Remove proj_create_from_proj_string() and proj_create_from_user_input(), and make proj_create() do more or less what proj_create_from_user_input() did before (fixes #1214)

10 files changed, 388 insertions, 293 deletions

diff --git a/src/4D_api.cpp b/src/4D_api.cpp
index 710b59e3..5502c96f 100644
--- a/src/4D_api.cpp
+++ b/src/4D_api.cpp
@@ -462,7 +462,7 @@ Returns 1 on success, 0 on failure
         if (nullptr==def)
             return 0;
         sprintf (def, "break_cs2cs_recursion     proj=axisswap  axis=%s", P->axis);
-        Q = proj_create (P->ctx, def);
+        Q = pj_create_internal (P->ctx, def);
         free (def);
         if (nullptr==Q)
             return 0;
@@ -477,7 +477,7 @@ Returns 1 on success, 0 on failure
         if (nullptr==def)
             return 0;
         sprintf (def, "break_cs2cs_recursion     proj=vgridshift  grids=%s", gridnames);
-        Q = proj_create (P->ctx, def);
+        Q = pj_create_internal (P->ctx, def);
         free (def);
         if (nullptr==Q)
             return 0;
@@ -492,7 +492,7 @@ Returns 1 on success, 0 on failure
         if (nullptr==def)
             return 0;
         sprintf (def, "break_cs2cs_recursion     proj=hgridshift  grids=%s", gridnames);
-        Q = proj_create (P->ctx, def);
+        Q = pj_create_internal (P->ctx, def);
         free (def);
         if (nullptr==Q)
             return 0;
@@ -524,7 +524,7 @@ Returns 1 on success, 0 on failure
         if (nullptr==def)
             return 0;
         sprintf (def, "break_cs2cs_recursion     proj=helmert exact %s convention=position_vector", s);
-        Q = proj_create (P->ctx, def);
+        Q = pj_create_internal (P->ctx, def);
         free(def);
         if (nullptr==Q)
             return 0;
@@ -550,14 +550,14 @@ Returns 1 on success, 0 on failure
                 *next_pos = '.';
             }
         }
-        Q = proj_create (P->ctx, def);
+        Q = pj_create_internal (P->ctx, def);
         if (nullptr==Q)
             return 0;
         P->cart = skip_prep_fin (Q);
 
         if (!P->is_geocent) {
             sprintf (def, "break_cs2cs_recursion     proj=cart  ellps=WGS84");
-            Q = proj_create (P->ctx, def);
+            Q = pj_create_internal (P->ctx, def);
             if (nullptr==Q)
                 return 0;
             P->cart_wgs84 = skip_prep_fin (Q);
@@ -568,9 +568,10 @@ Returns 1 on success, 0 on failure
 }
 
 
-
 /*************************************************************************************/
-PJ *proj_create (PJ_CONTEXT *ctx, const char *definition) {
+PJ *pj_create_internal (PJ_CONTEXT *ctx, const char *definition) {
+/*************************************************************************************/
+
 /**************************************************************************************
     Create a new PJ object in the context ctx, using the given definition. If ctx==0,
     the default context is used, if definition==0, or invalid, a null-pointer is
@@ -623,8 +624,6 @@ PJ *proj_create (PJ_CONTEXT *ctx, const char *definition) {
     return P;
 }
 
-
-
 /*************************************************************************************/
 PJ *proj_create_argv (PJ_CONTEXT *ctx, int argc, char **argv) {
 /**************************************************************************************
@@ -657,6 +656,34 @@ indicator, as in {"+proj=utm", "+zone=32"}, or leave it out, as in {"proj=utm",
     return P;
 }
 
+/*************************************************************************************/
+PJ *pj_create_argv_internal (PJ_CONTEXT *ctx, int argc, char **argv) {
+/**************************************************************************************
+Same as proj_create_argv() but calls pj_create_internal() instead of proj_create() internally
+**************************************************************************************/
+    PJ *P;
+    const char *c;
+
+    if (nullptr==ctx)
+        ctx = pj_get_default_ctx ();
+    if (nullptr==argv) {
+        proj_context_errno_set(ctx, PJD_ERR_NO_ARGS);
+        return nullptr;
+    }
+
+    /* We assume that free format is used, and build a full proj_create compatible string */
+    c = pj_make_args (argc, argv);
+    if (nullptr==c) {
+        proj_context_errno_set(ctx, ENOMEM);
+        return nullptr;
+    }
+
+    P = pj_create_internal (ctx, c);
+
+    pj_dealloc ((char *) c);
+    return P;
+}
+
 /** Create an area of use */
 PJ_AREA * proj_area_create(void) {
     return static_cast<PJ_AREA*>(pj_calloc(1, sizeof(PJ_AREA)));
@@ -761,7 +788,7 @@ PJ  *proj_create_crs_to_crs (PJ_CONTEXT *ctx, const char *source_crs, const char
     - a PROJ string, like "+proj=longlat +datum=WGS84".
       When using that syntax, the axis order and unit for geographic CRS will
       be longitude, latitude, and the unit degrees.
-    - more generally any string accepted by proj_create_from_user_input()
+    - more generally any string accepted by proj_create()
 
     An "area of use" can be specified in area. When it is supplied, the more
     accurate transformation between two given systems can be chosen.
@@ -772,27 +799,23 @@ PJ  *proj_create_crs_to_crs (PJ_CONTEXT *ctx, const char *source_crs, const char
 
 ******************************************************************************/
     const char* proj_string;
-    const char* const optionsProj4Mode[] = { "USE_PROJ4_INIT_RULES=YES", nullptr };
 
     if( !ctx ) {
         ctx = pj_get_default_ctx();
     }
 
-    const char* const* optionsImportCRS =
-        proj_context_get_use_proj4_init_rules(ctx, FALSE) ? optionsProj4Mode : nullptr;
-
     try
     {
         std::string source_crs_modified(pj_add_type_crs_if_needed(source_crs));
         std::string target_crs_modified(pj_add_type_crs_if_needed(target_crs));
 
-        auto src = proj_create_from_user_input(ctx, source_crs_modified.c_str(), optionsImportCRS);
+        auto src = proj_create(ctx, source_crs_modified.c_str());
         if( !src ) {
             proj_context_log_debug(ctx, "Cannot instantiate source_crs");
             return nullptr;
         }
 
