Diff: c-utility/src/base32.c

Revision:

0:f7f1f0d76dd6

diff -r 000000000000 -r f7f1f0d76dd6 c-utility/src/base32.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/c-utility/src/base32.c	Thu Aug 23 06:52:14 2018 +0000
@@ -0,0 +1,392 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+#include <stdlib.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <ctype.h>
+#include "azure_c_shared_utility/buffer_.h"
+#include "azure_c_shared_utility/xlogging.h"
+#include "azure_c_shared_utility/gballoc.h"
+#include "azure_c_shared_utility/strings.h"
+
+#include "azure_c_shared_utility/base32.h"
+
+static const unsigned char BASE32_EQUAL_SIGN = 32;
+
+static const char BASE32_VALUES[] = "abcdefghijklmnopqrstuvwxyz234567=";
+#define TARGET_BLOCK_SIZE       5
+#define INVALID_CHAR_POS        260
+
+#define BASE32_INPUT_SIZE       8
+
+#define ASCII_VALUE_MAX         0x80
+
+static size_t base32_encoding_length(size_t src_len)
+{
+    return (((src_len + TARGET_BLOCK_SIZE - 1) / TARGET_BLOCK_SIZE) * 8);
+}
+
+static size_t base32_decoding_length(size_t src_len)
+{
+    return ((src_len*TARGET_BLOCK_SIZE) / 8);
+}
+
+static unsigned char convert_value_to_base32_char(unsigned char value)
+{
+    unsigned char result;
+
+    if (value >= 50 && value <= 55)
+    {
+        result = 0x1a+(value-50);
+    }
+    else if (value == 61)
+    {
+        result = 0x20;
+    }
+    else if ((value <= 49) || (value >= 56 && value <= 64))
+    {
+        result = 0xFF;
+    }
+    else if (value >= 65 && value <= 90)
+    {
+        result = 0x00 + (value - 65);
+    }
+    else if (value >= 91 && value <= 96)
+    {
+        result = 0xFF;
+    }
+    else if (value >= 97 && value <= 123)
+    {
+        result = 0x00 + (value - 97);
+    }
+    else // value > 123
+    {
+        result = 0xFF;
+    }
+    return result;
+}
+
+static char* base32_encode_impl(const unsigned char* source, size_t src_size)
+{
+    char* result;
+
+    // Allocate target buffer
+    size_t output_len = base32_encoding_length(src_size);
+    /* Codes_SRS_BASE32_07_009: [ base32_encode_impl shall allocate the buffer to the size of the encoding value. ] */
+    if ((result = (char*)malloc(output_len + 1)) == NULL)
+    {
+        LogError("Failure allocating output buffer");
+    }
+    else
+    {
+        const unsigned char* iterator = source;
+        size_t block_len = 0;
+        size_t result_len = 0;
+        unsigned char pos1 = 0;
+        unsigned char pos2 = 0;
+        unsigned char pos3 = 0;
+        unsigned char pos4 = 0;
+        unsigned char pos5 = 0;
+        unsigned char pos6 = 0;
+        unsigned char pos7 = 0;
+        unsigned char pos8 = 0;
+
+        memset(result, 0, output_len + 1);
+
+        // Go through the source buffer sectioning off blocks of 5
+        /* Codes_SRS_BASE32_07_010: [ base32_encode_impl shall look through source and separate each block into 5 bit chunks ] */
+        while (src_size >= 1 && result != NULL)
+        {
+            pos1 = pos2 = pos3 = pos4 = pos5 = pos6 = pos7 = pos8 = 0;
+            block_len = src_size > TARGET_BLOCK_SIZE ? TARGET_BLOCK_SIZE : src_size;
+            // Fall through switch block to process the 5 (or smaller) block
+            switch (block_len)
+            {
+            case 5:
+                pos8 = (iterator[4] & 0x1f);
+                pos7 = ((iterator[4] & 0xe0) >> 5);
+                // fall through
+            case 4:
+                pos7 |= ((iterator[3] & 0x03) << 3);
+                pos6 = ((iterator[3] & 0x7c) >> 2);
+                pos5 = ((iterator[3] & 0x80) >> 7);
+                // fall through
+            case 3:
+                pos5 |= ((iterator[2] & 0x0f) << 1);
+                pos4 = ((iterator[2] & 0xf0) >> 4);
+                // fall through
+            case 2:
+                pos4 |= ((iterator[1] & 0x01) << 4);
+                pos3 = ((iterator[1] & 0x3e) >> 1);
+                pos2 = ((iterator[1] & 0xc0) >> 6);
+                // fall through
+            case 1:
+                pos2 |= ((iterator[0] & 0x07) << 2);
+                pos1 = ((iterator[0] & 0xf8) >> 3);
+                break;
+            }
+            // Move the iterator the block size
+            iterator += block_len;
+            // and decrement the src_size;
+            src_size -= block_len;
+
+            /* Codes_SRS_BASE32_07_012: [ If the src_size is not divisible by 8, base32_encode_impl shall pad the remaining places with =. ] */
+            switch (block_len)
+            {
+                case 1: pos3 = pos4 = 32; // fall through
+                case 2: pos5 = 32; // fall through
+                case 3: pos6 = pos7 = 32; // fall through
+                case 4: pos8 = 32; // fall through
+                case 5:
+                    break;
+            }
+
