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

#include "header.h"
#include "rmalloc.h"

#define CREATE_SIZE 1

extern symbol *create_s(void) {
  symbol *p;
  void *mem = rm_malloc(HEAD + (CREATE_SIZE + 1) * sizeof(symbol));
  if (mem == NULL) return NULL;
  p = (symbol *)(HEAD + (char *)mem);
  CAPACITY(p) = CREATE_SIZE;
  SET_SIZE(p, 0);
  return p;
}

extern void lose_s(symbol *p) {
  if (p == NULL) return;
  rm_free((char *)p - HEAD);
}

/*
   new_p = skip_utf8(p, c, lb, l, n); skips n characters forwards from p + c
   if n +ve, or n characters backwards from p + c - 1 if n -ve. new_p is the new
   position, or 0 on failure.

   -- used to implement hop and next in the utf8 case.
*/

extern int skip_utf8(const symbol *p, int c, int lb, int l, int n) {
  int b;
  if (n >= 0) {
    for (; n > 0; n--) {
      if (c >= l) return -1;
      b = p[c++];
      if (b >= 0xC0) { /* 1100 0000 */
        while (c < l) {
          b = p[c];
          if (b >= 0xC0 || b < 0x80) break;
          /* break unless b is 10------ */
          c++;
        }
      }
    }
  } else {
    for (; n < 0; n++) {
      if (c <= lb) return -1;
      b = p[--c];
      if (b >= 0x80) { /* 1000 0000 */
        while (c > lb) {
          b = p[c];
          if (b >= 0xC0) break; /* 1100 0000 */
          c--;
        }
      }
    }
  }
  return c;
}

/* Code for character groupings: utf8 cases */

static int get_utf8(const symbol *p, int c, int l, int *slot) {
  int b0, b1;
  if (c >= l) return 0;
  b0 = p[c++];
  if (b0 < 0xC0 || c == l) { /* 1100 0000 */
    *slot = b0;
    return 1;
  }
  b1 = p[c++];
  if (b0 < 0xE0 || c == l) { /* 1110 0000 */
    *slot = (b0 & 0x1F) << 6 | (b1 & 0x3F);
    return 2;
  }
  *slot = (b0 & 0xF) << 12 | (b1 & 0x3F) << 6 | (p[c] & 0x3F);
  return 3;
}

static int get_b_utf8(const symbol *p, int c, int lb, int *slot) {
  int b0, b1;
  if (c <= lb) return 0;
  b0 = p[--c];
  if (b0 < 0x80 || c == lb) { /* 1000 0000 */
    *slot = b0;
    return 1;
  }
  b1 = p[--c];
  if (b1 >= 0xC0 || c == lb) { /* 1100 0000 */
    *slot = (b1 & 0x1F) << 6 | (b0 & 0x3F);
    return 2;
  }
  *slot = (p[c] & 0xF) << 12 | (b1 & 0x3F) << 6 | (b0 & 0x3F);
  return 3;
}

extern int in_grouping_U(struct SN_env *z, const unsigned char *s, int min, int max, int repeat) {
  do {
    int ch;
    int w = get_utf8(z->p, z->c, z->l, &ch);
    if (!w) return -1;
    if (ch > max || (ch -= min) < 0 || (s[ch >> 3] & (0X1 << (ch & 0X7))) == 0) return w;
    z->c += w;
  } while (repeat);
  return 0;
}

extern int in_grouping_b_U(struct SN_env *z, const unsigned char *s, int min, int max, int repeat) {
  do {
    int ch;
    int w = get_b_utf8(z->p, z->c, z->lb, &ch);
    if (!w) return -1;
    if (ch > max || (ch -= min) < 0 || (s[ch >> 3] & (0X1 << (ch & 0X7))) == 0) return w;
    z->c -= w;
  } while (repeat);
  return 0;
}

extern int out_grouping_U(struct SN_env *z, const unsigned char *s, int min, int max, int repeat) {
  do {
    int ch;
    int w = get_utf8(z->p, z->c, z->l, &ch);
    if (!w) return -1;
    if (!(ch > max || (ch -= min) < 0 || (s[ch >> 3] & (0X1 << (ch & 0X7))) == 0)) return w;
    z->c += w;
  } while (repeat);
  return 0;
}

extern int out_grouping_b_U(struct SN_env *z, const unsigned char *s, int min, int max,
                            int repeat) {
  do {
    int ch;
    int w = get_b_utf8(z->p, z->c, z->lb, &ch);
    if (!w) return -1;
    if (!(ch > max || (ch -= min) < 0 || (s[ch >> 3] & (0X1 << (ch & 0X7))) == 0)) return w;
    z->c -= w;
  } while (repeat);
  return 0;
}