-        auto dst = proj_create_from_user_input(ctx, target_crs_modified.c_str(), optionsImportCRS);
+        auto dst = proj_create(ctx, target_crs_modified.c_str());
         if( !dst ) {
             proj_context_log_debug(ctx, "Cannot instantiate target_crs");
             proj_destroy(src);
diff --git a/src/apps/cs2cs.cpp b/src/apps/cs2cs.cpp
index bde4f813..1c49965a 100644
--- a/src/apps/cs2cs.cpp
+++ b/src/apps/cs2cs.cpp
@@ -210,12 +210,10 @@ static void process(FILE *fid)
 /************************************************************************/
 
 static PJ *instanciate_crs(const std::string &definition,
-                               const char *const *optionsImportCRS,
                                bool &isGeog, double &toRadians,
                                bool &isLatFirst) {
-    PJ *crs = proj_create_from_user_input(nullptr,
-                                          pj_add_type_crs_if_needed(definition).c_str(),
-                                          optionsImportCRS);
+    PJ *crs = proj_create(nullptr,
+                          pj_add_type_crs_if_needed(definition).c_str());
     if (!crs) {
         return nullptr;
     }
@@ -536,16 +534,13 @@ int main(int argc, char **argv) {
         emess(3, "missing source and target coordinate systems");
     }
 
-    const char *const optionsProj4Mode[] = {"USE_PROJ4_INIT_RULES=YES",
-                                            nullptr};
-    const char *const *optionsImportCRS =
-        proj_context_get_use_proj4_init_rules(nullptr, TRUE) ? optionsProj4Mode
-                                                             : nullptr;
+    proj_context_use_proj4_init_rules(nullptr,
+        proj_context_get_use_proj4_init_rules(nullptr, TRUE));
 
     PJ *src = nullptr;
     if (!fromStr.empty()) {
         bool ignored;
-        src = instanciate_crs(fromStr, optionsImportCRS, srcIsGeog,
+        src = instanciate_crs(fromStr, srcIsGeog,
                               srcToRadians, ignored);
         if (!src) {
             emess(3, "cannot instantiate source coordinate system");
@@ -554,7 +549,7 @@ int main(int argc, char **argv) {
 
     PJ *dst = nullptr;
     if (!toStr.empty()) {
-        dst = instanciate_crs(toStr, optionsImportCRS, destIsGeog,
+        dst = instanciate_crs(toStr, destIsGeog,
                               destToRadians, destIsLatLong);
         if (!dst) {
             emess(3, "cannot instantiate target coordinate system");
diff --git a/src/init.cpp b/src/init.cpp
index 2ed34a09..8af3d26c 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -238,6 +238,10 @@ Expand key from buffer or (if not in buffer) from init file
     char *definition = nullptr;
     paralist *init_items = nullptr;
 
+    if( !ctx ) {
+        ctx = pj_get_default_ctx();
+    }
+
     /* support "init=file:section", "+init=file:section", and "file:section" format */
     xkey = strstr (key, "init=");
     if (nullptr==xkey)
@@ -270,7 +274,6 @@ Expand key from buffer or (if not in buffer) from init file
         }
 
         if( !exists ) {
-            const char* const optionsProj4Mode[] = { "USE_PROJ4_INIT_RULES=YES", nullptr };
             char szInitStr[7 + 64];
             PJ* src;
             const char* proj_string;
@@ -287,7 +290,10 @@ Expand key from buffer or (if not in buffer) from init file
             strcpy(szInitStr, "+init=");
             strcat(szInitStr, xkey);
 
-            src = proj_create_from_user_input(ctx, szInitStr, optionsProj4Mode);
+            auto old_proj4_init_rules = ctx->use_proj4_init_rules;
+            ctx->use_proj4_init_rules = true;
+            src = proj_create(ctx, szInitStr);
+            ctx->use_proj4_init_rules = old_proj4_init_rules;
             if( !src ) {
                 return nullptr;
             }
diff --git a/src/internal.cpp b/src/internal.cpp
index fbc7c9a1..84db5d82 100644
--- a/src/internal.cpp
+++ b/src/internal.cpp
@@ -207,6 +207,8 @@ consuming their surrounding whitespace.
 
     pj_chomp (c);
     n = strlen (c);
+    if (n==0)
+        return c;
 
     /* First collapse repeated whitespace (including +/;) */
     i = 0;
diff --git a/src/iso19111/c_api.cpp b/src/iso19111/c_api.cpp
index d13c33c7..06a3c02e 100644
--- a/src/iso19111/c_api.cpp
+++ b/src/iso19111/c_api.cpp
@@ -47,6 +47,7 @@
 #include "proj/util.hpp"
 
 #include "proj/internal/internal.hpp"
+#include "proj/internal/io_internal.hpp"
 
 // PROJ include order is sensitive
 // clang-format off
@@ -91,25 +92,6 @@ static void PROJ_NO_INLINE proj_log_debug(PJ_CONTEXT *ctx, const char *function,
 
 //! @cond Doxygen_Suppress
 
-/** Auxiliary structure to PJ_CONTEXT storing C++ context stuff. */
-struct projCppContext {
-    DatabaseContextNNPtr databaseContext;
-    std::string lastUOMName_{};
-
-    explicit projCppContext(PJ_CONTEXT *ctx, const char *dbPath = nullptr,
-                            const char *const *auxDbPaths = nullptr)
-        : databaseContext(DatabaseContext::create(
-              dbPath ? dbPath : std::string(), toVector(auxDbPaths), ctx)) {}
-
-    static std::vector<std::string> toVector(const char *const *auxDbPaths) {
-        std::vector<std::string> res;
-        for (auto iter = auxDbPaths; iter && *iter; ++iter) {
-            res.emplace_back(std::string(*iter));
-        }
-        return res;
-    }
-};
-
 // ---------------------------------------------------------------------------
 
