unfold_hdr.c

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#include "stralloc.h"
#include "case.h"
#include "byte.h"
#include "errtxt.h"
#include "mime.h"
#include "idx.h"
#include "logmsg.h"
#include "errtxt.h"
 
#define WHO "unfold_hdr"

 
static stralloc tmpdata = {0};
 
static void die_nomem() { logmsg(WHO,111,FATAL,ERR_NOMEM); }
 
static int trimre(char **cpp,char *cpend,stralloc *prefix)
{
  int r = 0;
  char *cp;
  char *cpnew;
  int junk;
  unsigned int i,j;
  unsigned int serial;
 
  cp = *cpp;
  serial = prefix->len;                     /* pointer to serial number */
  if (serial)
    serial = byte_rchr(prefix->s,prefix->len,'#');
 
  junk = 1;
  while (junk) {
    junk = 0;
    while (cp <= cpend && (*cp == ' ' || *cp == '\t')) 
      cp++;
    cpnew = cp;
    while (++cpnew <= cpend) {              /* /(..+:\s)/ is a reply indicator */
      if (*cpnew == ' ') {
        if (cpnew < cp + 3) break;          /* at least 3 char before ' ' */
        if (*(cpnew - 1) != ':') break;     /* require ':' before ' ' */
        if (cpnew > cp + 5) {               /* if > 4 char before ':' require */
          char ch;
          ch = *(cpnew - 2);                /* XX^3, XX[3], XX(3) */
          if (ch != ')' && ch != ']' && (ch < '0' || ch > '9'))
          break;
        }
        junk = 1;
        r |= 1;
        cp = cpnew + 1;
        break;
      }
    }
    /* prefix removal is complicated by the inconsistent handling of ' ' */
    /* when there are rfc2047-encoded words in the subject. We first     */
    /* compare prefix before "serial" ignoring space, then skip the      */
    /* number, then compare after "serial". If both matched we've found  */
    /* the prefix. */
 
    if (serial) {
      cpnew = cp;
      i = 0;
      while (i < serial && cpnew <= cpend) {
        if (*cpnew != ' ') {
          if (prefix->s[i] == ' ') {
            ++i;
            continue;
          }
          if (*cpnew != prefix->s[i]) break;
          ++i;
        }
        ++cpnew;
      }
      if (i == serial) {                    /* match before serial */
        j = prefix->len;
        if (serial != j) {                  /* got a '#' */
          while (cpnew <= cpend && *cpnew == ' ' || (*cpnew <= '9' && *cpnew >= '0')) 
            ++cpnew;                        /* skip number/space */
          i = serial + 1;
          while (i < j && cpnew <= cpend) {
            if (*cpnew != ' ') {
              if (prefix->s[i] == ' ') {
                ++i;
                continue;
              }
              if (*cpnew != prefix->s[i]) break;
              ++i;
            }
            ++cpnew;
          }
        }
        if (i == j) {
          cp = cpnew;
          junk = 1;
          r |= 2;
        }
      }
    }
  }
  *cpp = cp;
 
  return r;
}

 
static int trimend(char *indata,unsigned long *np)
{
  char *cplast;
  int junk;
  int r = 0;
 
  if (*np == 0) return 0;
 
  cplast = indata + *np - 1;                     /* points to last char on line */
  junk = 1;
  while (junk) {
    junk = 0;
    while (cplast >= indata && (*cplast == ' ' || *cplast == '\t' || *cplast == '\r' || *cplast == '\n')) 
      --cplast;
    if (cplast - indata  >= 5 && case_startb(cplast - 5,6,"-Reply")) {
      cplast -= 6;
      r = 1;
      junk = 1;
    }
  }
  *np = (unsigned int) (cplast - indata + 1);    /* new length */
  return r;
}

 
int unfold_hdr(char *indata,unsigned long n,stralloc *outdata,const char *charset,stralloc *prefix,int flagtrimsub)
{
  int r = 0;
  char *cp, *cpesc, *cpnext, *cpend, *cpout;
  char state, cset, newcset;
  int reg, newreg;
 
  cp = indata;                                   /* JIS X 0201 -> ISO646 us-ascii */
  cpend = cp + n - 1;
  cpnext = cp;
  if (!stralloc_copys(&tmpdata,"")) die_nomem();
  if (!stralloc_ready(&tmpdata,n)) die_nomem();
 
  if(!case_diffb(charset,11,"iso-2022-jp")) {
    /* iso-2022-jp-2 (rfc1554) and its subset iso-2022-jp. The reg #s */
    /* are from the rfc. Don't ask why they have multiple length G0   */
    /* charset designations ... JIS X 0201-roman is identical to      */
    /* iso646 us-ascii except for currency and tilde. Making them the */
    /* same increases hits without significant loss. JIS X 0208-1978  */
    /* is superceded by JIS X 0208-1983 and converted here as well.   */
 
