freywaros/src/lib/string.c

#include "src/lib/string.h"
#include <stdarg.h>

uint8_t bytes_equal(const char *l, const char *r, uint64_t count) {
  while (count--) {
    if (*l++ != *r++) {
      return 0;
    }
  }
  return 1;
}

uint8_t string_empty(const char *s) {
  return *s == '\0';
}

uint64_t string_length(const char *s) {
  const char *e = s;
  while (*e) {
    e++;
  }
  return (uint64_t)(e - s);
}

uint8_t string_equal(const char *l, const char *r) {
  while (*l && *r) {
    if (*l != *r) {
      return 0;
    }
    l++;
    r++;
  }
  return *l == *r;
}

uint64_t string_split(char *string, char separator, uint64_t max, char **result) {
  uint64_t count = 1;
  *result = string;

  while (*string && count < max) {
    if (*string == separator) {
      *string = '\0';
      result++;
      *result = string + 1;
      count++;
    }
    string++;
  }
  return count;
}

uint64_t string_byte_to_hex(uint8_t value, uint64_t max, char *result) {
  if (max == 0) {
    return 0;
  }

  if (max == 1) {
    result[0] = '\0';
    return 0;
  }

  if (max == 2) {
    result[0] = '0';
    result[1] = '\0';
    return 1;
  }

  char tmp[3] = "00";

  uint8_t i = 0;
  while (value) {
    uint8_t nibble = value & 0xF;
    tmp[i++] = nibble < 10 ? '0' + nibble : 'a' + nibble - 10;
    value >>= 4;
  }

  result[0] = '0';
  result[1] = 'x';

  i = 2;
  while (i < 4 && i < max - 1) {
    result[i] = tmp[3 - i];
    i++;
  }
  result[i] = '\0';
  return i;
}

uint64_t string_uint_to_decimal(uint64_t value, uint64_t max, char *result) {
  if (max == 0) {
    return 0;
  }

  char tmp[20];
  uint8_t len = 0;

  if (value == 0) {
    tmp[len++] = '0';
  } else {
    while (value && len < 20) {
      tmp[len++] = '0' + (value % 10);
      value /= 10;
    }
  }

  uint8_t i = 0;
  while (i < len && i < max - 1) {
    result[i] = tmp[len - 1 - i];
    i++;
  }
  result[i] = '\0';
  return i;
}

uint64_t string_int_to_decimal(int64_t value, uint64_t max, char *result) {
  if (max == 0) {
    return 0;
  }

  if (value >= 0) {
    return string_uint_to_decimal((uint64_t)value, max, result);
  }

  result[0] = '-';
  return 1 + string_uint_to_decimal((uint64_t)(-value), max - 1, result + 1);
}

uint64_t string_uint_to_hex(uint64_t value, uint64_t max, char *result) {
  if (max == 0) {
    return 0;
  }

  if (max == 1) {
    result[0] = '\0';
    return 0;
  }

  if (max == 2) {
    result[0] = '0';
    result[1] = '\0';
    return 1;
  }

  char tmp[17] = "0000000000000000";

  uint8_t i = 0;
  while (value) {
    uint8_t nibble = value & 0xF;
    tmp[i++] = nibble < 10 ? '0' + nibble : 'A' + nibble - 10;
    value >>= 4;
  }

  result[0] = '0';
  result[1] = 'x';

  i = 2;
  while (i < 18 && i < max - 1) {
    result[i] = tmp[17 - i];
    i++;
  }
  result[i] = '\0';
  return i;
}

uint64_t string_format(const char *format, uint64_t max, char *output, ...) {
  va_list args;
  va_start(args, output);

  uint64_t limit = max - 1;

  uint64_t fi = 0, ri = 0;
  while (format[fi] && ri < limit) {
    if (format[fi] != '%') {
      output[ri++] = format[fi++];
    } else {
      switch (format[fi + 1]) {
      case 'c':
        output[ri++] = (char)va_arg(args, int);
        fi += 2;
        break;
      case 'd':
        string_int_to_decimal(va_arg(args, int64_t), limit - ri, output + ri);
        while (output[ri]) {
          ri++;
        }
        fi += 2;
        break;
      case 'u':
        string_uint_to_decimal(va_arg(args, uint64_t), limit - ri, output + ri);
        while (output[ri]) {
          ri++;
        }
        fi += 2;
        break;
      case 'x':
        string_uint_to_hex(va_arg(args, uint64_t), limit - ri, output + ri);
        while (output[ri]) {
          ri++;
        }
        fi += 2;
        break;
      case 's': {
        char *s = va_arg(args, char *);
        while (*s && ri < limit) {
          output[ri++] = *s;
          s++;
        }
        fi += 2;
        break;
      }
      case '%': {
        output[ri++] = '%';
        fi += 2;
        break;
      }
      default:
        output[ri++] = format[fi++];
        output[ri++] = format[fi++];
        break;
      }
    }
  }
  output[ri] = '\0';
  va_end(args);

  return ri;
}