Add tdemarkdown part - embeddable lightweight markdown viewing component.

TDEMarkdown is based on the md4c library and using TDEHTML for rendering
its output. For enhanced safety, on HTML widget is turned off everything
we don't need for viewing. It integrates nicely into Konqueror and
supports both Commonmark and GitHub markdown syntaxes.

Signed-off-by: Mavridis Philippe <mavridisf@gmail.com>

Prepare to merge tdemarkdown into tdelibs.

Signed-off-by: Slávek Banko <slavek.banko@axis.cz>
(cherry picked from commit 95279fbf6dfeb43d80590740a9259d7caa614177)

1 files changed, 205 insertions, 0 deletions

diff --git a/tdemarkdown/md4c/md2html/cmdline.c b/tdemarkdown/md4c/md2html/cmdline.c
new file mode 100644
index 000000000..c3fddfaa4
--- /dev/null
+++ b/tdemarkdown/md4c/md2html/cmdline.c
@@ -0,0 +1,205 @@
+/*
+ * C Reusables
+ * <http://github.com/mity/c-reusables>
+ *
+ * Copyright (c) 2017-2020 Martin Mitas
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "cmdline.h"
+
+#include <stdio.h>
+#include <string.h>
+
+
+#ifdef _WIN32
+    #define snprintf    _snprintf
+#endif
+
+
+#define CMDLINE_AUXBUF_SIZE     32
+
+
+
+static int
+cmdline_handle_short_opt_group(const CMDLINE_OPTION* options, const char* arggroup,
+        int (*callback)(int /*optval*/, const char* /*arg*/, void* /*userdata*/),
+        void* userdata)
+{
+    const CMDLINE_OPTION* opt;
+    int i;
+    int ret = 0;
+
+    for(i = 0; arggroup[i] != '\0'; i++) {
+        for(opt = options; opt->id != 0; opt++) {
+            if(arggroup[i] == opt->shortname)
+                break;
+        }
+
+        if(opt->id != 0  &&  !(opt->flags & CMDLINE_OPTFLAG_REQUIREDARG)) {
+            ret = callback(opt->id, NULL, userdata);
+        } else {
+            /* Unknown option. */
+            char badoptname[3];
+            badoptname[0] = '-';
+            badoptname[1] = arggroup[i];
+            badoptname[2] = '\0';
+            ret = callback((opt->id != 0 ? CMDLINE_OPTID_MISSINGARG : CMDLINE_OPTID_UNKNOWN),
+                            badoptname, userdata);
+        }
+
+        if(ret != 0)
+            break;
+    }
+
+    return ret;
+}
+
+int
+cmdline_read(const CMDLINE_OPTION* options, int argc, char** argv,
+        int (*callback)(int /*optval*/, const char* /*arg*/, void* /*userdata*/),
+        void* userdata)
+{
+    const CMDLINE_OPTION* opt;
+    char auxbuf[CMDLINE_AUXBUF_SIZE+1];
+    int fast_optarg_decision = 1;
+    int after_doubledash = 0;
+    int i = 1;
+    int ret = 0;
+
+    auxbuf[CMDLINE_AUXBUF_SIZE] = '\0';
+
+    /* Check whether there is any CMDLINE_OPTFLAG_COMPILERLIKE option with
+     * a name not starting with '-'. That would imply we can to check for
+     * non-option arguments only after refusing all such options. */
+    for(opt = options; opt->id != 0; opt++) {
+        if((opt->flags & CMDLINE_OPTFLAG_COMPILERLIKE)  &&  opt->longname[0] != '-')
+            fast_optarg_decision = 0;
+    }
+
+    while(i < argc) {
+        if(after_doubledash  ||  strcmp(argv[i], "-") == 0) {
+            /* Non-option argument.
+             * Standalone "-" usually means "read from stdin" or "write to
+             * stdout" so treat it always as a non-option. */
+            ret = callback(CMDLINE_OPTID_NONE, argv[i], userdata);
+        } else if(strcmp(argv[i], "--") == 0) {
+            /* End of options. All the remaining tokens are non-options
+             * even if they start with a dash. */
+            after_doubledash = 1;
+        } else if(fast_optarg_decision  &&  argv[i][0] != '-') {
+            /* Non-option argument. */
+            ret = callback(CMDLINE_OPTID_NONE, argv[i], userdata);
+        } else {
+            for(opt = options; opt->id != 0; opt++) {
+                if(opt->flags & CMDLINE_OPTFLAG_COMPILERLIKE) {
+                    size_t len = strlen(opt->longname);
+                    if(strncmp(argv[i], opt->longname, len) == 0) {
+                        /* Compiler-like option. */
+                        if(argv[i][len] != '\0')
+                            ret = callback(opt->id, argv[i] + len, userdata);
+                        else if(i+1 < argc)
