152 lines
5.2 KiB
C
152 lines
5.2 KiB
C
/* @license 2020 Neil Edelman, distributed under the terms of the
|
|
[MIT License](https://opensource.org/licenses/MIT).
|
|
|
|
@subtitle To string trait
|
|
|
|
Interface defined by `BOX_`, `BOX`, and `BOX_CONTENT`.
|
|
|
|
@param[STR_(n)]
|
|
A one-argument macro producing a name that is responsible for the name of the
|
|
to string function. Should be something like
|
|
`STR_(to_string) -> widget_foo_to_string`. The caller is responsible for
|
|
undefining `STR_`.
|
|
|
|
@param[TO_STRING]
|
|
Function implementing <typedef:<PZ>to_string_fn>.
|
|
|
|
@param[TO_STRING_LEFT, TO_STRING_RIGHT]
|
|
7-bit characters, defaults to '(' and ')'.
|
|
|
|
@param[TO_STRING_EXTERN, TO_STRING_INTERN]
|
|
Normally the space to put the temporary strings is static, one per file. With
|
|
this, it's possible to have a global storage to save space: have one file have
|
|
`TO_STRING_INTERN` as the first box, the other files `TO_STRING_EXTERN`. This
|
|
is unsynchronized.
|
|
|
|
@fixme `extern` untested.
|
|
|
|
@std C89 */
|
|
|
|
#if !defined(BOX_) || !defined(BOX) || !defined(BOX_CONTENT) \
|
|
|| !defined(STR_) || !defined(TO_STRING)
|
|
#error Unexpected preprocessor symbols.
|
|
#endif
|
|
|
|
#if defined(TO_STRING_H) \
|
|
&& (defined(TO_STRING_EXTERN) || defined(TO_STRING_INTERN)) /* <!-- not */
|
|
#error Should be the on the first to_string in the compilation unit.
|
|
#else /* not --><!-- !not */
|
|
#if defined(TO_STRING_EXTERN) && defined(TO_STRING_INTERN) /* <!-- two */
|
|
#error These can not be defined together.
|
|
#endif /* two --> */
|
|
#endif /* !not --> */
|
|
|
|
#ifndef TO_STRING_H /* <!-- idempotent */
|
|
#define TO_STRING_H
|
|
#include <string.h>
|
|
#if defined(TO_STRING_CAT_) || defined(TO_STRING_CAT) || defined(PSTR_)
|
|
#error Unexpected defines.
|
|
#endif
|
|
/* <Kernighan and Ritchie, 1988, p. 231>. */
|
|
#define TO_STRING_CAT_(n, m) n ## _ ## m
|
|
#define TO_STRING_CAT(n, m) TO_STRING_CAT_(n, m)
|
|
#define PSTR_(n) TO_STRING_CAT(to_string, STR_(n))
|
|
#if defined(TO_STRING_EXTERN) || defined(TO_STRING_INTERN) /* <!-- ntern */
|
|
extern char to_string_buffers[4][256];
|
|
extern const unsigned to_string_buffers_no;
|
|
extern unsigned to_string_i;
|
|
#ifdef TO_STRING_INTERN /* <!-- intern */
|
|
char to_string_buffers[4][256];
|
|
const unsigned to_string_buffers_no = sizeof to_string_buffers
|
|
/ sizeof *to_string_buffers, to_string_buffer_size
|
|
= sizeof *to_string_buffers / sizeof **to_string_buffers;
|
|
unsigned to_string_buffer_i;
|
|
#endif /* intern --> */
|
|
#else /* ntern --><!-- static */
|
|
static char to_string_buffers[4][256];
|
|
static const unsigned to_string_buffers_no = sizeof to_string_buffers
|
|
/ sizeof *to_string_buffers, to_string_buffer_size
|
|
= sizeof *to_string_buffers / sizeof **to_string_buffers;
|
|
static unsigned to_string_buffer_i;
|
|
#endif /* static --> */
|
|
#endif /* idempotent --> */
|
|
|
|
#ifndef TO_STRING_LEFT
|
|
#define TO_STRING_LEFT '('
|
|
#endif
|
|
#ifndef TO_STRING_RIGHT
|
|
#define TO_STRING_RIGHT ')'
|
|
#endif
|
|
|
|
typedef BOX PSTR_(box);
|
|
typedef BOX_CONTENT PSTR_(element_c);
|
|
|
|
/** <src/to_string.h>: responsible for turning the argument into a 12-`char`
|
|
null-terminated output string. */
|
|
typedef void (*PSTR_(to_string_fn))(PSTR_(element_c), char (*)[12]);
|
|
/* Check that `TO_STRING` is a function implementing
|
|
<typedef:<PSTR>to_string>. */
|
|
static const PSTR_(to_string_fn) PSTR_(to_string) = (TO_STRING);
|
|
|
|
/** <src/to_string.h>: print the contents of `box` in a static string buffer of
|
|
256 bytes, with limitations of only printing 4 things at a time. `<STR>` is
|
|
loosely contracted to be a name `<X>box[<X_TO_STRING_NAME>]`.
