toml.c

/*

  MIT License

  Copyright (c) CK Tan
  https://github.com/cktan/tomlc99

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.

*/
#define _POSIX_C_SOURCE 200809L
#include "toml.h"
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static void *(*ppmalloc)(size_t) = malloc;
static void (*ppfree)(void *) = free;

void toml_set_memutil(void *(*xxmalloc)(size_t), void (*xxfree)(void *)) {
  if (xxmalloc)
    ppmalloc = xxmalloc;
  if (xxfree)
    ppfree = xxfree;
}

#define ALIGN8(sz) (((sz) + 7) & ~7)
#define MALLOC(a) ppmalloc(a)
#define FREE(a) ppfree(a)

#define malloc(x) error - forbidden - use MALLOC instead
#define free(x) error - forbidden - use FREE instead
#define calloc(x, y) error - forbidden - use CALLOC instead

static void *CALLOC(size_t nmemb, size_t sz) {
  int nb = ALIGN8(sz) * nmemb;
  void *p = MALLOC(nb);
  if (p) {
    memset(p, 0, nb);
  }
  return p;
}

// some old platforms define strdup macro -- drop it.
#undef strdup
#define strdup(x) error - forbidden - use STRDUP instead

static char *STRDUP(const char *s) {
  int len = strlen(s);
  char *p = MALLOC(len + 1);
  if (p) {
    memcpy(p, s, len);
    p[len] = 0;
  }
  return p;
}

// some old platforms define strndup macro -- drop it.
#undef strndup
#define strndup(x) error - forbiden - use STRNDUP instead

static char *STRNDUP(const char *s, size_t n) {
  size_t len = strnlen(s, n);
  char *p = MALLOC(len + 1);
  if (p) {
    memcpy(p, s, len);
    p[len] = 0;
  }
  return p;
}

/**
 * Convert a char in utf8 into UCS, and store it in *ret.
 * Return #bytes consumed or -1 on failure.
 */
int toml_utf8_to_ucs(const char *orig, int len, int64_t *ret) {
  const unsigned char *buf = (const unsigned char *)orig;
  unsigned i = *buf++;
  int64_t v;

  /* 0x00000000 - 0x0000007F:
     0xxxxxxx
  */
  if (0 == (i >> 7)) {
    if (len < 1)
      return -1;
    v = i;
    return *ret = v, 1;
  }
  /* 0x00000080 - 0x000007FF:
     110xxxxx 10xxxxxx
  */
  if (0x6 == (i >> 5)) {
    if (len < 2)
      return -1;
    v = i & 0x1f;
    for (int j = 0; j < 1; j++) {
      i = *buf++;
      if (0x2 != (i >> 6))
        return -1;
      v = (v << 6) | (i & 0x3f);
    }
    return *ret = v, (const char *)buf - orig;
  }

  /* 0x00000800 - 0x0000FFFF:
     1110xxxx 10xxxxxx 10xxxxxx
  */
  if (0xE == (i >> 4)) {
    if (len < 3)
      return -1;
    v = i & 0x0F;
    for (int j = 0; j < 2; j++) {
      i = *buf++;
      if (0x2 != (i >> 6))
        return -1;
      v = (v << 6) | (i & 0x3f);
    }
    return *ret = v, (const char *)buf - orig;
  }

  /* 0x00010000 - 0x001FFFFF:
     11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
  */
  if (0x1E == (i >> 3)) {
    if (len < 4)
      return -1;
    v = i & 0x07;
    for (int j = 0; j < 3; j++) {
      i = *buf++;
      if (0x2 != (i >> 6))
        return -1;
      v = (v << 6) | (i & 0x3f);
    }
    return *ret = v, (const char *)buf - orig;
  }

  /* 0x00200000 - 0x03FFFFFF:
     111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
  */
  if (0x3E == (i >> 2)) {
    if (len < 5)
      return -1;
    v = i & 0x03;
    for (int j = 0; j < 4; j++) {
      i = *buf++;
      if (0x2 != (i >> 6))
        return -1;
      v = (v << 6) | (i & 0x3f);
    }
    return *ret = v, (const char *)buf - orig;
  }

  /* 0x04000000 - 0x7FFFFFFF:
     1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
  */
  if (0x7e == (i >> 1)) {
    if (len < 6)
      return -1;
    v = i & 0x01;
    for (int j = 0; j < 5; j++) {
      i = *buf++;
      if (0x2 != (i >> 6))
        return -1;
      v = (v << 6) | (i & 0x3f);
    }
    return *ret = v, (const char *)buf - orig;
  }
  return -1;
}

/**
 *	Convert a UCS char to utf8 code, and return it in buf.
 *	Return #bytes used in buf to encode the char, or
 *	-1 on error.
 */
int toml_ucs_to_utf8(int64_t code, char buf[6]) {
  /* http://stackoverflow.com/questions/6240055/manually-converting-unicode-codepoints-into-utf-8-and-utf-16
   */
  /* The UCS code values 0xd800–0xdfff (UTF-16 surrogates) as well
   * as 0xfffe and 0xffff (UCS noncharacters) should not appear in
   * conforming UTF-8 streams.
   */
  if (0xd800 <= code && code <= 0xdfff)
    return -1;
  if (0xfffe <= code && code <= 0xffff)
    return -1;

  /* 0x00000000 - 0x0000007F:
     0xxxxxxx
  */
  if (code < 0)
    return -1;
  if (code <= 0x7F) {
    buf[0] = (unsigned char)code;
    return 1;
  }

  /* 0x00000080 - 0x000007FF:
     110xxxxx 10xxxxxx
  */
  if (code <= 0x000007FF) {
    buf[0] = (unsigned char)(0xc0 | (code >> 6));
    buf[1] = (unsigned char)(0x80 | (code & 0x3f));
    return 2;
  }

  /* 0x00000800 - 0x0000FFFF:
     1110xxxx 10xxxxxx 10xxxxxx
  */
  if (code <= 0x0000FFFF) {
    buf[0] = (unsigned char)(0xe0 | (code >> 12));
    buf[1] = (unsigned char)(0x80 | ((code >> 6) & 0x3f));
    buf[2] = (unsigned char)(0x80 | (code & 0x3f));
    return 3;
  }

  /* 0x00010000 - 0x001FFFFF:
     11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
  */
  if (code <= 0x001FFFFF) {
    buf[0] = (unsigned char)(0xf0 | (code >> 18));
    buf[1] = (unsigned char)(0x80 | ((code >> 12) & 0x3f));
    buf[2] = (unsigned char)(0x80 | ((code >> 6) & 0x3f));
    buf[3] = (unsigned char)(0x80 | (code & 0x3f));
    return 4;
  }

  /* 0x00200000 - 0x03FFFFFF:
     111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
  */
  if (code <= 0x03FFFFFF) {
    buf[0] = (unsigned char)(0xf8 | (code >> 24));
    buf[1] = (unsigned char)(0x80 | ((code >> 18) & 0x3f));
    buf[2] = (unsigned char)(0x80 | ((code >> 12) & 0x3f));
    buf[3] = (unsigned char)(0x80 | ((code >> 6) & 0x3f));
    buf[4] = (unsigned char)(0x80 | (code & 0x3f));
    return 5;
  }

  /* 0x04000000 - 0x7FFFFFFF:
     1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
  */
  if (code <= 0x7FFFFFFF) {
    buf[0] = (unsigned char)(0xfc | (code >> 30));
    buf[1] = (unsigned char)(0x80 | ((code >> 24) & 0x3f));
    buf[2] = (unsigned char)(0x80 | ((code >> 18) & 0x3f));
    buf[3] = (unsigned char)(0x80 | ((code >> 12) & 0x3f));
    buf[4] = (unsigned char)(0x80 | ((code >> 6) & 0x3f));
    buf[5] = (unsigned char)(0x80 | (code & 0x3f));
    return 6;
  }

  return -1;
}

/*
 *	TOML has 3 data structures: value, array, table.
 *	Each of them can have identification key.
 */
typedef struct toml_keyval_t toml_keyval_t;
struct toml_keyval_t {
  const char *key; /* key to this value */
  const char *val; /* the raw value */
};

typedef struct toml_arritem_t toml_arritem_t;
struct toml_arritem_t {
  int valtype; /* for value kind: 'i'nt, 'd'ouble, 'b'ool, 's'tring, 't'ime,
                  'D'ate, 'T'imestamp */
  char *val;
  toml_array_t *arr;
  toml_table_t *tab;
};

struct toml_array_t {
  const char *key; /* key to this array */
  int kind;        /* element kind: 'v'alue, 'a'rray, or 't'able, 'm'ixed */
  int type;        /* for value kind: 'i'nt, 'd'ouble, 'b'ool, 's'tring, 't'ime,
                      'D'ate, 'T'imestamp, 'm'ixed */

  int nitem; /* number of elements */
  toml_arritem_t *item;
};

struct toml_table_t {
  const char *key; /* key to this table */
  bool implicit;   /* table was created implicitly */
  bool readonly;   /* no more modification allowed */

