = 0; i < shProg->NumProgramResourceList; i++, res++) { if (res->Type != programInterface) continue; /* Resource basename. */ const char *rname = _mesa_program_resource_name(res); unsigned baselen = strlen(rname); unsigned baselen_without_array_index = baselen; const char *rname_last_square_bracket = strrchr(rname, '['); bool found = false; bool rname_has_array_index_zero = false; /* From ARB_program_interface_query spec: * * "uint GetProgramResourceIndex(uint program, enum programInterface, * const char *name); * [...] * If <name> exactly matches the name string of one of the active * resources for <programInterface>, the index of the matched resource is * returned. Additionally, if <name> would exactly match the name string * of an active resource if "[0]" were appended to <name>, the index of * the matched resource is returned. [...]" * * "A string provided to GetProgramResourceLocation or * GetProgramResourceLocationIndex is considered to match an active variable * if: * * * the string exactly matches the name of the active variable; * * * if the string identifies the base name of an active array, where the * string would exactly match the name of the variable if the suffix * "[0]" were appended to the string; [...]" */ /* Remove array's index from interface block name comparison only if * array's index is zero and the resulting string length is the same * than the provided name's length. */ if (rname_last_square_bracket) { baselen_without_array_index -= strlen(rname_last_square_bracket); rname_has_array_index_zero = (strncmp(rname_last_square_bracket, "[0]\0", 4) == 0) && (baselen_without_array_index == strlen(name)); } if (strncmp(rname, name, baselen) == 0) found = true; else if (rname_has_array_index_zero && strncmp(rname, name, baselen_without_array_index) == 0) found = true; if (found) { switch (programInterface) { case GL_UNIFORM_BLOCK: case GL_SHADER_STORAGE_BLOCK: /* Basename match, check if array or struct. */ if (rname_has_array_index_zero || name[baselen] == '\0' || name[baselen] == '[' || name[baselen] == '.') { return res; } break; case GL_TRANSFORM_FEEDBACK_VARYING: case GL_BUFFER_VARIABLE: case GL_UNIFORM: case GL_VERTEX_SUBROUTINE_UNIFORM: case GL_GEOMETRY_SUBROUTINE_UNIFORM: case GL_FRAGMENT_SUBROUTINE_UNIFORM: case GL_COMPUTE_SUBROUTINE_UNIFORM: case GL_TESS_CONTROL_SUBROUTINE_UNIFORM: case GL_TESS_EVALUATION_SUBROUTINE_UNIFORM: case GL_VERTEX_SUBROUTINE: case GL_GEOMETRY_SUBROUTINE: case GL_FRAGMENT_SUBROUTINE: case GL_COMPUTE_SUBROUTINE: case GL_TESS_CONTROL_SUBROUTINE: case GL_TESS_EVALUATION_SUBROUTINE: if (name[baselen] == '.') { return res; } /* fall-through */ case GL_PROGRAM_INPUT: case GL_PROGRAM_OUTPUT: if (name[baselen] == '\0') { return res; } else if (name[baselen] == '[' && valid_array_index(name, array_index)) { return res; } break; default: assert(!"not implemented for given interface"); } } } return NULL; }
