From 4adcb962d555cba7af8e1de42d203f03d28d81a5 Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sesse@debian.org>
Date: Mon, 1 Jun 2009 22:25:13 +0200
Subject: [PATCH] Move some parts of the driver code into its own function.

---
 driver.c | 39 ++++++++++++++++-----------------------
 driver.h | 23 +++++++++++++++++++++++
 2 files changed, 39 insertions(+), 23 deletions(-)
 create mode 100644 driver.h

diff --git a/driver.c b/driver.c
index dfa61dd..c4f48ac 100644
--- a/driver.c
+++ b/driver.c
@@ -5,24 +5,11 @@
 #include "bytesource.h"
 #include "choice.h"
 #include "dehuff.h"
+#include "driver.h"
 #include "idct.h"
 #include "input.h"
 #include "zigzag.h"
 
-struct jpeg_image {
-	unsigned precision;
-	unsigned width, height;
-	unsigned num_components;
-	unsigned hsample[256], vsample[256], qtable[256];
-	unsigned max_hsample, max_vsample;
-	unsigned stride[256];
-	unsigned num_blocks_horizontal, num_blocks_vertical;
-	uint32_t qvalues[256][DCTSIZE2];
-	void* idct_data[256];
-	uint8_t* pixel_data[256];
-	uint8_t* pixel_write_pointer[256];
-};
-
 ssize_t stdio_read(void* userdata, uint8_t* buf, size_t count) 
 {
 	return fread(buf, 1, count, (FILE*)userdata);
@@ -261,14 +248,12 @@ void skip_segment(struct byte_source* source)
 	}
 }
 	
-int main(void)
+void read_jpeg(struct jpeg_image* jpeg, FILE *input)
 {
-	struct jpeg_image jpeg;
-	memset(&jpeg, 0, sizeof(jpeg));
-	init_choices();
-
+	memset(jpeg, 0, sizeof(*jpeg));
+	
 	struct byte_source source;
-	init_byte_source(&source, stdio_read, stdin);
+	init_byte_source(&source, stdio_read, input);
 
 	huffman_tables_t tables;
 
@@ -306,11 +291,11 @@ int main(void)
 			break;
 		case 0xdb:
 			/* DQT */
-			read_dqt(&source, &jpeg);
+			read_dqt(&source, jpeg);
 			break;
 		case 0xc0:
 			/* SOF0 (baseline DCT, Huffman encoded) */
-			read_sof(&source, &jpeg);
+			read_sof(&source, jpeg);
 			break;
 		case 0xd8:
 			/* SOI */
@@ -324,7 +309,7 @@ int main(void)
 			break;
 		case 0xda:
 			/* SOS (start of scan) */
-			read_scan(&source, &jpeg, &tables);
+			read_scan(&source, jpeg, &tables);
 			break;
 		default:
 			fprintf(stderr, "Error: Unknown marker 0x%02x\n", m2);
@@ -332,3 +317,11 @@ int main(void)
 		}
 	}
 }
+	
+int main(void)
+{
+	init_choices();
+
+	struct jpeg_image jpeg;
+	read_jpeg(&jpeg, stdin);
+}
diff --git a/driver.h b/driver.h
new file mode 100644
index 0000000..2a359d5
--- /dev/null
+++ b/driver.h
@@ -0,0 +1,23 @@
+#ifndef _DRIVER_H
+#define _DRIVER_H 1
+
+#include <stddef.h>
+#include "idct.h"
+
+struct jpeg_image {
+	unsigned precision;
+	unsigned width, height;
+	unsigned num_components;
+	unsigned hsample[256], vsample[256], qtable[256];
+	unsigned max_hsample, max_vsample;
+	unsigned stride[256];
+	unsigned num_blocks_horizontal, num_blocks_vertical;
+	uint32_t qvalues[256][DCTSIZE2];
+	void* idct_data[256];
+	uint8_t* pixel_data[256];
+	uint8_t* pixel_write_pointer[256];
+};
+
+void read_jpeg(struct jpeg_image* jpeg, FILE *input);
+
+#endif /* !defined(_DRIVER_H) */
-- 
2.39.2