添加视频压缩代码

others/C/video_compression/src/string_utils.c

@@ -0,0 +1,120 @@
+#include "string_utils.h"
+#include <ctype.h>
+#include <string.h>
+#include <stdlib.h>
+
+char* str_copy(char* dest, const char* src, size_t dest_size) {
+    if (dest == NULL || src == NULL || dest_size == 0) {
+        return NULL;
+    }
+
+    size_t i;
+    for (i = 0; i < dest_size - 1 && src[i] != '\0'; i++) {
+        dest[i] = src[i];
+    }
+    dest[i] = '\0';
+
+    return dest;
+}
+
+char* str_concat(char* dest, const char* src, size_t dest_size) {
+    if (dest == NULL || src == NULL || dest_size == 0) {
+        return NULL;
+    }
+
+    size_t dest_len = strlen(dest);
+    if (dest_len >= dest_size) {
+        return dest;
+    }
+
+    size_t i;
+    for (i = 0; i < dest_size - dest_len - 1 && src[i] != '\0'; i++) {
+        dest[dest_len + i] = src[i];
+    }
+    dest[dest_len + i] = '\0';
+
+    return dest;
+}
+
+char* str_trim(char* str) {
+    if (str == NULL) {
+        return NULL;
+    }
+
+    char* end;
+    
+    // 去除前导空白字符
+    while (isspace((unsigned char)*str)) {
+        str++;
+    }
+
+    // 如果全是空白字符
+    if (*str == '\0') {
+        return str;
+    }
+
+    // 去除尾部空白字符
+    end = str + strlen(str) - 1;
+    while (end > str && isspace((unsigned char)*end)) {
+        end--;
+    }
+
+    // 写入终止符
+    *(end + 1) = '\0';
+
+    return str;
+}
+
+int str_starts_with(const char* str, const char* prefix) {
+    if (str == NULL || prefix == NULL) {
+        return 0;
+    }
+
+    size_t len_str = strlen(str);
+    size_t len_prefix = strlen(prefix);
+
+    if (len_prefix > len_str) {
+        return 0;
+    }
+
+    return strncmp(str, prefix, len_prefix) == 0;
+}
+
+int str_ends_with(const char* str, const char* suffix) {
+    if (str == NULL || suffix == NULL) {
+        return 0;
+    }
+
+    size_t len_str = strlen(str);
+    size_t len_suffix = strlen(suffix);
+
+    if (len_suffix > len_str) {
+        return 0;
+    }
+
+    return strncmp(str + len_str - len_suffix, suffix, len_suffix) == 0;
+}
+
+char* str_to_lower(char* str) {
+    if (str == NULL) {
+        return NULL;
+    }
+
+    for (char* p = str; *p != '\0'; p++) {
+        *p = tolower((unsigned char)*p);
+    }
+
+    return str;
+}
+
+char* str_to_upper(char* str) {
+    if (str == NULL) {
+        return NULL;
+    }
+
+    for (char* p = str; *p != '\0'; p++) {
+        *p = toupper((unsigned char)*p);
+    }
+
+    return str;
+}