/* Code for character groupings: non-utf8 cases */

extern int in_grouping(struct SN_env *z, const unsigned char *s, int min, int max, int repeat) {
  do {
    int ch;
    if (z->c >= z->l) return -1;
    ch = z->p[z->c];
    if (ch > max || (ch -= min) < 0 || (s[ch >> 3] & (0X1 << (ch & 0X7))) == 0) return 1;
    z->c++;
  } while (repeat);
  return 0;
}

extern int in_grouping_b(struct SN_env *z, const unsigned char *s, int min, int max, int repeat) {
  do {
    int ch;
    if (z->c <= z->lb) return -1;
    ch = z->p[z->c - 1];
    if (ch > max || (ch -= min) < 0 || (s[ch >> 3] & (0X1 << (ch & 0X7))) == 0) return 1;
    z->c--;
  } while (repeat);
  return 0;
}

extern int out_grouping(struct SN_env *z, const unsigned char *s, int min, int max, int repeat) {
  do {
    int ch;
    if (z->c >= z->l) return -1;
    ch = z->p[z->c];
    if (!(ch > max || (ch -= min) < 0 || (s[ch >> 3] & (0X1 << (ch & 0X7))) == 0)) return 1;
    z->c++;
  } while (repeat);
  return 0;
}

extern int out_grouping_b(struct SN_env *z, const unsigned char *s, int min, int max, int repeat) {
  do {
    int ch;
    if (z->c <= z->lb) return -1;
    ch = z->p[z->c - 1];
    if (!(ch > max || (ch -= min) < 0 || (s[ch >> 3] & (0X1 << (ch & 0X7))) == 0)) return 1;
    z->c--;
  } while (repeat);
  return 0;
}

extern int eq_s(struct SN_env *z, int s_size, const symbol *s) {
  if (z->l - z->c < s_size || memcmp(z->p + z->c, s, s_size * sizeof(symbol)) != 0) return 0;
  z->c += s_size;
  return 1;
}

extern int eq_s_b(struct SN_env *z, int s_size, const symbol *s) {
  if (z->c - z->lb < s_size || memcmp(z->p + z->c - s_size, s, s_size * sizeof(symbol)) != 0)
    return 0;
  z->c -= s_size;
  return 1;
}

extern int eq_v(struct SN_env *z, const symbol *p) {
  return eq_s(z, SIZE(p), p);
}

extern int eq_v_b(struct SN_env *z, const symbol *p) {
  return eq_s_b(z, SIZE(p), p);
}

extern int find_among(struct SN_env *z, const struct among *v, int v_size) {

  int i = 0;
  int j = v_size;

  int c = z->c;
  int l = z->l;
  symbol *q = z->p + c;

  const struct among *w;

  int common_i = 0;
  int common_j = 0;

  int first_key_inspected = 0;

  while (1) {
    int k = i + ((j - i) >> 1);
    int diff = 0;
    int common = common_i < common_j ? common_i : common_j; /* smaller */
    w = v + k;
    {
      int i2;
      for (i2 = common; i2 < w->s_size; i2++) {
        if (c + common == l) {
          diff = -1;
          break;
        }
        diff = q[common] - w->s[i2];
        if (diff != 0) break;
        common++;
      }
    }
    if (diff < 0) {
      j = k;
      common_j = common;
    } else {
      i = k;
      common_i = common;
    }
    if (j - i <= 1) {
      if (i > 0) break;  /* v->s has been inspected */
      if (j == i) break; /* only one item in v */

      /* - but now we need to go round once more to get
         v->s inspected. This looks messy, but is actually
         the optimal approach.  */

      if (first_key_inspected) break;
      first_key_inspected = 1;
    }
  }
  while (1) {
    w = v + i;
    if (common_i >= w->s_size) {
      z->c = c + w->s_size;
      if (w->function == 0) return w->result;
      {
        int res = w->function(z);
        z->c = c + w->s_size;
        if (res) return w->result;
      }
    }
    i = w->substring_i;
    if (i < 0) return 0;
  }
}

/* find_among_b is for backwards processing. Same comments apply */

extern int find_among_b(struct SN_env *z, const struct among *v, int v_size) {

  int i = 0;
  int j = v_size;

  int c = z->c;
  int lb = z->lb;
  symbol *q = z->p + c - 1;

  const struct among *w;

  int common_i = 0;
  int common_j = 0;

  int first_key_inspected = 0;

  while (1) {
    int k = i + ((j - i) >> 1);
    int diff = 0;
    int common = common_i < common_j ? common_i : common_j;
    w = v + k;
    {
      int i2;
      for (i2 = w->s_size - 1 - common; i2 >= 0; i2--) {
        if (c - common == lb) {
          diff = -1;
          break;
        }
        diff = q[-common] - w->s[i2];
        if (diff != 0) break;
        common++;
      }
    }
    if (diff < 0) {
      j = k;
      common_j = common;
    } else {
      i = k;
      common_i = common;
    }
    if (j - i <= 1) {
      if (i > 0) break;
      if (j == i) break;
      if (first_key_inspected) break;
      first_key_inspected = 1;
    }
  }
  while (1) {
    w = v + i;
    if (common_i >= w->s_size) {
      z->c = c - w->s_size;
      if (w->function == 0) return w->result;
      {
        int res = w->function(z);
        z->c = c - w->s_size;
        if (res) return w->result;
      }
    }
    i = w->substring_i;
    if (i < 0) return 0;
  }
}

