Diff: BaseJpefDecode.cpp

Revision:

0:7121d9fb45f4

Child:

1:58dfd5386a92

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/BaseJpefDecode.cpp	Sun Oct 07 12:03:40 2012 +0000
@@ -0,0 +1,173 @@
+#include "mbed.h"
+#include "BaseJpegDecode.h"
+
+#if 0
+#define DBG(...) do{fprintf(stderr,"[%s@%d] ",__PRETTY_FUNCTION__,__LINE__);fprintf(stderr,__VA_ARGS__);} while(0);
+#define DBG_WAIT(A) wait_ms(A)
+#else
+#define DBG(...)
+#define DBG_WAIT(A)
+#endif
+
+#define MARK_SOF 0xc0
+#define MARK_DHT 0xc4
+#define MARK_RST0 0xd0
+#define MARK_RST7 0xd7
+#define MARK_SOI 0xd8
+#define MARK_EOI 0xd9
+#define MARK_SOS 0xda
+#define MARK_DQT 0xdb
+#define MARK_DRI 0xdd
+#define MARK_APP 0xe0
+
+#define SEQ_INIT 0
+#define SEQ_MARK 1
+#define SEQ_LEN  2
+#define SEQ_LEN2 3
+#define SEQ_SKIP 4
+#define SEQ_SOS  5
+#define SEQ_SOS2 6
+
+#define HT_DC 0
+#define HT_AC 1
+
+BaseJpegDecode::BaseJpegDecode()
+{
+    m_yblocks = JPEG_MCU_YBLOCKS; // 2 or 4
+    clear();
+    pHD = new HuffmanDecode;
+}
+
+void BaseJpegDecode::clear()
+{
+    m_seq = SEQ_INIT;
+}
+
+void BaseJpegDecode::input(uint8_t* buf, int len)
+{
+    for(int i = 0; i < len; i++) {
+        input(buf[i]);
+    }
+}
+
+void BaseJpegDecode::restart()
+{
+    m_block = 0;
+    m_scan = 0;
+    m_old_DC_value[0] = 0;
+    m_old_DC_value[1] = 0;
+    m_bitpat.clear();
+    m_huff = NULL;
+}
+
+void BaseJpegDecode::input(uint8_t c)
+{
+    switch(m_seq) {
+        case SEQ_INIT:
+            if (c == 0xff) {
+                m_seq = SEQ_MARK;
+            }
+            break;
+        case SEQ_MARK:
+            outputMARK(c);
+            if (c == MARK_SOI || c == MARK_EOI) {
+                m_seq = SEQ_INIT;
+                break;
+            }
+            m_mark = c;
+            m_seq = SEQ_LEN;
+            break;
+        case SEQ_LEN:
+            m_skip = c;
+            m_seq = SEQ_LEN2;
+            break;
+        case SEQ_LEN2:
+            m_skip <<= 8;
+            m_skip |= c;
+            m_skip -= 2;
+            m_seq = SEQ_SKIP;
+            break;
+        case SEQ_SKIP:
+            if (--m_skip > 0) {
+                break;
+            }
+            if (m_mark == MARK_SOS) {
+                m_seq = SEQ_SOS;
+                m_mcu = 0;
+                restart();
+                break;
+            }
+            m_seq = SEQ_INIT;
+            break;
+        case SEQ_SOS:
+            if (c == 0xff) {
+                m_seq = SEQ_SOS2;
+                break;
+            }
+            inputScan(c);
+            break;
+        case SEQ_SOS2:
+            if (c == 0x00) {
+                inputScan(0xff);
+                m_seq = SEQ_SOS;
+                break;
+            } else if (c >= MARK_RST0 && c <= MARK_RST7) {
+                restart();
+                m_seq = SEQ_SOS;
+                break;
+            }
+            outputMARK(c);
+            m_seq = SEQ_INIT;
+            break;
+        default:
+            break;
+    }
+}
+
+void BaseJpegDecode::inputScan(uint8_t c)
+{
+    m_bitpat += c;
+    while(m_bitpat.size() > 0) {
+        int tc = (m_scan == 0) ? HT_DC : HT_AC;
+        int th = (m_block < m_yblocks) ? 0 : 1;
+        DBG("%d %d %08x %d\n", tc, th, m_bitpat.peek(32), m_bitpat.size());
+        if (m_huff == NULL) {
+            m_huff = pHD->Lookup(tc, th, &m_bitpat);
+            if (m_huff == NULL) {
+                break;
+            }
+            m_bitpat.get(m_huff->code_size); // skip code
+        }
+        if (m_huff->value_size > m_bitpat.size()) {
+            break;
+        }
+        DBG("%d %d %d %02x\n", m_huff->run, m_huff->value_size, m_huff->code_size, m_huff->code);
+        int value = pHD->getValue(m_huff, &m_bitpat);
+        if (tc == HT_DC) {
+            value += m_old_DC_value[th];
+            outputDC(m_mcu, m_block, value);
+            m_old_DC_value[th] = value;
+            m_scan++;
+        } else { // AC
+            if (m_huff->value_size == 0 && m_huff->run == 0) { // EOB
+                DBG("AC EOB\n");
+                m_scan = 64;
+            } else {
+                for(int i = 0; i < m_huff->run; i++) {
+                    outputAC(m_mcu, m_block, m_scan, 0);
+                    m_scan++;
+                }
+                outputAC(m_mcu, m_block, m_scan, value);
+                m_scan++;
+            }
+            if (m_scan >= 64) {
+                m_scan = 0;
+                if (++m_block >= (m_yblocks+2)) {
+                    m_block = 0;
+                    m_mcu++;
+                }
+            }
+        }
+        m_huff = NULL;
+    }
+}