+                            ret = callback(opt->id, argv[++i], userdata);
+                        else
+                            ret = callback(CMDLINE_OPTID_MISSINGARG, opt->longname, userdata);
+                        break;
+                    }
+                } else if(opt->longname != NULL  &&  strncmp(argv[i], "--", 2) == 0) {
+                    size_t len = strlen(opt->longname);
+                    if(strncmp(argv[i]+2, opt->longname, len) == 0) {
+                        /* Regular long option. */
+                        if(argv[i][2+len] == '\0') {
+                            /* with no argument provided. */
+                            if(!(opt->flags & CMDLINE_OPTFLAG_REQUIREDARG))
+                                ret = callback(opt->id, NULL, userdata);
+                            else
+                                ret = callback(CMDLINE_OPTID_MISSINGARG, argv[i], userdata);
+                            break;
+                        } else if(argv[i][2+len] == '=') {
+                            /* with an argument provided. */
+                            if(opt->flags & (CMDLINE_OPTFLAG_OPTIONALARG | CMDLINE_OPTFLAG_REQUIREDARG)) {
+                                ret = callback(opt->id, argv[i]+2+len+1, userdata);
+                            } else {
+                                snprintf(auxbuf, CMDLINE_AUXBUF_SIZE, "--%s", opt->longname);
+                                ret = callback(CMDLINE_OPTID_BOGUSARG, auxbuf, userdata);
+                            }
+                            break;
+                        } else {
+                            continue;
+                        }
+                    }
+                } else if(opt->shortname != '\0'  &&  argv[i][0] == '-') {
+                    if(argv[i][1] == opt->shortname) {
+                        /* Regular short option. */
+                        if(opt->flags & CMDLINE_OPTFLAG_REQUIREDARG) {
+                            if(argv[i][2] != '\0')
+                                ret = callback(opt->id, argv[i]+2, userdata);
+                            else if(i+1 < argc)
+                                ret = callback(opt->id, argv[++i], userdata);
+                            else
+                                ret = callback(CMDLINE_OPTID_MISSINGARG, argv[i], userdata);
+                            break;
+                        } else {
+                            ret = callback(opt->id, NULL, userdata);
+
+                            /* There might be more (argument-less) short options
+                             * grouped together. */
+                            if(ret == 0  &&  argv[i][2] != '\0')
+                                ret = cmdline_handle_short_opt_group(options, argv[i]+2, callback, userdata);
+                            break;
+                        }
+                    }
+                }
+            }
+
+            if(opt->id == 0) {  /* still not handled? */
+                if(argv[i][0] != '-') {
+                    /* Non-option argument. */
+                    ret = callback(CMDLINE_OPTID_NONE, argv[i], userdata);
+                } else {
+                    /* Unknown option. */
+                    char* badoptname = argv[i];
+
+                    if(strncmp(badoptname, "--", 2) == 0) {
+                        /* Strip any argument from the long option. */
+                        char* assignment = strchr(badoptname, '=');
+                        if(assignment != NULL) {
+                            size_t len = assignment - badoptname;
+                            if(len > CMDLINE_AUXBUF_SIZE)
+                                len = CMDLINE_AUXBUF_SIZE;
+                            strncpy(auxbuf, badoptname, len);
+                            auxbuf[len] = '\0';
+                            badoptname = auxbuf;
+                        }
+                    }
+
+                    ret = callback(CMDLINE_OPTID_UNKNOWN, badoptname, userdata);
+                }
+            }
+        }
+
+        if(ret != 0)
+            return ret;
+        i++;
+    }
+
+    return ret;
+}
+