Separation Generator to a dedicated repo

Change-Id: Id94831651c3266861435272a6e36c7884bef2c45
Signed-off-by: Romain Forlot <romain.forlot@iot.bzh>

5 files changed, 588 insertions, 0 deletions

diff --git a/libs/bitfield-c/src/bitfield/8byte.c b/libs/bitfield-c/src/bitfield/8byte.c
new file mode 100644
index 00000000..9325ed1b
--- /dev/null
+++ b/libs/bitfield-c/src/bitfield/8byte.c
@@ -0,0 +1,61 @@
+#include <bitfield/bitfield.h>
+#include <bitfield/8byte.h>
+#include <stddef.h>
+#include <limits.h>
+#include <string.h>
+
+#define EIGHTBYTE_BIT (8 * sizeof(uint64_t))
+
+uint8_t eightbyte_get_nibble(const uint64_t source, const uint8_t nibble_index,
+        const bool data_is_big_endian) {
+    return (uint8_t) eightbyte_get_bitfield(source, NIBBLE_SIZE * nibble_index,
+            NIBBLE_SIZE, data_is_big_endian);
+}
+
+uint8_t eightbyte_get_byte(uint64_t source, const uint8_t byte_index,
+        const bool data_is_big_endian) {
+    if(data_is_big_endian) {
+        source = __builtin_bswap64(source);
+    }
+    return (source >> (EIGHTBYTE_BIT - ((byte_index + 1) * CHAR_BIT))) & 0xFF;
+}
+
+// TODO is this funciton necessary anymore? is it any faster for uint64_t than
+// get_bitfield(data[], ...)? is the performance better on a 32 bit platform
+// like the PIC32?
+uint64_t eightbyte_get_bitfield(uint64_t source, const uint16_t offset,
+        const uint16_t bit_count, const bool data_is_big_endian) {
+    int startByte = offset / CHAR_BIT;
+    int endByte = (offset + bit_count - 1) / CHAR_BIT;
+
+    if(!data_is_big_endian) {
+        source = __builtin_bswap64(source);
+    }
+
+    uint8_t* bytes = (uint8_t*)&source;
+    uint64_t ret = bytes[startByte];
+    if(startByte != endByte) {
+        // The lowest byte address contains the most significant bit.
+        uint8_t i;
+        for(i = startByte + 1; i <= endByte; i++) {
+            ret = ret << 8;
+            ret = ret | bytes[i];
+        }
+    }
+
+    ret >>= 8 - find_end_bit(offset + bit_count);
+    return ret & bitmask(bit_count);
+}
+
+bool eightbyte_set_bitfield(uint64_t value, const uint16_t offset,
+        const uint16_t bit_count, uint64_t* destination) {
+    if(value > bitmask(bit_count)) {
+        return false;
+    }
+
+    int shiftDistance = EIGHTBYTE_BIT - offset - bit_count;
+    value <<= shiftDistance;
+    *destination &= ~(bitmask(bit_count) << shiftDistance);
+    *destination |= value;
+    return true;
+}
diff --git a/libs/bitfield-c/src/bitfield/8byte.h b/libs/bitfield-c/src/bitfield/8byte.h
new file mode 100644
index 00000000..04512690
--- /dev/null
+++ b/libs/bitfield-c/src/bitfield/8byte.h
@@ -0,0 +1,88 @@
+#ifndef __8BYTE_H__
+#define __8BYTE_H__
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Public: Reads a subset of bits into a uint64_t.
+ *
+ * source - the bytes in question.
+ * offset - the starting index of the bit field (beginning from 0).
+ * bit_count - the width of the bit field to extract.
+ * data_is_big_endian - if the data passed in is little endian, set this to false and it
+ *      will be flipped before grabbing the bit field.
+ *
+ * Bit fields are positioned according to big-endian bit layout.
