Add //IGNORE support for iconv compatibility.

Author: ChenPi11

include/cppp/reiconv.h.in

@@ -177,6 +177,14 @@ extern _CPPP_API int reiconv_convert_static_size(reiconv_t cd, const char* input
  */
 extern _CPPP_API int reiconv_convert(reiconv_t cd, const char *input_data, size_t input_length, char **output_data_ptr, size_t *output_length_ptr);
 
+/**
+ * @brief Open a conversion descriptor. For iconv compatibility.
+ * @param tocode The output buffer encoding. Supports "//IGNORE".
+ * @param fromcode The input buffer encoding.
+ * @return The conversion descriptor. (reiconv_t)(-1) is returned if error occured with errno set.
+ */
+extern _CPPP_API reiconv_t reiconv_open(const char *tocode, const char *fromcode);
+
 /**
  * @brief Do conversion. For iconv compatibility.
  * @note At most `*inbytesleft` bytes starting at `*inbuf`.

include/iconv.h.in

@@ -46,15 +46,13 @@
  */
 #define iconv_t reiconv_t
 
-/**
- * @brief Open a conversion descriptor.
- * @param tocode The target encoding.
+ /**
+ * @brief Open a conversion descriptor. For iconv compatibility.
+ * @param tocode The target encoding. Supports "//IGNORE".
  * @param fromcode The source encoding.
  * @return The conversion descriptor. (iconv_t)(-1) on error with errno set.
- * @note This function is equivalent to `reiconv_open_from_name(fromcode, tocode)`.
- * @see reiconv_open_from_name
  */
-#define iconv_open(tocode, fromcode) reiconv_open_from_name(fromcode, tocode, false)
+#define iconv_open reiconv_open
 
 /**
  * @brief Convert at most `*inbytesleft` bytes from `*inbuf` according to the code conversion

lib/encoding_indexes.h

@@ -5,7 +5,6 @@
  * @copyright Copyright (C) 2024 The C++ Plus Project.
  */
 /*
- * Copyright (C) 2024 The C++ Plus Project.
  * This file is part of the cppp-reiconv library.
  *
  * The cppp-reiconv library is free software; you can redistribute it

lib/iconv.c

@@ -88,8 +88,7 @@ _CPPP_API int reiconv_lookup_from_codepage(int codepage)
 
 _CPPP_API reiconv_t reiconv_open_from_index(int fromcode, int tocode, bool discard_ilseq)
 {
-    struct conv_struct *cd;
-    cd = (struct conv_struct *)malloc(sizeof(struct conv_struct));
+    struct conv_struct *cd = (struct conv_struct *)malloc(sizeof(struct conv_struct));
     if (cd == NULL)
     {
         errno = ENOMEM;
@@ -142,6 +141,51 @@ _CPPP_API reiconv_t reiconv_open_from_name(const char *fromcode, const char *toc
     return reiconv_open_from_index(from_index, to_index, discard_ilseq);
 }
 
+_CPPP_API reiconv_t reiconv_open(const char *tocode, const char *fromcode)
+{
+    char fromcode_buf[MAX_WORD_LENGTH + 2];
+    char tocode_buf[MAX_WORD_LENGTH + 2];
+
+    size_t fromcode_len = reiconv_name_canonicalize(fromcode, fromcode_buf);
+    size_t tocode_len = reiconv_name_canonicalize(tocode, tocode_buf);
+
+    bool discard_ilseq = false;
+
+    for (size_t i = 0; i < fromcode_len; i++)
+    {
+        if (i < fromcode_len && fromcode_buf[i] == '/')
+        {
+            fromcode_buf[i] = '\0';
+            if (i + 7 < fromcode_len && memcmp(fromcode_buf + i + 1, "/IGNORE", 8) == 0)
+            {
+                discard_ilseq = true;
+            }
+        }
+    }
+
+    for (size_t i = 0; i < tocode_len; i++)
+    {
+        if (tocode_buf[i] == '/')
+        {
+            tocode_buf[i] = '\0';
+            if (i + 7 < fromcode_len && memcmp(tocode_buf + i + 1, "/IGNORE", 8) == 0)
+            {
+                discard_ilseq = true;
+            }
+        }
+    }
+
+    int from_index = reiconv_lookup_from_name(fromcode_buf);
+    int to_index = reiconv_lookup_from_name(tocode_buf);
+    if (from_index == -1 || to_index == -1)
+    {
+        errno = EINVAL;
+        return (reiconv_t)(-1);
+    }
+
+    return reiconv_open_from_index(from_index, to_index, discard_ilseq);
+}
+
 _CPPP_API size_t reiconv_iconv(reiconv_t cd, char **inbuf, size_t *inbytesleft, char **outbuf, size_t *outbytesleft)
 {
     if (inbuf == NULL || *inbuf == NULL)