ppdfviewer, basic, bits and string view

c/stringview/stringv.c

@@ -0,0 +1,60 @@
+#include "stringv.h"
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+
+/*
+ * @brief Create a string view from a const char* and  set their lenght
+ *
+ * @details This string view provides a view of a string. It does not allocate
+ * memory, therefore, it lives only while the source is alive. The
+ * lenght is a bytes number of the string. It does not represents the number of
+ * characters.
+ *
+ * @param str pointer from the original string. It can be NULL.
+ *
+ * @return a StringView with the view of original string with corresponding
+ * lenght.
+ */
+
+#define STRING_VIEW_NULL (StringView){.text = NULL, .lenght = 0}
+
+StringView sv_from_cstr(const char *str) {
+    if (str == NULL) {
+        return STRING_VIEW_NULL;
+    }
+    return (StringView){.text = (char *)str, .lenght = strlen(str)};
+}
+
+StringView sv_left(const StringView *sv, size_t l) {
+    if (sv == NULL) {
+        perror("sv_left: pointer is NULL\n");
+        return STRING_VIEW_NULL;
+    }
+    if (sv->text == NULL) {
+        perror("sv_left: text pointer is NULL\n");
+        return STRING_VIEW_NULL;
+    }
+    if (sv->lenght < l) {
+        perror("sv_left: text length is less than specified length\n");
+        return STRING_VIEW_NULL;
+    }
+    return (StringView){.text = sv->text, .lenght = l};
+}
+
+StringView sv_right(const StringView *sv, size_t r) {
+    if (sv == NULL) {
+        perror("sv_right: pointer is NULL\n");
+        return STRING_VIEW_NULL;
+    }
+    if (sv->text == NULL) {
+        perror("sv_right: text pointer is NULL\n");
+        return STRING_VIEW_NULL;
+    }
+    if (sv->lenght < r) {
+        perror("sv_right: text length is less than specified length\n");
+        return STRING_VIEW_NULL;
+    }
+    size_t nlength = sv->lenght - r;
+    return (StringView){.text = sv->text + nlength, .lenght = r};
+}