From a213818a689e41df697d1b2baf6864fc62859fdb Mon Sep 17 00:00:00 2001
From: Jeffrey Armstrong <jeff@approximatrix.com>
Date: Tue, 11 May 2021 21:03:34 -0400
Subject: Added a utility module for parsing query strings that is probably a
 bit too advanced for what we're doing.

---
 captain/queryutils.f90 | 176 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 176 insertions(+)
 create mode 100644 captain/queryutils.f90

diff --git a/captain/queryutils.f90 b/captain/queryutils.f90
new file mode 100644
index 0000000..c6b5d83
--- /dev/null
+++ b/captain/queryutils.f90
@@ -0,0 +1,176 @@
+module query_utilities
+implicit none
+
+    type :: query_component
+        character(len=:), pointer::key
+        character(len=:), pointer::value
+        
+        contains
+        
+        procedure :: parse => query_component_parse
+        procedure :: destroy => query_component_destroy
+        procedure :: has_key => query_component_has_key
+        
+    end type query_component
+    
+    type :: query
+    
+        character(len=:), pointer::full
+        
+        type(query_component), dimension(:), pointer::components
+        
+        contains
+        
+        procedure :: init => query_init
+        procedure :: destroy => query_destroy
+        procedure :: component_count => query_component_count
+        
+    end type query
+    
+contains
+
+    subroutine query_component_parse(self, comptext)
+    implicit none
+    
+        class(query_component), intent(out)::self
+        character(*), intent(in)::comptext
+        
+        character(len=:), allocatable::decoded
+        integer::i_in, i_out, i_equals, chnum
+        
+        allocate(character(len=len_trim(comptext)) :: decoded)
+        
+        i_equals = 0
+        i_out = 1
+        i_in = 1
+        do while(i_in <= len_trim(comptext))
+            if(comptext(i_in:i_in) /= '%') then
+                decoded(i_out:i_out) = comptext(i_in:i_in)
+                if(comptext(i_in:i_in) == '=') then
+                    i_equals = i_out
+                end if
+                i_in = i_in + 1
+            else
+                i_in = i_in + 1
+                read(comptext(i_in:i_in+1), '(Z2)') chnum
+                decoded(i_out:i_out) = achar(chnum)
+                i_in = i_in + 2
+            end if
+            i_out = i_out + 1
+        end do
+        
+        if(i_equals == 0) then
+            allocate(character(len=len_trim(decoded)) :: self%value)
+            self%value = decoded
+        else
+            allocate(character(len=i_equals-1) :: self%key)
+            self%key = decoded(1:i_equals-1)
+            
+            allocate(character(len=len_trim(decoded)-i_equals) :: self%value)
+            self%value = decoded(i_equals+1:len_trim(decoded))
+        end if
+        
+        deallocate(decoded)
+        
+    end subroutine query_component_parse
+    
+    elemental subroutine query_component_destroy(self)
+    implicit none
+    
+        class(query_component), intent(inout)::self
+        
+        if(associated(self%key)) then
+            deallocate(self%key)
+        end if
+        
+        if(associated(self%value)) then
+            deallocate(self%value)
+        end if
+        
+    end subroutine query_component_destroy
+
+    pure function query_component_has_key(self) result(res)
+    implicit none
+    
+        class(query_component), intent(in)::self
+        logical::res
+        
+        res = associated(self%key)
+        
+    end function query_component_has_key
+    
+    subroutine query_init(self, str)
+    implicit none
+        
+        class(query), intent(out)::self
+        character(len=*), intent(in)::str
+        
+        integer::ampersands, i, i_end, i_comp
+        
+        allocate(character(len=len_trim(str)) :: self%full)
+        self%full = str
+        
+        ampersands = 0
+        do i = 1, len(self%full)
+            if(self%full(i:i) == '&') then
+                ampersands = ampersands + 1
+            end if
+        end do
+        
+        allocate(self%components(ampersands + 1))
+        
+        ! Split and parse each component
+        if(ampersands == 0) then
+            call self%components(1)%parse(self%full)
+        else
+            i_comp = 1
+            i = 1
+            i_end = index(self%full, '&')
+            do while(i_comp < ampersands + 1)
+                call self%components(i_comp)%parse(self%full(i:i_end-1))
+                i = i_end + 1
+                do i_end = i, len_trim(self%full)
+                    if(self%full(i_end:i_end) == '&') then
+                        exit
+                    end if
+                end do
+                i_comp = i_comp + 1
+            end do
+            call self%components(i_comp)%parse(self%full(i:i_end-1))
+        end if
+    
+    end subroutine query_init
+    
+    pure function query_component_count(self)
+    implicit none
+        
+        class(query), intent(in)::self
+        integer::query_component_count
+        
+        if(associated(self%components)) then
+            query_component_count = size(self%components)
+        else
+            query_component_count = 0
+        end if
+    
+    end function query_component_count
+    
+    subroutine query_destroy(self)
+    implicit none
+    
+        class(query), intent(inout)::self
+        
+        if(associated(self%full)) then
+            deallocate(self%full)
+            self%full => null()
+        end if
+        
+        if(associated(self%components)) then
+            call self%components%destroy()
+            deallocate(self%components)
+            self%components => null()
+        end if
+            
+    end subroutine query_destroy
+    
+end module query_utilities
-- 
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