/*
 * Copyright (C) 2003 David Roundy
 * Most of the UTF code is Copyright (C) 1999-2001 Free Software Foundation, Inc.
 * This file is part of darcs.
 *
 * Darcs is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Library General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with the GNU LIBICONV Library; see the file COPYING.LIB.
 * If not, write to the Free Software Foundation, Inc., 51 Franklin Street,
 * Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */
#include "fpstring.h"

#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#ifdef _WIN32
#include <windows.h>
#else
#include <sys/mman.h>
#endif

/* A locale-independent isspace(3) so patches are interpreted the same
 * everywhere. */
#define ISSPACE(c) \
    ((c) == ' ' || (c) == '\t' || (c) == '\n' || (c) == '\r')

int first_white(const char *s, int len)
{
    const char *start;
    const char *end;

    for (start = s, end = s + len; s < end && !ISSPACE(*s); s++);

    return s - start;
}

int first_nonwhite(const char *s, int len)
{
    const char *start;
    const char *end;

    for (start = s, end = s + len; s < end && ISSPACE(*s); s++);

    return s - start;
}

int has_funky_char(const char *s, int len)
{
  // We check first for the more likely \0 so we can break out of
  // memchr that much sooner.
  return !!(memchr(s, 0, len) || memchr(s, 26, len));

}

// mmapping...

#ifdef _WIN32

/* I have no idea if this works or not, and it is very tied to the usage
 * of mmap in FastPackedString. Most arguments are ignored...
 */

char *my_mmap(size_t length, int fd)
{
  exit(1); /* mmap is not implemented on Windows */
}

int munmap(void *start, size_t length)
{
    UnmapViewOfFile(start);
}

#else

char *my_mmap(size_t len, int fd) {
  void *maybeok = mmap(NULL, len, PROT_READ, MAP_SHARED, fd, 0);
  if (maybeok == MAP_FAILED) return NULL;
  else return (char *)maybeok;
}

#endif

// ForeignPtr debugging stuff...

static int num_alloced = 0;

void debug_free(void *p) {
  num_alloced--;
  fprintf(stderr, "Freeing %p (%d left)\n", p, num_alloced);
}

void debug_alloc(void *p, const char *name) {
  num_alloced++;
  fprintf(stderr, "Allocating %p named %s (%d left)\n",
          p, name, num_alloced);
}

/* Specification: RFC 2279 */

int utf8_to_ints(HsInt *pwc, const unsigned char *s, int n) {
  /* returns number of unicode chars in the output.  The output array is
     assumed to have the same number of elements as the input array, which
     is n. */

  HsInt *pwc_original = pwc;
  while (n > 0) {
    unsigned char c = s[0];

    if (c < 0x80) {
      *pwc++ = c;
      n--;
      s++;
    } else if (c < 0xc2) {
      return -1;
    } else if (c < 0xe0) {
      if (n < 2) return -1;
      if (!((s[1] ^ 0x80) < 0x40)) return -1;
      *pwc++ = ((unsigned) (c & 0x1f) << 6)
        | (unsigned) (s[1] ^ 0x80);
      n -= 2;
      s += 2;
    } else if (c < 0xf0) {
      if (n < 3) return -1;
      if (!((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
            && (c >= 0xe1 || s[1] >= 0xa0)))
        return -1;
      *pwc++ = ((unsigned) (c & 0x0f) << 12)
        | ((unsigned) (s[1] ^ 0x80) << 6)
        | (unsigned) (s[2] ^ 0x80);
      n -= 3;
      s += 3;
    } else if (c < 0xf8 && sizeof(unsigned)*8 >= 32) {
      if (n < 4) return -1;
      if (!((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
            && (s[3] ^ 0x80) < 0x40
            && (c >= 0xf1 || s[1] >= 0x90)))
        return -1;
      *pwc++ = ((unsigned) (c & 0x07) << 18)
        | ((unsigned) (s[1] ^ 0x80) << 12)
        | ((unsigned) (s[2] ^ 0x80) << 6)
        | (unsigned) (s[3] ^ 0x80);
      n -= 4;
      s += 4;
    } else if (c < 0xfc && sizeof(unsigned)*8 >= 32) {
      if (n < 5) return -1;
      if (!((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
            && (s[3] ^ 0x80) < 0x40 && (s[4] ^ 0x80) < 0x40
            && (c >= 0xf9 || s[1] >= 0x88)))
        return -1;
      *pwc++ = ((unsigned) (c & 0x03) << 24)
        | ((unsigned) (s[1] ^ 0x80) << 18)
        | ((unsigned) (s[2] ^ 0x80) << 12)
        | ((unsigned) (s[3] ^ 0x80) << 6)
        | (unsigned) (s[4] ^ 0x80);
      n -= 5;
      s += 5;
    } else if (c < 0xfe && sizeof(unsigned)*8 >= 32) {
      if (n < 6) return -1;
      if (!((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
            && (s[3] ^ 0x80) < 0x40 && (s[4] ^ 0x80) < 0x40
            && (s[5] ^ 0x80) < 0x40
            && (c >= 0xfd || s[1] >= 0x84)))
        return -1;
      *pwc++ = ((unsigned) (c & 0x01) << 30)
        | ((unsigned) (s[1] ^ 0x80) << 24)
        | ((unsigned) (s[2] ^ 0x80) << 18)
        | ((unsigned) (s[3] ^ 0x80) << 12)
        | ((unsigned) (s[4] ^ 0x80) << 6)
        | (unsigned) (s[5] ^ 0x80);
      n -= 6;
      s += 6;
    } else
      return -1;
  }
  return pwc - pwc_original;
}

/* Conversion to and from hex */

void conv_to_hex(unsigned char *dest, unsigned char *from, int num_chars)
{
    static char hex[] = "0123456789abcdef";
    unsigned char *end;

    for (end = from + num_chars; from < end; from++) {
        *dest++ = hex[*from >> 4];
        *dest++ = hex[*from & 0xf];
    }

    return;
}

#define NYBBLE_TO_INT(c) \
    ((c) - ((c) >= 'a' ? 'a' - 10 : '0'))

void conv_from_hex(unsigned char *dest, unsigned char *from, int num_chars)
{
    unsigned char *end;
    unsigned char c;

    end = dest + num_chars;
    while (dest < end) {
        c = NYBBLE_TO_INT(*from) << 4, from++;
        *dest++ = c | NYBBLE_TO_INT(*from), from++;
    }

    return;
}