/* Increase the size of the buffer pointed to by p to at least n symbols.
 * If insufficient memory, returns NULL and frees the old buffer.
 */
static symbol *increase_size(symbol *p, int n) {
  symbol *q;
  int new_size = n + 20;
  void *mem = rm_realloc((char *)p - HEAD, HEAD + (new_size + 1) * sizeof(symbol));
  if (mem == NULL) {
    lose_s(p);
    return NULL;
  }
  q = (symbol *)(HEAD + (char *)mem);
  CAPACITY(q) = new_size;
  return q;
}

/* to replace symbols between c_bra and c_ket in z->p by the
   s_size symbols at s.
   Returns 0 on success, -1 on error.
   Also, frees z->p (and sets it to NULL) on error.
*/
extern int replace_s(struct SN_env *z, int c_bra, int c_ket, int s_size, const symbol *s,
                     int *adjptr) {
  int adjustment;
  int len;
  if (z->p == NULL) {
    z->p = create_s();
    if (z->p == NULL) return -1;
  }
  adjustment = s_size - (c_ket - c_bra);
  len = SIZE(z->p);
  if (adjustment != 0) {
    if (adjustment + len > CAPACITY(z->p)) {
      z->p = increase_size(z->p, adjustment + len);
      if (z->p == NULL) return -1;
    }
    memmove(z->p + c_ket + adjustment, z->p + c_ket, (len - c_ket) * sizeof(symbol));
    SET_SIZE(z->p, adjustment + len);
    z->l += adjustment;
    if (z->c >= c_ket)
      z->c += adjustment;
    else if (z->c > c_bra)
      z->c = c_bra;
  }
  if (s_size) memmove(z->p + c_bra, s, s_size * sizeof(symbol));
  if (adjptr != NULL) *adjptr = adjustment;
  return 0;
}

static int slice_check(struct SN_env *z) {

  if (z->bra < 0 || z->bra > z->ket || z->ket > z->l || z->p == NULL ||
      z->l > SIZE(z->p)) /* this line could be removed */
  {
#if 0
        fprintf(stderr, "faulty slice operation:\n");
        debug(z, -1, 0);
#endif
    return -1;
  }
  return 0;
}

extern int slice_from_s(struct SN_env *z, int s_size, const symbol *s) {
  if (slice_check(z)) return -1;
  return replace_s(z, z->bra, z->ket, s_size, s, NULL);
}

extern int slice_from_v(struct SN_env *z, const symbol *p) {
  return slice_from_s(z, SIZE(p), p);
}

extern int slice_del(struct SN_env *z) {
  return slice_from_s(z, 0, 0);
}

extern int insert_s(struct SN_env *z, int bra, int ket, int s_size, const symbol *s) {
  int adjustment;
  if (replace_s(z, bra, ket, s_size, s, &adjustment)) return -1;
  if (bra <= z->bra) z->bra += adjustment;
  if (bra <= z->ket) z->ket += adjustment;
  return 0;
}

extern int insert_v(struct SN_env *z, int bra, int ket, const symbol *p) {
  int adjustment;
  if (replace_s(z, bra, ket, SIZE(p), p, &adjustment)) return -1;
  if (bra <= z->bra) z->bra += adjustment;
  if (bra <= z->ket) z->ket += adjustment;
  return 0;
}

extern symbol *slice_to(struct SN_env *z, symbol *p) {
  if (slice_check(z)) {
    lose_s(p);
    return NULL;
  }
  {
    int len = z->ket - z->bra;
    if (CAPACITY(p) < len) {
      p = increase_size(p, len);
      if (p == NULL) return NULL;
    }
    memmove(p, z->p + z->bra, len * sizeof(symbol));
    SET_SIZE(p, len);
  }
  return p;
}

extern symbol *assign_to(struct SN_env *z, symbol *p) {
  int len = z->l;
  if (CAPACITY(p) < len) {
    p = increase_size(p, len);
    if (p == NULL) return NULL;
  }
  memmove(p, z->p, len * sizeof(symbol));
  SET_SIZE(p, len);
  return p;
}

extern int len_utf8(const symbol *p) {
  int size = SIZE(p);
  int len = 0;
  while (size--) {
    symbol b = *p++;
    if (b >= 0xC0 || b < 0x80) ++len;
  }
  return len;
}

#if 0
extern void debug(struct SN_env * z, int number, int line_count) {
    int i;
    int limit = SIZE(z->p);
    /*if (number >= 0) printf("%3d (line %4d): '", number, line_count);*/
    if (number >= 0) printf("%3d (line %4d): [%d]'", number, line_count,limit);
    for (i = 0; i <= limit; i++) {
        if (z->lb == i) printf("{");
        if (z->bra == i) printf("[");
        if (z->c == i) printf("|");
        if (z->ket == i) printf("]");
        if (z->l == i) printf("}");
        if (i < limit)
        {   int ch = z->p[i];
            if (ch == 0) ch = '#';
            printf("%c", ch);
        }
    }
    printf("'\n");
}
#endif