|
|
@return Address of the static buffer. @order \Theta(1) @allow */
|
|
static const char *STR_(to_string)(const PSTR_(box) *const box) {
|
|
const char comma = ',', space = ' ', ellipsis[] = "…",
|
|
left = TO_STRING_LEFT, right = TO_STRING_RIGHT;
|
|
const size_t ellipsis_len = sizeof ellipsis - 1;
|
|
char *const buffer = to_string_buffers[to_string_buffer_i++], *b = buffer;
|
|
size_t advance;
|
|
PSTR_(element_c) x;
|
|
struct BOX_(forward) it;
|
|
int is_sep = 0;
|
|
/* Minimum size: "(" "XXXXXXXXXXX" "," "…" ")" "\0". */
|
|
assert(box && !(to_string_buffers_no & (to_string_buffers_no - 1))
|
|
&& to_string_buffer_size >= 1 + 11 + 1 + ellipsis_len + 1 + 1);
|
|
/* Advance the buffer for next time. */
|
|
to_string_buffer_i &= to_string_buffers_no - 1;
|
|
it = BOX_(forward)(box);
|
|
*b++ = left;
|
|
while(BOX_(is_element_c)(x = BOX_(next_c)(&it))) {
|
|
PSTR_(to_string)(x, (char (*)[12])b);
|
|
/* Paranoid about '\0'. */
|
|
for(advance = 0; *b != '\0' && advance < 11; b++, advance++);
|
|
is_sep = 1, *b++ = comma, *b++ = space;
|
|
/* Greedy typesetting: enough for "XXXXXXXXXXX" "," "…" ")" "\0". */
|
|
if((size_t)(b - buffer)
|
|
> to_string_buffer_size - 11 - 1 - ellipsis_len - 1 - 1)
|
|
if(BOX_(is_element_c)(BOX_(next_c)(&it))) goto ellipsis;
|
|
else break;
|
|
}
|
|
if(is_sep) b -= 2;
|
|
*b++ = right;
|
|
goto terminate;
|
|
ellipsis:
|
|
b--;
|
|
memcpy(b, ellipsis, ellipsis_len), b += ellipsis_len;
|
|
*b++ = right;
|
|
terminate:
|
|
*b++ = '\0';
|
|
assert(b - buffer <= to_string_buffer_size);
|
|
return buffer;
|
|
}
|
|
|
|
static void PSTR_(unused_to_string_coda)(void);
|
|
static void PSTR_(unused_to_string)(void)
|
|
{ STR_(to_string)(0); PSTR_(unused_to_string_coda)(); }
|
|
static void PSTR_(unused_to_string_coda)(void) { PSTR_(unused_to_string)(); }
|
|
|
|
#undef TO_STRING
|
|
#ifdef TO_STRING_NAME
|
|
#undef TO_STRING_NAME
|
|
#endif
|
|
#ifdef TO_STRING_EXTERN
|
|
#undef TO_STRING_EXTERN
|
|
#endif
|
|
#ifdef TO_STRING_INTERN
|
|
#undef TO_STRING_INTERN
|
|
#endif
|
|
#undef TO_STRING_LEFT
|
|
#undef TO_STRING_RIGHT
|