  /* key-values in the table */
  int nkval;
  toml_keyval_t **kval;

  /* arrays in the table */
  int narr;
  toml_array_t **arr;

  /* tables in the table */
  int ntab;
  toml_table_t **tab;
};

static inline void xfree(const void *x) {
  if (x)
    FREE((void *)(intptr_t)x);
}

enum tokentype_t {
  INVALID,
  DOT,
  COMMA,
  EQUAL,
  LBRACE,
  RBRACE,
  NEWLINE,
  LBRACKET,
  RBRACKET,
  STRING,
};
typedef enum tokentype_t tokentype_t;

typedef struct token_t token_t;
struct token_t {
  tokentype_t tok;
  int lineno;
  char *ptr; /* points into context->start */
  int len;
  int eof;
};

typedef struct context_t context_t;
struct context_t {
  char *start;
  char *stop;
  char *errbuf;
  int errbufsz;

  token_t tok;
  toml_table_t *root;
  toml_table_t *curtab;

  struct {
    int top;
    char *key[10];
    token_t tok[10];
  } tpath;
};

#define STRINGIFY(x) #x
#define TOSTRING(x) STRINGIFY(x)
#define FLINE __FILE__ ":" TOSTRING(__LINE__)

static int next_token(context_t *ctx, int dotisspecial);

/*
  Error reporting. Call when an error is detected. Always return -1.
*/
static int e_outofmemory(context_t *ctx, const char *fline) {
  snprintf(ctx->errbuf, ctx->errbufsz, "ERROR: out of memory (%s)", fline);
  return -1;
}

static int e_internal(context_t *ctx, const char *fline) {
  snprintf(ctx->errbuf, ctx->errbufsz, "internal error (%s)", fline);
  return -1;
}

static int e_syntax(context_t *ctx, int lineno, const char *msg) {
  snprintf(ctx->errbuf, ctx->errbufsz, "line %d: %s", lineno, msg);
  return -1;
}

static int e_badkey(context_t *ctx, int lineno) {
  snprintf(ctx->errbuf, ctx->errbufsz, "line %d: bad key", lineno);
  return -1;
}

static int e_keyexists(context_t *ctx, int lineno) {
  snprintf(ctx->errbuf, ctx->errbufsz, "line %d: key exists", lineno);
  return -1;
}

static int e_forbid(context_t *ctx, int lineno, const char *msg) {
  snprintf(ctx->errbuf, ctx->errbufsz, "line %d: %s", lineno, msg);
  return -1;
}

static void *expand(void *p, int sz, int newsz) {
  void *s = MALLOC(newsz);
  if (!s)
    return 0;

  if (p) {
    memcpy(s, p, sz);
    FREE(p);
  }
  return s;
}

static void **expand_ptrarr(void **p, int n) {
  void **s = MALLOC((n + 1) * sizeof(void *));
  if (!s)
    return 0;

  s[n] = 0;
  if (p) {
    memcpy(s, p, n * sizeof(void *));
    FREE(p);
  }
  return s;
}

static toml_arritem_t *expand_arritem(toml_arritem_t *p, int n) {
  toml_arritem_t *pp = expand(p, n * sizeof(*p), (n + 1) * sizeof(*p));
  if (!pp)
    return 0;

  memset(&pp[n], 0, sizeof(pp[n]));
  return pp;
}

static char *norm_lit_str(const char *src, int srclen, int multiline,
                          char *errbuf, int errbufsz) {
  char *dst = 0; /* will write to dst[] and return it */
  int max = 0;   /* max size of dst[] */
  int off = 0;   /* cur offset in dst[] */
  const char *sp = src;
  const char *sq = src + srclen;
  int ch;

  /* scan forward on src */
  for (;;) {
    if (off >= max - 10) { /* have some slack for misc stuff */
      int newmax = max + 50;
      char *x = expand(dst, max, newmax);
      if (!x) {
        xfree(dst);
        snprintf(errbuf, errbufsz, "out of memory");
        return 0;
      }
      dst = x;
      max = newmax;
    }

    /* finished? */
    if (sp >= sq)
      break;

    ch = *sp++;
    /* control characters other than tab is not allowed */
    if ((0 <= ch && ch <= 0x08) || (0x0a <= ch && ch <= 0x1f) || (ch == 0x7f)) {
      if (!(multiline && (ch == '\r' || ch == '\n'))) {
        xfree(dst);
        snprintf(errbuf, errbufsz, "invalid char U+%04x", ch);
        return 0;
      }
    }

    // a plain copy suffice
    dst[off++] = ch;
  }

  dst[off++] = 0;
  return dst;
}

/*
 * Convert src to raw unescaped utf-8 string.
 * Returns NULL if error with errmsg in errbuf.
 */
static char *norm_basic_str(const char *src, int srclen, int multiline,
                            char *errbuf, int errbufsz) {
  char *dst = 0; /* will write to dst[] and return it */
  int max = 0;   /* max size of dst[] */
  int off = 0;   /* cur offset in dst[] */
  const char *sp = src;
  const char *sq = src + srclen;
  int ch;

  /* scan forward on src */
  for (;;) {
    if (off >= max - 10) { /* have some slack for misc stuff */
      int newmax = max + 50;
      char *x = expand(dst, max, newmax);
      if (!x) {
        xfree(dst);
        snprintf(errbuf, errbufsz, "out of memory");
        return 0;
      }
      dst = x;
      max = newmax;
    }

    /* finished? */
    if (sp >= sq)
      break;

    ch = *sp++;
    if (ch != '\\') {
      /* these chars must be escaped: U+0000 to U+0008, U+000A to U+001F, U+007F
       */
      if ((0 <= ch && ch <= 0x08) || (0x0a <= ch && ch <= 0x1f) ||
          (ch == 0x7f)) {
        if (!(multiline && (ch == '\r' || ch == '\n'))) {
          xfree(dst);
          snprintf(errbuf, errbufsz, "invalid char U+%04x", ch);
          return 0;
        }
      }

      // a plain copy suffice
      dst[off++] = ch;
      continue;
    }

    /* ch was backslash. we expect the escape char. */
    if (sp >= sq) {
      snprintf(errbuf, errbufsz, "last backslash is invalid");
      xfree(dst);
      return 0;
    }

    /* for multi-line, we want to kill line-ending-backslash ... */
    if (multiline) {

      // if there is only whitespace after the backslash ...
      if (sp[strspn(sp, " \t\r")] == '\n') {
        /* skip all the following whitespaces */
        sp += strspn(sp, " \t\r\n");
        continue;
      }
    }

    /* get the escaped char */
    ch = *sp++;
    switch (ch) {
    case 'u':
    case 'U': {
      int64_t ucs = 0;
      int nhex = (ch == 'u' ? 4 : 8);
      for (int i = 0; i < nhex; i++) {
        if (sp >= sq) {
          snprintf(errbuf, errbufsz, "\\%c expects %d hex chars", ch, nhex);
          xfree(dst);
          return 0;
        }
        ch = *sp++;
        int v = ('0' <= ch && ch <= '9')
                    ? ch - '0'
                    : (('A' <= ch && ch <= 'F') ? ch - 'A' + 10 : -1);
        if (-1 == v) {
          snprintf(errbuf, errbufsz, "invalid hex chars for \\u or \\U");
          xfree(dst);
          return 0;
        }
        ucs = ucs * 16 + v;
      }
      int n = toml_ucs_to_utf8(ucs, &dst[off]);
      if (-1 == n) {
        snprintf(errbuf, errbufsz, "illegal ucs code in \\u or \\U");
        xfree(dst);
        return 0;
      }
      off += n;
    }
      continue;

    case 'b':
      ch = '\b';
      break;
    case 't':
      ch = '\t';
      break;
    case 'n':
      ch = '\n';
      break;
    case 'f':
      ch = '\f';
      break;
    case 'r':
      ch = '\r';
      break;
    case '"':
      ch = '"';
      break;
    case '\\':
      ch = '\\';
      break;
    default:
      snprintf(errbuf, errbufsz, "illegal escape char \\%c", ch);
      xfree(dst);
      return 0;
    }

    dst[off++] = ch;
  }

  // Cap with NUL and return it.
  dst[off++] = 0;
  return dst;
}

/* Normalize a key. Convert all special chars to raw unescaped utf-8 chars. */
static char *normalize_key(context_t *ctx, token_t strtok) {
  const char *sp = strtok.ptr;
  const char *sq = strtok.ptr + strtok.len;
  int lineno = strtok.lineno;
  char *ret;
  int ch = *sp;
  char ebuf[80];