 void proj_context_delete_cpp_context(struct projCppContext *cppContext) {
@@ -150,8 +132,9 @@ static PJ *pj_obj_create(PJ_CONTEXT *ctx, const IdentifiedObjectNNPtr &objIn) {
         try {
             auto formatter = PROJStringFormatter::create(
                 PROJStringFormatter::Convention::PROJ_5, dbContext);
-            auto pj = proj_create(
-                ctx, coordop->exportToPROJString(formatter.get()).c_str());
+            auto projString = coordop->exportToPROJString(formatter.get());
+            auto pj = pj_create_internal(
+                ctx, projString.empty() ? "+proj=affine" : projString.c_str());
             if (pj) {
                 pj->iso_obj = objIn;
                 return pj;
@@ -346,41 +329,20 @@ PJ *proj_clone(PJ_CONTEXT *ctx, const PJ *obj) {
  *
  * @param ctx PROJ context, or NULL for default context
  * @param text String (must not be NULL)
- * @param options null-terminated list of options, or NULL. Currently
- * supported options are:
- * <ul>
- * <li>USE_PROJ4_INIT_RULES=YES/NO. Defaults to NO. When set to YES,
- * init=epsg:XXXX syntax will be allowed and will be interpreted according to
- * PROJ.4 and PROJ.5 rules, that is geodeticCRS will have longitude, latitude
- * order and will expect/output coordinates in radians. ProjectedCRS will have
- * easting, northing axis order (except the ones with Transverse Mercator South
- * Orientated projection). In that mode, the epsg:XXXX syntax will be also
- * interprated the same way.</li>
- * </ul>
  * @return Object that must be unreferenced with proj_destroy(), or NULL in
  * case of error.
  */
-PJ *proj_create_from_user_input(PJ_CONTEXT *ctx, const char *text,
-                                const char *const *options) {
+PJ *proj_create(PJ_CONTEXT *ctx, const char *text) {
     SANITIZE_CTX(ctx);
     assert(text);
-    (void)options;
-    auto dbContext = getDBcontextNoException(ctx, __FUNCTION__);
+
+    // Only connect to proj.db if needed
+    if( strstr(text, "proj=") == nullptr || strstr(text, "init=") != nullptr ) {
+        getDBcontextNoException(ctx, __FUNCTION__);
+    }
     try {
-        bool usePROJ4InitRules = false;
-        for (auto iter = options; iter && iter[0]; ++iter) {
-            const char *value;
-            if ((value = getOptionValue(*iter, "USE_PROJ4_INIT_RULES="))) {
-                usePROJ4InitRules = ci_equal(value, "YES");
-            } else {
-                std::string msg("Unknown option :");
-                msg += *iter;
-                proj_log_error(ctx, __FUNCTION__, msg.c_str());
-                return nullptr;
-            }
-        }
         auto identifiedObject = nn_dynamic_pointer_cast<IdentifiedObject>(
-            createFromUserInput(text, dbContext, usePROJ4InitRules));
+            createFromUserInput(text, ctx));
         if (identifiedObject) {
             return pj_obj_create(ctx, NN_NO_CHECK(identifiedObject));
         }
@@ -520,43 +482,6 @@ PJ *proj_create_from_wkt(PJ_CONTEXT *ctx, const char *wkt,
 
 // ---------------------------------------------------------------------------
 
-/** \brief Instantiate an object from a PROJ string.
- *
- * This function calls osgeo::proj::io::PROJStringParser::createFromPROJString()
- *
- * The returned object must be unreferenced with proj_destroy() after use.
- * It should be used by at most one thread at a time.
- *
- * @param ctx PROJ context, or NULL for default context
- * @param proj_string PROJ string (must not be NULL)
- * @param options should be set to NULL for now
- * @return Object that must be unreferenced with proj_destroy(), or NULL in
- * case of error.
- */
-PJ *proj_create_from_proj_string(PJ_CONTEXT *ctx, const char *proj_string,
-                                 const char *const *options) {
-    SANITIZE_CTX(ctx);
-    (void)options;
-    assert(proj_string);
-    try {
-        PROJStringParser parser;
-        auto dbContext = getDBcontextNoException(ctx, __FUNCTION__);
-        if (dbContext) {
-            parser.attachDatabaseContext(NN_NO_CHECK(dbContext));
-        }
-        auto identifiedObject = nn_dynamic_pointer_cast<IdentifiedObject>(
-            parser.createFromPROJString(proj_string));
-        if (identifiedObject) {
-            return pj_obj_create(ctx, NN_NO_CHECK(identifiedObject));
-        }
-    } catch (const std::exception &e) {
-        proj_log_error(ctx, __FUNCTION__, e.what());
-    }
-    return nullptr;
-}
-
-// ---------------------------------------------------------------------------
-
 /** \brief Instantiate an object from a database lookup.
  *
  * The returned object must be unreferenced with proj_destroy() after use.
diff --git a/src/iso19111/io.cpp b/src/iso19111/io.cpp
index d403495b..b75d9fd6 100644
--- a/src/iso19111/io.cpp
+++ b/src/iso19111/io.cpp
@@ -4284,58 +4284,44 @@ BaseObjectNNPtr WKTParser::Private::build(const WKTNodeNNPtr &node) {
 
     throw ParsingException(concat("unhandled keyword: ", name));
 }
-//! @endcond
 
 // ---------------------------------------------------------------------------
 
-/** \brief Instantiate a sub-class of BaseObject from a user specified text.
- *
- * The text can be a:
- * <ul>
- * <li>WKT string</li>
- * <li>PROJ string</li>
- * <li>database code, prefixed by its authoriy. e.g. "EPSG:4326"</li>
- * <li>URN. e.g. "urn:ogc:def:crs:EPSG::4326",
- *     "urn:ogc:def:coordinateOperation:EPSG::1671"</li>
- * <li>an objet name. e.g "WGS 84", "WGS 84 / UTM zone 31N". In that case as
- *     uniqueness is not guaranteed, the function may apply heuristics to
- *     determine the appropriate best match.</li>
- * </ul>
- *
- * @param text One of the above mentioned text format
- * @param dbContext Database context, or nullptr (in which case database
- * lookups will not work)
- * @param usePROJ4InitRules When set to true,
- * init=epsg:XXXX syntax will be allowed and will be interpreted according to
- * PROJ.4 and PROJ.5 rules, that is geodeticCRS will have longitude, latitude
- * order and will expect/output coordinates in radians. ProjectedCRS will have
- * easting, northing axis order (except the ones with Transverse Mercator South
- * Orientated projection). In that mode, the epsg:XXXX syntax will be also
- * interprated the same way.
- * @throw ParsingException
- */
-BaseObjectNNPtr createFromUserInput(const std::string &text,
-                                    const DatabaseContextPtr &dbContext,
-                                    bool usePROJ4InitRules) {
+static BaseObjectNNPtr createFromUserInput(const std::string &text,
+                                           const DatabaseContextPtr &dbContext,
+                                           bool usePROJ4InitRules,
+                                           PJ_CONTEXT *ctx) {
 