+ *
+ * For example, the bit layout of the value "42" (i.e. 00101010 set at position
+ * 14 with length 6 is:
+ *
+ *     000000000000001010100000000000000000000000000000000000000000000
+ *
+ * and the same value and position but with length 8 is:
+ *
+ *     000000000000000010101000000000000000000000000000000000000000000
+ *
+ * If the architecture where is code is running is little-endian, the input data
+ * will be swapped before grabbing the bit field.
+ *
+ * Examples
+ *
+ *  uint64_t value = get_bitfield(data, 2, 4);
+ *
+ * Returns the value of the requested bit field, right aligned in a uint64_t.
+ */
+uint64_t eightbyte_get_bitfield(uint64_t source, const uint16_t offset,
+        const uint16_t bit_count, const bool data_is_big_endian);
+
+/* Public: Return a single nibble from the payload, with range checking.
+ *
+ * source - the source payload.
+ * nibble_index - the index of the nibble to retreive. The leftmost nibble is
+ *      index 0.
+ * data_is_big_endian - if the data passed in is little endian, set this to false and it
+ *      will be flipped before grabbing the bit field.
+ *
+ * Returns the retreived nibble, right aligned in a uint8_t.
+ */
+uint8_t eightbyte_get_nibble(const uint64_t source, const uint8_t nibble_index,
+        const bool data_is_big_endian);
+
+/* Public: Return a single byte from the payload, with range checking.
+ *
+ * source - the source byte array.
+ * byte_index - the index of the byte to retreive. The leftmost byte is index 0.
+ * data_is_big_endian - if the data passed in is little endian, set this to false and it
+ *      will be flipped before grabbing the bit field.
+ *
+ * Returns the retreived byte.
+ */
+uint8_t eightbyte_get_byte(const uint64_t source, const uint8_t byte_index,
+        const bool data_is_big_endian);
+
+/* Public: Set the bit field in the given data array to the new value.
+ *
+ * destination - a byte array with size at least offset + bit_count.
+ * value - the value to set in the bit field.
+ * offset - the starting index of the bit field (beginning from 0).
+ * bit_count - the number of bits to set in the data.
+ *
+ * Returns true if the bit_count is enough to fully represent the value, and
+ *      false if it will not fit.
+ */
+bool eightbyte_set_bitfield(uint64_t value,
+        const uint16_t offset, const uint16_t bit_count, uint64_t* destination);
+
+/* Private: Determine the index of the last bit used.
+ */
+uint8_t find_end_bit(const uint16_t num_bits);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // __8BYTE_H__
diff --git a/libs/bitfield-c/src/bitfield/bitarray.c b/libs/bitfield-c/src/bitfield/bitarray.c
new file mode 100644
index 00000000..dcb9a08f
--- /dev/null
+++ b/libs/bitfield-c/src/bitfield/bitarray.c
@@ -0,0 +1,145 @@
+#include <bitfield/bitfield.h>
+#include <stddef.h>
+#include <limits.h>
+#include <string.h>
+
+#define PREPARE_FIRST_COPY()                                      \
+    do {                                                          \
+    if (bit_count >= (CHAR_BIT - destination_offset_modulo)) {              \
+        *destination &= reverse_mask[destination_offset_modulo];              \
+        bit_count -= CHAR_BIT - destination_offset_modulo;                  \
+    } else {                                                      \
+        *destination &= reverse_mask[destination_offset_modulo]               \
+              | reverse_mask_xor[destination_offset_modulo + bit_count + 1];\
+         c &= reverse_mask[destination_offset_modulo + bit_count    ];\
+        bit_count = 0;                                              \
+    } } while (0)
+