  /* handle quoted string */
  if (ch == '\'' || ch == '\"') {
    /* if ''' or """, take 3 chars off front and back. Else, take 1 char off. */
    int multiline = 0;
    if (sp[1] == ch && sp[2] == ch) {
      sp += 3, sq -= 3;
      multiline = 1;
    } else
      sp++, sq--;

    if (ch == '\'') {
      /* for single quote, take it verbatim. */
      if (!(ret = STRNDUP(sp, sq - sp))) {
        e_outofmemory(ctx, FLINE);
        return 0;
      }
    } else {
      /* for double quote, we need to normalize */
      ret = norm_basic_str(sp, sq - sp, multiline, ebuf, sizeof(ebuf));
      if (!ret) {
        e_syntax(ctx, lineno, ebuf);
        return 0;
      }
    }

    /* newlines are not allowed in keys */
    if (strchr(ret, '\n')) {
      xfree(ret);
      e_badkey(ctx, lineno);
      return 0;
    }
    return ret;
  }

  /* for bare-key allow only this regex: [A-Za-z0-9_-]+ */
  const char *xp;
  for (xp = sp; xp != sq; xp++) {
    int k = *xp;
    if (isalnum(k))
      continue;
    if (k == '_' || k == '-')
      continue;
    e_badkey(ctx, lineno);
    return 0;
  }

  /* dup and return it */
  if (!(ret = STRNDUP(sp, sq - sp))) {
    e_outofmemory(ctx, FLINE);
    return 0;
  }
  return ret;
}

/*
 * Look up key in tab. Return 0 if not found, or
 * 'v'alue, 'a'rray or 't'able depending on the element.
 */
static int check_key(toml_table_t *tab, const char *key,
                     toml_keyval_t **ret_val, toml_array_t **ret_arr,
                     toml_table_t **ret_tab) {
  int i;
  void *dummy;

  if (!ret_tab)
    ret_tab = (toml_table_t **)&dummy;
  if (!ret_arr)
    ret_arr = (toml_array_t **)&dummy;
  if (!ret_val)
    ret_val = (toml_keyval_t **)&dummy;

  *ret_tab = 0;
  *ret_arr = 0;
  *ret_val = 0;

  for (i = 0; i < tab->nkval; i++) {
    if (0 == strcmp(key, tab->kval[i]->key)) {
      *ret_val = tab->kval[i];
      return 'v';
    }
  }
  for (i = 0; i < tab->narr; i++) {
    if (0 == strcmp(key, tab->arr[i]->key)) {
      *ret_arr = tab->arr[i];
      return 'a';
    }
  }
  for (i = 0; i < tab->ntab; i++) {
    if (0 == strcmp(key, tab->tab[i]->key)) {
      *ret_tab = tab->tab[i];
      return 't';
    }
  }
  return 0;
}

static int key_kind(toml_table_t *tab, const char *key) {
  return check_key(tab, key, 0, 0, 0);
}

/* Create a keyval in the table.
 */
static toml_keyval_t *create_keyval_in_table(context_t *ctx, toml_table_t *tab,
                                             token_t keytok) {
  /* first, normalize the key to be used for lookup.
   * remember to free it if we error out.
   */
  char *newkey = normalize_key(ctx, keytok);
  if (!newkey)
    return 0;

  /* if key exists: error out. */
  toml_keyval_t *dest = 0;
  if (key_kind(tab, newkey)) {
    xfree(newkey);
    e_keyexists(ctx, keytok.lineno);
    return 0;
  }

  /* make a new entry */
  int n = tab->nkval;
  toml_keyval_t **base;
  if (0 == (base = (toml_keyval_t **)expand_ptrarr((void **)tab->kval, n))) {
    xfree(newkey);
    e_outofmemory(ctx, FLINE);
    return 0;
  }
  tab->kval = base;

  if (0 == (base[n] = (toml_keyval_t *)CALLOC(1, sizeof(*base[n])))) {
    xfree(newkey);
    e_outofmemory(ctx, FLINE);
    return 0;
  }
  dest = tab->kval[tab->nkval++];

  /* save the key in the new value struct */
  dest->key = newkey;
  return dest;
}

/* Create a table in the table.
 */
static toml_table_t *create_keytable_in_table(context_t *ctx, toml_table_t *tab,
                                              token_t keytok) {
  /* first, normalize the key to be used for lookup.
   * remember to free it if we error out.
   */
  char *newkey = normalize_key(ctx, keytok);
  if (!newkey)
    return 0;

  /* if key exists: error out */
  toml_table_t *dest = 0;
  if (check_key(tab, newkey, 0, 0, &dest)) {
    xfree(newkey); /* don't need this anymore */

    /* special case: if table exists, but was created implicitly ... */
    if (dest && dest->implicit) {
      /* we make it explicit now, and simply return it. */
      dest->implicit = false;
      return dest;
    }
    e_keyexists(ctx, keytok.lineno);
    return 0;
  }

  /* create a new table entry */
  int n = tab->ntab;
  toml_table_t **base;
  if (0 == (base = (toml_table_t **)expand_ptrarr((void **)tab->tab, n))) {
    xfree(newkey);
    e_outofmemory(ctx, FLINE);
    return 0;
  }
  tab->tab = base;

  if (0 == (base[n] = (toml_table_t *)CALLOC(1, sizeof(*base[n])))) {
    xfree(newkey);
    e_outofmemory(ctx, FLINE);
    return 0;
  }
  dest = tab->tab[tab->ntab++];

  /* save the key in the new table struct */
  dest->key = newkey;
  return dest;
}

/* Create an array in the table.
 */
static toml_array_t *create_keyarray_in_table(context_t *ctx, toml_table_t *tab,
                                              token_t keytok, char kind) {
  /* first, normalize the key to be used for lookup.
   * remember to free it if we error out.
   */
  char *newkey = normalize_key(ctx, keytok);
  if (!newkey)
    return 0;

  /* if key exists: error out */
  if (key_kind(tab, newkey)) {
    xfree(newkey); /* don't need this anymore */
    e_keyexists(ctx, keytok.lineno);
    return 0;
  }

  /* make a new array entry */
  int n = tab->narr;
  toml_array_t **base;
  if (0 == (base = (toml_array_t **)expand_ptrarr((void **)tab->arr, n))) {
    xfree(newkey);
    e_outofmemory(ctx, FLINE);
    return 0;
  }
  tab->arr = base;

  if (0 == (base[n] = (toml_array_t *)CALLOC(1, sizeof(*base[n])))) {
    xfree(newkey);
    e_outofmemory(ctx, FLINE);
    return 0;
  }
  toml_array_t *dest = tab->arr[tab->narr++];

  /* save the key in the new array struct */
  dest->key = newkey;
  dest->kind = kind;
  return dest;
}

static toml_arritem_t *create_value_in_array(context_t *ctx,
                                             toml_array_t *parent) {
  const int n = parent->nitem;
  toml_arritem_t *base = expand_arritem(parent->item, n);
  if (!base) {
    e_outofmemory(ctx, FLINE);
    return 0;
  }
  parent->item = base;
  parent->nitem++;
  return &parent->item[n];
}

/* Create an array in an array
 */
static toml_array_t *create_array_in_array(context_t *ctx,
                                           toml_array_t *parent) {
  const int n = parent->nitem;
  toml_arritem_t *base = expand_arritem(parent->item, n);
  if (!base) {
    e_outofmemory(ctx, FLINE);
    return 0;
  }
  toml_array_t *ret = (toml_array_t *)CALLOC(1, sizeof(toml_array_t));
  if (!ret) {
    e_outofmemory(ctx, FLINE);
    return 0;
  }
  base[n].arr = ret;
  parent->item = base;
  parent->nitem++;
  return ret;
}