-    for (const auto &wktConstants : WKTConstants::constants()) {
-        if (ci_starts_with(text, wktConstants)) {
-            return WKTParser()
-                .attachDatabaseContext(dbContext)
-                .setStrict(false)
-                .createFromWKT(text);
+    if (!ci_starts_with(text, "step proj=") &&
+        !ci_starts_with(text, "step +proj=")) {
+        for (const auto &wktConstants : WKTConstants::constants()) {
+            if (ci_starts_with(text, wktConstants)) {
+                return WKTParser()
+                    .attachDatabaseContext(dbContext)
+                    .setStrict(false)
+                    .createFromWKT(text);
+            }
         }
     }
+
     const char *textWithoutPlusPrefix = text.c_str();
     if (textWithoutPlusPrefix[0] == '+')
         textWithoutPlusPrefix++;
 
     if (strncmp(textWithoutPlusPrefix, "proj=", strlen("proj=")) == 0 ||
+        text.find(" +proj=") != std::string::npos ||
+        text.find(" proj=") != std::string::npos ||
         strncmp(textWithoutPlusPrefix, "init=", strlen("init=")) == 0 ||
+        text.find(" +init=") != std::string::npos ||
+        text.find(" init=") != std::string::npos ||
         strncmp(textWithoutPlusPrefix, "title=", strlen("title=")) == 0) {
         return PROJStringParser()
             .attachDatabaseContext(dbContext)
-            .setUsePROJ4InitRules(usePROJ4InitRules)
+            .attachContext(ctx)
+            .setUsePROJ4InitRules(ctx != nullptr
+                                      ? (proj_context_get_use_proj4_init_rules(
+                                             ctx, false) == TRUE)
+                                      : usePROJ4InitRules)
             .createFromPROJString(text);
     }
 
@@ -4452,6 +4438,69 @@ BaseObjectNNPtr createFromUserInput(const std::string &text,
 
     throw ParsingException("unrecognized format / unknown name");
 }
+//! @endcond
+
+// ---------------------------------------------------------------------------
+
+/** \brief Instantiate a sub-class of BaseObject from a user specified text.
+ *
+ * The text can be a:
+ * <ul>
+ * <li>WKT string</li>
+ * <li>PROJ string</li>
+ * <li>database code, prefixed by its authoriy. e.g. "EPSG:4326"</li>
+ * <li>URN. e.g. "urn:ogc:def:crs:EPSG::4326",
+ *     "urn:ogc:def:coordinateOperation:EPSG::1671"</li>
+ * <li>an objet name. e.g "WGS 84", "WGS 84 / UTM zone 31N". In that case as
+ *     uniqueness is not guaranteed, the function may apply heuristics to
+ *     determine the appropriate best match.</li>
+ * </ul>
+ *
+ * @param text One of the above mentioned text format
+ * @param dbContext Database context, or nullptr (in which case database
+ * lookups will not work)
+ * @param usePROJ4InitRules When set to true,
+ * init=epsg:XXXX syntax will be allowed and will be interpreted according to
+ * PROJ.4 and PROJ.5 rules, that is geodeticCRS will have longitude, latitude
+ * order and will expect/output coordinates in radians. ProjectedCRS will have
+ * easting, northing axis order (except the ones with Transverse Mercator South
+ * Orientated projection). In that mode, the epsg:XXXX syntax will be also
+ * interprated the same way.
+ * @throw ParsingException
+ */
+BaseObjectNNPtr createFromUserInput(const std::string &text,
+                                    const DatabaseContextPtr &dbContext,
+                                    bool usePROJ4InitRules) {
+    return createFromUserInput(text, dbContext, usePROJ4InitRules, nullptr);
+}
+
+// ---------------------------------------------------------------------------
+
+/** \brief Instantiate a sub-class of BaseObject from a user specified text.
+ *
+ * The text can be a:
+ * <ul>
+ * <li>WKT string</li>
+ * <li>PROJ string</li>
+ * <li>database code, prefixed by its authoriy. e.g. "EPSG:4326"</li>
+ * <li>URN. e.g. "urn:ogc:def:crs:EPSG::4326",
+ *     "urn:ogc:def:coordinateOperation:EPSG::1671"</li>
+ * <li>an objet name. e.g "WGS 84", "WGS 84 / UTM zone 31N". In that case as
+ *     uniqueness is not guaranteed, the function may apply heuristics to
+ *     determine the appropriate best match.</li>
+ * </ul>
+ *
+ * @param text One of the above mentioned text format
+ * @param ctx PROJ context
+ * @throw ParsingException
+ */
+BaseObjectNNPtr createFromUserInput(const std::string &text, PJ_CONTEXT *ctx) {
+    return createFromUserInput(
+        text, ctx != nullptr && ctx->cpp_context
+                  ? ctx->cpp_context->databaseContext.as_nullable()
+                  : nullptr,
+        false, ctx);
+}
 
 // ---------------------------------------------------------------------------
 
@@ -5223,17 +5272,68 @@ void PROJStringFormatter::Private::appendToResult(const char *str) {
 static void
 PROJStringSyntaxParser(const std::string &projString, std::vector<Step> &steps,
                        std::vector<Step::KeyValue> &globalParamValues,
-                       std::string &title, std::string &vunits,
-                       std::string &vto_meter) {
+                       std::string &title) {
     std::string word;
     std::istringstream iss(projString, std::istringstream::in);
-    bool inverted = false;
-    bool prevWasStep = false;
-    bool inProj = false;
-    bool inPipeline = false;
     bool prevWasTitle = false;
-    bool prevWasInit = false;
 