+static const uint8_t reverse_mask[] =
+    { 0x55, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff };
+static const uint8_t reverse_mask_xor[] =
+    { 0xff, 0x7f, 0x3f, 0x1f, 0x0f, 0x07, 0x03, 0x01, 0x00 };
+
+bool copy_bits(const uint8_t* source_origin, const uint16_t source_length,
+        const uint16_t source_offset, uint16_t bit_count,
+        uint8_t* destination_origin, const uint16_t destination_length,
+        const uint16_t destination_offset) {
+    if(bit_count < 1) {
+        return false;
+    }
+
+    if(source_offset + bit_count > source_length * CHAR_BIT ||
+            destination_offset + bit_count > destination_length * CHAR_BIT ) {
+        return false;
+    }
+
+    const uint8_t* source = source_origin + (source_offset / CHAR_BIT);
+    uint8_t* destination = destination_origin + (destination_offset / CHAR_BIT);
+    int source_offset_modulo = source_offset % CHAR_BIT;
+    int destination_offset_modulo = destination_offset % CHAR_BIT;
+
+    if(source_offset_modulo == destination_offset_modulo) {
+        if(source_offset_modulo > 0) {
+            uint8_t c = reverse_mask_xor[destination_offset_modulo] & *source++;
+            PREPARE_FIRST_COPY();
+            *destination++ |= c;
+        }
+
+        int byte_len = bit_count / CHAR_BIT;
+        int bit_count_modulo = bit_count % CHAR_BIT;
+
+        if(byte_len > 0) {
+            memcpy(destination, source, byte_len);
+            source += byte_len;
+            destination += byte_len;
+        }
+
+        if(bit_count_modulo > 0) {
+            *destination &= reverse_mask_xor[bit_count_modulo];
+            *destination |= reverse_mask[bit_count_modulo] & *source;
+        }
+    } else {
+        int bit_diff_left_shift;
+        int bit_diff_right_shift;
+        uint8_t c;
+        /*
+         * Begin: Line things up on destination.
+         */
+        if(source_offset_modulo > destination_offset_modulo) {
+            bit_diff_left_shift = source_offset_modulo - destination_offset_modulo;
+            bit_diff_right_shift = CHAR_BIT - bit_diff_left_shift;
+
+            c = *source++ << bit_diff_left_shift;
+            c |= *source >> bit_diff_right_shift;
+            c &= reverse_mask_xor[destination_offset_modulo];
+        } else {
+            bit_diff_right_shift = destination_offset_modulo - source_offset_modulo;
+            bit_diff_left_shift = CHAR_BIT - bit_diff_right_shift;
+
+            c = *source >> bit_diff_right_shift &
+                    reverse_mask_xor[destination_offset_modulo];
+        }
+        PREPARE_FIRST_COPY();
+        *destination++ |= c;
+
+        /*
+         * Middle: copy with only shifting the source.
+         */
+        int byte_len = bit_count / CHAR_BIT;
+        while(--byte_len >= 0) {
+            c = *source++ << bit_diff_left_shift;
+            c |= *source >> bit_diff_right_shift;
+            *destination++ = c;
+        }
+
+        /*
+         * End: copy the remaing bits;
+         */
+        int bit_count_modulo = bit_count % CHAR_BIT;
+        if(bit_count_modulo > 0) {
+            c = *source++ << bit_diff_left_shift;
+            c |= *source >> bit_diff_right_shift;
+            c &= reverse_mask[bit_count_modulo];
+
+            *destination &= reverse_mask_xor[bit_count_modulo];
+            *destination |= c;
+        }
+    }
+    return true;
+}
+
+uint16_t bits_to_bytes(uint32_t bits) {
+    uint8_t byte_count = bits / CHAR_BIT;
+    if(bits % CHAR_BIT != 0) {
+        ++byte_count;
+    }
+    return byte_count;
+}
+
+/**
+ * Find the ending bit of a bitfield within the final byte.
+ *
+ * Returns: a bit position from 0 to 7.