/* Create a table in an array
 */
static toml_table_t *create_table_in_array(context_t *ctx,
                                           toml_array_t *parent) {
  int n = parent->nitem;
  toml_arritem_t *base = expand_arritem(parent->item, n);
  if (!base) {
    e_outofmemory(ctx, FLINE);
    return 0;
  }
  toml_table_t *ret = (toml_table_t *)CALLOC(1, sizeof(toml_table_t));
  if (!ret) {
    e_outofmemory(ctx, FLINE);
    return 0;
  }
  base[n].tab = ret;
  parent->item = base;
  parent->nitem++;
  return ret;
}

static int skip_newlines(context_t *ctx, int isdotspecial) {
  while (ctx->tok.tok == NEWLINE) {
    if (next_token(ctx, isdotspecial))
      return -1;
    if (ctx->tok.eof)
      break;
  }
  return 0;
}

static int parse_keyval(context_t *ctx, toml_table_t *tab);

static inline int eat_token(context_t *ctx, tokentype_t typ, int isdotspecial,
                            const char *fline) {
  if (ctx->tok.tok != typ)
    return e_internal(ctx, fline);

  if (next_token(ctx, isdotspecial))
    return -1;

  return 0;
}

/* We are at '{ ... }'.
 * Parse the table.
 */
static int parse_inline_table(context_t *ctx, toml_table_t *tab) {
  if (eat_token(ctx, LBRACE, 1, FLINE))
    return -1;

  for (;;) {
    if (ctx->tok.tok == NEWLINE)
      return e_syntax(ctx, ctx->tok.lineno,
                      "newline not allowed in inline table");

    /* until } */
    if (ctx->tok.tok == RBRACE)
      break;

    if (ctx->tok.tok != STRING)
      return e_syntax(ctx, ctx->tok.lineno, "expect a string");

    if (parse_keyval(ctx, tab))
      return -1;

    if (ctx->tok.tok == NEWLINE)
      return e_syntax(ctx, ctx->tok.lineno,
                      "newline not allowed in inline table");

    /* on comma, continue to scan for next keyval */
    if (ctx->tok.tok == COMMA) {
      if (eat_token(ctx, COMMA, 1, FLINE))
        return -1;
      continue;
    }
    break;
  }

  if (eat_token(ctx, RBRACE, 1, FLINE))
    return -1;

  tab->readonly = 1;

  return 0;
}

static int valtype(const char *val) {
  toml_timestamp_t ts;
  if (*val == '\'' || *val == '"')
    return 's';
  if (0 == toml_rtob(val, 0))
    return 'b';
  if (0 == toml_rtoi(val, 0))
    return 'i';
  if (0 == toml_rtod(val, 0))
    return 'd';
  if (0 == toml_rtots(val, &ts)) {
    if (ts.year && ts.hour)
      return 'T'; /* timestamp */
    if (ts.year)
      return 'D'; /* date */
    return 't';   /* time */
  }
  return 'u'; /* unknown */
}

/* We are at '[...]' */
static int parse_array(context_t *ctx, toml_array_t *arr) {
  if (eat_token(ctx, LBRACKET, 0, FLINE))
    return -1;

  for (;;) {
    if (skip_newlines(ctx, 0))
      return -1;

    /* until ] */
    if (ctx->tok.tok == RBRACKET)
      break;

    switch (ctx->tok.tok) {
    case STRING: {
      /* set array kind if this will be the first entry */
      if (arr->kind == 0)
        arr->kind = 'v';
      else if (arr->kind != 'v')
        arr->kind = 'm';

      char *val = ctx->tok.ptr;
      int vlen = ctx->tok.len;

      /* make a new value in array */
      toml_arritem_t *newval = create_value_in_array(ctx, arr);
      if (!newval)
        return e_outofmemory(ctx, FLINE);

      if (!(newval->val = STRNDUP(val, vlen)))
        return e_outofmemory(ctx, FLINE);

      newval->valtype = valtype(newval->val);

      /* set array type if this is the first entry */
      if (arr->nitem == 1)
        arr->type = newval->valtype;
      else if (arr->type != newval->valtype)
        arr->type = 'm'; /* mixed */

      if (eat_token(ctx, STRING, 0, FLINE))
        return -1;
      break;
    }

    case LBRACKET: { /* [ [array], [array] ... ] */
      /* set the array kind if this will be the first entry */
      if (arr->kind == 0)
        arr->kind = 'a';
      else if (arr->kind != 'a')
        arr->kind = 'm';

      toml_array_t *subarr = create_array_in_array(ctx, arr);
      if (!subarr)
        return -1;
      if (parse_array(ctx, subarr))
        return -1;
      break;
    }

    case LBRACE: { /* [ {table}, {table} ... ] */
      /* set the array kind if this will be the first entry */
      if (arr->kind == 0)
        arr->kind = 't';
      else if (arr->kind != 't')
        arr->kind = 'm';

      toml_table_t *subtab = create_table_in_array(ctx, arr);
      if (!subtab)
        return -1;
      if (parse_inline_table(ctx, subtab))
        return -1;
      break;
    }

    default:
      return e_syntax(ctx, ctx->tok.lineno, "syntax error");
    }

    if (skip_newlines(ctx, 0))
      return -1;

    /* on comma, continue to scan for next element */
    if (ctx->tok.tok == COMMA) {
      if (eat_token(ctx, COMMA, 0, FLINE))
        return -1;
      continue;
    }
    break;
  }

  if (eat_token(ctx, RBRACKET, 1, FLINE))
    return -1;
  return 0;
}

/* handle lines like these:
   key = "value"
   key = [ array ]
   key = { table }
*/
static int parse_keyval(context_t *ctx, toml_table_t *tab) {
  if (tab->readonly) {
    return e_forbid(ctx, ctx->tok.lineno,
                    "cannot insert new entry into existing table");
  }

  token_t key = ctx->tok;
  if (eat_token(ctx, STRING, 1, FLINE))
    return -1;

  if (ctx->tok.tok == DOT) {
    /* handle inline dotted key.
       e.g.
       physical.color = "orange"
       physical.shape = "round"
    */
    toml_table_t *subtab = 0;
    {
      char *subtabstr = normalize_key(ctx, key);
      if (!subtabstr)
        return -1;

      subtab = toml_table_in(tab, subtabstr);
      xfree(subtabstr);
    }
    if (!subtab) {
      subtab = create_keytable_in_table(ctx, tab, key);
      if (!subtab)
        return -1;
    }
    if (next_token(ctx, 1))
      return -1;
    if (parse_keyval(ctx, subtab))
      return -1;
    return 0;
  }

  if (ctx->tok.tok != EQUAL) {
    return e_syntax(ctx, ctx->tok.lineno, "missing =");
  }

  if (next_token(ctx, 0))
    return -1;

  switch (ctx->tok.tok) {
  case STRING: { /* key = "value" */
    toml_keyval_t *keyval = create_keyval_in_table(ctx, tab, key);
    if (!keyval)
      return -1;
    token_t val = ctx->tok;

    assert(keyval->val == 0);
    if (!(keyval->val = STRNDUP(val.ptr, val.len)))
      return e_outofmemory(ctx, FLINE);

    if (next_token(ctx, 1))
      return -1;

    return 0;
  }

  case LBRACKET: { /* key = [ array ] */
    toml_array_t *arr = create_keyarray_in_table(ctx, tab, key, 0);
    if (!arr)
      return -1;
    if (parse_array(ctx, arr))
      return -1;
    return 0;
  }

  case LBRACE: { /* key = { table } */
    toml_table_t *nxttab = create_keytable_in_table(ctx, tab, key);
    if (!nxttab)
      return -1;
    if (parse_inline_table(ctx, nxttab))
      return -1;
    return 0;
  }

  default:
    return e_syntax(ctx, ctx->tok.lineno, "syntax error");
  }
  return 0;
}

typedef struct tabpath_t tabpath_t;
struct tabpath_t {
  int cnt;
  token_t key[10];
};

/* at [x.y.z] or [[x.y.z]]
 * Scan forward and fill tabpath until it enters ] or ]]
 * There will be at least one entry on return.
 */
static int fill_tabpath(context_t *ctx) {
  int lineno = ctx->tok.lineno;
  int i;

