mirror of https://github.com/nirenjan/libx52.git
85 lines
2.5 KiB
C
85 lines
2.5 KiB
C
/*
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* Saitek X52 Pro Character Map Lookup
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*
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* This file implements functions to perform a lookup of a UTF-8 character
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* in the generated lookup table.
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*
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* Copyright (C) 2015 Nirenjan Krishnan (nirenjan@nirenjan.org)
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*
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* SPDX-License-Identifier: GPL-2.0-only WITH Classpath-exception-2.0
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*/
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#include "config.h"
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#include <stdint.h>
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#include <errno.h>
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#include "libx52util.h"
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#include "x52_char_map.h"
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/**
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* @brief Convert UTF8 string to X52 character map.
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*
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* This function takes in a UTF-8 string and converts it to the character
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* map used by the X52Pro MFD. Unrecognized characters are silently dropped.
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*
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* @param[in] input Input string in UTF-8. Must be NUL-terminated
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* @param[out] output Output buffer
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* @param[inout] len Length of output buffer
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*
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* @returns 0 on success, -EINVAL on invalid parameters, -E2BIG if the buffer
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* filled up before converting the entire string.
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*/
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int libx52util_convert_utf8_string(const uint8_t *input,
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uint8_t *output, size_t *len)
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{
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struct map_entry *entry;
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size_t index;
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int retval = 0;
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unsigned char local_index;
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if (!input || !output || !len || !*len) {
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return -EINVAL;
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}
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index = 0;
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entry = &map_root[*input];
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while (*input) {
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input++;
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if (entry->type == TYPE_ENTRY) {
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output[index] = entry->value;
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index++;
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if (index >= *len) {
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retval = -E2BIG;
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break;
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}
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entry = &map_root[*input];
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} else if (entry->type == TYPE_POINTER) {
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local_index = *input;
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if (local_index < 0x80 || local_index >= 0xC0) {
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/* Invalid input, skip till we find the start of another
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* valid UTF-8 character
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*/
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while (*input >= 0x80 && *input < 0xC0) {
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input++; /* Skip invalid characters */
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}
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/* New UTF-8 character, reset the entry pointer */
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entry = &map_root[*input];
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} else {
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/* Mask off the upper bits, we only care about the lower 6 bits */
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local_index &= 0x3F;
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entry = &(entry->next[local_index]);
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}
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} else {
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/* Invalid value, skip */
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while (*input >= 0x80 && *input < 0xC0) {
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input++; /* Skip invalid characters */
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}
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}
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}
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*len = index;
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return retval;
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}
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