unsigned _mesa_program_resource_prop(struct gl_shader_program *shProg, struct gl_program_resource *res, GLuint index, const GLenum prop, GLint *val, const char *caller) { GET_CURRENT_CONTEXT(ctx); #define VALIDATE_TYPE(type)\ if (res->Type != type)\ goto invalid_operation; #define VALIDATE_TYPE_2(type1, type2)\ if (res->Type != type1 && res->Type != type2)\ goto invalid_operation; switch(prop) { case GL_NAME_LENGTH: switch (res->Type) { case GL_ATOMIC_COUNTER_BUFFER: goto invalid_operation; default: /* Resource name length + terminator. */ *val = _mesa_program_resource_name_len(res) + 1; } return 1; case GL_TYPE: switch (res->Type) { case GL_UNIFORM: case GL_BUFFER_VARIABLE: *val = RESOURCE_UNI(res)->type->gl_type; return 1; case GL_PROGRAM_INPUT: case GL_PROGRAM_OUTPUT: *val = RESOURCE_VAR(res)->type->gl_type; return 1; case GL_TRANSFORM_FEEDBACK_VARYING: *val = RESOURCE_XFB(res)->Type; return 1; default: goto invalid_operation; } case GL_ARRAY_SIZE: switch (res->Type) { case GL_UNIFORM: case GL_BUFFER_VARIABLE: /* Test if a buffer variable is an array or an unsized array. * Unsized arrays return zero as array size. */ if (RESOURCE_UNI(res)->is_shader_storage && RESOURCE_UNI(res)->array_stride > 0) *val = RESOURCE_UNI(res)->array_elements; else *val = MAX2(RESOURCE_UNI(res)->array_elements, 1); return 1; case GL_PROGRAM_INPUT: case GL_PROGRAM_OUTPUT: *val = MAX2(_mesa_program_resource_array_size(res), 1); return 1; case GL_TRANSFORM_FEEDBACK_VARYING: *val = MAX2(RESOURCE_XFB(res)->Size, 1); return 1; default: goto invalid_operation; } case GL_OFFSET: VALIDATE_TYPE_2(GL_UNIFORM, GL_BUFFER_VARIABLE); *val = RESOURCE_UNI(res)->offset; return 1; case GL_BLOCK_INDEX: VALIDATE_TYPE_2(GL_UNIFORM, GL_BUFFER_VARIABLE); *val = RESOURCE_UNI(res)->block_index; return 1; case GL_ARRAY_STRIDE: VALIDATE_TYPE_2(GL_UNIFORM, GL_BUFFER_VARIABLE); *val = RESOURCE_UNI(res)->array_stride; return 1; case GL_MATRIX_STRIDE: VALIDATE_TYPE_2(GL_UNIFORM, GL_BUFFER_VARIABLE); *val = RESOURCE_UNI(res)->matrix_stride; return 1; case GL_IS_ROW_MAJOR: VALIDATE_TYPE_2(GL_UNIFORM, GL_BUFFER_VARIABLE); *val = RESOURCE_UNI(res)->row_major; return 1; case GL_ATOMIC_COUNTER_BUFFER_INDEX: VALIDATE_TYPE(GL_UNIFORM); *val = RESOURCE_UNI(res)->atomic_buffer_index; return 1; case GL_BUFFER_BINDING: case GL_BUFFER_DATA_SIZE: case GL_NUM_ACTIVE_VARIABLES: case GL_ACTIVE_VARIABLES: return get_buffer_property(shProg, res, prop, val, caller); case GL_REFERENCED_BY_COMPUTE_SHADER: if (!_mesa_has_compute_shaders(ctx)) goto invalid_enum; /* fallthrough */ case GL_REFERENCED_BY_VERTEX_SHADER: case GL_REFERENCED_BY_TESS_CONTROL_SHADER: case GL_REFERENCED_BY_TESS_EVALUATION_SHADER: case GL_REFERENCED_BY_GEOMETRY_SHADER: case GL_REFERENCED_BY_FRAGMENT_SHADER: switch (res->Type) { case GL_UNIFORM: case GL_PROGRAM_INPUT: case GL_PROGRAM_OUTPUT: case GL_UNIFORM_BLOCK: case GL_BUFFER_VARIABLE: case GL_SHADER_STORAGE_BLOCK: case GL_ATOMIC_COUNTER_BUFFER: *val = is_resource_referenced(shProg, res, index, stage_from_enum(prop)); return 1; default: goto invalid_operation; } case GL_LOCATION: switch (res->Type) { case GL_UNIFORM: case GL_PROGRAM_INPUT: case GL_PROGRAM_OUTPUT: *val = program_resource_location(shProg, res, _mesa_program_resource_name(res), 0); return 1; default: goto invalid_operation; } case GL_LOCATION_INDEX: if (res->Type != GL_PROGRAM_OUTPUT) goto invalid_operation; *val = RESOURCE_VAR(res)->data.index; return 1; case GL_NUM_COMPATIBLE_SUBROUTINES: if (res->Type != GL_VERTEX_SUBROUTINE_UNIFORM && res->Type != GL_FRAGMENT_SUBROUTINE_UNIFORM && res->Type != GL_GEOMETRY_SUBROUTINE_UNIFORM && res->Type != GL_COMPUTE_SUBROUTINE_UNIFORM && res->Type != GL_TESS_CONTROL_SUBROUTINE_UNIFORM && res->Type != GL_TESS_EVALUATION_SUBROUTINE_UNIFORM) goto invalid_operation; *val = RESOURCE_UNI(res)->num_compatible_subroutines; return 1; case GL_COMPATIBLE_SUBROUTINES: { const struct gl_uniform_storage *uni; struct gl_shader *sh; unsigned count, i; int j; if (res->Type != GL_VERTEX_SUBROUTINE_UNIFORM && res->Type != GL_FRAGMENT_SUBROUTINE_UNIFORM && res->Type != GL_GEOMETRY_SUBROUTINE_UNIFORM && res->Type != GL_COMPUTE_SUBROUTINE_UNIFORM && res->Type != GL_TESS_CONTROL_SUBROUTINE_UNIFORM && res->Type != GL_TESS_EVALUATION_SUBROUTINE_UNIFORM) goto invalid_operation; uni = RESOURCE_UNI(res); sh = shProg->_LinkedShaders[_mesa_shader_stage_from_subroutine_uniform(res->Type)]; count = 0; for (i = 0; i < sh->NumSubroutineFunctions; i++) { struct gl_subroutine_function *fn = &sh->SubroutineFunctions[i]; for (j = 0; j < fn->num_compat_types; j++) { if (fn->types[j] == uni->type) { val[count++] = i; break; } } } return count; } case GL_TOP_LEVEL_ARRAY_SIZE: VALIDATE_TYPE(GL_BUFFER_VARIABLE); *val = RESOURCE_UNI(res)->top_level_array_size; return 1; case GL_TOP_LEVEL_ARRAY_STRIDE: VALIDATE_TYPE(GL_BUFFER_VARIABLE); *val = RESOURCE_UNI(res)->top_level_array_stride; return 1; /* GL_ARB_tessellation_shader */ case GL_IS_PER_PATCH: switch (res->Type) { case GL_PROGRAM_INPUT: case GL_PROGRAM_OUTPUT: *val = RESOURCE_VAR(res)->data.patch; return 1; default: goto invalid_operation; } default: goto invalid_enum; } #undef VALIDATE_TYPE #undef VALIDATE_TYPE_2 invalid_enum: _mesa_error(ctx, GL_INVALID_ENUM, "%s(%s prop %s)", caller, _mesa_enum_to_string(res->Type), _mesa_enum_to_string(prop)); return 0; invalid_operation: _mesa_error(ctx, GL_INVALID_OPERATION, "%s(%s prop %s)", caller, _mesa_enum_to_string(res->Type), _mesa_enum_to_string(prop)); return 0; }
void GLAPIENTRY _mesa_GetProgramInterfaceiv(GLuint program, GLenum programInterface, GLenum pname, GLint *params) { GET_CURRENT_CONTEXT(ctx); unsigned i; struct gl_shader_program *shProg = _mesa_lookup_shader_program_err(ctx, program, "glGetProgramInterfaceiv"); if (!shProg) return; if (!params) { _mesa_error(ctx, GL_INVALID_OPERATION, "glGetProgramInterfaceiv(params NULL)"); return; } /* Validate interface. */ if (!supported_interface_enum(programInterface)) { _mesa_error(ctx, GL_INVALID_OPERATION, "glGetProgramInterfaceiv(%s)", _mesa_lookup_enum_by_nr(programInterface)); return; } /* Validate pname against interface. */ switch(pname) { case GL_ACTIVE_RESOURCES: for (i = 0, *params = 0; i < shProg->NumProgramResourceList; i++) if (shProg->ProgramResourceList[i].Type == programInterface) (*params)++; break; case GL_MAX_NAME_LENGTH: if (programInterface == GL_ATOMIC_COUNTER_BUFFER) { _mesa_error(ctx, GL_INVALID_OPERATION, "glGetProgramInterfaceiv(%s pname %s)", _mesa_lookup_enum_by_nr(programInterface), _mesa_lookup_enum_by_nr(pname)); return; } /* Name length consists of base name, 3 additional chars '[0]' if * resource is an array and finally 1 char for string terminator. */ for (i = 0, *params = 0; i < shProg->NumProgramResourceList; i++) { if (shProg->ProgramResourceList[i].Type != programInterface) continue; const char *name = _mesa_program_resource_name(&shProg->ProgramResourceList[i]); unsigned array_size = _mesa_program_resource_array_size(&shProg->ProgramResourceList[i]); *params = MAX2(*params, strlen(name) + (array_size ? 