/*
  Copyright 2011-2020 David Robillard <d@drobilla.net>

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#include "string_utils.h"

#include "serd/serd.h"

#include <math.h>
#include <stdint.h>
#include <stdlib.h>

void
serd_free(void* const ptr)
{
  free(ptr);
}

const uint8_t*
serd_strerror(const SerdStatus status)
{
  switch (status) {
  case SERD_SUCCESS:
    return (const uint8_t*)"Success";
  case SERD_FAILURE:
    return (const uint8_t*)"Non-fatal failure";
  case SERD_ERR_UNKNOWN:
    return (const uint8_t*)"Unknown error";
  case SERD_ERR_BAD_SYNTAX:
    return (const uint8_t*)"Invalid syntax";
  case SERD_ERR_BAD_ARG:
    return (const uint8_t*)"Invalid argument";
  case SERD_ERR_NOT_FOUND:
    return (const uint8_t*)"Not found";
  case SERD_ERR_ID_CLASH:
    return (const uint8_t*)"Blank node ID clash";
  case SERD_ERR_BAD_CURIE:
    return (const uint8_t*)"Invalid CURIE";
  case SERD_ERR_INTERNAL:
    return (const uint8_t*)"Internal error";
  }
  return (const uint8_t*)"Unknown error"; // never reached
}

static void
serd_update_flags(const uint8_t c, SerdNodeFlags* const flags)
{
  switch (c) {
  case '\r':
  case '\n':
    *flags |= SERD_HAS_NEWLINE;
    break;
  case '"':
    *flags |= SERD_HAS_QUOTE;
    break;
  default:
    break;
  }
}

size_t
serd_substrlen(const uint8_t* const str,
               const size_t         len,
               size_t* const        n_bytes,
               SerdNodeFlags* const flags)
{
  size_t        n_chars = 0;
  size_t        i       = 0;
  SerdNodeFlags f       = 0;
  for (; i < len && str[i]; ++i) {
    if ((str[i] & 0xC0) != 0x80) { // Start of new character
      ++n_chars;
      serd_update_flags(str[i], &f);
    }
  }
  if (n_bytes) {
    *n_bytes = i;
  }
  if (flags) {
    *flags = f;
  }
  return n_chars;
}

size_t
serd_strlen(const uint8_t* const str,
            size_t* const        n_bytes,
            SerdNodeFlags* const flags)
{
  size_t        n_chars = 0;
  size_t        i       = 0;
  SerdNodeFlags f       = 0;
  for (; str[i]; ++i) {
    if ((str[i] & 0xC0) != 0x80) { // Start of new character
      ++n_chars;
      serd_update_flags(str[i], &f);
    }
  }
  if (n_bytes) {
    *n_bytes = i;
  }
  if (flags) {
    *flags = f;
  }
  return n_chars;
}

static double
read_sign(const char** const sptr)
{
  double sign = 1.0;

  switch (**sptr) {
  case '-':
    sign = -1.0;
    ++(*sptr);
    break;
  case '+':
    ++(*sptr);
    break;
  default:
    break;
  }

  return sign;
}

double
serd_strtod(const char* const str, char** const endptr)
{
  double result = 0.0;

  // Point s at the first non-whitespace character
  const char* s = str;
  while (is_space(*s)) {
    ++s;
  }

  // Read leading sign if necessary
  const double sign = read_sign(&s);

  // Parse integer part
  for (; is_digit(*s); ++s) {
    result = (result * 10.0) + (*s - '0');
  }

  // Parse fractional part
  if (*s == '.') {
    double denom = 10.0;
    for (++s; is_digit(*s); ++s) {
      result += (*s - '0') / denom;
      denom *= 10.0;
    }
  }

  // Parse exponent
  if (*s == 'e' || *s == 'E') {
    ++s;
    double expt      = 0.0;
    double expt_sign = read_sign(&s);
    for (; is_digit(*s); ++s) {
      expt = (expt * 10.0) + (*s - '0');
    }
    result *= pow(10, expt * expt_sign);
  }

  if (endptr) {
    *endptr = (char*)s;
  }

  return result * sign;
}