+    if (projString.find("proj=pipeline") == std::string::npos) {
+        const bool hasProj = projString.find("proj=") == 0 ||
+                             projString.find("+proj=") == 0 ||
+                             projString.find(" proj=") != std::string::npos ||
+                             projString.find(" +proj=") != std::string::npos;
+        const bool hasInit = projString.find("init=") == 0 ||
+                             projString.find("+init=") == 0 ||
+                             projString.find(" init=") != std::string::npos ||
+                             projString.find(" +init=") != std::string::npos;
+        if (hasProj || hasInit) {
+            steps.push_back(Step());
+        }
+
+        while (iss >> word) {
+            if (word[0] == '+') {
+                word = word.substr(1);
+            } else if (prevWasTitle && word.find('=') == std::string::npos) {
+                title += " ";
+                title += word;
+                continue;
+            }
+
+            prevWasTitle = false;
+            if (starts_with(word, "proj=") && !hasInit) {
+                assert(hasProj);
+                auto stepName = word.substr(strlen("proj="));
+                steps.back().name = stepName;
+            } else if (starts_with(word, "init=")) {
+                assert(hasInit);
+                auto initName = word.substr(strlen("init="));
+                steps.back().name = initName;
+                steps.back().isInit = true;
+            } else if (word == "inv") {
+                if (!steps.empty()) {
+                    steps.back().inverted = true;
+                }
+            } else if (starts_with(word, "title=")) {
+                title = word.substr(strlen("title="));
+                prevWasTitle = true;
+            } else if (word != "step") {
+                const auto pos = word.find('=');
+                auto key = word.substr(0, pos);
+                auto pair = (pos != std::string::npos)
+                                ? Step::KeyValue(key, word.substr(pos + 1))
+                                : Step::KeyValue(key);
+                if (steps.empty()) {
+                    globalParamValues.push_back(pair);
+                } else {
+                    steps.back().paramValues.push_back(pair);
+                }
+            }
+        }
+        return;
+    }
+
+    bool inPipeline = false;
+    bool invGlobal = false;
     while (iss >> word) {
         if (word[0] == '+') {
             word = word.substr(1);
@@ -5248,52 +5348,31 @@ PROJStringSyntaxParser(const std::string &projString, std::vector<Step> &steps,
             if (inPipeline) {
                 throw ParsingException("nested pipeline not supported");
             }
-            inverted = false;
-            prevWasStep = false;
-            inProj = true;
             inPipeline = true;
         } else if (word == "step") {
             if (!inPipeline) {
                 throw ParsingException("+step found outside pipeline");
             }
-            inverted = false;
-            prevWasStep = true;
-            prevWasInit = false;
+            steps.push_back(Step());
         } else if (word == "inv") {
-            if (prevWasStep) {
-                inverted = true;
+            if (steps.empty()) {
+                invGlobal = true;
             } else {
-                if (steps.empty()) {
-                    throw ParsingException("+inv found at unexpected place");
-                }
                 steps.back().inverted = true;
             }
-            prevWasStep = false;
-        } else if (starts_with(word, "proj=")) {
+        } else if (inPipeline && !steps.empty() && starts_with(word, "proj=") &&
+                   steps.back().name.empty()) {
             auto stepName = word.substr(strlen("proj="));
-            if (prevWasInit) {
-                steps.back() = Step();
-                prevWasInit = false;
-            } else {
-                steps.push_back(Step());
-            }
             steps.back().name = stepName;
-            steps.back().inverted = inverted;
-            prevWasStep = false;
-            inProj = true;
-        } else if (starts_with(word, "init=")) {
-            if (prevWasInit) {
-                throw ParsingException("+init= found at unexpected place");
-            }
+        } else if (inPipeline && !steps.empty() && starts_with(word, "init=") &&
+                   steps.back().name.empty()) {
             auto initName = word.substr(strlen("init="));
-            steps.push_back(Step());
             steps.back().name = initName;
             steps.back().isInit = true;
-            steps.back().inverted = inverted;
-            prevWasStep = false;
-            prevWasInit = true;
-            inProj = true;
-        } else if (inProj) {
+        } else if (!inPipeline && starts_with(word, "title=")) {
+            title = word.substr(strlen("title="));
+            prevWasTitle = true;
+        } else {
             const auto pos = word.find('=');
             auto key = word.substr(0, pos);
             auto pair = (pos != std::string::npos)
@@ -5304,21 +5383,14 @@ PROJStringSyntaxParser(const std::string &projString, std::vector<Step> &steps,
             } else {
                 steps.back().paramValues.push_back(pair);
             }
-            prevWasStep = false;
-        } else if (starts_with(word, "vunits=")) {
-            vunits = word.substr(strlen("vunits="));
-        } else if (starts_with(word, "vto_meter=")) {
-            vto_meter = word.substr(strlen("vto_meter="));
-        } else if (word == "type=crs" &&
-                   (!vunits.empty() || !vto_meter.empty())) {
-            // ok
-        } else if (starts_with(word, "title=")) {
-            title = word.substr(strlen("title="));
-            prevWasTitle = true;
-        } else {
-            throw ParsingException("Unexpected token: " + word);
         }
     }
+    if (invGlobal) {
+        for (auto &step : steps) {
+            step.inverted = !step.inverted;
+        }
+        std::reverse(steps.begin(), steps.end());
+    }
 }
 
 // ---------------------------------------------------------------------------
@@ -5328,10 +5400,7 @@ void PROJStringFormatter::ingestPROJString(
 {
     std::vector<Step> steps;
     std::string title;
-    std::string vunits;
-    std::string vto_meter;
-    PROJStringSyntaxParser(str, steps, d->globalParamValues_, title, vunits,
-                           vto_meter);
+    PROJStringSyntaxParser(str, steps, d->globalParamValues_, title);
     d->steps_.insert(d->steps_.end(), steps.begin(), steps.end());
 }
 
@@ -5605,6 +5674,7 @@ const DatabaseContextPtr &PROJStringFormatter::databaseContext() const {
 
 struct PROJStringParser::Private {
     DatabaseContextPtr dbContext_{};
+    PJ_CONTEXT *ctx_{};
     bool usePROJ4InitRules_ = false;
     std::vector<std::string> warningList_{};
 
@@ -5632,6 +5702,17 @@ struct PROJStringParser::Private {
 
     template <class T>
     // cppcheck-suppress functionStatic
+    const std::string &getGlobalParamValue(const T key) {
+        for (const auto &pair : globalParamValues_) {
+            if (ci_equal(pair.key, key)) {
+                return pair.value;
+            }
+        }
+        return emptyString;
+    }
+
+    template <class T>
+    // cppcheck-suppress functionStatic
     const std::string &getParamValue(const Step &step, const T key) {
         for (const auto &pair : globalParamValues_) {
             if (ci_equal(pair.key, key)) {
@@ -5713,6 +5794,15 @@ PROJStringParser::attachDatabaseContext(const DatabaseContextPtr &dbContext) {
 
