笨拙地字符串压缩和解压缩

公司进行C语言考试，题目是压缩小写字符串。
input: abbcdd
output:a2bc2d
完成压缩函数后自己想了下如果解压缩该怎么实现。
input: a2b10cd
output: abbccccccccccd

函数需要的结构体和宏

struct rawString
{
    char *str;
    unsigned long len;
};

struct zipString
{
    char *str;
    unsigned long len;
};

#define STR_LEN_MAX 1024
#define NUM_LEN 64

压缩函数

struct zipString* stringZip(const struct rawString *pInputStr)
{
    char * pStrTemp = NULL;
    char * pStrBox = NULL;
    const struct rawString *pInputTemp = pInputStr;
    struct zipString *pOutputTemp ;
    int i = 0, count = 1, num_len = 0;
    char chTemp = '\0';


    if ((NULL == pInputTemp) || (NULL == pInputTemp->str) || (0 == pInputTemp->len)) {
        return NULL;
    }
    if (pInputTemp->len != (unsigned long)strlen(pInputTemp->str)) {
        return NULL;
    }


    pStrTemp = (char *)malloc(pInputTemp->len + 1);
    if (NULL == pStrTemp) {
        return NULL;
    }
    pStrBox = pStrTemp;
    memset(pStrTemp, '\0', pInputTemp->len + 1);

    while ('\0' != *(pInputTemp->str + i)) {

        if ((*(pInputTemp->str + i) < 'a') || (*(pInputTemp->str + i) > 'z')) {
            free(pStrBox);
            printf("String is wrong!\n");
            return NULL;
        }

        chTemp = *(pInputTemp->str + i);

        /*判断当前字符和下一个字符相同*/
        if (chTemp == *(pInputTemp->str + i + 1)) {
            count += 1;
            i++;
            continue;
        } else { /*判断当前字符和下一个字符不同*/

            /*前面不存在与当前相同的字符*/
            if (1 == count) {
                *pStrTemp = chTemp;
                pStrTemp ++;
                i++;
                continue;
            } else { /*前面存在与当前相同的字符*/

                while (count != 0) {
                     count /= 10;
                     num_len += 1;
                }

                pStrTemp += (num_len + 1);
                i++;

                count = 1;
                num_len = 0;
                continue;
            }

        }
    }
    *(pStrBox + pInputTemp->len) = '\0';

    pOutputTemp = (struct zipString *)malloc(sizeof(struct zipString));
    if (NULL == pOutputTemp) {
        return NULL;
    }
    pOutputTemp->str = pStrBox;
    pOutputTemp->len = strlen(pStrBox);

    return pOutputTemp;
}

解压缩函数

struct rawString * stringUnZip(const struct zipString *pInputStr)
{
    int i = 0, chNum = 1, copyTime = 0, strLen = 0, numLen = 0;
    char tempStr[STR_LEN_MAX + 1] = {'\0'};
    char tempNum[NUM_LEN + 1] = {'\0'};
    char *pTempStr = tempStr;
    char *pTempNum = tempNum;
    char *pStr = NULL;
    struct rawString * pRawStr = NULL;

    if((NULL == pInputStr) || (NULL == pInputStr->str)) {
        return NULL;
    }

    if(pInputStr->len != strlen(pInputStr->str)) {
        return NULL;
    }

    while(*(pInputStr->str + i) != '\0') {
        /*判断是否是非法字符*/
        if(((*(pInputStr->str + i) < '0') || (*(pInputStr->str + i) > '9')) &&
                ((*(pInputStr->str + i) < 'a') || (*(pInputStr->str + i) > 'z'))) {
            return NULL;
        }

        if ((*(pInputStr->str + i) >= 'a') && (*(pInputStr->str + i) <= 'z')) {
            if(strLen > (STR_LEN_MAX)) {
                printf("Strlen is too long!\n");
                return NULL;
            }

            /*前一位不是数字*/
            if(0 == numLen) {
                sprintf(pTempStr, "%c", *(pInputStr->str + i));
                pTempStr++;
                strLen++; /*计算总长度*/
            } else if (numLen > 0) { /*遇到数字后第一个字符*/
                /*在保留*/
                tempNum[numLen] = '\0';
                copyTime = atoi(tempNum);
                while (copyTime > 0) {
                    sprintf(pTempStr, "%c", *(pInputStr->str + i));
                    pTempStr++;
                    strLen++; /*计算总长度*/
                    copyTime--;
                }
                numLen = 0;
            } else {
                printf("charactor is wrong!\n");
                return NULL;
            }
            i++;
            continue;
        } else {
            numLen += 1;

            /*数字最长64位*/
            if(numLen > (NUM_LEN)) {
                return NULL;
            }
            /*第一个数字或一组新数字的第一个数*/
            if(1 == numLen) {
                /*第一个数字是0*/
                if('0' == *(pInputStr->str + i)) {
                    numLen = 0;
                    i++;
                    continue;
                }
                memset(tempNum, '\0', NUM_LEN);
                pTempNum = tempNum;
            }
            sprintf(pTempNum, "%c", *(pInputStr->str + i));
            pTempNum++;
            i++;
            continue;
        }
    }

    tempStr[STR_LEN_MAX] = '\0';

    pStr = (char *)malloc(STR_LEN_MAX + 1);
    if(NULL == pStr) {
        return NULL;
    }
    memset(pStr, '\0', STR_LEN_MAX + 1);
    sprintf(pStr, "%s", tempStr);

    pRawStr = (struct rawString *)malloc(sizeof(struct rawString));
    if(NULL == pRawStr) {
        return NULL;
    }

    pRawStr->str = pStr;
    pRawStr->len = strlen(pRawStr->str);

    return pRawStr;
}