Initial commit

.gitignore

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+*.o
+*.a
+crctest

Makefile

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+
+
+.PHONY: all
+all: tinycrc.a crctest
+
+.PHONY: clean
+clean:
+	rm -f crctest.cpp.o tinycrc.a
+	$(MAKE) -C src clean
+
+crctest: crctest.cpp.o tinycrc.a
+	gcc -g -o $@ $< tinycrc.a
+
+tinycrc.a:
+	$(MAKE) -C src tinycrc.a
+	cp src/tinycrc.a .
+
+%.cpp.o: %.cpp
+	gcc -c -o $@ $<

crctest.cpp

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+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <cstring>
+#include "src/tinycrc.h"
+
+
+
+int main()
+{
+    uint8_t* buffer = (uint8_t*)malloc(32);
+
+    sprintf((char*)buffer, "Hello %s!", "World");
+
+    uint32_t crc32 = tinycrc_crc32(buffer, 32);
+    uint16_t crc16 = tinycrc_crc16(buffer, 32);
+    uint8_t crc8 = tinycrc_crc8(buffer, 32);
+
+    printf("%-32s | crc32 | %08x\n", (char*)buffer, crc32);
+    printf("%-32s | crc16 |     %04x\n", (char*)buffer, crc16);
+    printf("%-32s | crc8  |       %02x\n", (char*)buffer, crc8);
+
+    sprintf((char*)buffer, "Hello %s!", "Worlds");
+
+    crc32 = tinycrc_crc32(buffer, 32);
+    crc16 = tinycrc_crc16(buffer, 32);
+    crc8 = tinycrc_crc8(buffer, 32);
+
+    printf("%-32s | crc32 | %08x\n", (char*)buffer, crc32);
+    printf("%-32s | crc16 |     %04x\n", (char*)buffer, crc16);
+    printf("%-32s | crc8  |       %02x\n", (char*)buffer, crc8);
+
+    sprintf((char*)buffer, "%s %d", "foobarxyzzy", 42);
+
+    crc32 = tinycrc_crc32(buffer, 32);
+    crc16 = tinycrc_crc16(buffer, 32);
+    crc8 = tinycrc_crc8(buffer, 32);
+
+    printf("%-32s | crc32 | %08x\n", (char*)buffer, crc32);
+    printf("%-32s | crc16 |     %04x\n", (char*)buffer, crc16);
+    printf("%-32s | crc8  |       %02x\n", (char*)buffer, crc8);
+
+    free(buffer);
+
+
+}

src/Makefile

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+
+OBJS=crc32.o crc16.o crc8.o
+
+.PHONY: all
+all: tinycrc.a
+
+.PHONY: clean
+clean:
+	rm -f tinycrc.a $(OBJS)
+
+%.o: %.cpp
+	g++ -g -c -o $@ $<
+
+tinycrc.a: $(OBJS)
+	ar qc $@ $(OBJS)

src/crc16.cpp

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+#include "tinycrc.h"
+
+/*
+    CRC16
+*/
+
+uint16_t tinycrc_crc16(const uint8_t *data, uint16_t size)
+{
+    unsigned char x;
+    unsigned short crc = 0xFFFF;
+
+    if (data == nullptr) {
+        return 0;
+    }
+
+    for (int index = 0 ; index < size ; ++index) {
+        x = crc >> 8 ^ *data++;
+        x ^= x>>4;
+        crc = (crc << 8) ^ ((unsigned short)(x << 12)) ^ ((unsigned short)(x <<5)) ^ ((unsigned short)x);
+    }
+    return crc & 0xFFFF;
+}

src/crc32.cpp

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+#include <stdio.h>
+#include <ctype.h>
+#include "tinycrc.h"
+
+/*
+    CRC32
+*/
+
+uint32_t tinycrc_crc32(const uint8_t* data, uint16_t size)
+{
+
+    const unsigned long crc_table[16] = {
+        0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
+        0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
+        0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
+        0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
+    };
+
+    if (data == nullptr) {
+        return 0;
+    }
+
+    unsigned long crc = ~0L;
+
+    for (int index = 0 ; index < size ; ++index) {
+        crc = crc_table[(crc ^ data[index]) & 0x0f] ^ (crc >> 4);
+        crc = crc_table[(crc ^ (data[index] >> 4)) & 0x0f] ^ (crc >> 4);
+        crc = ~crc;
+    }
+
+    return crc & 0xFFFFFFFF;
+
+};

src/crc8.cpp

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+#include "tinycrc.h"
+
+/*
+    CRC8 (from https://devcoons.com/crc8/)
+*/
+
+uint8_t tinycrc_crc8(const uint8_t* data, uint16_t length) 
+{
+   char crc = 0x00;
+   char extract;
+   char sum;
+   for(int i=0;i<length;i++)
+   {
+      extract = *data;
+      for (char tempI = 8; tempI; tempI--) 
+      {
+         sum = (crc ^ extract) & 0x01;
+         crc >>= 1;
+         if (sum)
+            crc ^= 0x8C;
+         extract >>= 1;
+      }
+      data++;
+   }
+   return crc;
+}

src/tinycrc.h

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+#pragma once
+#include <stdint.h>
+
+uint32_t tinycrc_crc32(const uint8_t* data, uint16_t size);
+
+uint16_t tinycrc_crc16(const uint8_t* data, uint16_t size);
+
+uint8_t tinycrc_crc8(const uint8_t* data, uint16_t length);