/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.

 *

 * This software is licensed as described in the file COPYING, which

 * you should have received as part of this distribution. The terms

 * are also available at https://curl.se/docs/copyright.html.

 *

 * You may opt to use, copy, modify, merge, publish, distribute and/or sell

 * copies of the Software, and permit persons to whom the Software is

 * furnished to do so, under the terms of the COPYING file.

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY

 * KIND, either express or implied.

 *

 * SPDX-License-Identifier: curl

 *

 ***************************************************************************/

#include "curlx/strparse.h"

void curlx_str_init(struct Curl_str *out)

{

  out->str = NULL;

  out->len = 0;

}

void curlx_str_assign(struct Curl_str *out, const char *str, size_t len)

{

  out->str = str;

  out->len = len;

}

/* remove bytes from the end of the string, never remove more bytes than what

   the string holds! */

void curlx_str_trim(struct Curl_str *out, size_t len)

{

  DEBUGASSERT(out);

  DEBUGASSERT(out->len >= len);

  out->len -= len;

}

/* Get a word until the first DELIM or end of string. At least one byte long.

   return non-zero on error. If 'max' is zero, it will always return error. */

int curlx_str_until(const char **linep, struct Curl_str *out,

                    const size_t max, char delim)

{

  const char *s;

  size_t len = 0;

  DEBUGASSERT(linep);

  DEBUGASSERT(*linep);

  DEBUGASSERT(out);

  DEBUGASSERT(delim);

  s = *linep;

  curlx_str_init(out);

  while(*s && (*s != delim)) {

    s++;

    if(++len > max) {

      return STRE_BIG;

    }

  }

  if(!len)

    return STRE_SHORT;

  out->str = *linep;

  out->len = len;

  *linep = s; /* point to the first byte after the word */

  return STRE_OK;

}

/* Get a word until the first space or end of string. At least one byte long.

   return non-zero on error */

int curlx_str_word(const char **linep, struct Curl_str *out, const size_t max)

{

  return curlx_str_until(linep, out, max, ' ');

}

/* Get a word until a newline byte or end of string. At least one byte long.

   return non-zero on error */

int curlx_str_untilnl(const char **linep, struct Curl_str *out,

                      const size_t max)

{

  const char *s = *linep;

  size_t len = 0;

  DEBUGASSERT(linep && *linep && out && max);

  curlx_str_init(out);

  while(*s && !ISNEWLINE(*s)) {

    s++;

    if(++len > max)

      return STRE_BIG;

  }

  if(!len)

    return STRE_SHORT;

  out->str = *linep;

  out->len = len;

  *linep = s; /* point to the first byte after the word */

  return STRE_OK;

}

/* Get a "quoted" word. Escaped quotes are supported.

   return non-zero on error */

int curlx_str_quotedword(const char **linep, struct Curl_str *out,

                         const size_t max)

{

  const char *s = *linep;

  size_t len = 0;

  DEBUGASSERT(linep && *linep && out && max);

  curlx_str_init(out);

  if(*s != '\"')

    return STRE_BEGQUOTE;

  s++;

  while(*s && (*s != '\"')) {

    if(*s == '\\' && s[1]) {

      s++;

      if(++len > max)

        return STRE_BIG;

    }

    s++;

    if(++len > max)

      return STRE_BIG;

  }

  if(*s != '\"')

    return STRE_ENDQUOTE;

  out->str = (*linep) + 1;

  out->len = len;

  *linep = s + 1;

  return STRE_OK;

}

/* Advance over a single character.

   return non-zero on error */

int curlx_str_single(const char **linep, char byte)

{

  DEBUGASSERT(linep && *linep);

  if(**linep != byte)

    return STRE_BYTE;

  (*linep)++; /* move over it */

  return STRE_OK;

}

/* Advance over a single space.

   return non-zero on error */

int curlx_str_singlespace(const char **linep)

{

  return curlx_str_single(linep, ' ');

}

/* given an ASCII character and max ascii, return TRUE if valid */

#define valid_digit(x, m) \

  (((x) >= '0') && ((x) <= (m)) && curlx_hexasciitable[(x) - '0'])

/* We use 16 for the zero index (and the necessary bitwise AND in the loop)

   to be able to have a non-zero value there to make valid_digit() able to

   use the info */

const unsigned char curlx_hexasciitable[] = {

  16, 1, 2, 3, 4, 5, 6, 7, 8, 9, /* 0x30: 0 - 9 */

  0, 0, 0, 0, 0, 0, 0,

  10, 11, 12, 13, 14, 15,        /* 0x41: A - F */

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  10, 11, 12, 13, 14, 15         /* 0x61: a - f */

};

