mirror of https://github.com/jorio/Pomme.git
123 lines
2.3 KiB
C++
123 lines
2.3 KiB
C++
#include "structpack.h"
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#include <algorithm>
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#include <stdexcept>
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static int Unpack(const char* format, char* buffer)
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{
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int totalBytes = 0;
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int repeat = 0;
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for (const char* c2 = format; *c2; c2++)
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{
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char c = *c2;
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int fieldLength = -1;
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switch (c)
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{
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case '>': // big endian indicator (for compat with python's struct) - OK just ignore
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continue;
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case ' ':
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case '\r':
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case '\n':
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case '\t':
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continue;
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case '0': case '1': case '2': case '3': case '4':
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case '5': case '6': case '7': case '8': case '9':
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if (repeat) repeat *= 10;
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repeat += c - '0';
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continue;
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case 'x': // pad byte
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case 'c': // char
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case 'b': // signed char
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case 'B': // unsigned char
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case '?': // bool
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fieldLength = 1;
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break;
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case 'h': // short
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case 'H': // unsigned short
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fieldLength = 2;
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break;
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case 'i': // int
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case 'I': // unsigned int
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case 'l': // long
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case 'L': // unsigned long
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case 'f': // float
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fieldLength = 4;
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break;
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case 'q': // long long
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case 'Q': // unsigned long long
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case 'd': // double
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fieldLength = 8;
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break;
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default:
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throw std::invalid_argument("unknown format char in structpack format");
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}
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if (totalBytes % fieldLength != 0)
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{
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throw std::invalid_argument("illegal word alignment in structpack format");
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}
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if (!repeat)
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repeat = 1;
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bool doSwap = fieldLength > 1;
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if (buffer)
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{
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if (doSwap)
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{
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for (int i = 0; i < repeat; i++)
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{
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std::reverse(buffer, buffer + fieldLength);
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buffer += fieldLength;
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}
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}
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else
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{
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buffer += repeat * fieldLength;
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}
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}
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totalBytes += repeat * fieldLength;
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repeat = 0;
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}
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return totalBytes;
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}
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int ByteswapStructs(const char* format, int structSize, int structCount, void* buffer)
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{
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char* byteBuffer = (char*) buffer;
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int totalBytes = 0;
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for (int i = 0; i < structCount; i++)
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{
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int newSize = Unpack(format, byteBuffer);
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byteBuffer += newSize;
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totalBytes += newSize;
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}
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if (totalBytes != structSize * structCount)
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{
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throw std::invalid_argument("unexpected length after byteswap");
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}
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return totalBytes;
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}
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int ByteswapInts(int intSize, int intCount, void* buffer)
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{
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char* byteBuffer = (char*) buffer;
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for (int i = 0; i < intCount; i++)
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{
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std::reverse(byteBuffer, byteBuffer + intSize);
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byteBuffer += intSize;
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}
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return intCount * intSize;
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}
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