From fe6b2fe2f6cfb71d33cc06ba26be961569e585cc Mon Sep 17 00:00:00 2001
From: Vlasta Vesely <vlastavesely@protonmail.ch>
Date: Wed, 25 Apr 2018 18:11:56 +0200
Subject: [PATCH] define transliteration context

---
 Makefile          |  2 +-
 iast.c            | 21 +++++++++++++++++++++
 iast.h            |  8 ++++++++
 transliteration.c | 24 +++++++++++++++++++++++-
 transliteration.h | 12 +++++++++++-
 5 files changed, 64 insertions(+), 3 deletions(-)
 create mode 100644 iast.c
 create mode 100644 iast.h

diff --git a/Makefile b/Makefile
index 9796375..57c4fad 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 .PHONY: all clean
 
 all:
-	$(CC) main.c syllable.c utf8.c transliteration.c -o main
+	$(CC) main.c syllable.c utf8.c transliteration.c iast.c -o main
 	./main
 
 clean:
diff --git a/iast.c b/iast.c
new file mode 100644
index 0000000..b7dc704
--- /dev/null
+++ b/iast.c
@@ -0,0 +1,21 @@
+#include <stdlib.h>
+#include "iast.h"
+
+static const struct transliteration_letter table_letters[] = {
+
+	/* Vowels */
+	{0x0905, "a"},		/* अ */
+	{0x0906, "ā"},		/* आ */
+
+	{0, NULL}
+};
+
+struct transliteration_context *transliteration_context_iast_alloc()
+{
+	struct transliteration_context *context;
+
+	context = malloc(sizeof(*context));
+	context->table_letters = table_letters;
+
+	return context;
+}
diff --git a/iast.h b/iast.h
new file mode 100644
index 0000000..607e370
--- /dev/null
+++ b/iast.h
@@ -0,0 +1,8 @@
+#ifndef __IAST_H
+#define __IAST_H
+
+#include "transliteration.h"
+
+struct transliteration_context *transliteration_context_iast_alloc();
+
+#endif /* __IAST_H */
diff --git a/transliteration.c b/transliteration.c
index b838747..646894e 100644
--- a/transliteration.c
+++ b/transliteration.c
@@ -5,7 +5,22 @@
 #include "syllable.h"
 #include "utf8.h"
 
-char *transliterate_devanagari_to_latin(const char *text)
+struct transliteration_letter *find_letter_by_code(unsigned long c,
+	struct transliteration_letter *table)
+{
+	struct transliteration_letter *walk = table;
+
+	while (walk->code != 0) {
+		if (c == walk->code)
+			return walk;
+		walk++;
+	}
+
+	return NULL;
+}
+
+char *transliterate_devanagari_to_latin(const char *text,
+	struct transliteration_context *context)
 {
 	unsigned int length = strlen(text);
 	const char *ptr = text;
@@ -13,6 +28,7 @@ char *transliterate_devanagari_to_latin(const char *text)
 	char *tmp;
 	unsigned long c;
 	struct syllable *head, *tail;
+	struct transliteration_letter *letter;
 
 	head = syllable_alloc("");
 	tail = head;
@@ -21,6 +37,12 @@ char *transliterate_devanagari_to_latin(const char *text)
 		c = utf8_unpack_char(ptr);
 		ptr += utf8_char_length(c);
 
+		letter = find_letter_by_code(c, context->table_letters);
+		if (letter != NULL) {
+			tail = syllable_append(tail, letter->data);
+			continue;
+		}
+
 		tmp = utf8_code_to_string(c);
 		tail = syllable_append(tail, tmp);
 		free(tmp);
diff --git a/transliteration.h b/transliteration.h
index d1da50e..2b95123 100644
--- a/transliteration.h
+++ b/transliteration.h
@@ -1,6 +1,16 @@
 #ifndef __TRANSLITERATION_H
 #define __TRANSLITERATION_H
 
-char *transliterate_devanagari_to_latin(const char *text);
+struct transliteration_letter {
+	unsigned long code;
+	const char *data;
+};
+
+struct transliteration_context {
+	const struct transliteration_letter *table_letters;
+};
+
+char *transliterate_devanagari_to_latin(const char *text,
+	struct transliteration_context *context);
 
 #endif /* __TRANSLITERATION_H */