54 lines
1.1 KiB
C
54 lines
1.1 KiB
C
//---
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// gint:usb:string - STRING descriptor management
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//---
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#include <gint/usb.h>
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#include <stdlib.h>
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#include <string.h>
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/* String descriptor array */
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static usb_dc_string_t **array = NULL;
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static int array_size = 0;
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uint16_t usb_dc_string(uint16_t const *literal, size_t len)
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{
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if(array_size == 255) return 0;
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/* Determine the length of the string */
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if(len == 0)
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{
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while(literal[len]) len++;
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}
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if(2*len + 2 >= 256) return 0;
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/* Allocate a new descriptor */
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usb_dc_string_t *dc = malloc(sizeof *dc + 2*len);
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if(!dc) return 0;
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dc->bLength = 2*len + 2;
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dc->bDescriptorType = USB_DC_STRING;
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for(size_t i = 0; i < len; i++) dc->data[i] = htole16(literal[i]);
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/* Try to make room in the array */
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size_t new_size = (array_size + 1) * sizeof(*array);
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usb_dc_string_t **new_array = realloc(array, new_size);
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if(!new_array)
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{
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free(dc);
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return 0;
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}
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array = new_array;
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array[array_size++] = dc;
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/* IDs are numbered 1 to 255 */
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return (array_size - 1) + 1;
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}
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usb_dc_string_t *usb_dc_string_get(uint16_t id)
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{
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if((int)id < 1 || id - 1 >= array_size) return NULL;
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return array[id - 1];
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}
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