  /* clear tpath */
  for (i = 0; i < ctx->tpath.top; i++) {
    char **p = &ctx->tpath.key[i];
    xfree(*p);
    *p = 0;
  }
  ctx->tpath.top = 0;

  for (;;) {
    if (ctx->tpath.top >= 10)
      return e_syntax(ctx, lineno,
                      "table path is too deep; max allowed is 10.");

    if (ctx->tok.tok != STRING)
      return e_syntax(ctx, lineno, "invalid or missing key");

    char *key = normalize_key(ctx, ctx->tok);
    if (!key)
      return -1;
    ctx->tpath.tok[ctx->tpath.top] = ctx->tok;
    ctx->tpath.key[ctx->tpath.top] = key;
    ctx->tpath.top++;

    if (next_token(ctx, 1))
      return -1;

    if (ctx->tok.tok == RBRACKET)
      break;

    if (ctx->tok.tok != DOT)
      return e_syntax(ctx, lineno, "invalid key");

    if (next_token(ctx, 1))
      return -1;
  }

  if (ctx->tpath.top <= 0)
    return e_syntax(ctx, lineno, "empty table selector");

  return 0;
}

/* Walk tabpath from the root, and create new tables on the way.
 * Sets ctx->curtab to the final table.
 */
static int walk_tabpath(context_t *ctx) {
  /* start from root */
  toml_table_t *curtab = ctx->root;

  for (int i = 0; i < ctx->tpath.top; i++) {
    const char *key = ctx->tpath.key[i];

    toml_keyval_t *nextval = 0;
    toml_array_t *nextarr = 0;
    toml_table_t *nexttab = 0;
    switch (check_key(curtab, key, &nextval, &nextarr, &nexttab)) {
    case 't':
      /* found a table. nexttab is where we will go next. */
      break;

    case 'a':
      /* found an array. nexttab is the last table in the array. */
      if (nextarr->kind != 't')
        return e_internal(ctx, FLINE);

      if (nextarr->nitem == 0)
        return e_internal(ctx, FLINE);

      nexttab = nextarr->item[nextarr->nitem - 1].tab;
      break;

    case 'v':
      return e_keyexists(ctx, ctx->tpath.tok[i].lineno);

    default: { /* Not found. Let's create an implicit table. */
      int n = curtab->ntab;
      toml_table_t **base =
          (toml_table_t **)expand_ptrarr((void **)curtab->tab, n);
      if (0 == base)
        return e_outofmemory(ctx, FLINE);

      curtab->tab = base;

      if (0 == (base[n] = (toml_table_t *)CALLOC(1, sizeof(*base[n]))))
        return e_outofmemory(ctx, FLINE);

      if (0 == (base[n]->key = STRDUP(key)))
        return e_outofmemory(ctx, FLINE);

      nexttab = curtab->tab[curtab->ntab++];

      /* tabs created by walk_tabpath are considered implicit */
      nexttab->implicit = true;
    } break;
    }

    /* switch to next tab */
    curtab = nexttab;
  }

  /* save it */
  ctx->curtab = curtab;

  return 0;
}

/* handle lines like [x.y.z] or [[x.y.z]] */
static int parse_select(context_t *ctx) {
  assert(ctx->tok.tok == LBRACKET);

  /* true if [[ */
  int llb = (ctx->tok.ptr + 1 < ctx->stop && ctx->tok.ptr[1] == '[');
  /* need to detect '[[' on our own because next_token() will skip whitespace,
     and '[ [' would be taken as '[[', which is wrong. */

  /* eat [ or [[ */
  if (eat_token(ctx, LBRACKET, 1, FLINE))
    return -1;
  if (llb) {
    assert(ctx->tok.tok == LBRACKET);
    if (eat_token(ctx, LBRACKET, 1, FLINE))
      return -1;
  }

  if (fill_tabpath(ctx))
    return -1;

  /* For [x.y.z] or [[x.y.z]], remove z from tpath.
   */
  token_t z = ctx->tpath.tok[ctx->tpath.top - 1];
  xfree(ctx->tpath.key[ctx->tpath.top - 1]);
  ctx->tpath.top--;

  /* set up ctx->curtab */
  if (walk_tabpath(ctx))
    return -1;

  if (!llb) {
    /* [x.y.z] -> create z = {} in x.y */
    toml_table_t *curtab = create_keytable_in_table(ctx, ctx->curtab, z);
    if (!curtab)
      return -1;
    ctx->curtab = curtab;
  } else {
    /* [[x.y.z]] -> create z = [] in x.y */
    toml_array_t *arr = 0;
    {
      char *zstr = normalize_key(ctx, z);
      if (!zstr)
        return -1;
      arr = toml_array_in(ctx->curtab, zstr);
      xfree(zstr);
    }
    if (!arr) {
      arr = create_keyarray_in_table(ctx, ctx->curtab, z, 't');
      if (!arr)
        return -1;
    }
    if (arr->kind != 't')
      return e_syntax(ctx, z.lineno, "array mismatch");

    /* add to z[] */
    toml_table_t *dest;
    {
      toml_table_t *t = create_table_in_array(ctx, arr);
      if (!t)
        return -1;

      if (0 == (t->key = STRDUP("__anon__")))
        return e_outofmemory(ctx, FLINE);

      dest = t;
    }

    ctx->curtab = dest;
  }

  if (ctx->tok.tok != RBRACKET) {
    return e_syntax(ctx, ctx->tok.lineno, "expects ]");
  }
  if (llb) {
    if (!(ctx->tok.ptr + 1 < ctx->stop && ctx->tok.ptr[1] == ']')) {
      return e_syntax(ctx, ctx->tok.lineno, "expects ]]");
    }
    if (eat_token(ctx, RBRACKET, 1, FLINE))
      return -1;
  }

  if (eat_token(ctx, RBRACKET, 1, FLINE))
    return -1;

  if (ctx->tok.tok != NEWLINE)
    return e_syntax(ctx, ctx->tok.lineno, "extra chars after ] or ]]");

  return 0;
}

toml_table_t *toml_parse(char *conf, char *errbuf, int errbufsz) {
  context_t ctx;

  // clear errbuf
  if (errbufsz <= 0)
    errbufsz = 0;
  if (errbufsz > 0)
    errbuf[0] = 0;

  // init context
  memset(&ctx, 0, sizeof(ctx));
  ctx.start = conf;
  ctx.stop = ctx.start + strlen(conf);
  ctx.errbuf = errbuf;
  ctx.errbufsz = errbufsz;

  // start with an artificial newline of length 0
  ctx.tok.tok = NEWLINE;
  ctx.tok.lineno = 1;
  ctx.tok.ptr = conf;
  ctx.tok.len = 0;

  // make a root table
  if (0 == (ctx.root = CALLOC(1, sizeof(*ctx.root)))) {
    e_outofmemory(&ctx, FLINE);
    // Do not goto fail, root table not set up yet
    return 0;
  }

  // set root as default table
  ctx.curtab = ctx.root;

  /* Scan forward until EOF */
  for (token_t tok = ctx.tok; !tok.eof; tok = ctx.tok) {
    switch (tok.tok) {

    case NEWLINE:
      if (next_token(&ctx, 1))
        goto fail;
      break;

    case STRING:
      if (parse_keyval(&ctx, ctx.curtab))
        goto fail;

      if (ctx.tok.tok != NEWLINE) {
        e_syntax(&ctx, ctx.tok.lineno, "extra chars after value");
        goto fail;
      }

      if (eat_token(&ctx, NEWLINE, 1, FLINE))
        goto fail;
      break;

    case LBRACKET: /* [ x.y.z ] or [[ x.y.z ]] */
      if (parse_select(&ctx))
        goto fail;
      break;

    default:
      e_syntax(&ctx, tok.lineno, "syntax error");
      goto fail;
    }
  }

  /* success */
  for (int i = 0; i < ctx.tpath.top; i++)
    xfree(ctx.tpath.key[i]);
  return ctx.root;

fail:
  // Something bad has happened. Free resources and return error.
  for (int i = 0; i < ctx.tpath.top; i++)
    xfree(ctx.tpath.key[i]);
  toml_free(ctx.root);
  return 0;
}

toml_table_t *toml_parse_file(FILE *fp, char *errbuf, int errbufsz) {
  int bufsz = 0;
  char *buf = 0;
  int off = 0;

  /* read from fp into buf */
  while (!feof(fp)) {

    if (off == bufsz) {
      int xsz = bufsz + 1000;
      char *x = expand(buf, bufsz, xsz);
      if (!x) {
        snprintf(errbuf, errbufsz, "out of memory");
        xfree(buf);
        return 0;
      }
      buf = x;
      bufsz = xsz;
    }

    errno = 0;
    int n = fread(buf + off, 1, bufsz - off, fp);
    if (ferror(fp)) {
      snprintf(errbuf, errbufsz, "%s",
               errno ? strerror(errno) : "Error reading file");
      xfree(buf);
      return 0;
    }
    off += n;
  }

