mirror of
https://github.com/zap-proto/c.git
synced 2026-10-30 15:05:52 +00:00
zeekay
a4debdba80
C had no front end for the schema language at all. The compiler directory holds a code generator plugin, which is handed a request by another tool and never sees schema text, so a .zap file could not be read here in either form -- indentation or braces. zapgen reads it. Whitespace-significant source is rewritten into the brace form BEFORE the parser, exactly as the Go reference does it: a near identity that only adds the two tokens the brace grammar requires where the indented form leaves them out. A file already in braces comes back byte for byte, so one grammar reads both styles and neither is a dialect of the other. The identifier grammar is not restated. Its Unicode ranges are taken from Go's own tables by gen/table, so a name this parser accepts is a name the Go parser accepts, and a Go release that moves Unicode moves both. The generated header gives each struct a view over the message bytes and one reader per field at a fixed offset. Reading is in place and total: a field past the end reads zero, a pointer into the head or out of the message reads null. zap_view.h is the one place that says so. Checked against the Go front end on every .zap in the estate plus 55 adversarial cases and 15000 random ones: the brace form each writes is byte-identical, the layout each reads is field-for-field the same, and they accept and refuse the same files for the same stated reason. A message built by the Go runtime reads back through these bindings with every field equal.
27 lines
723 B
C
27 lines
723 B
C
/* SPDX-License-Identifier: BSD-3-Clause-Eco */
|
|
/*
|
|
* arena.h - one lifetime for everything a parse produces.
|
|
*
|
|
* A schema is read, projected and dropped. Nothing outlives the file it
|
|
* came from, so every node and every name is cut from the same arena and
|
|
* released in one call. There is no per-node ownership to get wrong.
|
|
*/
|
|
|
|
#ifndef ZAPGEN_ARENA_H
|
|
#define ZAPGEN_ARENA_H
|
|
|
|
#include <stddef.h>
|
|
|
|
struct arena;
|
|
|
|
struct arena *arena_new(void);
|
|
void arena_free(struct arena *a);
|
|
|
|
/* arena_get returns n zeroed bytes, or NULL when the allocation fails. */
|
|
void *arena_get(struct arena *a, size_t n);
|
|
|
|
/* arena_str copies n bytes and terminates them. */
|
|
char *arena_str(struct arena *a, const char *s, size_t n);
|
|
|
|
#endif
|