rewritehost.c

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#include "stralloc.h"
#include "str.h"
#include "case.h"
#include "byte.h"
#include "rewritehost.h"
 
static stralloc work = {0};
 
static int doit(char *rule)
{
  int colon;
  char ch;
  int prefixlen;
 
  ch = *rule++;
  if ((ch != '?') && (ch != '=') && (ch != '*') && (ch != '-')) return 1;
  colon = str_chr(rule,':');
  if (!rule[colon]) return 1;
  if (work.len < colon) return 1;
 
  prefixlen = work.len - colon;
  if ((ch == '=') && prefixlen) return 1;
  if (case_diffb(rule,colon,work.s + prefixlen)) return 1;
 
  if (ch == '?') {
    if (byte_chr(work.s,prefixlen,'.') < prefixlen) return 1;
    if (byte_chr(work.s,prefixlen,'[') < prefixlen) return 1;
    if (byte_chr(work.s,prefixlen,']') < prefixlen) return 1;
  }
 
  work.len = prefixlen;
  if (ch == '-') work.len = 0;
 
  return stralloc_cats(&work,rule + colon + 1);
}
 
static int appendwork(stralloc *out,stralloc *rules)
{
  int i;
  int j;
 
  for (j = i = 0;j < rules->len;++j)
    if (!rules->s[j]) {
      if (!doit(rules->s + i)) return 0;
      i = j + 1;
    }
  return stralloc_cat(out,&work);
}
 
static int appendaddr(stralloc *out,char *in,unsigned int len,stralloc *rules)
{
  int at;
 
  at = byte_chr(in,len,'@');
  if (!at) if (len <= 1) return 1;
  if (!stralloc_catb(out,in,at)) return 0;
  if (!stralloc_append(out,"@")) return 0;
  if (at < len) ++at;
  if (!stralloc_copyb(&work,in + at,len - at)) return 0;
  return appendwork(out,rules);
}
 
int rewritehost(stralloc *out,char *in,unsigned int len,stralloc *rules)
{
  if (!stralloc_copys(out,"")) return 0;
  if (!stralloc_copyb(&work,in,len)) return 0;
  return appendwork(out,rules);
}
 
int rewritehost_addr(stralloc *out,char *in,unsigned int len,stralloc *rules)
{
  if (!stralloc_copys(out,"")) return 0;
  return appendaddr(out,in,len,rules);
}
 
int rewritehost_list(stralloc *out,char *in,unsigned int len,stralloc *rules)
{
  int i;
  int j;
 
  if (!stralloc_copys(out,"")) return 0;
  for (j = i = 0;j < len;++j)
    if (!in[j]) {
      if (in[i] == '+') {
        if (!stralloc_append(out,"+")) return 0;
        if (!appendaddr(out,in + i + 1,j - i - 1,rules)) return 0;
        if (!stralloc_0(out)) return 0;
      }
      else
        if (!stralloc_catb(out,in + i,j - i + 1)) return 0;
      i = j + 1;
    }
  return 1;
}