  /* tag on a NUL to cap the string */
  if (off == bufsz) {
    int xsz = bufsz + 1;
    char *x = expand(buf, bufsz, xsz);
    if (!x) {
      snprintf(errbuf, errbufsz, "out of memory");
      xfree(buf);
      return 0;
    }
    buf = x;
    bufsz = xsz;
  }
  buf[off] = 0;

  /* parse it, cleanup and finish */
  toml_table_t *ret = toml_parse(buf, errbuf, errbufsz);
  xfree(buf);
  return ret;
}

static void xfree_kval(toml_keyval_t *p) {
  if (!p)
    return;
  xfree(p->key);
  xfree(p->val);
  xfree(p);
}

static void xfree_tab(toml_table_t *p);

static void xfree_arr(toml_array_t *p) {
  if (!p)
    return;

  xfree(p->key);
  const int n = p->nitem;
  for (int i = 0; i < n; i++) {
    toml_arritem_t *a = &p->item[i];
    if (a->val)
      xfree(a->val);
    else if (a->arr)
      xfree_arr(a->arr);
    else if (a->tab)
      xfree_tab(a->tab);
  }
  xfree(p->item);
  xfree(p);
}

static void xfree_tab(toml_table_t *p) {
  int i;

  if (!p)
    return;

  xfree(p->key);

  for (i = 0; i < p->nkval; i++)
    xfree_kval(p->kval[i]);
  xfree(p->kval);

  for (i = 0; i < p->narr; i++)
    xfree_arr(p->arr[i]);
  xfree(p->arr);

  for (i = 0; i < p->ntab; i++)
    xfree_tab(p->tab[i]);
  xfree(p->tab);

  xfree(p);
}

void toml_free(toml_table_t *tab) { xfree_tab(tab); }

static void set_token(context_t *ctx, tokentype_t tok, int lineno, char *ptr,
                      int len) {
  token_t t;
  t.tok = tok;
  t.lineno = lineno;
  t.ptr = ptr;
  t.len = len;
  t.eof = 0;
  ctx->tok = t;
}

static void set_eof(context_t *ctx, int lineno) {
  set_token(ctx, NEWLINE, lineno, ctx->stop, 0);
  ctx->tok.eof = 1;
}

/* Scan p for n digits compositing entirely of [0-9] */
static int scan_digits(const char *p, int n) {
  int ret = 0;
  for (; n > 0 && isdigit(*p); n--, p++) {
    ret = 10 * ret + (*p - '0');
  }
  return n ? -1 : ret;
}

static int scan_date(const char *p, int *YY, int *MM, int *DD) {
  int year, month, day;
  year = scan_digits(p, 4);
  month = (year >= 0 && p[4] == '-') ? scan_digits(p + 5, 2) : -1;
  day = (month >= 0 && p[7] == '-') ? scan_digits(p + 8, 2) : -1;
  if (YY)
    *YY = year;
  if (MM)
    *MM = month;
  if (DD)
    *DD = day;
  return (year >= 0 && month >= 0 && day >= 0) ? 0 : -1;
}

static int scan_time(const char *p, int *hh, int *mm, int *ss) {
  int hour, minute, second;
  hour = scan_digits(p, 2);
  minute = (hour >= 0 && p[2] == ':') ? scan_digits(p + 3, 2) : -1;
  second = (minute >= 0 && p[5] == ':') ? scan_digits(p + 6, 2) : -1;
  if (hh)
    *hh = hour;
  if (mm)
    *mm = minute;
  if (ss)
    *ss = second;
  return (hour >= 0 && minute >= 0 && second >= 0) ? 0 : -1;
}

static int scan_string(context_t *ctx, char *p, int lineno, int dotisspecial) {
  char *orig = p;
  if (0 == strncmp(p, "'''", 3)) {
    char *q = p + 3;

    while (1) {
      q = strstr(q, "'''");
      if (0 == q) {
        return e_syntax(ctx, lineno, "unterminated triple-s-quote");
      }
      while (q[3] == '\'')
        q++;
      break;
    }

    set_token(ctx, STRING, lineno, orig, q + 3 - orig);
    return 0;
  }

  if (0 == strncmp(p, "\"\"\"", 3)) {
    char *q = p + 3;

    while (1) {
      q = strstr(q, "\"\"\"");
      if (0 == q) {
        return e_syntax(ctx, lineno, "unterminated triple-d-quote");
      }
      if (q[-1] == '\\') {
        q++;
        continue;
      }
      while (q[3] == '\"')
        q++;
      break;
    }

    // the string is [p+3, q-1]

    int hexreq = 0; /* #hex required */
    int escape = 0;
    for (p += 3; p < q; p++) {
      if (escape) {
        escape = 0;
        if (strchr("btnfr\"\\", *p))
          continue;
        if (*p == 'u') {
          hexreq = 4;
          continue;
        }
        if (*p == 'U') {
          hexreq = 8;
          continue;
        }
        if (p[strspn(p, " \t\r")] == '\n')
          continue; /* allow for line ending backslash */
        return e_syntax(ctx, lineno, "bad escape char");
      }
      if (hexreq) {
        hexreq--;
        if (strchr("0123456789ABCDEF", *p))
          continue;
        return e_syntax(ctx, lineno, "expect hex char");
      }
      if (*p == '\\') {
        escape = 1;
        continue;
      }
    }
    if (escape)
      return e_syntax(ctx, lineno, "expect an escape char");
    if (hexreq)
      return e_syntax(ctx, lineno, "expected more hex char");

    set_token(ctx, STRING, lineno, orig, q + 3 - orig);
    return 0;
  }

  if ('\'' == *p) {
    for (p++; *p && *p != '\n' && *p != '\''; p++)
      ;
    if (*p != '\'') {
      return e_syntax(ctx, lineno, "unterminated s-quote");
    }

    set_token(ctx, STRING, lineno, orig, p + 1 - orig);
    return 0;
  }

  if ('\"' == *p) {
    int hexreq = 0; /* #hex required */
    int escape = 0;
    for (p++; *p; p++) {
      if (escape) {
        escape = 0;
        if (strchr("btnfr\"\\", *p))
          continue;
        if (*p == 'u') {
          hexreq = 4;
          continue;
        }
        if (*p == 'U') {
          hexreq = 8;
          continue;
        }
        return e_syntax(ctx, lineno, "bad escape char");
      }
      if (hexreq) {
        hexreq--;
        if (strchr("0123456789ABCDEF", *p))
          continue;
        return e_syntax(ctx, lineno, "expect hex char");
      }
      if (*p == '\\') {
        escape = 1;
        continue;
      }
      if (*p == '\'') {
        if (p[1] == '\'' && p[2] == '\'') {
          return e_syntax(ctx, lineno, "triple-s-quote inside string lit");
        }
        continue;
      }
      if (*p == '\n')
        break;
      if (*p == '"')
        break;
    }
    if (*p != '"') {
      return e_syntax(ctx, lineno, "unterminated quote");
    }

    set_token(ctx, STRING, lineno, orig, p + 1 - orig);
    return 0;
  }

  /* check for timestamp without quotes */
  if (0 == scan_date(p, 0, 0, 0) || 0 == scan_time(p, 0, 0, 0)) {
    // forward thru the timestamp
    p += strspn(p, "0123456789.:+-Tt Zz");
    // squeeze out any spaces at end of string
    for (; p[-1] == ' '; p--)
      ;
    // tokenize
    set_token(ctx, STRING, lineno, orig, p - orig);
    return 0;
  }

  /* literals */
  for (; *p && *p != '\n'; p++) {
    int ch = *p;
    if (ch == '.' && dotisspecial)
      break;
    if ('A' <= ch && ch <= 'Z')
      continue;
    if ('a' <= ch && ch <= 'z')
      continue;
    if (strchr("0123456789+-_.", ch))
      continue;
    break;
  }

  set_token(ctx, STRING, lineno, orig, p - orig);
  return 0;
}

static int next_token(context_t *ctx, int dotisspecial) {
  int lineno = ctx->tok.lineno;
  char *p = ctx->tok.ptr;
  int i;

  /* eat this tok */
  for (i = 0; i < ctx->tok.len; i++) {
    if (*p++ == '\n')
      lineno++;
  }

