text: #ifndef _INFRA_STRING_H_
  #define _INFRA_STRING_H_
  
  #include "linkkit/infra/infra_types.h"
  
  int8_t infra_hex2char(uint8_t hex);
  void infra_hex2str(uint8_t *input, uint16_t input_len, char *output);
  void infra_int2str(uint32_t input, char output[10]);
  char *infra_strtok(char *str, const char *delim);
  int infra_randstr(char *random, int length);
  void LITE_hexstr_convert(char *input, int input_len, unsigned char *output, int output_len);
  int infra_str2int(const char *input, int *val);
  void LITE_hexbuf_convert(unsigned char *digest, char *out, int in_len, int uppercase);
  int32_t infra_json_value(const char *input, uint32_t input_len, const char *key, uint32_t key_len, char **value, uint32_t *value_len);
  #endif
  
  