+            /* Codes_SRS_BASE32_07_011: [ base32_encode_impl shall then map the 5 bit chunks into one of the BASE32 values (a-z,2,3,4,5,6,7) values. ] */
+            result[result_len++] = BASE32_VALUES[pos1];
+            result[result_len++] = BASE32_VALUES[pos2];
+            result[result_len++] = BASE32_VALUES[pos3];
+            result[result_len++] = BASE32_VALUES[pos4];
+            result[result_len++] = BASE32_VALUES[pos5];
+            result[result_len++] = BASE32_VALUES[pos6];
+            result[result_len++] = BASE32_VALUES[pos7];
+            result[result_len++] = BASE32_VALUES[pos8];
+        }
+    }
+    return result;
+}
+
+static BUFFER_HANDLE base32_decode_impl(const char* source)
+{
+    BUFFER_HANDLE result;
+
+    size_t src_length = strlen(source);
+    if (src_length % BASE32_INPUT_SIZE != 0)
+    {
+        /* Codes_SRS_BASE32_07_021: [ If the source length is not evenly divisible by 8, base32_decode_impl shall return NULL. ] */
+        LogError("Failure invalid input length %lu", src_length);
+        result = NULL;
+    }
+    else
+    {
+        size_t dest_size = 0;
+        unsigned char* temp_buffer;
+        unsigned char* dest_buff;
+        bool continue_processing = true;
+        unsigned char input[8];
+        const char* iterator = source;
+
+        /* Codes_SRS_BASE32_07_022: [ base32_decode_impl shall allocate a temp buffer to store the in process value. ] */
+        size_t allocation_len = base32_decoding_length(src_length);
+        if ((temp_buffer = (unsigned char*)malloc(allocation_len)) == NULL)
+        {
+            /* Codes_SRS_BASE32_07_023: [ If an error is encountered, base32_decode_impl shall return NULL. ] */
+            LogError("Failure allocating buffer");
+            result = NULL;
+        }
+        else
+        {
+            dest_buff = temp_buffer;
+            while (*iterator != '\0')
+            {
+                size_t index = 0;
+                /* Codes_SRS_BASE32_07_024: [ base32_decode_impl shall loop through and collect 8 characters from the source variable. ] */
+                for (index = 0; index < BASE32_INPUT_SIZE; index++)
+                {
+                    input[index] = *iterator;
+                    iterator++;
+                    if (input[index] >= ASCII_VALUE_MAX)
+                    {
+                        LogError("Failure source encoding");
+                        continue_processing = false;
+                        break;
+                    }
+
+                    input[index] = convert_value_to_base32_char(input[index]);
+                }
+
+                if (!continue_processing)
+                {
+                    result = NULL;
+                    break;
+                }
+                else if ((dest_size + TARGET_BLOCK_SIZE) > allocation_len)
+                {
+                    LogError("Failure target length exceeded");
+                    result = NULL;
+                    continue_processing = false;
+                    break;
+                }
+                else
+                {
+                    // Codes_SRS_BASE32_07_025: [ base32_decode_impl shall group 5 bytes at a time into the temp buffer. ] 
+                    *dest_buff++ = ((input[0] & 0x1f) << 3) | ((input[1] & 0x1c) >> 2);
+                    *dest_buff++ = ((input[1] & 0x03) << 6) | ((input[2] & 0x1f) << 1) | ((input[3] & 0x10) >> 4);
+                    *dest_buff++ = ((input[3] & 0x0f) << 4) | ((input[4] & 0x1e) >> 1);
+                    *dest_buff++ = ((input[4] & 0x01) << 7) | ((input[5] & 0x1f) << 2) | ((input[6] & 0x18) >> 3);
+                    *dest_buff++ = ((input[6] & 0x07) << 5) | (input[7] & 0x1f);
+                    dest_size += TARGET_BLOCK_SIZE;
+                    // If there is padding remove it
+                    // Because we are packing 5 bytes into an 8 byte variable we need to check every other
+                    // variable for padding
+                    if (input[7] == BASE32_EQUAL_SIGN)
+                    {
+                        --dest_size;
+                        if (input[5] == BASE32_EQUAL_SIGN)
+                        {
+                            --dest_size;
+                            if (input[4] == BASE32_EQUAL_SIGN)
+                            {
+                                --dest_size;
+                                if (input[2] == BASE32_EQUAL_SIGN)
+                                {
+                                    --dest_size;
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+
+            if (!continue_processing)
+            {
+                result = NULL;
+            }
+            else
+            {
+                /* Codes_SRS_BASE32_07_026: [ Once base32_decode_impl is complete it shall create a BUFFER with the temp buffer. ] */
+                result = BUFFER_create(temp_buffer, dest_size);
