kc3-lang/libxkbcommon/src/utils-numbers.h

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• Hash : d2f7b9cd
  Author :
  Date : 2025-04-04T17:29:35
  

  rules: Do not use strto* parsers
  

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• src/utils-numbers.h

• /*
   * Copyright © 2025 Pierre Le Marre <dev@wismill.eu>
   * SPDX-License-Identifier: MIT
   */
  #pragma once
  
  #include "config.h"
  
  #include <stdbool.h>
  #include <stdint.h>
  
  #include "utils.h"
  
  /*
   * Define various parsers to avoid the use of strto* -- it’s slower and accepts
   * a bunch of stuff we don’t want to allow, like signs, spaces, even locale stuff.
   *
   * But the real feature is that it does not require a NULL-terminated string, so
   * it works safely *also* on any buffer, assuming the correct corresponding size
   * is provided. For NULL-terminated strings, just pass `SIZE_MAX` as the length:
   * the parsers will *always* stop on a NULL character.
   */
  
  #define MAKE_PARSE_DEC_TO(type, max)                         \
  static inline int                                            \
  parse_dec_to_##type(const char *s, size_t len, type (*out))  \
  {                                                            \
      type result = 0;                                         \
      size_t i;                                                \
      for (i = 0;                                              \
           i < len && (unsigned char)(s[i] - '0') < 10U &&     \
           result <= (max) / 10 &&                             \
           result * 10 <= (max) - (unsigned char) (s[i] - '0');\
           i++) {                                              \
          result = result * 10 + (s[i] - '0');                 \
      }                                                        \
      *out = result;                                           \
      /* Check if there is more to parse */                    \
      /* We can safely convert the length to int on success */ \
      return (i >= len || (unsigned char)(s[i] - '0') >= 10U)  \
             ? (int) i                                         \
             : -1;                                             \
  }
  
  /**
   * Parse a `uint32_t` in decimal format.
   *
   * @returns -1 on error (overflow) or the count of characters parsed.
   */
  MAKE_PARSE_DEC_TO(uint32_t, UINT32_MAX)
  
  /**
   * Parse a `uint64_t` in decimal format.
   *
   * @returns -1 on error (overflow) or the count of characters parsed.
   */
  MAKE_PARSE_DEC_TO(uint64_t, UINT64_MAX)
  
  #undef MAKE_PARSE_DEC_TO
  
  static const unsigned char digits__[] = {
      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0,  1,  2,  3,  4,  5,  6,  7,  8,
      9,  -1, -1, -1, -1, -1, -1, -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
      21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, -1, -1, -1, -1,
      -1, -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
      27, 28, 29, 30, 31, 32, 33, 34, 35, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
      -1, -1, -1, -1, -1, -1, -1, -1, -1
  };
  
  #define MAKE_PARSE_HEX_TO(type, max)                           \
  static inline int                                              \
  parse_hex_to_##type(const char *s, size_t len, type (*out))    \
  {                                                              \
      type result = 0;                                           \
      size_t i = 0;                                              \
      for (; i < len && digits__[(unsigned char) s[i]] < 16u &&  \
           result <= (max) >> 4;                                 \
           i++) {                                                \
          result = result * 16 + digits__[(unsigned char) s[i]]; \
      }                                                          \
      *out = result;                                             \
      /* Check if there is more to parse */                      \
      /* We can safely convert the length to int on success */   \
      return (i >= len || !is_xdigit(s[i])) ? (int) i : -1;      \
  }
  
  /**
   * Parse a `uint32_t` in hexdecimal format.
   *
   * @returns -1 on error (overflow) or the count of characters parsed.
   */
  MAKE_PARSE_HEX_TO(uint32_t, UINT32_MAX)
  
  /**
   * Parse a `uint64_t` in hexdecimal format.
   *
   * @returns -1 on error (overflow) or the count of characters parsed.
   */
  MAKE_PARSE_HEX_TO(uint64_t, UINT64_MAX)
  
  #undef MAKE_PARSE_HEX_TO
  

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