+ */
+uint8_t find_end_bit(const uint16_t numBits) {
+    int endBit = numBits % CHAR_BIT;
+    return endBit == 0 ? CHAR_BIT : endBit;
+}
+
+bool copy_bits_right_aligned(const uint8_t source[], const uint16_t source_length,
+                const uint16_t offset, const uint16_t bit_count,
+                uint8_t* destination, const uint16_t destination_length) {
+    return copy_bits(source, source_length, offset, bit_count, destination,
+            destination_length,
+            // provide a proper destination offset so the result is right
+            // aligned
+            (destination_length - bits_to_bytes(bit_count)) * CHAR_BIT +
+                 CHAR_BIT - find_end_bit(bit_count));
+}
+
+bool copy_bytes_right_aligned(const uint8_t source[], const uint16_t source_length,
+                const uint16_t offset, const uint16_t byte_count,
+                uint8_t* destination, const uint16_t destination_length) {
+    return copy_bits_right_aligned(source, source_length, offset * CHAR_BIT,
+            byte_count * CHAR_BIT, destination, destination_length);
+}
diff --git a/libs/bitfield-c/src/bitfield/bitfield.c b/libs/bitfield-c/src/bitfield/bitfield.c
new file mode 100644
index 00000000..795f0208
--- /dev/null
+++ b/libs/bitfield-c/src/bitfield/bitfield.c
@@ -0,0 +1,74 @@
+#include <bitfield/bitfield.h>
+#include <limits.h>
+#include <string.h>
+#include <stddef.h>
+#include <sys/param.h>
+
+uint64_t bitmask(const uint8_t bit_count) {
+    return (((uint64_t)0x1) << bit_count) - 1;
+}
+
+uint8_t get_nibble(const uint8_t source[], const uint8_t source_length,
+                const uint8_t nibble_index) {
+    uint8_t byte_index = nibble_index / 2;
+    uint8_t result = get_byte(source, source_length, byte_index);
+    if(nibble_index % 2 == 0) {
+        result >>= NIBBLE_SIZE;
+    }
+    result &= bitmask(NIBBLE_SIZE);
+    return result;
+}
+
+uint8_t get_byte(const uint8_t source[], const uint8_t source_length,
+        const uint8_t byte_index) {
+    if(byte_index < source_length) {
+        return source[byte_index];
+    }
+    return 0;
+}
+
+uint64_t get_bitfield(const uint8_t source[], const uint8_t source_length,
+                const uint16_t offset, const uint16_t bit_count) {
+    if(bit_count > 64 || bit_count < 1) {
+        // TODO error reporting?
+        return 0;
+    }
+
+    ArrayOrBytes combined;
+    memset(combined.bytes, 0, sizeof(combined.bytes));
+    if(copy_bits_right_aligned(source, source_length, offset, bit_count,
+            combined.bytes, sizeof(combined.bytes))) {
+        if(BYTE_ORDER == LITTLE_ENDIAN) {
+            combined.whole = __builtin_bswap64(combined.whole);
+        }
+    } else {
+        // debug("couldn't copy enough bits from source")
+    }
+    return combined.whole;
+}
+
+bool set_nibble(const uint16_t nibble_index, const uint8_t value,
+        uint8_t* destination, const uint16_t destination_length) {
+    return copy_bits(&value, CHAR_BIT, NIBBLE_SIZE, NIBBLE_SIZE, destination,
+            destination_length, nibble_index * NIBBLE_SIZE);
+}
+
+bool set_bitfield(const uint64_t value, const uint16_t offset,
+        const uint16_t bit_count, uint8_t destination[],
+        uint16_t destination_length) {
+    if(value > bitmask(bit_count)) {
+        return false;
+    }
+
+    ArrayOrBytes combined = {
+        whole: value
+    };
+
+    if(BYTE_ORDER == LITTLE_ENDIAN) {
+        combined.whole = __builtin_bswap64(combined.whole);
+    }
+
+    return copy_bits(combined.bytes, sizeof(combined.bytes),
+            sizeof(combined.bytes) * CHAR_BIT - bit_count, bit_count,
+            destination, destination_length, offset);
+}
diff --git a/libs/bitfield-c/src/bitfield/bitfield.h b/libs/bitfield-c/src/bitfield/bitfield.h
new file mode 100644
index 00000000..df92639a
--- /dev/null
+++ b/libs/bitfield-c/src/bitfield/bitfield.h
@@ -0,0 +1,220 @@
+#ifndef __BITFIELD_H__
+#define __BITFIELD_H__
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#define NIBBLE_SIZE (CHAR_BIT / 2)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Public: Reads a subset of bits into a uint64_t, right aligned so they may be
+ * interpreted as a number.