3 : 0) + 1); } break; case GL_MAX_NUM_ACTIVE_VARIABLES: switch (programInterface) { case GL_UNIFORM_BLOCK: for (i = 0, *params = 0; i < shProg->NumProgramResourceList; i++) { if (shProg->ProgramResourceList[i].Type == programInterface) { struct gl_uniform_block *block = (struct gl_uniform_block *) shProg->ProgramResourceList[i].Data; *params = MAX2(*params, block->NumUniforms); } } break; case GL_ATOMIC_COUNTER_BUFFER: for (i = 0, *params = 0; i < shProg->NumProgramResourceList; i++) { if (shProg->ProgramResourceList[i].Type == programInterface) { struct gl_active_atomic_buffer *buffer = (struct gl_active_atomic_buffer *) shProg->ProgramResourceList[i].Data; *params = MAX2(*params, buffer->NumUniforms); } } break; default: _mesa_error(ctx, GL_INVALID_OPERATION, "glGetProgramInterfaceiv(%s pname %s)", _mesa_lookup_enum_by_nr(programInterface), _mesa_lookup_enum_by_nr(pname)); }; break; case GL_MAX_NUM_COMPATIBLE_SUBROUTINES: default: _mesa_error(ctx, GL_INVALID_OPERATION, "glGetProgramInterfaceiv(pname %s)", _mesa_lookup_enum_by_nr(pname)); } }
unsigned _mesa_program_resource_prop(struct gl_shader_program *shProg, struct gl_program_resource *res, GLuint index, const GLenum prop, GLint *val, const char *caller) { GET_CURRENT_CONTEXT(ctx); #define VALIDATE_TYPE(type)\ if (res->Type != type)\ goto invalid_operation; switch(prop) { case GL_NAME_LENGTH: if (res->Type == GL_ATOMIC_COUNTER_BUFFER) goto invalid_operation; /* Base name +3 if array '[0]' + terminator. */ *val = strlen(_mesa_program_resource_name(res)) + (_mesa_program_resource_array_size(res) > 0 ? 3 : 0) + 1; return 1; case GL_TYPE: switch (res->Type) { case GL_UNIFORM: *val = RESOURCE_UNI(res)->type->gl_type; return 1; case GL_PROGRAM_INPUT: case GL_PROGRAM_OUTPUT: *val = RESOURCE_VAR(res)->type->gl_type; return 1; case GL_TRANSFORM_FEEDBACK_VARYING: *val = RESOURCE_XFB(res)->Type; return 1; default: goto invalid_operation; } case GL_ARRAY_SIZE: switch (res->Type) { case GL_UNIFORM: *val = MAX2(RESOURCE_UNI(res)->array_elements, 1); return 1; case GL_PROGRAM_INPUT: case GL_PROGRAM_OUTPUT: *val = MAX2(RESOURCE_VAR(res)->type->length, 1); return 1; case GL_TRANSFORM_FEEDBACK_VARYING: *val = MAX2(RESOURCE_XFB(res)->Size, 1); return 1; default: goto invalid_operation; } case GL_OFFSET: VALIDATE_TYPE(GL_UNIFORM); *val = RESOURCE_UNI(res)->offset; return 1; case GL_BLOCK_INDEX: VALIDATE_TYPE(GL_UNIFORM); *val = RESOURCE_UNI(res)->block_index; return 1; case GL_ARRAY_STRIDE: VALIDATE_TYPE(GL_UNIFORM); *val = RESOURCE_UNI(res)->array_stride; return 1; case GL_MATRIX_STRIDE: VALIDATE_TYPE(GL_UNIFORM); *val = RESOURCE_UNI(res)->matrix_stride; return 1; case GL_IS_ROW_MAJOR: VALIDATE_TYPE(GL_UNIFORM); *val = RESOURCE_UNI(res)->row_major; return 1; case GL_ATOMIC_COUNTER_BUFFER_INDEX: VALIDATE_TYPE(GL_UNIFORM); *val = RESOURCE_UNI(res)->atomic_buffer_index; return 1; case GL_BUFFER_BINDING: case GL_BUFFER_DATA_SIZE: case GL_NUM_ACTIVE_VARIABLES: case GL_ACTIVE_VARIABLES: return get_buffer_property(shProg, res, prop, val, caller); case GL_REFERENCED_BY_COMPUTE_SHADER: if (!