 // ---------------------------------------------------------------------------
 
+//! @cond Doxygen_Suppress
+PROJStringParser &PROJStringParser::attachContext(PJ_CONTEXT *ctx) {
+    d->ctx_ = ctx;
+    return *this;
+}
+//! @endcond
+
+// ---------------------------------------------------------------------------
+
 /** \brief Set how init=epsg:XXXX syntax should be interpreted.
  *
  * @param enable When set to true,
@@ -7269,18 +7359,16 @@ static const metadata::ExtentPtr &getExtent(const crs::CRS *crs) {
  */
 BaseObjectNNPtr
 PROJStringParser::createFromPROJString(const std::string &projString) {
-    std::string vunits;
-    std::string vto_meter;
-
     d->steps_.clear();
     d->title_.clear();
     d->globalParamValues_.clear();
     d->projString_ = projString;
     PROJStringSyntaxParser(projString, d->steps_, d->globalParamValues_,
-                           d->title_, vunits, vto_meter);
+                           d->title_);
 
     if (d->steps_.empty()) {
-
+        const auto &vunits = d->getGlobalParamValue("vunits");
+        const auto &vto_meter = d->getGlobalParamValue("vto_meter");
         if (!vunits.empty() || !vto_meter.empty()) {
             Step fakeStep;
             if (!vunits.empty()) {
@@ -7301,9 +7389,10 @@ PROJStringParser::createFromPROJString(const std::string &projString) {
         }
     }
 
-    if ((d->steps_.size() == 1 ||
+    if (((d->steps_.size() == 1 &&
+          d->getParamValue(d->steps_[0], "type") == "crs") ||
          (d->steps_.size() == 2 && d->steps_[1].name == "unitconvert")) &&
-        isGeocentricStep(d->steps_[0].name)) {
+        !d->steps_[0].inverted && isGeocentricStep(d->steps_[0].name)) {
         return d->buildBoundOrCompoundCRSIfNeeded(
             0, d->buildGeocentricCRS(0, (d->steps_.size() == 2 &&
                                          d->steps_[1].name == "unitconvert")
@@ -7313,8 +7402,7 @@ PROJStringParser::createFromPROJString(const std::string &projString) {
 
     // +init=xxxx:yyyy syntax
     if (d->steps_.size() == 1 && d->steps_[0].isInit &&
-        (d->steps_[0].paramValues.size() == 0 ||
-         d->getParamValue(d->steps_[0], "type") == "crs")) {
+        !d->steps_[0].inverted) {
 
         // Those used to come from a text init file
         // We only support them in compatibility mode
@@ -7345,9 +7433,14 @@ PROJStringParser::createFromPROJString(const std::string &projString) {
             if (!file_found) {
                 auto obj = createFromUserInput(stepName, d->dbContext_, true);
                 auto crs = dynamic_cast<CRS *>(obj.get());
-                if (crs) {
+                if (crs &&
+                    (d->steps_[0].paramValues.empty() ||
+                     (d->steps_[0].paramValues.size() == 1 &&
+                      d->getParamValue(d->steps_[0], "type") == "crs"))) {
                     PropertyMap properties;
-                    properties.set(IdentifiedObject::NAME_KEY, crs->nameStr());
+                    properties.set(IdentifiedObject::NAME_KEY,
+                                   d->title_.empty() ? crs->nameStr()
+                                                     : d->title_);
                     const auto &extent = getExtent(crs);
                     if (extent) {
                         properties.set(
@@ -7356,12 +7449,12 @@ PROJStringParser::createFromPROJString(const std::string &projString) {
                     }
                     auto geogCRS = dynamic_cast<GeographicCRS *>(crs);
                     if (geogCRS) {
-                        // Override with longitude latitude in radian
+                        // Override with longitude latitude in degrees
                         return GeographicCRS::create(
                             properties, geogCRS->datum(),
                             geogCRS->datumEnsemble(),
                             EllipsoidalCS::createLongitudeLatitude(
-                                UnitOfMeasure::RADIAN));
+                                UnitOfMeasure::DEGREE));
                     }
                     auto projCRS = dynamic_cast<ProjectedCRS *>(crs);
                     if (projCRS) {
@@ -7377,8 +7470,31 @@ PROJStringParser::createFromPROJString(const std::string &projString) {
                                         ->unit()));
                         }
                     }
+                    return obj;
+                }
+                auto projStringExportable =
+                    dynamic_cast<IPROJStringExportable *>(crs);
+                if (projStringExportable) {
+                    std::string expanded;
+                    if (!d->title_.empty()) {
+                        expanded = "title=";
+                        expanded += d->title_;
+                    }
+                    for (const auto &pair : d->steps_[0].paramValues) {
+                        if (!expanded.empty())
+                            expanded += ' ';
+                        expanded += '+';
+                        expanded += pair.key;
+                        if (!pair.value.empty()) {
+                            expanded += '=';
+                            expanded += pair.value;
+                        }
+                    }
+                    expanded += ' ';
+                    expanded += projStringExportable->exportToPROJString(
+                        PROJStringFormatter::create().get());
+                    return createFromPROJString(expanded);
                 }
-                return obj;
             }
         }
 