+ *
+ * source - the bytes in question.
+ * source_size - the number of bytes in the source.
+ * offset - the starting index of the bit field (beginning from 0).
+ * bit_count - the width of the bit field to extract. This must be less than or
+ *      equal to 64.
+ *
+ * Bit fields are positioned according to big-endian bit layout and the data is
+ * swapped automatically as necessary depending on the compiled architecture.
+ *
+ * For example, the bit layout of the value "42" (i.e. 00101010 set at position
+ * 14 with length 6 is:
+ *
+ *     000000000000001010100000000000000000000000000000000000000000000
+ *
+ * and the same value and position but with length 8 is:
+ *
+ *     000000000000000010101000000000000000000000000000000000000000000
+ *
+ * Examples
+ *
+ *  uint64_t value = get_bitfield(data, data_size, 2, 4);
+ *
+ * Returns the value of the requested bit field, right aligned in a uint64_t.
+ */
+uint64_t get_bitfield(const uint8_t source[], const uint8_t source_length,
+                const uint16_t offset, const uint16_t bit_count);
+
+/* Public: Return a single nibble from the byte array, with range checking.
+ *
+ * source - the source byte array.
+ * source_length - the total length of the source array.
+ * nibble_index - the index of the nibble to retreive. The leftmost nibble is
+ *      index 0.
+ *
+ * Returns the retreived nibble, right aligned in a uint8_t.
+ */
+uint8_t get_nibble(const uint8_t source[], const uint8_t source_length,
+                const uint8_t nibble_index);
+
+/* Public: Return a single byte from the byte array, with range checking.
+ *
+ * source - the source byte array.
+ * source_length - the total length of the source array.
+ * byte_index - the index of the byte to retreive. The leftmost byte is index 0.
+ *
+ * Returns the retreived byte.
+ */
+uint8_t get_byte(const uint8_t source[], const uint8_t source_length,
+        const uint8_t byte_index);
+
+/* Public: Copy a range of bits from one bit array to another.
+ *
+ * The range does not need to be byte aligned, and the source and destination do
+ * not have to be the same size (as long as the desitnation has enough room to
+ * fit the range).
+ *
+ * A bit array with regards to this function always has the leftmost bit in byte
+ * 0, i.e. bit index is the leftmost bit of byte 0. Endianness does not matter.
+ *
+ * For example:
+ *
+ *      uint8_t source[4] = {0x11, 0x22, 0x33, 0x44};
+ *      uint8_t destination[4] = {0};
+ *      copy_bits(source, sizeof(source), 8, 8, destination,
+ *              sizeof(destination), 0);
+ *      // destination[0] == 0x22
+ *      // destination[1] == 0x0
+ *      // destination[2] == 0x0
+ *      // destination[3] == 0x0
+ *
+ * Thanks to
+ * http://stackoverflow.com/questions/3534535/whats-a-time-efficient-algorithm-to-copy-unaligned-bit-arrays
+ * for the implementation of the algorithm.
+ *
+ * source_origin - the source array.
+ * source_length - the total length of the source array in bytes,
+ *      for range checking.
+ * source_offset - an offset in bits to start the copy from the source array.
+ *      Specify 0 to start from source_origin.
+ * bit_count - the number of bits to copy.
+ * destination_origin - the destination array.
+ * desitnation_length - the total length of the destination array in bytes,
+ *      for range checking.
+ * destination_offset - an offset in bits to start placing the copied range into
+ *      the destination array. Specify 0 to start from the beginning of the
+ *      destination. If you are copying a range not aligned on a byte, you
+ *      probably want to set this to a positive offset to right the resulting
+ *      bits in the destination.
+ *
+ * Returns true if the copy was successful and false if the range exceeded the
+ * size of the source or destination, or if the range size negative or 0.
+ */
+bool copy_bits(const uint8_t* source_origin, const uint16_t source_length,
+        const uint16_t source_offset, uint16_t bit_count,
+        uint8_t* destination_origin, const uint16_t destination_length,
+        const uint16_t destination_offset);
+
+/* Public: Copy a range of bits from one array to another, right aligning the
+ * result.
