feat(implode): add implode implementation ✨

Author: 0xwal

demo/CMakeLists.txt

@@ -8,7 +8,9 @@ list(APPEND _ALL_DEMO
      words_count
      parse_int
      index_of
-     explode)
+     explode
+     implode
+ )
 
 foreach (d ${_ALL_DEMO})
 

demo/implode.c

@@ -0,0 +1,15 @@
+#include <explode.h>
+#include <implode.h>
+#include <stdio.h>
+
+int main() {
+  explode_s list = explode_make("hello world hello C", ' ');
+
+  const char *value = implode_make((const char **)list.values, "<=>");
+
+  printf("output: %s\n", value);
+
+  implode_clean((char *)value);
+
+  explode_clean(&list);
+}

src/CMakeLists.txt

@@ -45,6 +45,9 @@ add_library(${PROJECT_NAME}
             include/explode.h
             explode.c
 
+            include/implode.h
+            implode.c
+
             include/concat.h
             concat.c)
 

src/implode.c

@@ -0,0 +1,62 @@
+#include "include/implode.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct {
+  size_t size;
+  char *data;
+  const char **list;
+} state;
+
+size_t _len(const char *input) {
+  size_t i = 0;
+  while (input[i] != '\0') {
+    i++;
+  }
+  return i;
+}
+
+void _copy(char *dist, const char *source, size_t len) {
+  for (int i = 0; i < len; i++) {
+    dist[i] = source[i];
+  }
+}
+
+char *implode_make(const char **list, const char *separator) {
+  if (list == NULL) {
+    return NULL;
+  }
+
+  state s = {
+      .list = list,
+      .size = 0,
+      .data = NULL,
+  };
+
+  const char **pointer = list;
+
+  const char hasSep = separator != NULL;
+
+  size_t sepLen = hasSep ? _len(separator) : 0;
+
+  char *out = NULL;
+  size_t i = 0;
+
+  while (s.list[i] != NULL) {
+    size_t itemLength = _len(s.list[i]);
+    size_t newSize = itemLength + sepLen;
+    out = realloc(out, s.size + newSize);
+    _copy(out + s.size, s.list[i], itemLength);
+    if (hasSep)
+      _copy(out + s.size + itemLength, separator, sepLen);
+    s.size += newSize;
+    i++;
+  }
+
+  if (hasSep)
+    out[s.size - sepLen] = 0;
+
+  return out;
+}
+
+void implode_clean(const char *value) { free(value); }

src/include/implode.h

@@ -0,0 +1,13 @@
+#ifndef INDEX_OF_H
+#define INDEX_OF_H
+
+#include "common.h"
+
+BEGIN_DECL
+
+char *implode_make(const char **list, const char *separator);
+void implode_clean(const char *value);
+
+END_DECL
+
+#endif // INDEX_OF_H

tests/CMakeLists.txt

@@ -26,6 +26,7 @@ target_sources(${PROJECT_NAME} PRIVATE
                start_with.test.cpp
                end_with.test.cpp
                explode.test.cpp
+               implode.test.cpp
                concat.test.cpp
                )
 

tests/implode.test.cpp

@@ -0,0 +1,43 @@
+#include <catch2/catch.hpp>
+#include <implode.h>
+
+TEST_CASE("implode_make") {
+  SECTION("can implode_make an array to a string #1") {
+    const char *input[] = {"abc", "def", NULL};
+    const char *r = implode_make(input, ",");
+    REQUIRE(r != NULL);
+    REQUIRE_THAT(r, Catch::Matchers::Equals("abc,def"));
+    implode_clean(r);
+  }
+
+  SECTION("can implode_make an array to a string with different length") {
+    const char *input[] = {"1234", "12", "1", "12345", NULL};
+    const char *r = implode_make(input, ",");
+    REQUIRE(r != NULL);
+    REQUIRE_THAT(r, Catch::Matchers::Equals("1234,12,1,12345"));
+    implode_clean(r);
+  }
+
+  SECTION("can implode_make an array to a string with separator that has "
+          "multiple chars") {
+    const char *input[] = {"1234", "12", "1", "12345", NULL};
+    const char *r = implode_make(input, "|===| ");
+    REQUIRE(r != NULL);
+    REQUIRE_THAT(r, Catch::Matchers::Equals("1234|===| 12|===| 1|===| 12345"));
+    implode_clean(r);
+  }
+
+  SECTION("can implode_make to a string with no seperator") {
+    const char *input[] = {"1234", "12", "1", "12345", NULL};
+    const char *r = implode_make(input, NULL);
+    REQUIRE(r != NULL);
+    REQUIRE_THAT(r, Catch::Matchers::Equals("123412112345"));
+    implode_clean(r);
+  }
+
+  SECTION("returns NULL when input is NULLL") {
+    const char *r = implode_make(NULL, ",");
+    REQUIRE(r == NULL);
+    implode_clean(r);
+  }
+}