@@ -7386,18 +7502,23 @@ PROJStringParser::createFromPROJString(const std::string &projString) {
         if (!init) {
             throw ParsingException("out of memory");
         }
-        PJ_CONTEXT *ctx = proj_context_create();
+        PJ_CONTEXT *ctx = d->ctx_ ? d->ctx_ : proj_context_create();
         if (!ctx) {
             pj_dealloc(init);
             throw ParsingException("out of memory");
         }
         paralist *list = pj_expand_init(ctx, init);
-        proj_context_destroy(ctx);
+        if (ctx != d->ctx_) {
+            proj_context_destroy(ctx);
+        }
         if (!list) {
             pj_dealloc(init);
             throw ParsingException("cannot expand " + projString);
         }
         std::string expanded;
+        if (!d->title_.empty()) {
+            expanded = "title=" + d->title_;
+        }
         bool first = true;
         bool has_init_term = false;
         for (auto t = list; t;) {
@@ -7417,6 +7538,14 @@ PROJStringParser::createFromPROJString(const std::string &projString) {
             pj_dealloc(t);
             t = n;
         }
+        for (const auto &pair : d->steps_[0].paramValues) {
+            expanded += " +";
+            expanded += pair.key;
+            if (!pair.value.empty()) {
+                expanded += '=';
+                expanded += pair.value;
+            }
+        }
 
         if (!has_init_term) {
             return createFromPROJString(expanded);
@@ -7434,7 +7563,7 @@ PROJStringParser::createFromPROJString(const std::string &projString) {
     int iFirstCart = -1;
     int iSecondCart = -1;
     int iMolodensky = -1;
-    bool unexpectedStructure = false;
+    bool unexpectedStructure = d->steps_.empty();
     for (int i = 0; i < static_cast<int>(d->steps_.size()); i++) {
         const auto &stepName = d->steps_[i].name;
         if (isGeographicStep(stepName)) {
@@ -7497,14 +7626,82 @@ PROJStringParser::createFromPROJString(const std::string &projString) {
         }
     }
 
-    if (d->steps_.size() == 1 && iHelmert < 0 && iMolodensky < 0 &&
-        d->getParamValue(d->steps_[0], "type") != "crs") {
+    if (iHelmert < 0 && iMolodensky < 0 && !d->steps_.empty()) {
+        // CRS candidate
+        if ((d->steps_.size() == 1 &&
+             d->getParamValue(d->steps_[0], "type") != "crs") ||
+            (d->steps_.size() > 1 && d->getGlobalParamValue("type") != "crs")) {
+            unexpectedStructure = true;
+        }
+    } else if (iHelmert >= 0 &&
+               (d->hasParamValue(d->steps_[iHelmert], "theta") ||
+                d->hasParamValue(d->steps_[iHelmert], "exact") ||
+                d->hasParamValue(d->steps_[iHelmert], "transpose") ||
+                d->hasParamValue(d->steps_[iHelmert], "towgs84"))) {
         unexpectedStructure = true;
     }
 
+    if (unexpectedStructure || iHelmert >= 0 || iMolodensky >= 0) {
+        struct Logger {
+            std::string msg{};
+
+            // cppcheck-suppress functionStatic
+            void setMessage(const char *msgIn) noexcept {
+                try {
+                    msg = msgIn;
+                } catch (const std::exception &) {
+                }
+            }
+
+            static void log(void *user_data, int level, const char *msg) {
+                if (level == PJ_LOG_ERROR) {
+                    static_cast<Logger *>(user_data)->setMessage(msg);
+                }
+            }
+        };
+
+        // If the structure is not recognized, then try to instantiate the
+        // pipeline, and if successful, wrap it in a PROJBasedOperation
+        Logger logger;
+        bool valid;
+
+        auto pj_context = d->ctx_ ? d->ctx_ : proj_context_create();
+        if (!pj_context) {
+            throw ParsingException("out of memory");
+        }
+        if (pj_context != d->ctx_) {
+            proj_log_func(pj_context, &logger, Logger::log);
+            proj_context_use_proj4_init_rules(pj_context,
+                                              d->usePROJ4InitRules_);
+        }
+        auto pj = pj_create_internal(pj_context, projString.c_str());
+        valid = pj != nullptr;
+        proj_destroy(pj);
+
+        if (!valid) {
+            std::string prefix("Error " +
+                               toString(proj_context_errno(pj_context)) + ": ");
+            if (logger.msg.empty()) {
+                logger.msg =
+                    prefix + proj_errno_string(proj_context_errno(pj_context));
+            } else {
+                logger.msg = prefix + logger.msg;
+            }
+        }
+
+        if (pj_context != d->ctx_) {
+            proj_context_destroy(pj_context);
+        }
+
+        if (!valid) {
+            throw ParsingException(logger.msg);
+        }
+    }
+
     if (!unexpectedStructure) {
-        if (iFirstGeogStep == 0 && iSecondGeogStep < 0 && iProjStep < 0 &&
-            iHelmert < 0 && iFirstCart < 0 && iMolodensky < 0 &&
+        if (iFirstGeogStep == 0 && !d->steps_[iFirstGeogStep].inverted &&
+            iSecondGeogStep < 0 && iProjStep < 0 && iHelmert < 0 &&
+            iFirstCart < 0 && iMolodensky < 0 &&
             (iFirstUnitConvert < 0 || iSecondUnitConvert < 0) &&
             (iFirstAxisSwap < 0 || iSecondAxisSwap < 0)) {
             const bool ignoreVUnits = false;
@@ -7534,9 +7731,6 @@ PROJStringParser::createFromPROJString(const std::string &projString) {
                     iFirstAxisSwap < iFirstGeogStep ? iSecondAxisSwap
                                                     : iFirstAxisSwap));
         }
-        if (d->steps_.size() == 1 && iHelmert == 0) {
-            return d->buildHelmertTransformation(iHelmert);
-        }
 
         if (iProjStep < 0 && iHelmert > 0 && iMolodensky < 0 &&
             (iFirstGeogStep < 0 || iFirstGeogStep == iFirstCart - 1 ||
@@ -7560,10 +7754,6 @@ PROJStringParser::createFromPROJString(const std::string &projString) {
                 iSecondAxisSwap, iSecondUnitConvert);
         }
 
-        if (d->steps_.size() == 1 && iMolodensky == 0) {
-            return d->buildMolodenskyTransformation(iMolodensky);
-        }
-
         if (iProjStep < 0 && iHelmert < 0 && iMolodensky > 0 &&
             (iFirstGeogStep < 0 || iFirstGeogStep == iMolodensky - 1 ||
              (iFirstGeogStep == iMolodensky + 1 && iSecondGeogStep < 0)) &&
@@ -7584,47 +7774,6 @@ PROJStringParser::createFromPROJString(const std::string &projString) {
         }
     }
 
