From b0a801a8555edbe36723929c3dd9a4ad3fa1e7ce Mon Sep 17 00:00:00 2001
From: Michael Uleysky <uleysky@poi.dvo.ru>
Date: Thu, 24 Sep 2015 13:34:16 +1000
Subject: [PATCH] Gmt module: Gmt module initial commit

---
 modules/gmt/makemod    |  1 +
 modules/gmt/modgmt.cpp | 86 ++++++++++++++++++++++++++++++++++++++++++
 modules/gmt/modgmt.h   | 31 +++++++++++++++
 3 files changed, 118 insertions(+)
 create mode 100644 modules/gmt/makemod
 create mode 100644 modules/gmt/modgmt.cpp
 create mode 100644 modules/gmt/modgmt.h

diff --git a/modules/gmt/makemod b/modules/gmt/makemod
new file mode 100644
index 0000000..94fc772
--- /dev/null
+++ b/modules/gmt/makemod
@@ -0,0 +1 @@
+MODLIBS+=-lgmt
\ No newline at end of file
diff --git a/modules/gmt/modgmt.cpp b/modules/gmt/modgmt.cpp
new file mode 100644
index 0000000..98b07b0
--- /dev/null
+++ b/modules/gmt/modgmt.cpp
@@ -0,0 +1,86 @@
+#include "modgmt.h"
+
+#if defined MODGMT_WORKAROUND_EXIT
+// Exit handler.
+static void gmtonexithandler(int ret, void* x)
+{
+ reinterpret_cast<struct gmtworkthreadpars*>(x)->ret=ret;
+ close(reinterpret_cast<struct gmtworkthreadpars*>(x)->fd);
+ pthread_exit(&(reinterpret_cast<struct gmtworkthreadpars*>(x)->ret));
+}
+#endif
+
+// This function call GMT_Call_Module in separate thread. It just a hack to workaround absence of callbacks.
+static void* gmtworkthread(void* x)
+{
+ struct gmtworkthreadpars* p=reinterpret_cast<struct gmtworkthreadpars*>(x);
+#if defined MODGMT_WORKAROUND_EXIT
+ on_exit(gmtonexithandler,x);
+#endif
+ GMT_Append_Option(p->api,GMT_Make_Option(p->api,'>',const_cast<char*>(("/dev/fd/"+std::to_string(p->fd)).c_str())),p->opts);
+ p->ret=GMT_Call_Module(p->api,p->module,GMT_MODULE_OPT,p->opts);
+#if defined MODGMT_WORKAROUND_EXIT
+ exit(p->ret);
+#endif
+ close(p->fd);
+ return &p->ret;
+}
+
+// Wrapper for GMT_Call_Module, res is output.
+int callgmtmodule(void *api, const char *module, struct GMT_OPTION *opts, std::string& res)
+{
+ int pipefd[2];
+ ssize_t br;
+ char buffer[4096];
+ pthread_t wthr;
+ struct gmtworkthreadpars p;
+ int *pret;
+
+ pipe(pipefd);
+ p.api=api;
+ p.module=module;
+ p.opts=opts;
+ p.fd=pipefd[1];
+
+ pthread_create(&wthr,0,&gmtworkthread,&p);
+
+ res.erase();
+ do
+ {
+  br=read(pipefd[0],buffer,4096);
+  res.append(buffer,br);
+ } while(0!=br);
+ close(pipefd[0]);
+ res.shrink_to_fit();
+ pthread_join(wthr,reinterpret_cast<void**>(&pret));
+
+ return *pret;
+}
+
+
+// Initialisation function
+int gmt_module_init(void* p)
+{
+ // Fill header and footer
+ struct GMT_OPTION* opts;
+ void* gmtapi;
+ int ret;
+ const char* ch="--GMT_HISTORY=f -C -P -K";
+ const char* cf="--GMT_HISTORY=f -C -P -O";
+ char* h=strdup(ch);
+ char* f=strdup(cf);
+
+ gmtapi=GMT_Create_Session("gmt_makemap",2,3,0);
+ if(0==gmtapi) return 1;
+ opts=GMT_Create_Options(gmtapi,0,h);
+ ret=callgmtmodule(gmtapi,"psclip",opts,header);
+ GMT_Destroy_Options(gmtapi,&opts);
+ opts=GMT_Create_Options(gmtapi,0,f);
+ if(0==ret) ret=callgmtmodule(gmtapi,"psclip",opts,footer);
+ GMT_Destroy_Options(gmtapi,&opts);
+ GMT_Destroy_Session(gmtapi);
+ free(h); free(f);
+ if(0!=ret) return ret;
+
+ return 0;
+}
diff --git a/modules/gmt/modgmt.h b/modules/gmt/modgmt.h
new file mode 100644
index 0000000..d2f3c00
--- /dev/null
+++ b/modules/gmt/modgmt.h
@@ -0,0 +1,31 @@
+#include <pthread.h>
+#include <unistd.h>
+#include <gmt.h>
+#include <string.h>
+#include "common.h"
+
+// Workaround exit() in GMT_Call_Module. May need because return mode of gmt api is not very reliable
+#if defined MODGMT_WORKAROUND_EXIT
+#define GMTMODE 0
+#else
+#define GMTMODE 3
+#endif
+
+// here we save header and footer of gmt-produced eps files
+std::string header,footer;
+
+// Parameters for working thread
+struct gmtworkthreadpars
+{
+ void* api;
+ const char* module;
+ struct GMT_OPTION* opts;
+ int fd;
+ int ret;
+};
+
+extern "C" {
+EXPORT int gmt_module_init(void* p);
+}
+
+int callgmtmodule(void *api, const char *module, struct GMT_OPTION *opts, std::string& res);
\ No newline at end of file