+                if (result == NULL)
+                {
+                    LogError("Failure: BUFFER_create failed to create decoded buffer");
+                }
+            }
+            free(temp_buffer);
+        }
+    }
+    return result;
+}
+
+BUFFER_HANDLE Base32_Decode(STRING_HANDLE handle)
+{
+    BUFFER_HANDLE result;
+    if (handle == NULL)
+    {
+        /* Codes_SRS_BASE32_07_016: [ If source is NULL Base32_Decoder shall return NULL. ] */
+        LogError("invalid parameter handle");
+        result = NULL;
+    }
+    else
+    {
+        const char* str_source = STRING_c_str(handle);
+        if (str_source == NULL)
+        {
+            /* Codes_SRS_BASE32_07_027: [ If the string in source value is NULL, Base32_Decoder shall return NULL. ] */
+            LogError("NULL value specified in string");
+            result = NULL;
+        }
+        else
+        {
+            /* Codes_SRS_BASE32_07_018: [ Base32_Decoder shall call base32_decode_impl to decode the base64 value. ] */
+            result = base32_decode_impl(str_source);
+        }
+    }
+    /* Codes_SRS_BASE32_07_017: [ On success Base32_Decoder shall return a BUFFER_HANDLE that contains the decoded bytes for source. ] */
+    return result;
+}
+
+BUFFER_HANDLE Base32_Decode_String(const char* source)
+{
+    BUFFER_HANDLE result;
+    if (source == NULL)
+    {
+        /* Codes_SRS_BASE32_07_008: [ If source is NULL Base32_Decoder_String shall return NULL. ] */
+        LogError("invalid parameter source=NULL");
+        result = NULL;
+    }
+    else
+    {
+        /* Codes_SRS_BASE32_07_020: [ Base32_Decoder_String shall call base32_decode_impl to decode the base64 value. ] */
+        result = base32_decode_impl(source);
+    }
+    /* Codes_SRS_BASE32_07_019: [ On success Base32_Decoder_String shall return a BUFFER_HANDLE that contains the decoded bytes for source. ] */
+    return result;
+}
+
+char* Base32_Encode_Bytes(const unsigned char* source, size_t size)
+{
+    char* result;
+    if (source == NULL)
+    {
+        /* Codes_SRS_BASE32_07_004: [ If source is NULL Base32_Encode shall return NULL. ] */
+        result = NULL;
+        LogError("Failure: Invalid input parameter source");
+    }
+    else if (size == 0)
+    {
+        /* Codes_SRS_BASE32_07_005: [ If size is 0 Base32_Encode shall return an empty string. ] */
+        result = malloc(1);
+        strcpy(result, "");
+    }
+    else
+    {
+        /* Codes_SRS_BASE32_07_007: [ Base32_Encode_Bytes shall call into base32_Encode_impl to encode the source data. ] */
+        result = base32_encode_impl(source, size);
+        if (result == NULL)
+        {
+            /* Codes_SRS_BASE32_07_014: [ Upon failure Base32_Encode_Bytes shall return NULL. ] */
+            LogError("encoding of unsigned char failed.");
+        }
+    }
+    /* Codes_SRS_BASE32_07_006: [ If successful Base32_Encode shall return the base32 value of input. ] */
+    return result;
+}
+
+STRING_HANDLE Base32_Encode(BUFFER_HANDLE source)
+{
+    STRING_HANDLE result;
+    if (source == NULL)
+    {
+        /* Codes_SRS_BASE32_07_001: [ If source is NULL Base32_Encode shall return NULL. ] */
+        result = NULL;
+        LogError("Failure: Invalid input parameter");
+    }
+    else
+    {
+        size_t input_len = BUFFER_length(source);
+        const unsigned char* input_value = BUFFER_u_char(source);
+        if (input_value == NULL || input_len == 0)
+        {
+            /* Codes_SRS_BASE32_07_015: [ If size is 0 Base32_Encode shall return an empty string. ] */
+            result = STRING_new();
+            if (result == NULL)
+            {
+                LogError("Failure constructing new string.");
+            }
+        }
+        else
+        {
+            /* Codes_SRS_BASE32_07_003: [ Base32_Encode shall call into base32_Encode_impl to encode the source data. ] */
+            char* encoded = base32_encode_impl(input_value, input_len);
+            if (encoded == NULL)
+            {
+                /* Codes_SRS_BASE32_07_014: [ Upon failure base32_Encode shall return NULL. ] */
+                LogError("base32 encode implementation failed.");
+                result = NULL;
+            }
+            else
+            {
+                /* Codes_SRS_BASE32_07_012: [ base32_Encode shall wrap the base32_Encode_impl result into a STRING_HANDLE. ] */
+                result = STRING_construct(encoded);
+                if (result == NULL)
+                {
+                    /* Codes_SRS_BASE32_07_014: [ Upon failure base32_Encode shall return NULL. ] */
+                    LogError("string construction failed.");
+                }
+                free(encoded);
+            }
+        }
+    }
+    /* Codes_SRS_BASE32_07_002: [ If successful Base32_Encode shall return the base32 value of source. ] */
+    return result;
+}