_mesa_has_compute_shaders(ctx)) goto invalid_enum; /* fallthrough */ case GL_REFERENCED_BY_VERTEX_SHADER: case GL_REFERENCED_BY_GEOMETRY_SHADER: case GL_REFERENCED_BY_FRAGMENT_SHADER: switch (res->Type) { case GL_UNIFORM: case GL_PROGRAM_INPUT: case GL_PROGRAM_OUTPUT: case GL_UNIFORM_BLOCK: case GL_ATOMIC_COUNTER_BUFFER: *val = is_resource_referenced(shProg, res, index, stage_from_enum(prop)); return 1; default: goto invalid_operation; } case GL_LOCATION: switch (res->Type) { case GL_UNIFORM: case GL_PROGRAM_INPUT: case GL_PROGRAM_OUTPUT: *val = program_resource_location(shProg, res, _mesa_program_resource_name(res)); return 1; default: goto invalid_operation; } case GL_LOCATION_INDEX: if (res->Type != GL_PROGRAM_OUTPUT) goto invalid_operation; *val = RESOURCE_VAR(res)->data.index; return 1; /* GL_ARB_tessellation_shader */ case GL_IS_PER_PATCH: case GL_REFERENCED_BY_TESS_CONTROL_SHADER: case GL_REFERENCED_BY_TESS_EVALUATION_SHADER: default: goto invalid_enum; } #undef VALIDATE_TYPE invalid_enum: _mesa_error(ctx, GL_INVALID_ENUM, "%s(%s prop %s)", caller, _mesa_lookup_enum_by_nr(res->Type), _mesa_lookup_enum_by_nr(prop)); return 0; invalid_operation: _mesa_error(ctx, GL_INVALID_OPERATION, "%s(%s prop %s)", caller, _mesa_lookup_enum_by_nr(res->Type), _mesa_lookup_enum_by_nr(prop)); return 0; }
/* Get full name of a program resource. */ bool _mesa_get_program_resource_name(struct gl_shader_program *shProg, GLenum programInterface, GLuint index, GLsizei bufSize, GLsizei *length, GLchar *name, const char *caller) { GET_CURRENT_CONTEXT(ctx); /* Find resource with given interface and index. */ struct gl_program_resource *res = _mesa_program_resource_find_index(shProg, programInterface, index); /* The error INVALID_VALUE is generated if <index> is greater than * or equal to the number of entries in the active resource list for * <programInterface>. */ if (!res) { _mesa_error(ctx, GL_INVALID_VALUE, "%s(index %u)", caller, index); return false; } if (bufSize < 0) { _mesa_error(ctx, GL_INVALID_VALUE, "%s(bufSize %d)", caller, bufSize); return false; } GLsizei localLength; if (length == NULL) length = &localLength; _mesa_copy_string(name, bufSize, length, _mesa_program_resource_name(res)); /* Page 61 (page 73 of the PDF) in section 2.11 of the OpenGL ES 3.0 * spec says: * * "If the active uniform is an array, the uniform name returned in * name will always be the name of the uniform array appended with * "[0]"." * * The same text also appears in the OpenGL 4.2 spec. It does not, * however, appear in any previous spec. Previous specifications are * ambiguous in this regard. However, either name can later be passed * to glGetUniformLocation (and related APIs), so there shouldn't be any * harm in always appending "[0]" to uniform array names. * * Geometry shader stage has different naming convention where the 'normal' * condition is an array, therefore for variables referenced in geometry * stage we do not add '[0]'. * * Note, that TCS outputs and TES inputs should not have index appended * either. */ bool add_index = !(((programInterface == GL_PROGRAM_INPUT) && res->StageReferences & (1 << MESA_SHADER_GEOMETRY))); if (add_index && _mesa_program_resource_array_size(res)) { int i; /* The comparison is strange because *length does *NOT* include the * terminating NUL, but maxLength does. */ for (i = 0; i < 3 && (*length + i + 1) < bufSize; i++) name[*length + i] = "[0]"[i]; name[*length + i] = '\0'; *length += i; } return true; }