libowfat/fmt/fmt_escapecharc.c

#include "fmt.h"

static void fmt_oct3(char* dest,uint8_t w) {
  dest[2]=(w&7)+'0'; w>>=3;
  dest[1]=(w&7)+'0'; w>>=3;
  dest[0]=(w&7)+'0';
}

size_t fmt_escapecharc(char* dest,uint32_t ch) {
  char c;
  if (ch>0xff) return 0;
  switch (ch) {
  case '\a': c='a'; goto doescape;
  case '\b': c='b'; goto doescape;
  case 0x1b: c='e'; goto doescape;
  case '\f': c='f'; goto doescape;
  case '\n': c='n'; goto doescape;
  case '\r': c='r'; goto doescape;
  case '\t': c='t'; goto doescape;
  case '\v': c='v'; goto doescape;
  case '\\':
    c='\\';
  doescape:
    if (dest) {
      dest[0]='\\';
      dest[1]=c;
    }
    return 2;
  default:
    if (dest) {
      dest[0]='\\';
      fmt_oct3(dest+1,ch&0xff);
    }
    return 4;
  }
}