-    struct Logger {
-        std::string msg{};
-
-        // cppcheck-suppress functionStatic
-        void setMessage(const char *msgIn) noexcept {
-            try {
-                msg = msgIn;
-            } catch (const std::exception &) {
-            }
-        }
-
-        static void log(void *user_data, int level, const char *msg) {
-            if (level == PJ_LOG_ERROR) {
-                static_cast<Logger *>(user_data)->setMessage(msg);
-            }
-        }
-    };
-
-    // If the structure is not recognized, then try to instantiate the
-    // pipeline, and if successful, wrap it in a PROJBasedOperation
-    Logger logger;
-    auto pj_context = proj_context_create();
-    if (!pj_context) {
-        throw ParsingException("out of memory");
-    }
-    proj_log_func(pj_context, &logger, Logger::log);
-    proj_context_use_proj4_init_rules(pj_context, d->usePROJ4InitRules_);
-    auto pj = proj_create(pj_context, projString.c_str());
-    bool valid = pj != nullptr;
-    proj_destroy(pj);
-
-    if (!valid && logger.msg.empty()) {
-        logger.setMessage(proj_errno_string(proj_context_errno(pj_context)));
-    }
-
-    proj_context_destroy(pj_context);
-
-    if (!valid) {
-        throw ParsingException(logger.msg);
-    }
-
     auto props = PropertyMap();
     if (!d->title_.empty()) {
         props.set(IdentifiedObject::NAME_KEY, d->title_);
diff --git a/src/pipeline.cpp b/src/pipeline.cpp
index b24f71e7..c4a9d2c0 100644
--- a/src/pipeline.cpp
+++ b/src/pipeline.cpp
@@ -456,7 +456,7 @@ PJ *OPERATION(pipeline,0) {
 
         err = proj_errno_reset (P);
 
-        next_step = proj_create_argv (P->ctx, current_argc, current_argv);
+        next_step = pj_create_argv_internal (P->ctx, current_argc, current_argv);
         proj_log_trace (P, "Pipeline: Step %d (%s) at %p", i, current_argv[0], next_step);
 
         if (nullptr==next_step) {
diff --git a/src/proj.h b/src/proj.h
index 2b4531ec..552f4b26 100644
--- a/src/proj.h
+++ b/src/proj.h
@@ -653,16 +653,16 @@ typedef enum
  * \defgroup iso19111_functions Binding in C of basic methods from the C++ API
  *  Functions for ISO19111 C API
  *
- * The PJ* objects returned by proj_create_from_user_input(), proj_create_from_wkt(),
- * proj_create_from_proj_string(), proj_create_from_database() and other functions
+ * The PJ* objects returned by proj_create_from_wkt(),
+ * proj_create_from_database() and other functions in that section
  * will have generally minimal interaction with the functions declared in the
  * upper section of this header file (calling those functions on those objects
  * will either return an error or default/non-sensical values). The exception is
  * for ISO19111 objects of type CoordinateOperation that can be exported as a
  * valid PROJ pipeline. In this case, the PJ objects will work for example with
  * proj_trans_generic().
- * Conversely, objects returned by proj_create() and proj_create_argv() will
- * return an error when used with functions of this section.
+ * Conversely, objects returned by proj_create() and proj_create_argv(), which
+ * are not of type CRS, will return an error when used with functions of this section.
  * @{
  */
 
@@ -686,19 +686,11 @@ const char PROJ_DLL *proj_context_get_database_metadata(PJ_CONTEXT* ctx,
 PJ_GUESSED_WKT_DIALECT PROJ_DLL proj_context_guess_wkt_dialect(PJ_CONTEXT *ctx,
                                                                const char *wkt);
 
-PJ PROJ_DLL *proj_create_from_user_input(PJ_CONTEXT *ctx,
-                                                 const char *text,
-                                                 const char* const *options);
-
 PJ PROJ_DLL *proj_create_from_wkt(PJ_CONTEXT *ctx, const char *wkt,
                                           const char* const *options,
                                           PROJ_STRING_LIST *out_warnings,
                                           PROJ_STRING_LIST *out_grammar_errors);
 
-PJ PROJ_DLL *proj_create_from_proj_string(PJ_CONTEXT *ctx,
-                                                  const char *proj_string,
-                                                  const char* const *options);
-
 PJ PROJ_DLL *proj_create_from_database(PJ_CONTEXT *ctx,
                                                const char *auth_name,
                                                const char *code,
diff --git a/src/proj_internal.h b/src/proj_internal.h
index 0cc99c81..dcfd6797 100644
--- a/src/proj_internal.h
+++ b/src/proj_internal.h
@@ -901,6 +901,9 @@ PJ* pj_init_ctx_with_allow_init_epsg( projCtx_t *ctx, int argc, char **argv, int
 
 std::string PROJ_DLL pj_add_type_crs_if_needed(const std::string& str);
 
+PJ *pj_create_internal (PJ_CONTEXT *ctx, const char *definition);
+PJ *pj_create_argv_internal (PJ_CONTEXT *ctx, int argc, char **argv);
+
 /* classic public API */
 #include "proj_api.h"
 
diff --git a/src/proj_symbol_rename.h b/src/proj_symbol_rename.h
index a7628e35..0ce342fd 100644
--- a/src/proj_symbol_rename.h
+++ b/src/proj_symbol_rename.h
@@ -102,6 +102,8 @@
 #define proj_context_get_use_proj4_init_rules internal_proj_context_get_use_proj4_init_rules
 #define proj_context_guess_wkt_dialect internal_proj_context_guess_wkt_dialect
 #define proj_context_set_database_path internal_proj_context_set_database_path
+#define proj_context_set_file_finder internal_proj_context_set_file_finder
+#define proj_context_set_search_paths internal_proj_context_set_search_paths
 #define proj_context_use_proj4_init_rules internal_proj_context_use_proj4_init_rules
 #define proj_convert_conversion_to_other_method internal_proj_convert_conversion_to_other_method
 #define proj_coord internal_proj_coord
@@ -190,8 +192,6 @@
 #define proj_create_engineering_crs internal_proj_create_engineering_crs
 #define proj_create_from_database internal_proj_create_from_database
 #define proj_create_from_name internal_proj_create_from_name
-#define proj_create_from_proj_string internal_proj_create_from_proj_string
-#define proj_create_from_user_input internal_proj_create_from_user_input
 #define proj_create_from_wkt internal_proj_create_from_wkt
 #define proj_create_geocentric_crs internal_proj_create_geocentric_crs
 #define proj_create_geocentric_crs_from_datum internal_proj_create_geocentric_crs_from_datum