+ *
+ * This is mostly useful if you want to cast the result to an integer type
+ * instead of a byte array.
+ *
+ * For example:
+ *
+ *      uint8_t source[4] = {0x11, 0x22, 0x33, 0x44};
+ *      uint8_t destination[4] = {0};
+ *      copy_bits_right_aligned(source, sizeof(source), 8, 8, destination,
+ *              sizeof(destination));
+ *      // destination[0] == 0x0
+ *      // destination[1] == 0x0
+ *      // destination[2] == 0x0
+ *      // destination[3] == 0x22
+ *
+ *      int value = (int)destination;
+ *      // value == 0x22 == 32
+ *
+ * The arguments are the same as copy_bits, but without the destination_offset
+ * option - that's set automatically to right align the result.
+ *
+ * Returns true if the copy was successful and false if the range exceeded the
+ * size of the source or destination, or if the range size negative or 0.
+ */
+bool copy_bits_right_aligned(const uint8_t source[], const uint16_t source_length,
+                const uint16_t offset, const uint16_t bit_count,
+                uint8_t* destination, const uint16_t destination_length);
+
+/* Public: Copy a range of bytes from one byte array to another.
+ *
+ * The source and destination do not have to be the same size (as long as the
+ * desitnation has enough room to fit the range).
+ *
+ * source_origin - the source array.
+ * source_length - the total length of the source array in bytes,
+ *      for range checking.
+ * source_offset - a byte offset to start the copy from the source array.
+ *      Specify 0 to start from source_origin.
+ * byte_count - the number of bytes to copy.
+ * destination_origin - the destination array.
+ * desitnation_length - the total length of the destination array in bytes,
+ *      for range checking.
+ * destination_offset - an offset in bytes to start placing the copied range into
+ *      the destination array. Specify 0 to start from the beginning of the
+ *      destination.
+ *
+ * Returns true if the copy was successful and false if the range exceeded the
+ * size of the source or destination, or if the range size negative or 0.
+ */
+bool copy_bytes_right_aligned(const uint8_t source[], const uint16_t source_length,
+                const uint16_t offset, const uint16_t byte_count,
+                uint8_t* destination, const uint16_t destination_length);
+
+/* Public: Set the a nibble in the given data array to the new value.
+ *
+ * nibble_index - the index of the nibble to retreive. The leftmost nibble is
+ *      index 0.
+ * value - the value to set in the bit field.
+ * destination - the destination array.
+ * destination_length - the total length of the destination array in bytes,
+ *      for range checking.
+ *
+ * Returns true if the bit_count is enough to fully represent the value, and
+ *      false if it will not fit.
+ */
+bool set_nibble(const uint16_t nibble_index, const uint8_t value,
+                uint8_t* destination, const uint16_t destination_length);
+
+/* Public: Set the bit field in the given data array to the new value.
+ *
+ * value - the value to set in the bit field.
+ * offset - the starting index of the bit field (beginning from 0).
+ * bit_count - the number of bits to set in the data.
+ * destination - the destination array.
+ * destination_length - the total length of the destination array in bytes,
+ *      for range checking.
+ *
+ * Returns true if the bit_count is enough to fully represent the value, and
+ *      false if it will not fit.
+ */
+bool set_bitfield(const uint64_t value, const uint16_t offset,
+        const uint16_t bit_count, uint8_t destination[],
+        uint16_t destination_length);
+
+/* Public: Return a right aligned bitmask for a uint64_t.
+ *
+ * bit_count - the number of bits to mask, right aligned.
+ */
+uint64_t bitmask(const uint8_t bit_count);
+
+/* Private:
+ */
+uint16_t bits_to_bytes(uint32_t bits);
+
+/* Private: A union to assist swapping between uint64_t and a uint8_t array.
+ */
+typedef union {
+    uint64_t whole;
+    uint8_t bytes[sizeof(uint64_t)];
+} ArrayOrBytes;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // __BITFIELD_H__