  /* make next tok */
  while (p < ctx->stop) {
    /* skip comment. stop just before the \n. */
    if (*p == '#') {
      for (p++; p < ctx->stop && *p != '\n'; p++)
        ;
      continue;
    }

    if (dotisspecial && *p == '.') {
      set_token(ctx, DOT, lineno, p, 1);
      return 0;
    }

    switch (*p) {
    case ',':
      set_token(ctx, COMMA, lineno, p, 1);
      return 0;
    case '=':
      set_token(ctx, EQUAL, lineno, p, 1);
      return 0;
    case '{':
      set_token(ctx, LBRACE, lineno, p, 1);
      return 0;
    case '}':
      set_token(ctx, RBRACE, lineno, p, 1);
      return 0;
    case '[':
      set_token(ctx, LBRACKET, lineno, p, 1);
      return 0;
    case ']':
      set_token(ctx, RBRACKET, lineno, p, 1);
      return 0;
    case '\n':
      set_token(ctx, NEWLINE, lineno, p, 1);
      return 0;
    case '\r':
    case ' ':
    case '\t':
      /* ignore white spaces */
      p++;
      continue;
    }

    return scan_string(ctx, p, lineno, dotisspecial);
  }

  set_eof(ctx, lineno);
  return 0;
}

const char *toml_key_in(const toml_table_t *tab, int keyidx) {
  if (keyidx < tab->nkval)
    return tab->kval[keyidx]->key;

  keyidx -= tab->nkval;
  if (keyidx < tab->narr)
    return tab->arr[keyidx]->key;

  keyidx -= tab->narr;
  if (keyidx < tab->ntab)
    return tab->tab[keyidx]->key;

  return 0;
}

int toml_key_exists(const toml_table_t *tab, const char *key) {
  int i;
  for (i = 0; i < tab->nkval; i++) {
    if (0 == strcmp(key, tab->kval[i]->key))
      return 1;
  }
  for (i = 0; i < tab->narr; i++) {
    if (0 == strcmp(key, tab->arr[i]->key))
      return 1;
  }
  for (i = 0; i < tab->ntab; i++) {
    if (0 == strcmp(key, tab->tab[i]->key))
      return 1;
  }
  return 0;
}

toml_raw_t toml_raw_in(const toml_table_t *tab, const char *key) {
  int i;
  for (i = 0; i < tab->nkval; i++) {
    if (0 == strcmp(key, tab->kval[i]->key))
      return tab->kval[i]->val;
  }
  return 0;
}

toml_array_t *toml_array_in(const toml_table_t *tab, const char *key) {
  int i;
  for (i = 0; i < tab->narr; i++) {
    if (0 == strcmp(key, tab->arr[i]->key))
      return tab->arr[i];
  }
  return 0;
}

toml_table_t *toml_table_in(const toml_table_t *tab, const char *key) {
  int i;
  for (i = 0; i < tab->ntab; i++) {
    if (0 == strcmp(key, tab->tab[i]->key))
      return tab->tab[i];
  }
  return 0;
}

toml_raw_t toml_raw_at(const toml_array_t *arr, int idx) {
  return (0 <= idx && idx < arr->nitem) ? arr->item[idx].val : 0;
}

char toml_array_kind(const toml_array_t *arr) { return arr->kind; }

char toml_array_type(const toml_array_t *arr) {
  if (arr->kind != 'v')
    return 0;

  if (arr->nitem == 0)
    return 0;

  return arr->type;
}

int toml_array_nelem(const toml_array_t *arr) { return arr->nitem; }

const char *toml_array_key(const toml_array_t *arr) {
  return arr ? arr->key : (const char *)NULL;
}

int toml_table_nkval(const toml_table_t *tab) { return tab->nkval; }

int toml_table_narr(const toml_table_t *tab) { return tab->narr; }

int toml_table_ntab(const toml_table_t *tab) { return tab->ntab; }

const char *toml_table_key(const toml_table_t *tab) {
  return tab ? tab->key : (const char *)NULL;
}

toml_array_t *toml_array_at(const toml_array_t *arr, int idx) {
  return (0 <= idx && idx < arr->nitem) ? arr->item[idx].arr : 0;
}

toml_table_t *toml_table_at(const toml_array_t *arr, int idx) {
  return (0 <= idx && idx < arr->nitem) ? arr->item[idx].tab : 0;
}

static int parse_millisec(const char *p, const char **endp);

int toml_rtots(toml_raw_t src_, toml_timestamp_t *ret) {
  if (!src_)
    return -1;

  const char *p = src_;
  int must_parse_time = 0;

  memset(ret, 0, sizeof(*ret));

  int *year = &ret->__buffer.year;
  int *month = &ret->__buffer.month;
  int *day = &ret->__buffer.day;
  int *hour = &ret->__buffer.hour;
  int *minute = &ret->__buffer.minute;
  int *second = &ret->__buffer.second;
  int *millisec = &ret->__buffer.millisec;

  /* parse date YYYY-MM-DD */
  if (0 == scan_date(p, year, month, day)) {
    ret->year = year;
    ret->month = month;
    ret->day = day;

    p += 10;
    if (*p) {
      // parse the T or space separator
      if (*p != 'T' && *p != 't' && *p != ' ')
        return -1;
      must_parse_time = 1;
      p++;
    }
  }

  /* parse time HH:MM:SS */
  if (0 == scan_time(p, hour, minute, second)) {
    ret->hour = hour;
    ret->minute = minute;
    ret->second = second;

    /* optionally, parse millisec */
    p += 8;
    if (*p == '.') {
      p++; /* skip '.' */
      const char *qq;
      *millisec = parse_millisec(p, &qq);
      ret->millisec = millisec;
      p = qq;
    }

    if (*p) {
      /* parse and copy Z */
      char *z = ret->__buffer.z;
      ret->z = z;
      if (*p == 'Z' || *p == 'z') {
        *z++ = 'Z';
        p++;
        *z = 0;

      } else if (*p == '+' || *p == '-') {
        *z++ = *p++;

        if (!(isdigit(p[0]) && isdigit(p[1])))
          return -1;
        *z++ = *p++;
        *z++ = *p++;

        if (*p == ':') {
          *z++ = *p++;

          if (!(isdigit(p[0]) && isdigit(p[1])))
            return -1;
          *z++ = *p++;
          *z++ = *p++;
        }

        *z = 0;
      }
    }
  }
  if (*p != 0)
    return -1;

  if (must_parse_time && !ret->hour)
    return -1;

  return 0;
}

/* Raw to boolean */
int toml_rtob(toml_raw_t src, int *ret_) {
  if (!src)
    return -1;
  int dummy;
  int *ret = ret_ ? ret_ : &dummy;

  if (0 == strcmp(src, "true")) {
    *ret = 1;
    return 0;
  }
  if (0 == strcmp(src, "false")) {
    *ret = 0;
    return 0;
  }
  return -1;
}

/* Raw to integer */
int toml_rtoi(toml_raw_t src, int64_t *ret_) {
  if (!src)
    return -1;

  char buf[100];
  char *p = buf;
  char *q = p + sizeof(buf);
  const char *s = src;
  int base = 0;
  int64_t dummy;
  int64_t *ret = ret_ ? ret_ : &dummy;

  /* allow +/- */
  if (s[0] == '+' || s[0] == '-')
    *p++ = *s++;

  /* disallow +_100 */
  if (s[0] == '_')
    return -1;

  /* if 0* ... */
  if ('0' == s[0]) {
    switch (s[1]) {
    case 'x':
      base = 16;
      s += 2;
      break;
    case 'o':
      base = 8;
      s += 2;
      break;
    case 'b':
      base = 2;
      s += 2;
      break;
    case '\0':
      return *ret = 0, 0;
    default:
      /* ensure no other digits after it */
      if (s[1])
        return -1;
    }
  }

  /* just strip underscores and pass to strtoll */
  while (*s && p < q) {
    int ch = *s++;
    if (ch == '_') {
      // disallow '__'
      if (s[0] == '_')
        return -1;
      // numbers cannot end with '_'
      if (s[0] == '\0')
        return -1;
      continue; /* skip _ */
    }
    *p++ = ch;
  }

  // if not at end-of-string or we ran out of buffer ...
  if (*s || p == q)
    return -1;

  /* cap with NUL */
  *p = 0;

  /* Run strtoll on buf to get the integer */
  char *endp;
  errno = 0;
  *ret = strtoll(buf, &endp, base);
  return (errno || *endp) ? -1 : 0;
}

int toml_rtod_ex(toml_raw_t src, double *ret_, char *buf, int buflen) {
  if (!src)
    return -1;

  char *p = buf;
  char *q = p + buflen;
  const char *s = src;
  double dummy;
  double *ret = ret_ ? ret_ : &dummy;