/* no support for 0x prefix nor leading spaces */

static int str_num_base(const char **linep, curl_off_t *nump, curl_off_t max,

                        int base) /* 8, 10 or 16, nothing else */

{

  curl_off_t num = 0;

  const char *p;

  int m = (base == 10) ? '9' :   /* the largest digit possible */

    (base == 16) ? 'f' : '7';

  DEBUGASSERT(linep && *linep && nump);

  DEBUGASSERT((base == 8) || (base == 10) || (base == 16));

  DEBUGASSERT(max >= 0); /* mostly to catch SIZE_MAX, which is too large */

  *nump = 0;

  p = *linep;

  if(!valid_digit(*p, m))

    return STRE_NO_NUM;

  if(max < base) {

    /* special-case low max scenario because check needs to be different */

    do {

      int n = curlx_hexval(*p++);

      num = (num * base) + n;

      if(num > max)

        return STRE_OVERFLOW;

    } while(valid_digit(*p, m));

  }

  else {

    curl_off_t cutoff = (max - (base - 1)) / base;

    while(valid_digit(*p, m)) {

      if(num <= cutoff)

        num = (num * base) + curlx_hexval(*p++);

      else {

        int n = curlx_hexval(*p++);

        if(num > ((max - n) / base))

          return STRE_OVERFLOW;

        num = (num * base) + n;

      }

    }

  }

  *nump = num;

  *linep = p;

  return STRE_OK;

}

/* Get an unsigned decimal number with no leading space or minus. Leading

   zeroes are accepted. return non-zero on error */

int curlx_str_number(const char **linep, curl_off_t *nump, curl_off_t max)

{

  return str_num_base(linep, nump, max, 10);

}

/* Get an unsigned hexadecimal number with no leading space or minus and no

   "0x" support. Leading zeroes are accepted. return non-zero on error */

int curlx_str_hex(const char **linep, curl_off_t *nump, curl_off_t max)

{

  return str_num_base(linep, nump, max, 16);

}

/* Get an unsigned octal number with no leading space or minus and no "0"

   prefix support. Leading zeroes are accepted. return non-zero on error */

int curlx_str_octal(const char **linep, curl_off_t *nump, curl_off_t max)

{

  return str_num_base(linep, nump, max, 8);

}

/*

 * Parse a positive number up to 63-bit number written in ASCII. Skip leading

 * blanks. No support for prefixes.

 */

int curlx_str_numblanks(const char **str, curl_off_t *num)

{

  curlx_str_passblanks(str);

  return curlx_str_number(str, num, CURL_OFF_T_MAX);

}

/* CR or LF

   return non-zero on error */

int curlx_str_newline(const char **linep)

{

  DEBUGASSERT(linep && *linep);

  if(ISNEWLINE(**linep)) {

    (*linep)++;

    return STRE_OK; /* yessir */

  }

  return STRE_NEWLINE;

}

#ifndef WITHOUT_LIBCURL

/* case insensitive compare that the parsed string matches the given string.

   Returns non-zero on match. */

int curlx_str_casecompare(struct Curl_str *str, const char *check)

{

  size_t clen = check ? strlen(check) : 0;

  return ((str->len == clen) && curl_strnequal(str->str, check, clen));

}

#endif

/* case sensitive string compare. Returns non-zero on match. */

int curlx_str_cmp(struct Curl_str *str, const char *check)

{

  if(check) {

    size_t clen = strlen(check);

    return ((str->len == clen) && !strncmp(str->str, check, clen));

  }

  return !!str->len;

}

/* Trim off 'num' number of bytes from the beginning (left side) of the

   string. If 'num' is larger than the string, return error. */

int curlx_str_nudge(struct Curl_str *str, size_t num)

{

  if(num <= str->len) {

    str->str += num;

    str->len -= num;

    return STRE_OK;

  }

  return STRE_OVERFLOW;

}

/* Get the following character sequence that consists only of bytes not

   present in the 'reject' string. Like strcspn(). */

int curlx_str_cspn(const char **linep, struct Curl_str *out,

                   const char *reject)

{

  const char *s = *linep;

  size_t len;

  DEBUGASSERT(linep && *linep);

  len = strcspn(s, reject);

  if(len) {

    out->str = s;

    out->len = len;

    *linep = &s[len];

    return STRE_OK;

  }

  curlx_str_init(out);

  return STRE_SHORT;

}

/* remove ISBLANK()s from both ends of the string */

void curlx_str_trimblanks(struct Curl_str *out)

{

  while(out->len && ISBLANK(*out->str))

    curlx_str_nudge(out, 1);

  /* trim trailing spaces and tabs */

  while(out->len && ISBLANK(out->str[out->len - 1]))

    out->len--;

}

/* increase the pointer until it has moved over all blanks */

void curlx_str_passblanks(const char **linep)

{

  while(ISBLANK(**linep))

    (*linep)++; /* move over it */

}