    while (cp < cpend) {
      if (*cp++ != ESC) continue;
      if (*cp == '(') {
        if (++cp > cpend) break;
        if (*cp == 'J') *cp = 'B';
         ++cp;
      } else if (*cp == '$') {
        if (++cp > cpend) break;
        if (*cp == '@') *cp = 'B';
        ++cp;
      }
    }
    cp = indata;                                 /* eliminate redundant ESC seqs */
    cpnext = cp;
    reg = 6;
    while (cp < cpend) {
      if (*cp++ != ESC) continue;
      cpesc = cp - 1;
      if (*cp == '$') {
        if (++cp > cpend) break;
        if (*cp == 'B') newreg = 87;
        else if (*cp == 'A') newreg = 58;
        else if (*cp == '(') {
          if (++cp > cpend) break;
          if (*cp == 'C') newreg = 149;
          else if (*cp == 'D') newreg = 159;
          else continue;
        } else continue;
      } else if (*cp == '(') {
        if (++cp > cpend) break;
        if (*cp == 'B') newreg = 6;
        else continue;
      } else continue;
      if (++cp > cpend) break;
      while (*cp == ' ' || *cp == '\t')
        if (++cp >= cpend) break;                /* skip space */
      if (*cp == ESC)                            /* maybe another G0 designation */
        if (*(cp+1) == '(' || *(cp+1) == '$') {  /* yep! */
          if (!stralloc_catb(&tmpdata,cpnext,cpesc-cpnext)) die_nomem();
          cpnext = cp;
      continue;
      }
      if (reg == newreg) {
        if (!stralloc_catb(&tmpdata,cpnext,cpesc-cpnext)) die_nomem();
        cpnext = cp;
      } else {
        reg = newreg;                            /* copy remainder of line */
      }
    }
    if (!stralloc_catb(&tmpdata,cpnext,cpend - cpnext + 1)) die_nomem();
    if (reg != 6) {                              /* need to return to us-ascii at the end of the line */
      if (!stralloc_cats(&tmpdata,TOASCII)) die_nomem();
    } else {                                    /* maybe "-Reply at the end?" */
      r = trimend(tmpdata.s,&tmpdata.len);
    }
 
  } else if (!case_diffb(charset,11,"iso-2022-cn") ||
             !case_diffb(charset,11,"iso-2022-kr")) {
    /* these use SI/SO and ESC $ ) x as the SO designation. In -cn and */
    /* -cn-ext, 'x' can be a number of different letters. In -kr it's  */
    /* always 'C'. This routine may work also for other iso-2022 sets  */
    /* also handles iso-2022-cn-ext */
 
    cpesc = (char *) 0;                          /* points to latest ESC */
    state = SI;                                  /* us-ascii */
    --cp;                                        /* set up for loop */
 
    while (++cp <= cpend) {
      if (*cp == SI || *cp == SO) {
        if (state == *cp) {                      /* already in state. Skip shift seq */
          if (!stralloc_catb(&tmpdata,cpnext,cp-cpnext-1)) die_nomem();
          cpnext = cp;
        } else                                   /* set new state */
          state = *cp;
        if (++cp > cpend) break;
        continue;
      }
      if (*cp != ESC) continue;
      if (cp + 3 > cpend) break;                 /* not space for full SO-designation */
      cpesc = cp;
      if (*cp != '$') continue;
      if (++cp > cpend) break;
      if (*cp != ')') continue;
      if (++cp > cpend) break;
      newcset = *cp;
      if (++cp > cpend) break;
      while (cp <= cpend && (*cp == ' ' || *cp == '\t')) ++cp;
      if (cp + 3 > cpend) break;                 /* no space for full SO-designation */
      if ((*cp == ESC && *(cp+1) == '$' && *(cp+2) == ')')
        || (newcset == cset)) {
            /* skip if a second SO-designation right after or */
            /* this SO-designation is already active, skip */
        if (!stralloc_catb(&tmpdata,cpnext,cpesc-cpnext)) die_nomem();
        --cp;                                    /* "unpeek" so that next iteration will see char */
        cpnext = cpesc + 4;
        continue;
      } else {
        cset = newcset;
        continue;
      }
    }
    if (!stralloc_catb(&tmpdata,cpnext,cpend - cpnext + 1)) die_nomem();  /* get remainder of line */
    if (state != SI)                             /* need to end in ascii */
      if (!stralloc_cats(&tmpdata,TOSI)) die_nomem();
    else                                         /* ascii end; maybe "-Reply" at the end? */
      r = trimend(tmpdata.s,&tmpdata.len);
 
  } else {                                       /* other character sets = no special treatment */
    r = trimend(cp,&n);                          /* -reply */
    if (!stralloc_copyb(&tmpdata,cp,n)) die_nomem();
  }
 
  cp = tmpdata.s;
  n = tmpdata.len;
  cpend = cp + n - 1;
  if (flagtrimsub) {                             /* remove leading reply indicators & prefix*/
    r |= trimre(&cp,cpend,prefix);
    n = (unsigned int) (cpend-cp+1);
  }
            /* there shouldn't be '\0' or '\n', but make sure as */
            /* it would break the message index */
 
  if (!stralloc_copys(outdata,"")) die_nomem();
  if (!stralloc_ready(outdata,n)) die_nomem();
  outdata->len = n;
  cpout = outdata->s;
  while (n--) {                                  /* '\n' and '\0' would break the subject index */
    if (!*cp || *cp == '\n') *cpout = ' ';
    else *cpout = *cp;
    ++cp; ++cpout;
  }
  return r;
}