  /* allow +/- */
  if (s[0] == '+' || s[0] == '-')
    *p++ = *s++;

  /* disallow +_1.00 */
  if (s[0] == '_')
    return -1;

  /* decimal point, if used, must be surrounded by at least one digit on each
   * side */
  {
    char *dot = strchr(s, '.');
    if (dot) {
      if (dot == s || !isdigit(dot[-1]) || !isdigit(dot[1]))
        return -1;
    }
  }

  /* zero must be followed by . or 'e', or NUL */
  if (s[0] == '0' && s[1] && !strchr("eE.", s[1]))
    return -1;

  /* just strip underscores and pass to strtod */
  while (*s && p < q) {
    int ch = *s++;
    if (ch == '_') {
      // disallow '__'
      if (s[0] == '_')
        return -1;
      // disallow last char '_'
      if (s[0] == 0)
        return -1;
      continue; /* skip _ */
    }
    *p++ = ch;
  }
  if (*s || p == q)
    return -1; /* reached end of string or buffer is full? */

  /* cap with NUL */
  *p = 0;

  /* Run strtod on buf to get the value */
  char *endp;
  errno = 0;
  *ret = strtod(buf, &endp);
  return (errno || *endp) ? -1 : 0;
}

int toml_rtod(toml_raw_t src, double *ret_) {
  char buf[100];
  return toml_rtod_ex(src, ret_, buf, sizeof(buf));
}

int toml_rtos(toml_raw_t src, char **ret) {
  int multiline = 0;
  const char *sp;
  const char *sq;

  *ret = 0;
  if (!src)
    return -1;

  // for strings, first char must be a s-quote or d-quote
  int qchar = src[0];
  int srclen = strlen(src);
  if (!(qchar == '\'' || qchar == '"')) {
    return -1;
  }

  // triple quotes?
  if (qchar == src[1] && qchar == src[2]) {
    multiline = 1;         // triple-quote implies multiline
    sp = src + 3;          // first char after quote
    sq = src + srclen - 3; // first char of ending quote

    if (!(sp <= sq && sq[0] == qchar && sq[1] == qchar && sq[2] == qchar)) {
      // last 3 chars in src must be qchar
      return -1;
    }

    /* skip new line immediate after qchar */
    if (sp[0] == '\n')
      sp++;
    else if (sp[0] == '\r' && sp[1] == '\n')
      sp += 2;

  } else {
    sp = src + 1;          // first char after quote
    sq = src + srclen - 1; // ending quote
    if (!(sp <= sq && *sq == qchar)) {
      /* last char in src must be qchar */
      return -1;
    }
  }

  // at this point:
  //     sp points to first valid char after quote.
  //     sq points to one char beyond last valid char.
  //     string len is (sq - sp).
  if (qchar == '\'') {
    *ret = norm_lit_str(sp, sq - sp, multiline, 0, 0);
  } else {
    *ret = norm_basic_str(sp, sq - sp, multiline, 0, 0);
  }

  return *ret ? 0 : -1;
}

toml_datum_t toml_string_at(const toml_array_t *arr, int idx) {
  toml_datum_t ret;
  memset(&ret, 0, sizeof(ret));
  ret.ok = (0 == toml_rtos(toml_raw_at(arr, idx), &ret.u.s));
  return ret;
}

toml_datum_t toml_bool_at(const toml_array_t *arr, int idx) {
  toml_datum_t ret;
  memset(&ret, 0, sizeof(ret));
  ret.ok = (0 == toml_rtob(toml_raw_at(arr, idx), &ret.u.b));
  return ret;
}

toml_datum_t toml_int_at(const toml_array_t *arr, int idx) {
  toml_datum_t ret;
  memset(&ret, 0, sizeof(ret));
  ret.ok = (0 == toml_rtoi(toml_raw_at(arr, idx), &ret.u.i));
  return ret;
}

toml_datum_t toml_double_at(const toml_array_t *arr, int idx) {
  toml_datum_t ret;
  memset(&ret, 0, sizeof(ret));
  ret.ok = (0 == toml_rtod(toml_raw_at(arr, idx), &ret.u.d));
  return ret;
}

toml_datum_t toml_timestamp_at(const toml_array_t *arr, int idx) {
  toml_timestamp_t ts;
  toml_datum_t ret;
  memset(&ret, 0, sizeof(ret));
  ret.ok = (0 == toml_rtots(toml_raw_at(arr, idx), &ts));
  if (ret.ok) {
    ret.ok = !!(ret.u.ts = MALLOC(sizeof(*ret.u.ts)));
    if (ret.ok) {
      *ret.u.ts = ts;
      if (ret.u.ts->year)
        ret.u.ts->year = &ret.u.ts->__buffer.year;
      if (ret.u.ts->month)
        ret.u.ts->month = &ret.u.ts->__buffer.month;
      if (ret.u.ts->day)
        ret.u.ts->day = &ret.u.ts->__buffer.day;
      if (ret.u.ts->hour)
        ret.u.ts->hour = &ret.u.ts->__buffer.hour;
      if (ret.u.ts->minute)
        ret.u.ts->minute = &ret.u.ts->__buffer.minute;
      if (ret.u.ts->second)
        ret.u.ts->second = &ret.u.ts->__buffer.second;
      if (ret.u.ts->millisec)
        ret.u.ts->millisec = &ret.u.ts->__buffer.millisec;
      if (ret.u.ts->z)
        ret.u.ts->z = ret.u.ts->__buffer.z;
    }
  }
  return ret;
}

toml_datum_t toml_string_in(const toml_table_t *arr, const char *key) {
  toml_datum_t ret;
  memset(&ret, 0, sizeof(ret));
  toml_raw_t raw = toml_raw_in(arr, key);
  if (raw) {
    ret.ok = (0 == toml_rtos(raw, &ret.u.s));
  }
  return ret;
}

toml_datum_t toml_bool_in(const toml_table_t *arr, const char *key) {
  toml_datum_t ret;
  memset(&ret, 0, sizeof(ret));
  ret.ok = (0 == toml_rtob(toml_raw_in(arr, key), &ret.u.b));
  return ret;
}

toml_datum_t toml_int_in(const toml_table_t *arr, const char *key) {
  toml_datum_t ret;
  memset(&ret, 0, sizeof(ret));
  ret.ok = (0 == toml_rtoi(toml_raw_in(arr, key), &ret.u.i));
  return ret;
}

toml_datum_t toml_double_in(const toml_table_t *arr, const char *key) {
  toml_datum_t ret;
  memset(&ret, 0, sizeof(ret));
  ret.ok = (0 == toml_rtod(toml_raw_in(arr, key), &ret.u.d));
  return ret;
}

toml_datum_t toml_timestamp_in(const toml_table_t *arr, const char *key) {
  toml_timestamp_t ts;
  toml_datum_t ret;
  memset(&ret, 0, sizeof(ret));
  ret.ok = (0 == toml_rtots(toml_raw_in(arr, key), &ts));
  if (ret.ok) {
    ret.ok = !!(ret.u.ts = MALLOC(sizeof(*ret.u.ts)));
    if (ret.ok) {
      *ret.u.ts = ts;
      if (ret.u.ts->year)
        ret.u.ts->year = &ret.u.ts->__buffer.year;
      if (ret.u.ts->month)
        ret.u.ts->month = &ret.u.ts->__buffer.month;
      if (ret.u.ts->day)
        ret.u.ts->day = &ret.u.ts->__buffer.day;
      if (ret.u.ts->hour)
        ret.u.ts->hour = &ret.u.ts->__buffer.hour;
      if (ret.u.ts->minute)
        ret.u.ts->minute = &ret.u.ts->__buffer.minute;
      if (ret.u.ts->second)
        ret.u.ts->second = &ret.u.ts->__buffer.second;
      if (ret.u.ts->millisec)
        ret.u.ts->millisec = &ret.u.ts->__buffer.millisec;
      if (ret.u.ts->z)
        ret.u.ts->z = ret.u.ts->__buffer.z;
    }
  }
  return ret;
}

static int parse_millisec(const char *p, const char **endp) {
  int ret = 0;
  int unit = 100; /* unit in millisec */
  for (; '0' <= *p && *p <= '9'; p++, unit /= 10) {
    ret += (*p - '0') * unit;
  }
  *endp = p;
  return ret;
}