#pragma once

#include "types.h"

// A bounded string builder, because there is no snprintf in this kernel.
//
// These lived inside kernel/dev/procfs.c, where they were written, and were
// static to it. The debugger's introspection registry needs the same thing --
// a subsystem rendering its own state into a caller's buffer, with no
// allocation and no way to run off the end -- and the choice was to write a
// second set or to move this one. See docs/plan/debugger.md, D2.
//
// Nothing here can overflow: every writer checks cap, and a full buffer
// silently drops the rest. That is the right trade for something whose callers
// are a /proc read and a crash-time dump; a builder that can fail is a builder
// every caller has to check, and none of them would.

struct sbuf {
  char *p;
  int   len;
  int   cap;
};

void sb_putc(struct sbuf *sb, char c);
void sb_puts(struct sbuf *sb, const char *s);

// A string in a fixed-width column, space-padded. Over-long values run past
// their column rather than being truncated: a misaligned row is easier to read
// than a mangled name.
void sb_pad(struct sbuf *sb, const char *s, int width);

// Four lowercase hex digits, zero-padded. PCI and USB identifiers are always
// written this way, and a lookup table keyed on "8086:100e" does not match
// "8086:100E" or "8086:10e".
void sb_puthex4(struct sbuf *sb, uint32 v);

void sb_putu(struct sbuf *sb, uint64 v);

// Zero-padded hex of a given width, for addresses.
void sb_puthex(struct sbuf *sb, uint64 v, int digits);

// A decimal number in a right-aligned column, so tables of sizes line up.
void sb_putu_pad(struct sbuf *sb, uint64 v, int width);

// "<label><value> <unit>\n" -- the shape almost every /proc line takes.
void sb_kv(struct sbuf *sb, const char *label, uint64 v, const char *unit);